From neil.johnson71 at gmail.com  Wed Dec  1 00:05:27 2021
From: neil.johnson71 at gmail.com (Neil Johnson)
Date: Tue, 30 Nov 2021 23:05:27 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <CACZGMxL=2=ocUhX-Jy6z=u+Ha7q_0SBeC87UMdJu_A1fLKK0yg@mail.gmail.com>

Hi,

ColinMuirDorward wrote:
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)

There are better forums for discussing this topic.  For example,
https://groupdiy.com/
https://www.diyaudio.com/

You can find folks there who are or were mixing desk designers for
most of the major professional names.

And as Tom says, there are many many many mixer schematics on the web,
so plenty of resources to learn from.  Allen&Heath, Mackie, DDA, SSL,
Neve, Soundcraft, etc.

Neil


From mbryant at futurehorizons.com  Wed Dec  1 00:12:02 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 30 Nov 2021 23:12:02 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <d918952e996f413c9f79da6d4ae6c45f@futurehorizons.com>

I designed my first mixer in 1971.  Crude by todays standard ? pair of BC184s with shunt feedback for microphone and guitar preamps, all into a single stereo bus.

Since then designed quite a few more.  Had an interview with Rupert Neve himself in Melbourn, Cambs in 1986 but we couldn?t agree on salary.   Later on had a period as R&D director at Soundcraft.

Currently in early planning stages of a low cost modular digital mixer.



From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of ColinMuirDorward via Synth-diy
Sent: 30 November 2021 17:44
To: *SYNTH DIY
Subject: [sdiy] DIY mixer/console

Who here has done or tried it?
Please feel free to share pictures, stories, warnings, etc :)
Cheers,
Colin

--
https://www.instagram.com/colinmuirdorward/
-
<https://www.instagram.com/colinmuirdorward/>
https://www.instagram.com/ssdp_studios/
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From jschwich53 at comcast.net  Wed Dec  1 02:13:17 2021
From: jschwich53 at comcast.net (Jay Schwichtenberg)
Date: Tue, 30 Nov 2021 17:13:17 -0800
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>

Unless you have some obscure needs that would be something I'd buy.

If time is money for you buy time you get all the PCBs laid out, made, 
stuffed and the metal work designed and done that's going to be a lot of 
time and effort. Then there is the question of cost, you doing a one of 
verses what a company that makes 100K of them a year.

Jay S.

On 11/30/2021 9:43 AM, ColinMuirDorward via Synth-diy wrote:
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)
> Cheers,
> Colin
>
> -- 
> https://www.instagram.com/colinmuirdorward/
> -
> <https://www.instagram.com/colinmuirdorward/>
> https://www.instagram.com/ssdp_studios/
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Usemarketplace at synth-diy.org
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From sines_list at scale.la  Wed Dec  1 04:03:22 2021
From: sines_list at scale.la (Todd Sines)
Date: Tue, 30 Nov 2021 22:03:22 -0500
Subject: [sdiy] DIY mixer/console
In-Reply-To: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
References: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
Message-ID: <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>

I made the mistake of dumping a useful and robust 14 channel Soundcraft signature MTK mixer (that I paid $300 for) which had built-in internal effects, parametric Mids and 2-3 FX Sends, as well as functioned as an audio interface, only to shrink the footprint by 1/4 the size with a Befaco HexMix & expander, which almost cost 2-3x the price.

It would be an interesting prospect, but with the needs people have, you are far better putting your energy elsewhere it seems. There are new boutique mixers on the market from some incredible designs out of Germany, but they have a price pack that is commensurate. I wish I was wrong ? because I?m still not happy with the ultra portable Eurorack mixer options these days!

Todd

> On Nov 30, 2021, at 8:21 PM, Jay Schwichtenberg via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> ?
> Unless you have some obscure needs that would be something I'd buy.
> 
> If time is money for you buy time you get all the PCBs laid out, made, stuffed and the metal work designed and done that's going to be a lot of time and effort. Then there is the question of cost, you doing a one of verses what a company that makes 100K of them a year.
> 
> Jay S.
> 
> On 11/30/2021 9:43 AM, ColinMuirDorward via Synth-diy wrote:
>> Who here has done or tried it?
>> Please feel free to share pictures, stories, warnings, etc :)
>> Cheers,
>> Colin
>> 
>> -- 
>> https://www.instagram.com/colinmuirdorward/
>> -
>> https://www.instagram.com/ssdp_studios/
>> 
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
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From fraveydank at gmail.com  Wed Dec  1 04:46:25 2021
From: fraveydank at gmail.com (David Riley)
Date: Tue, 30 Nov 2021 22:46:25 -0500
Subject: [sdiy] New FPAA experiments with Scilab/Modelica
In-Reply-To: <18E6F4C9-B25C-47E7-95CA-03D8A1C5F11E@ece.gatech.edu>
References: <18E6F4C9-B25C-47E7-95CA-03D8A1C5F11E@ece.gatech.edu>
Message-ID: <78507EAE-EA95-4D1B-B198-034460A3867C@gmail.com>

On Nov 28, 2021, at 1:09 PM, Lanterman, Aaron D via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Howdy Synth DIYers,
> 
> Lately I?ve been experimenting with a toolset for Field Programmable Analog Arrays based on floating gate technology. My colleague Jennifer Hasler and her team have created a toolset based on Scilab/Xcos in an Ubuntu image you can download and run in VirtualBox. It includes simulation capabilities using Modelica, which is embedded Scilab. I?m documenting some of my progress on YouTube.

Ooh, this is neat.  I spent about 10 years as an FPGA engineer, but I'm always super interested to see how programmable analog has moved along.  It was fairly primitive as of last I checked, but this sounds promising.

> I put together a playlist here:
> 
> https://www.youtube.com/watch?v=4XvQ4LVi0OA&list=PLOunECWxELQTCZEqIbHZpRmIEeQR80o3j
> 
> There?s videos on common source and common drain amplifiers, and voltage dividers that use OTAs instead of resistors (which seems very strange to me, coming from a PCB-level design background, but it turns out that transistors are ?cheap? on the chip whereas resistors are expensive in terms of real estate and complicated).
> 
> Jen likes to run her MOSFETs in the subthreshold regime; most books just call this ?off,? but it turns out there?s an exponential dependency of current on V_GS that?s reminiscent of BJTs vs. the square law I?m used to with MOSFETs.

I was going to ask if you had any reference for these equations because I'd never been exposed, but I assume this is your colleague?  https://www.youtube.com/watch?v=tNWV4ajz8SI

I'm quite excited to find out more, but if there's any plain reading for me to do, I vastly prefer it to watching videos.  In the absence of that, she's a good lecturer, so the videos are at least quite watchable!


- Dave




From modular at go2.pl  Wed Dec  1 11:40:51 2021
From: modular at go2.pl (Roman Sowa)
Date: Wed, 1 Dec 2021 11:40:51 +0100
Subject: [sdiy] DIY mixer/console
In-Reply-To: <petohd2a9olqo54jquos7b52.1638309336970@email.android.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <petohd2a9olqo54jquos7b52.1638309336970@email.android.com>
Message-ID: <fa6d6ec9-6ba8-6b94-322d-6d8130cf882d@go2.pl>

Here it is.
It is standing on top of 1U rack case that I planned to use for full 
featured microphone preamp/processor. That never happened :(
Now I think it was rather year 1992

Roman

W dniu 2021-11-30 o?22:55, Roman pisze:
> I did it around 1995. 12 channels, each with gain, hi/lo 
> eq, pan, mute and fader. Plus led level meter. All discrete. And I 
> actually used it? a lot back then. That was good lesson to never do it 
> again. A lot of parts, lots of wiring, little satifaction, really not 
> worth it.
> 
> I'll share pictures when I find them.
> 
> 
> Roman
> 
> 
> 
> ---- U?ytkownik ColinMuirDorward via Synth-diy napisa? ----
> 
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)
> Cheers,
> Colin
> 
> -- 
> https://www.instagram.com/colinmuirdorward/
> -
> <https://www.instagram.com/colinmuirdorward/>
> https://www.instagram.com/ssdp_studios/
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 
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From vladoman at gmail.com  Wed Dec  1 11:55:55 2021
From: vladoman at gmail.com (Vladimir Pantelic)
Date: Wed, 1 Dec 2021 11:55:55 +0100
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <d4a3bcc8-af3f-9c29-808d-07ff5adc75a2@gmail.com>

I built a "mixer" in 1989, it was a repurposed plastic sweets packaging
box with two RCA stereo pairs going in and two pairs going out. Toggle
switches allowed the signal of the connected CD players to be sent to
the main amp or a headphone amp for cueing. it was for a friends
birthday party and we had the police show up because the speaker sound
from the upper floor balcony carried for a mile ;) I call that a
successful project



On 30.11.21 18:43, ColinMuirDorward via Synth-diy wrote:
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)
> Cheers,
> Colin
> 
> -- 
> https://www.instagram.com/colinmuirdorward/
> -
> <https://www.instagram.com/colinmuirdorward/>
> https://www.instagram.com/ssdp_studios/
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 



From milesstevens89 at gmail.com  Wed Dec  1 12:12:39 2021
From: milesstevens89 at gmail.com (Miles Stevens)
Date: Wed, 1 Dec 2021 22:12:39 +1100
Subject: [sdiy] DIY mixer/console
In-Reply-To: <d4a3bcc8-af3f-9c29-808d-07ff5adc75a2@gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <d4a3bcc8-af3f-9c29-808d-07ff5adc75a2@gmail.com>
Message-ID: <CAEESrj=W7w13mzqFVtry5bKQJ0pJmNZzp_7_rDXWKqrv2J2aTg@mail.gmail.com>

Started and abandoned one a few years ago after doing a proof of concept
with two input channels and an aux / bus channel. If you want a desk and
are happy to solder - secondhand/broken desks start to look like a dream
when calculating the costs of metalwork alone.

https://fabricastronautblog.wordpress.com/2018/12/06/tanzimat-mixing-desk/

On Wed, 1 Dec 2021 at 21:58, Vladimir Pantelic via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I built a "mixer" in 1989, it was a repurposed plastic sweets packaging
> box with two RCA stereo pairs going in and two pairs going out. Toggle
> switches allowed the signal of the connected CD players to be sent to
> the main amp or a headphone amp for cueing. it was for a friends
> birthday party and we had the police show up because the speaker sound
> from the upper floor balcony carried for a mile ;) I call that a
> successful project
>
>
>
> On 30.11.21 18:43, ColinMuirDorward via Synth-diy wrote:
> > Who here has done or tried it?
> > Please feel free to share pictures, stories, warnings, etc :)
> > Cheers,
> > Colin
> >
> > --
> > https://www.instagram.com/colinmuirdorward/
> > -
> > <https://www.instagram.com/colinmuirdorward/>
> > https://www.instagram.com/ssdp_studios/
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From markverbos at gmail.com  Wed Dec  1 12:14:57 2021
From: markverbos at gmail.com (mark verbos)
Date: Wed, 1 Dec 2021 12:14:57 +0100
Subject: [sdiy] DIY mixer/console
In-Reply-To: <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>
References: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
 <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>
Message-ID: <22801B6D-4CFB-4C67-B50B-D9ECAF8B4C44@gmail.com>

I worked with Z?hl on the CV channel for thew AM-1 (presumably the incredible design from Germany mentioned below). Michael designed the custom mixers that were in the studios of Can and Conny Plank. He is extremely careful with noise and crosstalk. H wouldn?t allow me to use any digital clocking in the CV parts of the channel. Although not as expensive as an SSL or Neve, the Z?hl is ?price no object? by today?s standards and has taught me how a mixer becomes ?50,000.

That said, I bought a used 40 channel Soundcraft Vienna for ?800. That is a large format front of house live board from the 90?s. It has 8 sends, 8 busses, VCA groups, mute groups, balanced in/out, inserts on every channel NOT on send/receive jacks, sweepable hipass filter on each channel, serious 4 band semi perimetric EQ,  fuil meterbridge built in. It was about ?30,000 when new. But, it weighs about 150kg and uses an entire power circuit for itself, heating the room when on. 


maybe buying a mixer frame empty and making your own channels or buying something like I have and making your own replacement channels could work for you. Here in Germany I see Studer frames available empty all the time. 

Mark




> On Dec 1, 2021, at 4:03 AM, Todd Sines <sines_list at scale.la> wrote:
> 
> I made the mistake of dumping a useful and robust 14 channel Soundcraft signature MTK mixer (that I paid $300 for) which had built-in internal effects, parametric Mids and 2-3 FX Sends, as well as functioned as an audio interface, only to shrink the footprint by 1/4 the size with a Befaco HexMix & expander, which almost cost 2-3x the price.
> 
> It would be an interesting prospect, but with the needs people have, you are far better putting your energy elsewhere it seems. There are new boutique mixers on the market from some incredible designs out of Germany, but they have a price pack that is commensurate. I wish I was wrong ? because I?m still not happy with the ultra portable Eurorack mixer options these days!
> 
> Todd
> 
>> On Nov 30, 2021, at 8:21 PM, Jay Schwichtenberg via Synth-diy <synth-diy at synth-diy.org> wrote:
>> 
>> ?
>> Unless you have some obscure needs that would be something I'd buy.
>> 
>> If time is money for you buy time you get all the PCBs laid out, made, stuffed and the metal work designed and done that's going to be a lot of time and effort. Then there is the question of cost, you doing a one of verses what a company that makes 100K of them a year.
>> 
>> Jay S.
>> 
>> On 11/30/2021 9:43 AM, ColinMuirDorward via Synth-diy wrote:
>>> Who here has done or tried it?
>>> Please feel free to share pictures, stories, warnings, etc :)
>>> Cheers,
>>> Colin
>>> 
>>> -- 
>>> https://www.instagram.com/colinmuirdorward/ <https://www.instagram.com/colinmuirdorward/>
>>> -
>>>  <https://www.instagram.com/colinmuirdorward/>
>>> https://www.instagram.com/ssdp_studios/ <https://www.instagram.com/ssdp_studios/>
>>> 
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From tom at electricdruid.net  Wed Dec  1 12:29:26 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 1 Dec 2021 11:29:26 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <22801B6D-4CFB-4C67-B50B-D9ECAF8B4C44@gmail.com>
References: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
 <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>
 <22801B6D-4CFB-4C67-B50B-D9ECAF8B4C44@gmail.com>
Message-ID: <AC6D7025-FD95-48C9-BE28-686F66E06BD6@electricdruid.net>

Big old analogue desks are going for peanuts unless they?re something *really* famous - like ?this desk recorded Bohemian Rhapsody? famous! 

A friend of mine picked up a similar 40 channel Soundcraft studio desk from a university music dept. for a pittance. No-one else wanted something the size of a table. Even he didn?t keep it for long though. I don?t know what he did with it. I bet dozens have been junked.


> On 1 Dec 2021, at 11:14, mark verbos via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I worked with Z?hl on the CV channel for thew AM-1 (presumably the incredible design from Germany mentioned below). Michael designed the custom mixers that were in the studios of Can and Conny Plank. He is extremely careful with noise and crosstalk. H wouldn?t allow me to use any digital clocking in the CV parts of the channel. Although not as expensive as an SSL or Neve, the Z?hl is ?price no object? by today?s standards and has taught me how a mixer becomes ?50,000.
> 
> That said, I bought a used 40 channel Soundcraft Vienna for ?800. That is a large format front of house live board from the 90?s. It has 8 sends, 8 busses, VCA groups, mute groups, balanced in/out, inserts on every channel NOT on send/receive jacks, sweepable hipass filter on each channel, serious 4 band semi perimetric EQ,  fuil meterbridge built in. It was about ?30,000 when new. But, it weighs about 150kg and uses an entire power circuit for itself, heating the room when on. 
> 
> 
> maybe buying a mixer frame empty and making your own channels or buying something like I have and making your own replacement channels could work for you. Here in Germany I see Studer frames available empty all the time. 
> 
> Mark
> 
> 
> 
> 
>> On Dec 1, 2021, at 4:03 AM, Todd Sines <sines_list at scale.la <mailto:sines_list at scale.la>> wrote:
>> 
>> I made the mistake of dumping a useful and robust 14 channel Soundcraft signature MTK mixer (that I paid $300 for) which had built-in internal effects, parametric Mids and 2-3 FX Sends, as well as functioned as an audio interface, only to shrink the footprint by 1/4 the size with a Befaco HexMix & expander, which almost cost 2-3x the price.
>> 
>> It would be an interesting prospect, but with the needs people have, you are far better putting your energy elsewhere it seems. There are new boutique mixers on the market from some incredible designs out of Germany, but they have a price pack that is commensurate. I wish I was wrong ? because I?m still not happy with the ultra portable Eurorack mixer options these days!
>> 
>> Todd
>> 
>>> On Nov 30, 2021, at 8:21 PM, Jay Schwichtenberg via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
>>> 
>>> ?
>>> Unless you have some obscure needs that would be something I'd buy.
>>> 
>>> If time is money for you buy time you get all the PCBs laid out, made, stuffed and the metal work designed and done that's going to be a lot of time and effort. Then there is the question of cost, you doing a one of verses what a company that makes 100K of them a year.
>>> 
>>> Jay S.
>>> 
>>> On 11/30/2021 9:43 AM, ColinMuirDorward via Synth-diy wrote:
>>>> Who here has done or tried it?
>>>> Please feel free to share pictures, stories, warnings, etc :)
>>>> Cheers,
>>>> Colin
>>>> 
>>>> -- 
>>>> https://www.instagram.com/colinmuirdorward/ <https://www.instagram.com/colinmuirdorward/>
>>>> -
>>>>  <https://www.instagram.com/colinmuirdorward/>
>>>> https://www.instagram.com/ssdp_studios/ <https://www.instagram.com/ssdp_studios/>
>>>> 
>>>> _______________________________________________
>>>> Synth-diy mailing list
>>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> 
> _______________________________________________
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From mbryant at futurehorizons.com  Wed Dec  1 12:49:32 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Wed, 1 Dec 2021 11:49:32 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <AC6D7025-FD95-48C9-BE28-686F66E06BD6@electricdruid.net>
References: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
 <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>
 <22801B6D-4CFB-4C67-B50B-D9ECAF8B4C44@gmail.com>
 <AC6D7025-FD95-48C9-BE28-686F66E06BD6@electricdruid.net>
Message-ID: <9ed0aa1f06554f26aec2d71a3d447fa8@futurehorizons.com>


Quite a lot of mixers get stripped down for spares to keep others of the same design going a little longer.   The cards at the far ends of the mixer often get less use and so are often in pretty good condition.  It also helps if those channels haven?t had someone without basic soldering skills doing ?preventative recapping? of every electrolytic, when most of them still have decades of life in them.

But in the end some use faders that are no longer available or easily substituted, especially some of the earlier motorised fader designs.  Even some pots have long since obsoleted footprints.

And of course some mixers deserved to be junked even when new :-)

I believe the MCI500 of Bohemian Rhapsody fame may still be in the Quadrangle studio at Rockfield.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom Wiltshire
Sent: 01 December 2021 11:29
To: mark verbos
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] DIY mixer/console

Big old analogue desks are going for peanuts unless they?re something *really* famous - like ?this desk recorded Bohemian Rhapsody? famous!

A friend of mine picked up a similar 40 channel Soundcraft studio desk from a university music dept. for a pittance. No-one else wanted something the size of a table. Even he didn?t keep it for long though. I don?t know what he did with it. I bet dozens have been junked.



On 1 Dec 2021, at 11:14, mark verbos via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:

I worked with Z?hl on the CV channel for thew AM-1 (presumably the incredible design from Germany mentioned below). Michael designed the custom mixers that were in the studios of Can and Conny Plank. He is extremely careful with noise and crosstalk. H wouldn?t allow me to use any digital clocking in the CV parts of the channel. Although not as expensive as an SSL or Neve, the Z?hl is ?price no object? by today?s standards and has taught me how a mixer becomes ?50,000.

That said, I bought a used 40 channel Soundcraft Vienna for ?800. That is a large format front of house live board from the 90?s. It has 8 sends, 8 busses, VCA groups, mute groups, balanced in/out, inserts on every channel NOT on send/receive jacks, sweepable hipass filter on each channel, serious 4 band semi perimetric EQ,  fuil meterbridge built in. It was about ?30,000 when new. But, it weighs about 150kg and uses an entire power circuit for itself, heating the room when on.


maybe buying a mixer frame empty and making your own channels or buying something like I have and making your own replacement channels could work for you. Here in Germany I see Studer frames available empty all the time.

Mark





On Dec 1, 2021, at 4:03 AM, Todd Sines <sines_list at scale.la<mailto:sines_list at scale.la>> wrote:

I made the mistake of dumping a useful and robust 14 channel Soundcraft signature MTK mixer (that I paid $300 for) which had built-in internal effects, parametric Mids and 2-3 FX Sends, as well as functioned as an audio interface, only to shrink the footprint by 1/4 the size with a Befaco HexMix & expander, which almost cost 2-3x the price.

It would be an interesting prospect, but with the needs people have, you are far better putting your energy elsewhere it seems. There are new boutique mixers on the market from some incredible designs out of Germany, but they have a price pack that is commensurate. I wish I was wrong ? because I?m still not happy with the ultra portable Eurorack mixer options these days!

Todd


On Nov 30, 2021, at 8:21 PM, Jay Schwichtenberg via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
?
Unless you have some obscure needs that would be something I'd buy.
If time is money for you buy time you get all the PCBs laid out, made, stuffed and the metal work designed and done that's going to be a lot of time and effort. Then there is the question of cost, you doing a one of verses what a company that makes 100K of them a year.
Jay S.
On 11/30/2021 9:43 AM, ColinMuirDorward via Synth-diy wrote:
Who here has done or tried it?
Please feel free to share pictures, stories, warnings, etc :)
Cheers,
Colin

--
https://www.instagram.com/colinmuirdorward/
-
<https://www.instagram.com/colinmuirdorward/>
https://www.instagram.com/ssdp_studios/



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From rburnett at richieburnett.co.uk  Wed Dec  1 13:01:06 2021
From: rburnett at richieburnett.co.uk (rburnett at richieburnett.co.uk)
Date: Wed, 01 Dec 2021 12:01:06 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>

When I was younger and just getting into electronic music I designed and 
built my own 24-channel mixer with stereo outputs, 4 channel EQ on each 
channel, mic pre-amps, insertion points, pre- and post-fade FX sends, 
aux/tape returns, mute/solo switching etc.  I naively thought it would 
be cheap to do!  It was a pain making the enclosure (from wood!), took 
ages to solder up all the electronics (mostly on veroboard with lots of 
flying leads to the pots and switches!!!), and ended up being waaaaaay 
more expensive than I had imagined.

It also picked up numerous European Short-Wave radio stations at night, 
buzzed every time the heating switched on or off, and always had at 
least 2 channels with intermittent faults due to poor soldering at any 
one time!

It looked pretty cool, and I was happy from an achievement point of view 
(was easily satisfied in those days ;-))  but I was forever opening it 
up to fix stuff, and definitely wouldn't embark on anything like that 
again!

-Richie,




On 2021-11-30 17:43, ColinMuirDorward via Synth-diy wrote:
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)
> Cheers,
> Colin
> 
> --
> 
> https://www.instagram.com/colinmuirdorward/
> -
> 
> https://www.instagram.com/ssdp_studios/
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From kenny at beatkamp.com  Wed Dec  1 13:04:42 2021
From: kenny at beatkamp.com (kenny at beatkamp.com)
Date: Wed, 1 Dec 2021 12:04:42 -0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <9ed0aa1f06554f26aec2d71a3d447fa8@futurehorizons.com>
References: <8026e823-01b6-d873-a897-b4a1c320aeab@comcast.net>
 <42D6B1F4-C4E8-4B27-B434-9F6B44AB7C4E@scale.la>
 <22801B6D-4CFB-4C67-B50B-D9ECAF8B4C44@gmail.com>
 <AC6D7025-FD95-48C9-BE28-686F66E06BD6@electricdruid.net>
 <9ed0aa1f06554f26aec2d71a3d447fa8@futurehorizons.com>
Message-ID: <9f882a5de355696cb6fdbe591a63fd05.squirrel@www.beatkamp.com>


I have never gone further than banging together a few resistance
mixers.  The mere process of housing, wiring up and testing for
a basic 8x1 passive mixer has made me lose all interest in building
a real actual active console of any size.

That is incredibly hard work!

> And of course some mixers deserved to be junked even when new :-)
>

This made me smile :)



From tom at electricdruid.net  Wed Dec  1 13:08:09 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 1 Dec 2021 12:08:09 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>
Message-ID: <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>

Gagh! Brave man! That sounds like a mighty project.

The *first* thing I would do if I even considered taking on such a task would be to design a nice channel strip PCB with all the pots down one edge so that I had zero wiring to do!

Tom

> On 1 Dec 2021, at 12:01, rburnett at richieburnett.co.uk wrote:
> 
> When I was younger and just getting into electronic music I designed and built my own 24-channel mixer with stereo outputs, 4 channel EQ on each channel, mic pre-amps, insertion points, pre- and post-fade FX sends, aux/tape returns, mute/solo switching etc.  I naively thought it would be cheap to do!  It was a pain making the enclosure (from wood!), took ages to solder up all the electronics (mostly on veroboard with lots of flying leads to the pots and switches!!!), and ended up being waaaaaay more expensive than I had imagined.
> 
> It also picked up numerous European Short-Wave radio stations at night, buzzed every time the heating switched on or off, and always had at least 2 channels with intermittent faults due to poor soldering at any one time!
> 
> It looked pretty cool, and I was happy from an achievement point of view (was easily satisfied in those days ;-))  but I was forever opening it up to fix stuff, and definitely wouldn't embark on anything like that again!
> 
> -Richie,
> 
> 
> 
> 
> On 2021-11-30 17:43, ColinMuirDorward via Synth-diy wrote:
>> Who here has done or tried it?
>> Please feel free to share pictures, stories, warnings, etc :)
>> Cheers,
>> Colin
>> --
>> https://www.instagram.com/colinmuirdorward/
>> -
>> https://www.instagram.com/ssdp_studios/
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From rburnett at richieburnett.co.uk  Wed Dec  1 14:51:45 2021
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Wed, 1 Dec 2021 13:51:45 -0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>
 <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>
Message-ID: <BA6AEE0CFD1F4C018A2E71D931D555B3@DESKTOPUHPK2VO>

> Gagh! Brave man! That sounds like a mighty project.

In terms of electronics design it wasn't very challenging.  It just ended up 
being a relentless job of soldering and drilling holes in the panel for 
pots!

> The *first* thing I would do if I even considered taking on such a task 
> would be to design a nice channel strip PCB with all the pots down one 
> edge so that I had zero wiring to do!

Yeah, I totally agree.  But I was only about 19 when I started it.  I had no 
idea how to make a PCB back then, or any money to pay for the Photo-plot 
tooling.  I did however, have lots of wire, veroboard and a track cutter ! 
;-)

-Richie,


-- 
This email has been checked for viruses by AVG.
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From brazil.v at gmail.com  Wed Dec  1 15:03:34 2021
From: brazil.v at gmail.com (Vinicius Brazil)
Date: Wed, 1 Dec 2021 11:03:34 -0300
Subject: [sdiy] DIY mixer/console
In-Reply-To: <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>
 <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>
Message-ID: <CAF7fC2DWcj1s=5Hb7xBSz9MGKX__8zVCDbeeSkhrBXJgObyxjg@mail.gmail.com>

I did something like this in the 80's.
a 16-channel keyboard mixer for a studio, with send/return and eq?s. No
mic?s inputs.
I think it is still used today.
I made other smaller ones for my use.

<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
Virus-free.
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Wed, Dec 1, 2021 at 9:11 AM Tom Wiltshire <tom at electricdruid.net> wrote:

> Gagh! Brave man! That sounds like a mighty project.
>
> The *first* thing I would do if I even considered taking on such a task
> would be to design a nice channel strip PCB with all the pots down one edge
> so that I had zero wiring to do!
>
> Tom
>
> > On 1 Dec 2021, at 12:01, rburnett at richieburnett.co.uk wrote:
> >
> > When I was younger and just getting into electronic music I designed and
> built my own 24-channel mixer with stereo outputs, 4 channel EQ on each
> channel, mic pre-amps, insertion points, pre- and post-fade FX sends,
> aux/tape returns, mute/solo switching etc.  I naively thought it would be
> cheap to do!  It was a pain making the enclosure (from wood!), took ages to
> solder up all the electronics (mostly on veroboard with lots of flying
> leads to the pots and switches!!!), and ended up being waaaaaay more
> expensive than I had imagined.
> >
> > It also picked up numerous European Short-Wave radio stations at night,
> buzzed every time the heating switched on or off, and always had at least 2
> channels with intermittent faults due to poor soldering at any one time!
> >
> > It looked pretty cool, and I was happy from an achievement point of view
> (was easily satisfied in those days ;-))  but I was forever opening it up
> to fix stuff, and definitely wouldn't embark on anything like that again!
> >
> > -Richie,
> >
> >
> >
> >
> > On 2021-11-30 17:43, ColinMuirDorward via Synth-diy wrote:
> >> Who here has done or tried it?
> >> Please feel free to share pictures, stories, warnings, etc :)
> >> Cheers,
> >> Colin
> >> --
> >> https://www.instagram.com/colinmuirdorward/
> >> -
> >> https://www.instagram.com/ssdp_studios/
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mbryant at futurehorizons.com  Wed Dec  1 15:34:45 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Wed, 1 Dec 2021 14:34:45 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <BA6AEE0CFD1F4C018A2E71D931D555B3@DESKTOPUHPK2VO>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
 <0ae8f06811d17136fd934c76903d7816@richieburnett.co.uk>
 <C8109DAD-4633-4DE5-8EAD-F3988E64C60D@electricdruid.net>
 <BA6AEE0CFD1F4C018A2E71D931D555B3@DESKTOPUHPK2VO>
Message-ID: <7d4c1e4faec24f9fb6cd217c803c710b@futurehorizons.com>

I'm sure even Rupert Neve started out with some Veroboard.  Or maybe even tag-strip :-)

-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Richie Burnett
Sent: 01 December 2021 13:52
To: Tom Wiltshire
Cc: *SYNTH DIY
Subject: Re: [sdiy] DIY mixer/console

> Gagh! Brave man! That sounds like a mighty project.

In terms of electronics design it wasn't very challenging.  It just ended up being a relentless job of soldering and drilling holes in the panel for pots!

> The *first* thing I would do if I even considered taking on such a 
> task would be to design a nice channel strip PCB with all the pots 
> down one edge so that I had zero wiring to do!

Yeah, I totally agree.  But I was only about 19 when I started it.  I had no idea how to make a PCB back then, or any money to pay for the Photo-plot tooling.  I did however, have lots of wire, veroboard and a track cutter ! 
;-)

-Richie,


--
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From barryklein at cox.net  Thu Dec  2 06:26:34 2021
From: barryklein at cox.net (Barry Klein)
Date: Wed, 1 Dec 2021 21:26:34 -0800
Subject: [sdiy] Analog Devices SigmaDSP
Message-ID: <02AE9B55-2A95-4150-846B-3247596CB778@cox.net>

I?ve always been intrigued by Analog Devices SigmaStudio software as it looks so much like a software synth.  Any of you have experience with it and whether someone like me with very poor math and programming background could get some enjoyment trying an eval board with one? I suppose I?d be willing to try learning basics with a decent book?
There are so many different chips that I?m overwhelmed. I see diy board offerings for boom boxes that are amazingly cheap - Google Wondom DSP. I also have a daisy board but don?t have the programming skills to get anywhere with it.  I haven?t given up - just distracted now by this as we may use one at work. 



From mbryant at futurehorizons.com  Thu Dec  2 06:36:55 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Thu, 2 Dec 2021 05:36:55 +0000
Subject: [sdiy] Analog Devices SigmaDSP
In-Reply-To: <02AE9B55-2A95-4150-846B-3247596CB778@cox.net>
References: <02AE9B55-2A95-4150-846B-3247596CB778@cox.net>
Message-ID: <80aca8d1b22a4716b6c5a17ef0ae19bd@futurehorizons.com>

I use the ADAU1701, programming it with SigmaStudio.   You probably could build a synth with it by linking it with an MCU to do some of the slower control stuff, and to interface with MIDI or whatever.

There's also a similar, though not compatible TI part with moreorless the same spec.

As you say they are very cheap so get an eval and try it.  It's a bit frustrating getting Sigma Studio going at first - it's not the most intuitive of software packages - but by flicking around the pages you should get something going.  I think there are sine and other (possibly non-band-limited) waveform generators in there somewhere.


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Barry Klein via Synth-diy
Sent: 02 December 2021 05:27
To: Synth DIY
Subject: [sdiy] Analog Devices SigmaDSP

I?ve always been intrigued by Analog Devices SigmaStudio software as it looks so much like a software synth.  Any of you have experience with it and whether someone like me with very poor math and programming background could get some enjoyment trying an eval board with one? I suppose I?d be willing to try learning basics with a decent book? There are so many different chips that I?m overwhelmed. I see diy board offerings for boom boxes that are amazingly cheap - Google Wondom DSP. I also have a daisy board but don?t have the programming skills to get anywhere with it.  I haven?t given up - just distracted now by this as we may use one at work. 

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From barryklein at cox.net  Thu Dec  2 08:03:33 2021
From: barryklein at cox.net (Barry Klein)
Date: Wed, 1 Dec 2021 23:03:33 -0800
Subject: [sdiy] Analog Devices SigmaDSP
In-Reply-To: <80aca8d1b22a4716b6c5a17ef0ae19bd@futurehorizons.com>
References: <02AE9B55-2A95-4150-846B-3247596CB778@cox.net>
 <80aca8d1b22a4716b6c5a17ef0ae19bd@futurehorizons.com>
Message-ID: <D71026B9-B260-480D-ADFB-7090BA454277@cox.net>

Do you recall the TI part? I haven?t looked at them seriously yet. Do they have a similar programming interface, maybe Audioweaver or something?  For my work right now I am investigating ANR solutions. The actual programming of these would go to someone else - I just am investigating what is being done. There was one called RNnoise that was impressive.


> On Dec 1, 2021, at 9:36 PM, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> I use the ADAU1701, programming it with SigmaStudio.   You probably could build a synth with it by linking it with an MCU to do some of the slower control stuff, and to interface with MIDI or whatever.
> 
> There's also a similar, though not compatible TI part with moreorless the same spec.
> 
> As you say they are very cheap so get an eval and try it.  It's a bit frustrating getting Sigma Studio going at first - it's not the most intuitive of software packages - but by flicking around the pages you should get something going.  I think there are sine and other (possibly non-band-limited) waveform generators in there somewhere.
> 
> 
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Barry Klein via Synth-diy
> Sent: 02 December 2021 05:27
> To: Synth DIY
> Subject: [sdiy] Analog Devices SigmaDSP
> 
> I?ve always been intrigued by Analog Devices SigmaStudio software as it looks so much like a software synth.  Any of you have experience with it and whether someone like me with very poor math and programming background could get some enjoyment trying an eval board with one? I suppose I?d be willing to try learning basics with a decent book? There are so many different chips that I?m overwhelmed. I see diy board offerings for boom boxes that are amazingly cheap - Google Wondom DSP. I also have a daisy board but don?t have the programming skills to get anywhere with it.  I haven?t given up - just distracted now by this as we may use one at work. 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From mbryant at futurehorizons.com  Thu Dec  2 08:08:48 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Thu, 2 Dec 2021 07:08:48 +0000
Subject: [sdiy] Analog Devices SigmaDSP
In-Reply-To: <D71026B9-B260-480D-ADFB-7090BA454277@cox.net>
References: <02AE9B55-2A95-4150-846B-3247596CB778@cox.net>
 <80aca8d1b22a4716b6c5a17ef0ae19bd@futurehorizons.com>
 <D71026B9-B260-480D-ADFB-7090BA454277@cox.net>
Message-ID: <eacab7064d0e4fdda906028af1901950@futurehorizons.com>

TI have quite a few, but start at the TLV320AIC3256.

They use the PurePath development system
https://www.ti.com/tool/AICPUREPATH_STUDIO



-----Original Message-----
From: Barry Klein [mailto:barryklein at cox.net] 
Sent: 02 December 2021 07:04
To: Mike Bryant
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Analog Devices SigmaDSP

Do you recall the TI part? I haven?t looked at them seriously yet. Do they have a similar programming interface, maybe Audioweaver or something?  For my work right now I am investigating ANR solutions. The actual programming of these would go to someone else - I just am investigating what is being done. There was one called RNnoise that was impressive.


> On Dec 1, 2021, at 9:36 PM, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> I use the ADAU1701, programming it with SigmaStudio.   You probably could build a synth with it by linking it with an MCU to do some of the slower control stuff, and to interface with MIDI or whatever.
> 
> There's also a similar, though not compatible TI part with moreorless the same spec.
> 
> As you say they are very cheap so get an eval and try it.  It's a bit frustrating getting Sigma Studio going at first - it's not the most intuitive of software packages - but by flicking around the pages you should get something going.  I think there are sine and other (possibly non-band-limited) waveform generators in there somewhere.
> 
> 
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Barry Klein via Synth-diy
> Sent: 02 December 2021 05:27
> To: Synth DIY
> Subject: [sdiy] Analog Devices SigmaDSP
> 
> I?ve always been intrigued by Analog Devices SigmaStudio software as it looks so much like a software synth.  Any of you have experience with it and whether someone like me with very poor math and programming background could get some enjoyment trying an eval board with one? I suppose I?d be willing to try learning basics with a decent book? There are so many different chips that I?m overwhelmed. I see diy board offerings for boom boxes that are amazingly cheap - Google Wondom DSP. I also have a daisy board but don?t have the programming skills to get anywhere with it.  I haven?t given up - just distracted now by this as we may use one at work. 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org





From barryklein at cox.net  Thu Dec  2 08:13:14 2021
From: barryklein at cox.net (Barry Klein)
Date: Wed, 1 Dec 2021 23:13:14 -0800
Subject: [sdiy] Analog Devices SigmaDSP
In-Reply-To: <eacab7064d0e4fdda906028af1901950@futurehorizons.com>
References: <eacab7064d0e4fdda906028af1901950@futurehorizons.com>
Message-ID: <34924927-014E-461B-9C8F-6668CCE8129C@cox.net>

Cool. Thanks, was totally unaware of this.


> On Dec 1, 2021, at 11:09 PM, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> ?TI have quite a few, but start at the TLV320AIC3256.
> 
> They use the PurePath development system
> https://www.ti.com/tool/AICPUREPATH_STUDIO
> 
> 
> 
> -----Original Message-----
> From: Barry Klein [mailto:barryklein at cox.net] 
> Sent: 02 December 2021 07:04
> To: Mike Bryant
> Cc: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Analog Devices SigmaDSP
> 
> Do you recall the TI part? I haven?t looked at them seriously yet. Do they have a similar programming interface, maybe Audioweaver or something?  For my work right now I am investigating ANR solutions. The actual programming of these would go to someone else - I just am investigating what is being done. There was one called RNnoise that was impressive.
> 
> 
>> On Dec 1, 2021, at 9:36 PM, Mike Bryant <mbryant at futurehorizons.com> wrote:
>> 
>> I use the ADAU1701, programming it with SigmaStudio.   You probably could build a synth with it by linking it with an MCU to do some of the slower control stuff, and to interface with MIDI or whatever.
>> 
>> There's also a similar, though not compatible TI part with moreorless the same spec.
>> 
>> As you say they are very cheap so get an eval and try it.  It's a bit frustrating getting Sigma Studio going at first - it's not the most intuitive of software packages - but by flicking around the pages you should get something going.  I think there are sine and other (possibly non-band-limited) waveform generators in there somewhere.
>> 
>> 
>> -----Original Message-----
>> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Barry Klein via Synth-diy
>> Sent: 02 December 2021 05:27
>> To: Synth DIY
>> Subject: [sdiy] Analog Devices SigmaDSP
>> 
>> I?ve always been intrigued by Analog Devices SigmaStudio software as it looks so much like a software synth.  Any of you have experience with it and whether someone like me with very poor math and programming background could get some enjoyment trying an eval board with one? I suppose I?d be willing to try learning basics with a decent book? There are so many different chips that I?m overwhelmed. I see diy board offerings for boom boxes that are amazingly cheap - Google Wondom DSP. I also have a daisy board but don?t have the programming skills to get anywhere with it.  I haven?t given up - just distracted now by this as we may use one at work. 
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> 
> 




From office at stahlnow.com  Fri Dec  3 20:03:01 2021
From: office at stahlnow.com (=?utf-8?Q?Christoph_St=C3=A4hli?=)
Date: Fri, 03 Dec 2021 19:03:01 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
References: <CAGV3gy6OA5x4GTc=MUdt=jx-GD4e3d5FMyJCqi=s-Q2CepDmsg@mail.gmail.com>
Message-ID: <20211203190259.m6w3khkv3lgzwx65@stahlnow.localdomain>

Hi

I've made a lipo powered mini active mixer that is based on schematics
from RANE i found online. It is simplified from the original schmeatics
and probably not as much hi-fi. I'm not a trained engineer and it was my first
attempt to to an analogue mixer. The idea and case for the mixer was inspired by the korg
volcas.

Here's the github with kicad sources and openSCAD 3d case for laser cutting:

https://github.com/stahlnow/mischerli

I'm currently working on a new version with USB C and a mosfet switch to keep
the mixer on alltime if plugged in. Also I'm planning to have the option
for mono channels instead of stereo and only 'mono send' instead of
stereo.

I might do a post on this list another day if somebody is interested.

For me it was a good experience to do a very basic design of an active analogue mixer and case
without too crazy amount of work / parts / cost.

Cheers, stahl

On Tue, Nov 30, 2021 at 12:43:59PM -0500, ColinMuirDorward via Synth-diy wrote:
> Who here has done or tried it?
> Please feel free to share pictures, stories, warnings, etc :)
> Cheers,
> Colin
> 
> --
> https://www.instagram.com/colinmuirdorward/
> -
> https://www.instagram.com/ssdp_studios/

-- 
stahlnow.com | zweierstrasse 35, 8004 z?rich
pgp: 0x96589746706346b0
/msg stahl on libera.chat
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From quincas at gmail.com  Fri Dec  3 20:13:21 2021
From: quincas at gmail.com (Quincas Moreira)
Date: Fri, 3 Dec 2021 13:13:21 -0600
Subject: [sdiy] DIY mixer/console
In-Reply-To: <20211203190259.m6w3khkv3lgzwx65@stahlnow.localdomain>
References: <20211203190259.m6w3khkv3lgzwx65@stahlnow.localdomain>
Message-ID: <7B93D5E5-91D4-4B84-989B-B9F8EF1038C2@gmail.com>


Lipo powered? Are you Tyler Durden? ?
Sent from my iPhone

> On 3 Dec 2021, at 13:08, Christoph St?hli <office at stahlnow.com> wrote:
> 
> ?Hi
> 
> I've made a lipo powered mini active mixer that is based on schematics
> from RANE i found online. It is simplified from the original schmeatics
> and probably not as much hi-fi. I'm not a trained engineer and it was my first
> attempt to to an analogue mixer. The idea and case for the mixer was inspired by the korg
> volcas.
> 
> Here's the github with kicad sources and openSCAD 3d case for laser cutting:
> 
> https://github.com/stahlnow/mischerli
> 
> I'm currently working on a new version with USB C and a mosfet switch to keep
> the mixer on alltime if plugged in. Also I'm planning to have the option
> for mono channels instead of stereo and only 'mono send' instead of
> stereo.
> 
> I might do a post on this list another day if somebody is interested.
> 
> For me it was a good experience to do a very basic design of an active analogue mixer and case
> without too crazy amount of work / parts / cost.
> 
> Cheers, stahl
> 
>> On Tue, Nov 30, 2021 at 12:43:59PM -0500, ColinMuirDorward via Synth-diy wrote:
>> Who here has done or tried it?
>> Please feel free to share pictures, stories, warnings, etc :)
>> Cheers,
>> Colin
>> 
>> --
>> https://www.instagram.com/colinmuirdorward/
>> -
>> https://www.instagram.com/ssdp_studios/
> 
> -- 
> stahlnow.com | zweierstrasse 35, 8004 z?rich
> pgp: 0x96589746706346b0
> /msg stahl on libera.chat
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> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

From dcurriden at hotmail.com  Fri Dec  3 21:25:17 2021
From: dcurriden at hotmail.com (Dan Curriden)
Date: Fri, 3 Dec 2021 20:25:17 +0000
Subject: [sdiy] DIY mixer/console
In-Reply-To: <7B93D5E5-91D4-4B84-989B-B9F8EF1038C2@gmail.com>
References: <20211203190259.m6w3khkv3lgzwx65@stahlnow.localdomain>
 <7B93D5E5-91D4-4B84-989B-B9F8EF1038C2@gmail.com>
Message-ID: <SA1PR17MB5334915DB30086DCCCB42A17BB6A9@SA1PR17MB5334.namprd17.prod.outlook.com>

The first rule of Synth-DIY club is...
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Quincas Moreira via Synth-diy <synth-diy at synth-diy.org>
Sent: Friday, December 3, 2021 1:13 PM
To: Christoph St?hli <office at stahlnow.com>
Cc: ColinMuirDorward via Synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] DIY mixer/console


Lipo powered? Are you Tyler Durden? ?
Sent from my iPhone

> On 3 Dec 2021, at 13:08, Christoph St?hli <office at stahlnow.com> wrote:
>
> ?Hi
>
> I've made a lipo powered mini active mixer that is based on schematics
> from RANE i found online. It is simplified from the original schmeatics
> and probably not as much hi-fi. I'm not a trained engineer and it was my first
> attempt to to an analogue mixer. The idea and case for the mixer was inspired by the korg
> volcas.
>
> Here's the github with kicad sources and openSCAD 3d case for laser cutting:
>
> https://github.com/stahlnow/mischerli
>
> I'm currently working on a new version with USB C and a mosfet switch to keep
> the mixer on alltime if plugged in. Also I'm planning to have the option
> for mono channels instead of stereo and only 'mono send' instead of
> stereo.
>
> I might do a post on this list another day if somebody is interested.
>
> For me it was a good experience to do a very basic design of an active analogue mixer and case
> without too crazy amount of work / parts / cost.
>
> Cheers, stahl
>
>> On Tue, Nov 30, 2021 at 12:43:59PM -0500, ColinMuirDorward via Synth-diy wrote:
>> Who here has done or tried it?
>> Please feel free to share pictures, stories, warnings, etc :)
>> Cheers,
>> Colin
>>
>> --
>> https://www.instagram.com/colinmuirdorward/
>> -
>> https://www.instagram.com/ssdp_studios/
>
> --
> stahlnow.com | zweierstrasse 35, 8004 z?rich
> pgp: 0x96589746706346b0
> /msg stahl on libera.chat
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org
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From bjostarmark at yahoo.se  Tue Dec  7 21:26:17 2021
From: bjostarmark at yahoo.se (=?utf-8?Q?Bj=C3=B6rn_Starmark?=)
Date: Tue, 7 Dec 2021 21:26:17 +0100
Subject: [sdiy] Spice Music
Message-ID: <493257149.334520.1638908778245@yahoo.se>

Hi All,

This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files. You can listen to an example here: https://github.com/bjostarmark/spice-music/blob/master/Advanced/spice_music_v0_1b.mp3

Examples, instructions and tips can be found at:

https://github.com/bjostarmark/spice-music

All is in the public domain.

Comments invited!

Best Regards,
Bjorn Starmark

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From ben at stuyts.nl  Tue Dec  7 21:48:53 2021
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue, 7 Dec 2021 21:48:53 +0100
Subject: [sdiy] Spice Music
In-Reply-To: <493257149.334520.1638908778245@yahoo.se>
References: <493257149.334520.1638908778245@yahoo.se>
Message-ID: <EF79FE39-16EB-496D-8D99-DA688545B60D@stuyts.nl>

Hi Bj?rn,

Welcome to the list. Sounds interesting, but those links don?t work.

Ben


> On 7 Dec 2021, at 21:26, Bj?rn Starmark via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Hi All,
>  
> This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files. You can listen to an example here: https://github.com/bjostarmark/spice-music/blob/master/Advanced/spice_music_v0_1b.mp3 <https://github.com/bjostarmark/spice-music/blob/master/Advanced/spice_music_v0_1b.mp3>
>  
> Examples, instructions and tips can be found at:
>  
> https://github.com/bjostarmark/spice-music <https://github.com/bjostarmark/spice-music>
>  
> All is in the public domain.
>  
> Comments invited!
>  
> Best Regards,
> Bjorn Starmark
>  
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
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From bjostarmark at yahoo.se  Tue Dec  7 21:52:49 2021
From: bjostarmark at yahoo.se (=?utf-8?Q?Bj=C3=B6rn_Starmark?=)
Date: Tue, 7 Dec 2021 21:52:49 +0100
Subject: [sdiy] Spice Music
In-Reply-To: <EF79FE39-16EB-496D-8D99-DA688545B60D@stuyts.nl>
References: <493257149.334520.1638908778245@yahoo.se>
 <EF79FE39-16EB-496D-8D99-DA688545B60D@stuyts.nl>
Message-ID: <238515928.335845.1638910374455@yahoo.se>

Sorry,

Forgot  to make the repository public. Should work now.

/Bjorn

Skickades fr?n E-post f?r Windows

Fr?n: Ben Stuyts
Skickat: den 7 december 2021 21:49
Till: Bj?rn Starmark
Kopia: synth-diy at synth-diy.org
?mne: Re: [sdiy] Spice Music

Hi Bj?rn,

Welcome to the list. Sounds interesting, but those links don?t work.

Ben



On 7 Dec 2021, at 21:26, Bj?rn Starmark via Synth-diy <synth-diy at synth-diy.org> wrote:

Hi All,
?
This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files. You can listen to an example here:?https://github.com/bjostarmark/spice-music/blob/master/Advanced/spice_music_v0_1b.mp3
?
Examples, instructions and tips can be found at:
?
https://github.com/bjostarmark/spice-music
?
All is in the public domain.
?
Comments invited!
?
Best Regards,
Bjorn Starmark
?
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use?marketplace at synth-diy.org


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From neil.johnson71 at gmail.com  Tue Dec  7 22:22:43 2021
From: neil.johnson71 at gmail.com (Neil Johnson)
Date: Tue, 7 Dec 2021 21:22:43 +0000
Subject: [sdiy] Spice Music
In-Reply-To: <493257149.334520.1638908778245@yahoo.se>
References: <493257149.334520.1638908778245@yahoo.se>
Message-ID: <CACZGMxKqvkMXUsKOfUzkinzAXFKFTv8NAHMvHQD=r6tdsykiXw@mail.gmail.com>

Hi,

Bj?rn Starmark wrote:
> This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files.

Nice!

With a bit of fiddling I've done the wav-in->sim->wav-out in ngspice
and simetrix too.  Really good way to hear how a filter, phaser,
psychoacoustic effect, etc, could sound (insert usual caveat about
limits of simulation, etc).

Neil



From bjostarmark at yahoo.se  Wed Dec  8 08:28:42 2021
From: bjostarmark at yahoo.se (=?UTF-8?Q?Bj=C3=B6rn_Starmar?=)
Date: Wed, 8 Dec 2021 07:28:42 +0000 (UTC)
Subject: [sdiy] Spice Music
In-Reply-To: <CACZGMxKqvkMXUsKOfUzkinzAXFKFTv8NAHMvHQD=r6tdsykiXw@mail.gmail.com>
References: <493257149.334520.1638908778245@yahoo.se>
 <CACZGMxKqvkMXUsKOfUzkinzAXFKFTv8NAHMvHQD=r6tdsykiXw@mail.gmail.com>
Message-ID: <183864958.14646081.1638948522304@mail.yahoo.com>

Cool!?
I am pleased with The sound of the Diode ladder filter. I have not been able to reproduce the tb303 sound, though. More work required.?
/Bj?rn?

Skickat fr?n Yahoo Mail p? Android 
 
  P? tis, dec. 2021 klockan 22:23, Neil Johnson<neil.johnson71 at gmail.com> skrev:   Hi,

Bj?rn Starmark wrote:
> This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files.

Nice!

With a bit of fiddling I've done the wav-in->sim->wav-out in ngspice
and simetrix too.? Really good way to hear how a filter, phaser,
psychoacoustic effect, etc, could sound (insert usual caveat about
limits of simulation, etc).

Neil
  
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From synthdiy at adambaby.com  Wed Dec  8 08:49:31 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Wed, 8 Dec 2021 17:49:31 +1000
Subject: [sdiy] Spice Music
In-Reply-To: <183864958.14646081.1638948522304@mail.yahoo.com>
References: <493257149.334520.1638908778245@yahoo.se>
 <CACZGMxKqvkMXUsKOfUzkinzAXFKFTv8NAHMvHQD=r6tdsykiXw@mail.gmail.com>
 <183864958.14646081.1638948522304@mail.yahoo.com>
Message-ID: <76B11752-BB80-43EB-974A-CA5A36A280C1@adambaby.com>



> On 8 Dec 2021, at 17:28, Bj?rn Starmar via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Cool! 
> 
> I am pleased with The sound of the Diode ladder filter. I have not been able to reproduce the tb303 sound, though. More work required. 


The secret is in the power supply  ;-)


A




















> 
> /Bj?rn 
> 
> Skickat fr?n Yahoo Mail p? Android <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
> P? tis, dec. 2021 klockan 22:23, Neil Johnson
> <neil.johnson71 at gmail.com> skrev:
> Hi,
> 
> Bj?rn Starmark wrote:
> 
> > This is my first post on the forum. I have been simulating analog synth stuff in LTSpice for a while. LTspice can export .wav files.
> 
> 
> Nice!
> 
> With a bit of fiddling I've done the wav-in->sim->wav-out in ngspice
> and simetrix too.  Really good way to hear how a filter, phaser,
> psychoacoustic effect, etc, could sound (insert usual caveat about
> limits of simulation, etc).
> 
> Neil
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From rburnett at richieburnett.co.uk  Thu Dec  9 14:20:59 2021
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Thu, 09 Dec 2021 13:20:59 +0000
Subject: [sdiy] Spice Music
In-Reply-To: <493257149.334520.1638908778245@yahoo.se>
References: <493257149.334520.1638908778245@yahoo.se>
Message-ID: <j4huaxjk9x9eqdmn9dlmlv6v.1639056059155@email.android.com>

Cool stuff, thanks for sharing!

I managed to get good results modelling the tb-303 filter in LTspice. I think I had to tweak a couple of values though. I'll take a look and compare my model with yours.

-Richie,



---- Bj?rn Starmark via Synth-diy wrote ----

>_______________________________________________
>Synth-diy mailing list
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From lofideadbeat at gmail.com  Sat Dec 11 01:06:08 2021
From: lofideadbeat at gmail.com (Jean Bender)
Date: Sat, 11 Dec 2021 01:06:08 +0100
Subject: [sdiy] Need help understanding a schematic !
Message-ID: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>

Hi !
I have to repair a boss sps-10. The unit works when used in delay mod, but
nothing when used as pitch shifter.
But i also discovered that the tuner output is not working when the effect
is on, in delay mod or pitch shifter one. The output is only working when
the effect is powered but not engaged.
When i look at the scheme, i don"t get the way it's built, nor i can see
where i could find a faulty part. I assume some transistor is not working
and i'm looking for a voltage problem, but i'm a bit confused with the way
some parts are wired together.

Would someone here agree with explaining me how the different parts of this
effect work together ?
Actually i know how to troublecheck with my scope and multimeter, but i
stuck on how are working the remote effect input and tuner output.

Thanks for your help !
Best
J.

here is a link to the schematics and service manual !
http://www.univertron.com/SAS/manuals/Boss%20(Roland)/Boss%20RPS%2010/
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From mbryant at futurehorizons.com  Sat Dec 11 01:16:09 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 11 Dec 2021 00:16:09 +0000
Subject: [sdiy] Need help understanding a schematic !
In-Reply-To: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
References: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
Message-ID: <df277a0672bf4b3880960bcf52f8666f@futurehorizons.com>

Look on U10/4 and see if the signal is there in any mode.  Then look at the input to U10 on pin 14 for a slower PWM signal


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Jean Bender via Synth-diy
Sent: 11 December 2021 00:06
To: synth-diy at synth-diy.org
Subject: [sdiy] Need help understanding a schematic !

Hi !
I have to repair a boss sps-10. The unit works when used in delay mod, but nothing when used as pitch shifter.
But i also discovered that the tuner output is not working when the effect is on, in delay mod or pitch shifter one. The output is only working when the effect is powered but not engaged.
When i look at the scheme, i don"t get the way it's built, nor i can see where i could find a faulty part. I assume some transistor is not working and i'm looking for a voltage problem, but i'm a bit confused with the way some parts are wired together.

Would someone here agree with explaining me how the different parts of this effect work together ?
Actually i know how to troublecheck with my scope and multimeter, but i stuck on how are working the remote effect input and tuner output.

Thanks for your help !
Best
J.

here is a link to the schematics and service manual !
http://www.univertron.com/SAS/manuals/Boss%20(Roland)/Boss%20RPS%2010/
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From barryklein at cox.net  Sat Dec 11 01:44:01 2021
From: barryklein at cox.net (Barry Klein)
Date: Fri, 10 Dec 2021 16:44:01 -0800
Subject: [sdiy] Need help understanding a schematic !
In-Reply-To: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
References: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
Message-ID: <798394BE-A5B5-4DFC-8820-C812CE10059B@cox.net>

First verify your supply voltages. Then start at the pitch pot. Vary it and look with scope from there along the processor chip path. Analog switches and cmos parts die over time and are what you can replace so check if they seem to work and cross them off on your schematic.  

Sent from my iPhone

> On Dec 10, 2021, at 4:08 PM, Jean Bender via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> ?
> Hi !
> I have to repair a boss sps-10. The unit works when used in delay mod, but nothing when used as pitch shifter.
> But i also discovered that the tuner output is not working when the effect is on, in delay mod or pitch shifter one. The output is only working when the effect is powered but not engaged.
> When i look at the scheme, i don"t get the way it's built, nor i can see where i could find a faulty part. I assume some transistor is not working and i'm looking for a voltage problem, but i'm a bit confused with the way some parts are wired together.
> 
> Would someone here agree with explaining me how the different parts of this effect work together ?
> Actually i know how to troublecheck with my scope and multimeter, but i stuck on how are working the remote effect input and tuner output.
> 
> Thanks for your help !
> Best
> J.
> 
> here is a link to the schematics and service manual !
> http://www.univertron.com/SAS/manuals/Boss%20(Roland)/Boss%20RPS%2010/
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
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From jpdesroc at oricom.ca  Sun Dec 12 22:35:49 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Sun, 12 Dec 2021 16:35:49 -0500
Subject: [sdiy] My good old VGA oscilloscope plugged to my modular..
Message-ID: <000a01d7efa0$3b7afa40$b270eec0$@oricom.ca>

Here is a short video of my 2015 open source VGA Oscilloscope project.
It's made out of a small Microchip PIC micro with the help of some analog comparators circuitry. 
This box produces a vertical line that follows the incoming stereo audio signal connected to it. 
It then drives an external VGA display. 
A choice of 7 different colors can be applied to the vertical line. 
It just needs an old 4:3 VGA screen with a 800x600 resolution.

 

https://www.youtube.com/watch?v=VKMjb3CpOCE <https://www.youtube.com/watch?v=VKMjb3CpOCE&t=135s> &t=135s

 

Enjoy !

 

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From modular at go2.pl  Mon Dec 13 11:43:06 2021
From: modular at go2.pl (Roman Sowa)
Date: Mon, 13 Dec 2021 11:43:06 +0100
Subject: [sdiy] Need help understanding a schematic !
In-Reply-To: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
References: <CA+rzoo5xsHPXq+uUszxn+uDCR9oD33sWP4fcFbiMSXHqyHnr7g@mail.gmail.com>
Message-ID: <6176f754-f99e-4260-cd00-a91616700fa9@go2.pl>

Check if FPGA gets proper mode change signals, so if it gets proper 
logic levels at pins 18-23 at every mode switch position. It may be just 
dirty switch as well

check if DRAM gets address signals all the time in every mode, you 
should see massive train of pulses on most pins of the RAM.

It wouldn't hurt to see if ADC is working all the time or just in few 
modes. Check the output (pin 7) of LM311, that's possibly IC6. It should 
generate insane loads of semi-random pulses, maybe at 1MHz or so.

connect scope (and then audio amp) directly to DAC's ladder output - 
RA1, even before 5534 buffer, to see if FPGA generates some audio in 
every mode. If not, then check RA1 inputs as well.

check every clocks in the system in every mode - VCO I, VCO II, PLL on 
4046. It may be that one of pitch shifting VCOs is dead no matter what 
mode is selected, and it's simply not needed for plain delay.

One might say it's easy to spit with ideas like machine gun, while 
actually I'd rather look at it myself than try to actually nail the 
fault by email.

Roman

W dniu 2021-12-11 o?01:06, Jean Bender via Synth-diy pisze:
> Hi !
> I have to repair a boss sps-10. The unit works when used in delay mod, 
> but nothing when used as pitch shifter.
> But i also discovered that the tuner output is not working when the 
> effect is on, in delay mod or pitch shifter one. The output is only 
> working when the effect is powered but not engaged.
> When i look at the scheme, i don"t get the way it's built, nor i can see 
> where i could find a faulty part. I assume some transistor is not 
> working and i'm looking for a voltage problem, but i'm a bit confused 
> with the way some parts are wired together.
> 
> Would someone here agree with explaining me how the different parts of 
> this effect work together ?
> Actually i know how to troublecheck with my scope and multimeter, but i 
> stuck on how are working the remote effect input and tuner output.
> 
> Thanks for your help !
> Best
> J.
> 
> here is a link to the schematics and service manual !
> http://www.univertron.com/SAS/manuals/Boss%20(Roland)/Boss%20RPS%2010/ 
> <http://www.univertron.com/SAS/manuals/Boss%20(Roland)/Boss%20RPS%2010/>
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 


From rburnett at richieburnett.co.uk  Mon Dec 13 14:02:21 2021
From: rburnett at richieburnett.co.uk (rburnett at richieburnett.co.uk)
Date: Mon, 13 Dec 2021 13:02:21 +0000
Subject: [sdiy] My good old VGA oscilloscope plugged to my modular..
In-Reply-To: <000a01d7efa0$3b7afa40$b270eec0$@oricom.ca>
References: <000a01d7efa0$3b7afa40$b270eec0$@oricom.ca>
Message-ID: <043e6d61d7533440ad798d08a00061c1@richieburnett.co.uk>

Very pretty!  The perfect use for that old 4:3 analogue VGA monitor that 
everyone still has in the cupboard gathering dust.

-Richie,



On 2021-12-12 21:35, Jean-Pierre Desrochers wrote:
> Here is a short video of my 2015 open source VGA Oscilloscope project.
> It's made out of a small Microchip PIC micro with the help of some
> analog comparators circuitry.
> This box produces a vertical line that follows the incoming stereo
> audio signal connected to it.
> It then drives an external VGA display.
> A choice of 7 different colors can be applied to the vertical line.
> It just needs an old 4:3 VGA screen with a 800x600 resolution.
> 
> https://www.youtube.com/watch?v=VKMjb3CpOCE&t=135s
> 
> Enjoy !
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From guatis at gmail.com  Tue Dec 14 16:41:37 2021
From: guatis at gmail.com (=?UTF-8?Q?Benjam=C3=ADn_Velasco?=)
Date: Tue, 14 Dec 2021 12:41:37 -0300
Subject: [sdiy] Arp Soloist Service Manual/Schematics
Message-ID: <CAGHPcSB2RVznKeO4R4prsSy4FKtgj2XY8v7SYd4ENNfPQJSp1w@mail.gmail.com>

Hi guys,

I'm looking out there for a copy of the original Arp Soloist Service Manual
or schematics (not the Prosoloist). Anyone here have a copy?

regards

-- 
*Benjam?n Velasco Ossand?n*
Cel. 96344468
Casa. 27162400
Oficina. 29254154
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From jacobwatters at gmail.com  Tue Dec 14 16:48:00 2021
From: jacobwatters at gmail.com (Jacob Watters)
Date: Tue, 14 Dec 2021 10:48:00 -0500
Subject: [sdiy] Arp Soloist Service Manual/Schematics
In-Reply-To: <CAGHPcSB2RVznKeO4R4prsSy4FKtgj2XY8v7SYd4ENNfPQJSp1w@mail.gmail.com>
References: <CAGHPcSB2RVznKeO4R4prsSy4FKtgj2XY8v7SYd4ENNfPQJSp1w@mail.gmail.com>
Message-ID: <CAKcdib3ijMF3UB=Ef7BeAg999hMrFQ5UfDXT5X6dB1zex9uwTQ@mail.gmail.com>

Please include me if it is shared. I have one sitting in storage that I
need to fix up.

Thanks!

*Jacob Watters*
JacobWatters.com <http://jacobwatters.com/>


On Tue, Dec 14, 2021 at 10:44 AM Benjam?n Velasco via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Hi guys,
>
> I'm looking out there for a copy of the original Arp Soloist Service
> Manual or schematics (not the Prosoloist). Anyone here have a copy?
>
> regards
>
> --
> *Benjam?n Velasco Ossand?n*
> Cel. 96344468
> Casa. 27162400
> Oficina. 29254154
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From jpdesroc at oricom.ca  Wed Dec 15 02:34:11 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Tue, 14 Dec 2021 20:34:11 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
Message-ID: <000301d7f153$dd1aa710$974ff530$@oricom.ca>

Hi all,

I?m looking for a fast and accurate voltage follower circuit.
There are plenty of them on the web to build but they all
suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
The incoming voltage will be a varying 0 to +/-5v peak.
I thought about implementing a solution using a small PIC with ADC/DAC
but even if these micros are very cheap this solution would be overkill.. would it be ?

So far the available circuits have too much lag on their DC output.
(The envelope takes too much time to get back to zero after a fast incoming peak)

Any known & reliable circuits ?

JP

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From tom at electricdruid.net  Wed Dec 15 10:08:06 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 15 Dec 2021 09:08:06 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
Message-ID: <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>

Hi JP,

Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.

https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067>

It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.

The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.

HTH,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================



> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
> 
> Hi all,
> I?m looking for a fast and accurate voltage follower circuit.
> There are plenty of them on the web to build but they all
> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> The incoming voltage will be a varying 0 to +/-5v peak.
> I thought about implementing a solution using a small PIC with ADC/DAC
> but even if these micros are very cheap this solution would be overkill.. would it be ?
> So far the available circuits have too much lag on their DC output.
> (The envelope takes too much time to get back to zero after a fast incoming peak)
> Any known & reliable circuits ?
> JP
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
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From sdiy at haraldswerk.de  Wed Dec 15 10:44:13 2021
From: sdiy at haraldswerk.de (Harald)
Date: Wed, 15 Dec 2021 10:44:13 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
Message-ID: <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>

Well,

scroll a little back in this thread to page 7/8 and have a look at my 
comparison. Harry Bissell' envelope follower is in no way better than 
the classical approach. It is slower, has more ripple and is about 500mV 
off.
Harald

Am 15.12.21 um 10:08 schrieb Tom Wiltshire:
> Hi JP,
> 
> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> 
> https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067>
> 
> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> 
> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> 
> HTH,
> Tom
> 
> ==================
>         Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
>> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>>
>> Hi all,
>> I?m looking for a fast and accurate voltage follower circuit.
>> There are plenty of them on the web to build but they all
>> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
>> The incoming voltage will be a varying 0 to +/-5v peak.
>> I thought about implementing a solution using a small PIC with ADC/DAC
>> but even if these micros are very cheap this solution would be overkill.. would it be ?
>> So far the available circuits have too much lag on their DC output.
>> (The envelope takes too much time to get back to zero after a fast incoming peak)
>> Any known & reliable circuits ?
>> JP
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 


From tom at electricdruid.net  Wed Dec 15 11:13:27 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 15 Dec 2021 10:13:27 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>
Message-ID: <1700AFFF-281D-4786-9E34-DA16BC332043@electricdruid.net>

Here's a link to that page of the discussion:

https://modwiggler.com/forum/viewtopic.php?f=17&t=109067&start=175 <https://modwiggler.com/forum/viewtopic.php?f=17&t=109067&start=175>

TBH, Harald, I think the comparison is a bit unfair. You're comparing a 24dB active SK filter to a passive RC. Clearly one is going to have better filtering response to the other. 

Whether the FWR gives better performance than the peak-hold method is an interesting question, but that's not really dealt with. Also the test signal is very artificial. The slower decay on the Bissell envelope (not that slow - 150msecs?) actually matches typical guitar envelopes rather well, so perhaps that's why many people rate it highly, at least in the pedal world.

I do think your experiment makes a good point though - if you want a smoother output, you need better filtering. Many designs get by with a simple passive RC and leave it at that. With such a simple filter there *will* always be a trade-off between speed and ripple.


> On 15 Dec 2021, at 09:44, Harald <sdiy at haraldswerk.de> wrote:
> 
> Well,
> 
> scroll a little back in this thread to page 7/8 and have a look at my comparison. Harry Bissell' envelope follower is in no way better than the classical approach. It is slower, has more ripple and is about 500mV off.
> Harald
> 
> Am 15.12.21 um 10:08 schrieb Tom Wiltshire:
>> Hi JP,
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067> <https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067>>
>> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
>> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
>> HTH,
>> Tom
>> ==================
>>        Electric Druid
>> Synth & Stompbox DIY
>> ==================
>>> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>>> 
>>> Hi all,
>>> I?m looking for a fast and accurate voltage follower circuit.
>>> There are plenty of them on the web to build but they all
>>> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
>>> The incoming voltage will be a varying 0 to +/-5v peak.
>>> I thought about implementing a solution using a small PIC with ADC/DAC
>>> but even if these micros are very cheap this solution would be overkill.. would it be ?
>>> So far the available circuits have too much lag on their DC output.
>>> (The envelope takes too much time to get back to zero after a fast incoming peak)
>>> Any known & reliable circuits ?
>>> JP
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> <mailto:Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>>
>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy> <http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>>
>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> <mailto:marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
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From rburnett at richieburnett.co.uk  Wed Dec 15 12:21:23 2021
From: rburnett at richieburnett.co.uk (rburnett at richieburnett.co.uk)
Date: Wed, 15 Dec 2021 11:21:23 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <1700AFFF-281D-4786-9E34-DA16BC332043@electricdruid.net>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>
 <1700AFFF-281D-4786-9E34-DA16BC332043@electricdruid.net>
Message-ID: <a4f5b78720eba51e363eefbba267b3ea@richieburnett.co.uk>

> With such a simple filter
> there *will* always be a trade-off between speed and ripple.

Or to put it another way...  Increasing the order of the filter gives 
you a more favourable trade-off between speed of response and residual 
ripple.

-Richie,



From mbryant at futurehorizons.com  Wed Dec 15 12:37:43 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Wed, 15 Dec 2021 11:37:43 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <a4f5b78720eba51e363eefbba267b3ea@richieburnett.co.uk>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>
 <1700AFFF-281D-4786-9E34-DA16BC332043@electricdruid.net>
 <a4f5b78720eba51e363eefbba267b3ea@richieburnett.co.uk>
Message-ID: <a94298c195a84ed399ed8468af61e241@futurehorizons.com>

Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ?


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of rburnett at richieburnett.co.uk
Sent: 15 December 2021 11:21
To: Tom Wiltshire
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

> With such a simple filter
> there *will* always be a trade-off between speed and ripple.

Or to put it another way...  Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple.

-Richie,

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org




From tom at electricdruid.net  Wed Dec 15 12:59:29 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 15 Dec 2021 11:59:29 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <a94298c195a84ed399ed8468af61e241@futurehorizons.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <658beb5c-8433-c813-145c-e1056fd11c2a@haraldswerk.de>
 <1700AFFF-281D-4786-9E34-DA16BC332043@electricdruid.net>
 <a4f5b78720eba51e363eefbba267b3ea@richieburnett.co.uk>
 <a94298c195a84ed399ed8468af61e241@futurehorizons.com>
Message-ID: <FA08DECE-3E81-42A7-A3EA-E51968394778@electricdruid.net>

Some envelope generators do feature a "Decay" pot to change the time constant of the filter.

Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that.


> On 15 Dec 2021, at 11:37, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ?
> 
> 
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of rburnett at richieburnett.co.uk
> Sent: 15 December 2021 11:21
> To: Tom Wiltshire
> Cc: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
>> With such a simple filter
>> there *will* always be a trade-off between speed and ripple.
> 
> Or to put it another way...  Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple.
> 
> -Richie,
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 




From jpdesroc at oricom.ca  Wed Dec 15 16:05:39 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Wed, 15 Dec 2021 10:05:39 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
Message-ID: <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>

Hi Tom,

>Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>https://modwiggler.com/forum/viewtopic.php?t=109067

This is a very clever project and neat design.
But still too much ?lag? on the falling edges incoming signal.
So far.. a PIC would do best with least components..
Hmmmm...
As usual.. Thank you for you good suggestion anyway !
JP


De : Tom Wiltshire <tom at electricdruid.net> 
Envoy? : 15 d?cembre 2021 04:08
? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
Cc : Synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Hi JP,

Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.

https://modwiggler.com/forum/viewtopic.php?t=109067

It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.

The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.

HTH,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================




On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca> wrote:

Hi all,
I?m looking for a fast and accurate voltage follower circuit.
There are plenty of them on the web to build but they all
suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
The incoming voltage will be a varying 0 to +/-5v peak.
I thought about implementing a solution using a small PIC with ADC/DAC
but even if these micros are very cheap this solution would be overkill.. would it be ?
So far the available circuits have too much lag on their DC output.
(The envelope takes too much time to get back to zero after a fast incoming peak)
Any known & reliable circuits ?
JP
_______________________________________________
Synth-diy mailing list
mailto:Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use mailto:marketplace at synth-diy.org





From btremblay at me.com  Wed Dec 15 16:31:56 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Wed, 15 Dec 2021 10:31:56 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
Message-ID: <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>

I lost all interest in envelope followers when I tried out some designs and observed the lag. 
These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
Only The Residents got much mileage out of envelope followers over the years.

> On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
> 
> Hi Tom,
> 
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> This is a very clever project and neat design.
> But still too much ?lag? on the falling edges incoming signal.
> So far.. a PIC would do best with least components..
> Hmmmm...
> As usual.. Thank you for you good suggestion anyway !
> JP
> 
> 
> De : Tom Wiltshire <tom at electricdruid.net> 
> Envoy? : 15 d?cembre 2021 04:08
> ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
> Cc : Synth-diy at synth-diy.org
> Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> Hi JP,
> 
> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> 
> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> 
> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> 
> HTH,
> Tom
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
> 
> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca> wrote:
> 
> Hi all,
> I?m looking for a fast and accurate voltage follower circuit.
> There are plenty of them on the web to build but they all
> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> The incoming voltage will be a varying 0 to +/-5v peak.
> I thought about implementing a solution using a small PIC with ADC/DAC
> but even if these micros are very cheap this solution would be overkill.. would it be ?
> So far the available circuits have too much lag on their DC output.
> (The envelope takes too much time to get back to zero after a fast incoming peak)
> Any known & reliable circuits ?
> JP
> _______________________________________________
> Synth-diy mailing list
> mailto:Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use mailto:marketplace at synth-diy.org
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From cheater00social at gmail.com  Wed Dec 15 17:14:33 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Wed, 15 Dec 2021 17:14:33 +0100
Subject: [sdiy] Zener Diodes
Message-ID: <CAGn5V-_-X_FNXwKSm+ut3pK+2KvgYqu=XRXGvSNjNLW5rhrkDg@mail.gmail.com>

I am trying to understand something about Zener diodes. The way I was
taught is that they hold the voltage across them at 3.3V no matter
what (or some other voltage depending on the diode). So then what
happens if you take two of those in series, and parallel them with
another one? What will the voltage be across the two series diodes?
What will the voltage be towards the middle junction?

Thanks


From mskala at northcoastsynthesis.com  Wed Dec 15 18:01:52 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Wed, 15 Dec 2021 12:01:52 -0500 (EST)
Subject: [sdiy] Zener Diodes
In-Reply-To: <CAGn5V-_-X_FNXwKSm+ut3pK+2KvgYqu=XRXGvSNjNLW5rhrkDg@mail.gmail.com>
References: <CAGn5V-_-X_FNXwKSm+ut3pK+2KvgYqu=XRXGvSNjNLW5rhrkDg@mail.gmail.com>
Message-ID: <alpine.LNX.2.20.2112151152180.14950@kharasan.bonobo-conspiracy.ca>

On Wed, 15 Dec 2021, cheater cheater via Synth-diy wrote:
> taught is that they hold the voltage across them at 3.3V no matter
> what (or some other voltage depending on the diode). So then what
> happens if you take two of those in series, and parallel them with
> another one? What will the voltage be across the two series diodes?
> What will the voltage be towards the middle junction?

The Zener diode works by conducting an amount of current that is basically
exponentially increasing, with a curve that bends sharply up at the stated
Zener voltage.  So if you attach it to a constant-voltage source less than
the Zener voltage, you only get the voltage source's voltage, and very low
current.  The diode is not going to magically set the voltage to 3.3V when
the power supply only has 1V or 2V available.  On the other hand, with a
beefy constant-voltage supply at greater than the Zener voltage and low
impedance, you will actually see more than 3.3V across the diode, at very
high current, in the short interval before it explodes.

Applying that to your example, with two 3.3V diodes in series and a third
in parallel to the pair, you'd expect to see very close to 3.3V across the
entire arrangement, because any current that could try to increase the
overall voltage will be shunted away through the parallel diode until
either the power supply stops trying, or the parallel diode explodes.  On
the other branch you're applying 3.3V to a series combination of two of
these diodes.  You'd expect to see close to 1.15V across each, with very
low current; but that voltage may vary a bit because the diodes don't have
tightly controlled parameters at much less than their rated Zener voltage
and current, so they may not really be functioning identically to each
other even if they are identical type, and it's quite possible one might
end up dropping more than half and the other less.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From mskala at northcoastsynthesis.com  Wed Dec 15 18:59:48 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Wed, 15 Dec 2021 12:59:48 -0500 (EST)
Subject: [sdiy] Zener Diodes
In-Reply-To: <alpine.LNX.2.20.2112151152180.14950@kharasan.bonobo-conspiracy.ca>
References: <CAGn5V-_-X_FNXwKSm+ut3pK+2KvgYqu=XRXGvSNjNLW5rhrkDg@mail.gmail.com>
 <alpine.LNX.2.20.2112151152180.14950@kharasan.bonobo-conspiracy.ca>
Message-ID: <alpine.LNX.2.20.2112151259181.14950@kharasan.bonobo-conspiracy.ca>

On Wed, 15 Dec 2021, Matthew Skala via Synth-diy wrote:
> the other branch you're applying 3.3V to a series combination of two of
> these diodes.  You'd expect to see close to 1.15V across each, with very

Sorry, make that 1.65V.  The point is, half of 3.3V.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From cheater00social at gmail.com  Wed Dec 15 22:25:27 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Wed, 15 Dec 2021 22:25:27 +0100
Subject: [sdiy] Zener Diodes
In-Reply-To: <alpine.LNX.2.20.2112151259181.14950@kharasan.bonobo-conspiracy.ca>
References: <CAGn5V-_-X_FNXwKSm+ut3pK+2KvgYqu=XRXGvSNjNLW5rhrkDg@mail.gmail.com>
 <alpine.LNX.2.20.2112151152180.14950@kharasan.bonobo-conspiracy.ca>
 <alpine.LNX.2.20.2112151259181.14950@kharasan.bonobo-conspiracy.ca>
Message-ID: <CAGn5V-8u47XFL_O8-N-jahRJ2LaKrK0-Gxd5_iW0hUQjFOcvBA@mail.gmail.com>

Hey that makes perfect sense, thanks a lot! Appreciated.

On Wed, Dec 15, 2021 at 7:04 PM Matthew Skala via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> On Wed, 15 Dec 2021, Matthew Skala via Synth-diy wrote:
> > the other branch you're applying 3.3V to a series combination of two of
> > these diodes.  You'd expect to see close to 1.15V across each, with very
>
> Sorry, make that 1.65V.  The point is, half of 3.3V.
>
> --
> Matthew Skala
> North Coast Synthesis Ltd.
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From paulfrancisperry at gmail.com  Wed Dec 15 22:44:16 2021
From: paulfrancisperry at gmail.com (Paul Perry)
Date: Thu, 16 Dec 2021 08:44:16 +1100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
Message-ID: <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>

Unless it is precognitive, an envelope follower must have lag.
Of course, if you are not working live, you can play the track backwards
and process that.
It is illustrative to place a piece of card over a drawing of an
audio waveform, and gradually reveal more of it.
Then you can appreciate what you are asking the follower to do.
There are no perfect followers, but sometimes there are ones that are
useful for a particular application.

paul perry melbourne australia

On Thu, 16 Dec 2021 at 02:35, Benjamin Tremblay via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I lost all interest in envelope followers when I tried out some designs
> and observed the lag.
> These are mostly ?envelope smoothers? and most are barely any better than
> an old incandescent vactrol attenuator circuit used in FM broadcast.
> They mostly just drive non-musical effects under the category ?something
> weird happens when I play my guitar?.  Pre-filtering the audio probably
> helps but there?s no guidance on best all-round EQ.
> Only The Residents got much mileage out of envelope followers over the
> years.
>
> > On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca>
> wrote:
> >
> > Hi Tom,
> >
> >> Harry Bissell's envelope follower is well thought of for its
> combination of speed and accuracy.
> >> https://modwiggler.com/forum/viewtopic.php?t=109067
> >
> > This is a very clever project and neat design.
> > But still too much ?lag? on the falling edges incoming signal.
> > So far.. a PIC would do best with least components..
> > Hmmmm...
> > As usual.. Thank you for you good suggestion anyway !
> > JP
> >
> >
> > De : Tom Wiltshire <tom at electricdruid.net>
> > Envoy? : 15 d?cembre 2021 04:08
> > ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
> > Cc : Synth-diy at synth-diy.org
> > Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> >
> > Hi JP,
> >
> > Harry Bissell's envelope follower is well thought of for its combination
> of speed and accuracy.
> >
> > https://modwiggler.com/forum/viewtopic.php?t=109067
> >
> > It's a good circuit, but pretty complicated, especially for an effect
> pedal design. So like you, I thought "PIC!", and had a go at implementing
> it in firmware.
> >
> > The round-robin three peaks detectors are easy enough. Doing the output
> filtering is more demanding on a chip with no multiply, but I managed it by
> being choosy about the filter coefficients and keeping things binary
> friendly. The end result was pretty good and used a little PIC to the
> maximum extent.
> >
> > HTH,
> > Tom
> >
> > ==================
> >       Electric Druid
> > Synth & Stompbox DIY
> > ==================
> >
> >
> >
> >
> > On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:
> jpdesroc at oricom.ca> wrote:
> >
> > Hi all,
> > I?m looking for a fast and accurate voltage follower circuit.
> > There are plenty of them on the web to build but they all
> > suffer of inaccuracy and lag on the final DC output (final stage of low
> pass to smooth off the incoming peaks).
> > The incoming voltage will be a varying 0 to +/-5v peak.
> > I thought about implementing a solution using a small PIC with ADC/DAC
> > but even if these micros are very cheap this solution would be
> overkill.. would it be ?
> > So far the available circuits have too much lag on their DC output.
> > (The envelope takes too much time to get back to zero after a fast
> incoming peak)
> > Any known & reliable circuits ?
> > JP
> > _______________________________________________
> > Synth-diy mailing list
> > mailto:Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use mailto:marketplace at synth-diy.org
> >
> >
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From jpdesroc at oricom.ca  Wed Dec 15 22:56:59 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Wed, 15 Dec 2021 16:56:59 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
Message-ID: <002001d7f1fe$b01eba70$105c2f50$@oricom.ca>

Precognitive? Interesting.
This can be done easily with a PIC reading a moving input voltage
then output the computed results on its DAC for example a bit later
according to where the actual incoming waveform is heading (plus or minus). 

 

De : Paul Perry <paulfrancisperry at gmail.com> 
Envoy? : 15 d?cembre 2021 16:44
? : Benjamin Tremblay <btremblay at me.com>
Cc : Jean-Pierre Desrochers <jpdesroc at oricom.ca>; Synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

 

Unless it is precognitive, an envelope follower must have lag.

Of course, if you are not working live, you can play the track backwards and process that.

It is illustrative to place a piece of card over a drawing of an audio waveform, and gradually reveal more of it.

Then you can appreciate what you are asking the follower to do.

There are no perfect followers, but sometimes there are ones that are useful for a particular application.

 

paul perry melbourne australia

 

On Thu, 16 Dec 2021 at 02:35, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> > wrote:

I lost all interest in envelope followers when I tried out some designs and observed the lag. 
These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
Only The Residents got much mileage out of envelope followers over the years.

> On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi Tom,
> 
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> This is a very clever project and neat design.
> But still too much ?lag? on the falling edges incoming signal.
> So far.. a PIC would do best with least components..
> Hmmmm...
> As usual.. Thank you for you good suggestion anyway !
> JP
> 
> 
> De : Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net> > 
> Envoy? : 15 d?cembre 2021 04:08
> ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> >
> Cc : Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> Hi JP,
> 
> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> 
> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> 
> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> 
> HTH,
> Tom
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
> 
> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi all,
> I?m looking for a fast and accurate voltage follower circuit.
> There are plenty of them on the web to build but they all
> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> The incoming voltage will be a varying 0 to +/-5v peak.
> I thought about implementing a solution using a small PIC with ADC/DAC
> but even if these micros are very cheap this solution would be overkill.. would it be ?
> So far the available circuits have too much lag on their DC output.
> (The envelope takes too much time to get back to zero after a fast incoming peak)
> Any known & reliable circuits ?
> JP
> _______________________________________________
> Synth-diy mailing list
> mailto:Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use mailto:marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 


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From synthdiy at adambaby.com  Thu Dec 16 01:14:18 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Thu, 16 Dec 2021 10:14:18 +1000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
Message-ID: <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>



> On 16 Dec 2021, at 07:44, Paul Perry via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> There are no perfect followers, but sometimes there are ones that are useful for a particular application.


Exactly, which begs the question, what purpose does JP have for this no-lag follower? Because musically, most followers are ?good enough??

A





> 
> paul perry melbourne australia
> 
> On Thu, 16 Dec 2021 at 02:35, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
> I lost all interest in envelope followers when I tried out some designs and observed the lag. 
> These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
> They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
> Only The Residents got much mileage out of envelope followers over the years.
> 
> > On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca>> wrote:
> > 
> > Hi Tom,
> > 
> >> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> >> https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067>
> > 
> > This is a very clever project and neat design.
> > But still too much ?lag? on the falling edges incoming signal.
> > So far.. a PIC would do best with least components..
> > Hmmmm...
> > As usual.. Thank you for you good suggestion anyway !
> > JP
> > 
> > 
> > De : Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net>> 
> > Envoy? : 15 d?cembre 2021 04:08
> > ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca>>
> > Cc : Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> > Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> > 
> > Hi JP,
> > 
> > Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> > 
> > https://modwiggler.com/forum/viewtopic.php?t=109067 <https://modwiggler.com/forum/viewtopic.php?t=109067>
> > 
> > It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> > 
> > The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> > 
> > HTH,
> > Tom
> > 
> > ==================
> >       Electric Druid
> > Synth & Stompbox DIY
> > ==================
> > 
> > 
> > 
> > 
> > On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca>> wrote:
> > 
> > Hi all,
> > I?m looking for a fast and accurate voltage follower circuit.
> > There are plenty of them on the web to build but they all
> > suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> > The incoming voltage will be a varying 0 to +/-5v peak.
> > I thought about implementing a solution using a small PIC with ADC/DAC
> > but even if these micros are very cheap this solution would be overkill.. would it be ?
> > So far the available circuits have too much lag on their DC output.
> > (The envelope takes too much time to get back to zero after a fast incoming peak)
> > Any known & reliable circuits ?
> > JP
> > _______________________________________________
> > Synth-diy mailing list
> > mailto:Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> > http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
> > Selling or trading? Use mailto:marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> > 
> > 
> > 
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> > http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
> > Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
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> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> _______________________________________________
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> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From tom at electricdruid.net  Thu Dec 16 01:22:07 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Thu, 16 Dec 2021 00:22:07 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
Message-ID: <9C2E7BC4-6A81-404A-AA4C-657568212E06@electricdruid.net>

I think this ignores the considerable influence of both compression and the "autowah" or envelope-followed filter on popular music over the last three or four decades. Neither of which function without envelope followers. While (live) they might have necessary limitations due to physics and not being able to see the future, the fact remains that they are useful and musical, despite the imperfections.

I think it's instructive to study some of the "classic" effects circuits. I was *amazed* at how technically *bad* some of them are. But no-one cares. They're still classics, and now people are spending time and money developing digital emulations that capture every single failing of the original circuit, because it turns out that technical perfection just doesn't sound as good, or at least it doesn't sound like the thing that everyone wants it to sound like.

It's not all about minimising lag time. Realistic envelopes of actual instruments have significant decay. Envelope followers that mimic that can work well. Us synth people expect every parameter to be highly variable, but guitars and electric pianos don't have a "Decay" control so their players expectations are quite different.


> On 15 Dec 2021, at 15:31, Benjamin Tremblay <btremblay at me.com> wrote:
> 
> I lost all interest in envelope followers when I tried out some designs and observed the lag. 
> These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
> They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
> Only The Residents got much mileage out of envelope followers over the years.
> 
>> On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>> 
>> Hi Tom,
>> 
>>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>>> https://modwiggler.com/forum/viewtopic.php?t=109067
>> 
>> This is a very clever project and neat design.
>> But still too much ?lag? on the falling edges incoming signal.
>> So far.. a PIC would do best with least components..
>> Hmmmm...
>> As usual.. Thank you for you good suggestion anyway !
>> JP
>> 
>> 
>> De : Tom Wiltshire <tom at electricdruid.net> 
>> Envoy? : 15 d?cembre 2021 04:08
>> ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
>> Cc : Synth-diy at synth-diy.org
>> Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
>> 
>> Hi JP,
>> 
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> 
>> https://modwiggler.com/forum/viewtopic.php?t=109067
>> 
>> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
>> 
>> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
>> 
>> HTH,
>> Tom
>> 
>> ==================
>>      Electric Druid
>> Synth & Stompbox DIY
>> ==================
>> 
>> 
>> 
>> 
>> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca> wrote:
>> 
>> Hi all,
>> I?m looking for a fast and accurate voltage follower circuit.
>> There are plenty of them on the web to build but they all
>> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
>> The incoming voltage will be a varying 0 to +/-5v peak.
>> I thought about implementing a solution using a small PIC with ADC/DAC
>> but even if these micros are very cheap this solution would be overkill.. would it be ?
>> So far the available circuits have too much lag on their DC output.
>> (The envelope takes too much time to get back to zero after a fast incoming peak)
>> Any known & reliable circuits ?
>> JP
>> _______________________________________________
>> Synth-diy mailing list
>> mailto:Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use mailto:marketplace at synth-diy.org
>> 
>> 
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> 




From tom at electricdruid.net  Thu Dec 16 01:23:40 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Thu, 16 Dec 2021 00:23:40 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
Message-ID: <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>


> Begin forwarded message:
> 
> From: Mr&MrsAccount <hbissell at wowway.com>
> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> Date: 15 December 2021 at 15:19:38 WET
> To: Tom Wiltshire <tom at electricdruid.net>
> 
>  
>  
>  
> The worst case for the envelope follower is at the lowest frequencies, 80Hz for guitar.  That is where the ripple is the greatest. If you make the filtering
> slow enough to filter 80Hz there is a very long tail when the input signal goes away.  The normal guitar decay can be as long as seconds... but if you stop the strings
> if can be MUCH shorter, and the classical approach will still allow the envelope to decay slowly.
>  
> The reset clock should be set to about 100Hz  (not 8KHz).   
>  
> Its easy to filter the high frequencies and there is no benefit to the circuit for short tone bursts like in the comparison paper. The circuit is also not the best for triggering
> on an input signal where the lowest frequency is unknown or cannot be specified (like wideband music etc.)  It is intended for something like guitar or bass.
>  
> Harry Bissell
>  
> From: Tom <tom at electricdruid.net>
> To: Mike <mbryant at futurehorizons.com>
> Cc: rburnett at richieburnett.co.uk <rburnett at richieburnett.co.uk>; synth-diy <synth-diy at synth-diy.org>
> Date: Wednesday, 15 December 2021 7:05 AM EST
> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> Some envelope generators do feature a "Decay" pot to change the time constant of the filter. 
> 
> Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that. 
> 
> 
> > On 15 Dec 2021, at 11:37, Mike Bryant <mbryant at futurehorizons.com> wrote: 
> > 
> > Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ? 
> > 
> > 
> > -----Original Message----- 
> > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of rburnett at richieburnett.co.uk 
> > Sent: 15 December 2021 11:21 
> > To: Tom Wiltshire 
> > Cc: synth-diy at synth-diy.org 
> > Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? 
> > 
> >> With such a simple filter 
> >> there *will* always be a trade-off between speed and ripple. 
> > 
> > Or to put it another way... Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple. 
> > 
> > -Richie, 
> > 
> > _______________________________________________ 
> > Synth-diy mailing list 
> > Synth-diy at synth-diy.org 
> > http://synth-diy.org/mailman/listinfo/synth-diy 
> > Selling or trading? Use marketplace at synth-diy.org 
> > 
> 
> 
> _______________________________________________ 
> Synth-diy mailing list 
> Synth-diy at synth-diy.org 
> http://synth-diy.org/mailman/listinfo/synth-diy 
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From jpdesroc at oricom.ca  Thu Dec 16 01:36:56 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Wed, 15 Dec 2021 19:36:56 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
Message-ID: <003d01d7f215$0904e630$1b0eb290$@oricom.ca>

Here is my goal..

I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc. 

So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.

In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.



 

 

 

De : Synth-diy <synth-diy-bounces at synth-diy.org> De la part de Adam Inglis (synthDIY)
Envoy? : 15 d?cembre 2021 19:14
? : Synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

 

 





On 16 Dec 2021, at 07:44, Paul Perry via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> > wrote:

 

There are no perfect followers, but sometimes there are ones that are useful for a particular application.

 

 

Exactly, which begs the question, what purpose does JP have for this no-lag follower? Because musically, most followers are ?good enough??

 

A

 

 

 

 





 

paul perry melbourne australia

 

On Thu, 16 Dec 2021 at 02:35, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> > wrote:

I lost all interest in envelope followers when I tried out some designs and observed the lag. 
These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
Only The Residents got much mileage out of envelope followers over the years.

> On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi Tom,
> 
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> This is a very clever project and neat design.
> But still too much ?lag? on the falling edges incoming signal.
> So far.. a PIC would do best with least components..
> Hmmmm...
> As usual.. Thank you for you good suggestion anyway !
> JP
> 
> 
> De : Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net> > 
> Envoy? : 15 d?cembre 2021 04:08
> ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> >
> Cc : Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> Hi JP,
> 
> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> 
> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> 
> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> 
> HTH,
> Tom
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
> 
> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi all,
> I?m looking for a fast and accurate voltage follower circuit.
> There are plenty of them on the web to build but they all
> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> The incoming voltage will be a varying 0 to +/-5v peak.
> I thought about implementing a solution using a small PIC with ADC/DAC
> but even if these micros are very cheap this solution would be overkill.. would it be ?
> So far the available circuits have too much lag on their DC output.
> (The envelope takes too much time to get back to zero after a fast incoming peak)
> Any known & reliable circuits ?
> JP
> _______________________________________________
> Synth-diy mailing list
> mailto:Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use mailto:marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 


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From bjostarmark at yahoo.se  Thu Dec 16 06:31:47 2021
From: bjostarmark at yahoo.se (=?UTF-8?Q?Bj=C3=B6rn_Starmar?=)
Date: Thu, 16 Dec 2021 05:31:47 +0000 (UTC)
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
Message-ID: <2004300101.1446425.1639632707563@mail.yahoo.com>

 Hi,
I think you need a clamping circuit. Check out this link:
https://www.tutorialspoint.com/linear_integrated_circuits_applications/linear_integrated_circuits_applications_clampers.htm
BRBj?rn
    Den torsdag 16 december 2021 04:09:09 CET, Jean-Pierre Desrochers <jpdesroc at oricom.ca> skrev:  
 
 Hi Tom,

>Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>https://modwiggler.com/forum/viewtopic.php?t=109067

This is a very clever project and neat design.
But still too much ?lag? on the falling edges incoming signal.
So far.. a PIC would do best with least components..
Hmmmm...
As usual.. Thank you for you good suggestion anyway !
JP


De : Tom Wiltshire <tom at electricdruid.net> 
Envoy? : 15 d?cembre 2021 04:08
? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
Cc : Synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Hi JP,

Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.

https://modwiggler.com/forum/viewtopic.php?t=109067

It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.

The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.

HTH,
Tom

==================
? ? ? Electric Druid
Synth & Stompbox DIY
==================




On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca> wrote:

Hi all,
I?m looking for a fast and accurate voltage follower circuit.
There are plenty of them on the web to build but they all
suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
The incoming voltage will be a varying 0 to +/-5v peak.
I thought about implementing a solution using a small PIC with ADC/DAC
but even if these micros are very cheap this solution would be overkill.. would it be ?
So far the available circuits have too much lag on their DC output.
(The envelope takes too much time to get back to zero after a fast incoming peak)
Any known & reliable circuits ?
JP
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From markverbos at gmail.com  Thu Dec 16 12:29:03 2021
From: markverbos at gmail.com (mark verbos)
Date: Thu, 16 Dec 2021 12:29:03 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
Message-ID: <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>

The Roland SPV-355 Pitch to Voltage Synthesizer sends the signal through a simple ?dome filter? or 90 degree phase shifter before the follower. This allows the 4 phases to be diode OR?ed together and fill in the space between the umps in low frequencies. I have tried it in my pitch to voltage experiments and it didn?t help too much, but it is an interesting idea to get some frequency-decay independence.

Mark


 

> On Dec 16, 2021, at 1:23 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
> 
> 
>> Begin forwarded message:
>> 
>> From: Mr&MrsAccount <hbissell at wowway.com <mailto:hbissell at wowway.com>>
>> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
>> Date: 15 December 2021 at 15:19:38 WET
>> To: Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net>>
>> 
>>  
>>  
>>  
>> The worst case for the envelope follower is at the lowest frequencies, 80Hz for guitar.  That is where the ripple is the greatest. If you make the filtering
>> slow enough to filter 80Hz there is a very long tail when the input signal goes away.  The normal guitar decay can be as long as seconds... but if you stop the strings
>> if can be MUCH shorter, and the classical approach will still allow the envelope to decay slowly.
>>  
>> The reset clock should be set to about 100Hz  (not 8KHz).   
>>  
>> Its easy to filter the high frequencies and there is no benefit to the circuit for short tone bursts like in the comparison paper. The circuit is also not the best for triggering
>> on an input signal where the lowest frequency is unknown or cannot be specified (like wideband music etc.)  It is intended for something like guitar or bass.
>>  
>> Harry Bissell
>>  
>> From: Tom <tom at electricdruid.net <mailto:tom at electricdruid.net>>
>> To: Mike <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>>
>> Cc: rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk> <rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk>>; synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
>> Date: Wednesday, 15 December 2021 7:05 AM EST
>> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
>> 
>> Some envelope generators do feature a "Decay" pot to change the time constant of the filter. 
>> 
>> Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that. 
>> 
>> 
>> > On 15 Dec 2021, at 11:37, Mike Bryant <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>> wrote: 
>> > 
>> > Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ? 
>> > 
>> > 
>> > -----Original Message----- 
>> > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org <mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk> 
>> > Sent: 15 December 2021 11:21 
>> > To: Tom Wiltshire 
>> > Cc: synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> 
>> > Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? 
>> > 
>> >> With such a simple filter 
>> >> there *will* always be a trade-off between speed and ripple. 
>> > 
>> > Or to put it another way... Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple. 
>> > 
>> > -Richie, 
>> > 
>> > _______________________________________________ 
>> > Synth-diy mailing list 
>> > Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
>> > http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy> 
>> > Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 
>> > 
>> 
>> 
>> _______________________________________________ 
>> Synth-diy mailing list 
>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy> 
>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> _______________________________________________
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From mars at pingdynasty.com  Thu Dec 16 17:26:16 2021
From: mars at pingdynasty.com (Martin Klang)
Date: Thu, 16 Dec 2021 17:26:16 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
Message-ID: <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>

I think an envelope follower with no lag is called a rectifier.

Jokes aside, there are a number of options available but ultimately it 
comes down to filtering.

For digital envelope followers, I like to use a simple exponential 
average (aka leaky integrator, a first-order IIR filter) on the fully 
rectified signal and tune the time constant to the expected input 
signal. Generally you want it to be fast, but not so fast as to track 
the waveform oscillations, even at say 20 Hz. This makes a 
computationally very efficient follower with predictable results.


best,


Martin


On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
>
> Here is my goal..
>
> I need a circuit that will take an AC signal and will shift level it from
> a DC offset extracted from its min & max Peaks..
> Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
> The output would be the same waveform but shifted up to +5vdc.
>
> So 0 to +10vdc.
> That final waveform would be much usable for a 0-5vdc control voltage 
> input
> than the original AC waveform.
> Now the challenge is to do the same with a level changing AC signal.
>
> In the case of a _steady waveform_ this ?level shifter? could be an 
> opamp that would add half of the peak to peak voltage as an offset DC 
> voltage,
> But here I?m looking for something that will be more versatile
> to handle varying level waveform.
>
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From jpdesroc at oricom.ca  Thu Dec 16 17:30:15 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Thu, 16 Dec 2021 11:30:15 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <E1AD7E3D-26D5-4B26-8C6D-65C48BE2D193@gmail.com>
References: <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <E1AD7E3D-26D5-4B26-8C6D-65C48BE2D193@gmail.com>
Message-ID: <000501d7f29a$34de7ac0$9e9b7040$@oricom.ca>

Hi Jason,

That?s what is the closest to what I need.. YES !!
I?ll do some experiments with varying level waveforms..

Many thanks !

 

De : Jason Nanna <jasonnanna at gmail.com> 
Envoy? : 15 d?cembre 2021 21:36
? : Jean-Pierre Desrochers <jpdesroc at oricom.ca>
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

 

Have you considered a clamper?

 

 https://en.m.wikipedia.org/wiki/Clamper_(electronics)





On Dec 15, 2021, at 6:39 PM, Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:

?

Here is my goal..

I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc. 

So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.

In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.




 

 

 

De : Synth-diy <synth-diy-bounces at synth-diy.org <mailto:synth-diy-bounces at synth-diy.org> > De la part de Adam Inglis (synthDIY)
Envoy? : 15 d?cembre 2021 19:14
? : Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

 

 






On 16 Dec 2021, at 07:44, Paul Perry via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> > wrote:

 

There are no perfect followers, but sometimes there are ones that are useful for a particular application.

 

 

Exactly, which begs the question, what purpose does JP have for this no-lag follower? Because musically, most followers are ?good enough??

 

A

 

 

 

 






 

paul perry melbourne australia

 

On Thu, 16 Dec 2021 at 02:35, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> > wrote:

I lost all interest in envelope followers when I tried out some designs and observed the lag. 
These are mostly ?envelope smoothers? and most are barely any better than an old incandescent vactrol attenuator circuit used in FM broadcast.
They mostly just drive non-musical effects under the category ?something weird happens when I play my guitar?.  Pre-filtering the audio probably helps but there?s no guidance on best all-round EQ.
Only The Residents got much mileage out of envelope followers over the years.

> On Dec 15, 2021, at 10:05 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi Tom,
> 
>> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
>> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> This is a very clever project and neat design.
> But still too much ?lag? on the falling edges incoming signal.
> So far.. a PIC would do best with least components..
> Hmmmm...
> As usual.. Thank you for you good suggestion anyway !
> JP
> 
> 
> De : Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net> > 
> Envoy? : 15 d?cembre 2021 04:08
> ? : Jean-Pierre Desrochers <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> >
> Cc : Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> Hi JP,
> 
> Harry Bissell's envelope follower is well thought of for its combination of speed and accuracy.
> 
> https://modwiggler.com/forum/viewtopic.php?t=109067
> 
> It's a good circuit, but pretty complicated, especially for an effect pedal design. So like you, I thought "PIC!", and had a go at implementing it in firmware.
> 
> The round-robin three peaks detectors are easy enough. Doing the output filtering is more demanding on a chip with no multiply, but I managed it by being choosy about the filter coefficients and keeping things binary friendly. The end result was pretty good and used a little PIC to the maximum extent.
> 
> HTH,
> Tom
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
> 
> On 15 Dec 2021, at 01:34, Jean-Pierre Desrochers <mailto:jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca> > wrote:
> 
> Hi all,
> I?m looking for a fast and accurate voltage follower circuit.
> There are plenty of them on the web to build but they all
> suffer of inaccuracy and lag on the final DC output (final stage of low pass to smooth off the incoming peaks).
> The incoming voltage will be a varying 0 to +/-5v peak.
> I thought about implementing a solution using a small PIC with ADC/DAC
> but even if these micros are very cheap this solution would be overkill.. would it be ?
> So far the available circuits have too much lag on their DC output.
> (The envelope takes too much time to get back to zero after a fast incoming peak)
> Any known & reliable circuits ?
> JP
> _______________________________________________
> Synth-diy mailing list
> mailto:Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use mailto:marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 


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From mars at pingdynasty.com  Thu Dec 16 17:34:42 2021
From: mars at pingdynasty.com (Martin Klang)
Date: Thu, 16 Dec 2021 17:34:42 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
 <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
Message-ID: <f0578eb3-63fe-4eb6-f990-44cf56e0e527@pingdynasty.com>


Is that analogous to using a Hilbert transform (to get the analytic 
signal) to calculate the envelope? It works perfectly on continuous sine 
waves, and I believe it is used to extract amplitude modulation from a 
carrier wave. But not so good for audio.


Martin


On 16/12/2021 12:29, mark verbos via Synth-diy wrote:
> The Roland SPV-355 Pitch to Voltage Synthesizer sends the signal 
> through a simple ?dome filter? or 90 degree phase shifter before the 
> follower. This allows the 4 phases to be diode OR?ed together and fill 
> in the space between the umps in low frequencies. I have tried it in 
> my pitch to voltage experiments and it didn?t help too much, but it is 
> an interesting idea to get some frequency-decay independence.
>
> Mark
>
>
>
>
>> On Dec 16, 2021, at 1:23 AM, Tom Wiltshire <tom at electricdruid.net 
>> <mailto:tom at electricdruid.net>> wrote:
>>
>>
>>> Begin forwarded message:
>>>
>>> *From: *Mr&MrsAccount <hbissell at wowway.com <mailto:hbissell at wowway.com>>
>>> *Subject: **Re: [sdiy] Best & fastest envelope follower schematic.. 
>>> anybody ?*
>>> *Date: *15 December 2021 at 15:19:38 WET
>>> *To: *Tom Wiltshire <tom at electricdruid.net 
>>> <mailto:tom at electricdruid.net>>
>>>
>>> The worst case for the envelope follower is at the lowest 
>>> frequencies, 80Hz for guitar.? That is where the ripple is the 
>>> greatest. If you make the filtering
>>> slow enough to filter 80Hz there is a very long tail when the input 
>>> signal goes away.? The normal guitar decay can be as long as 
>>> seconds... but if you stop the strings
>>> if can be MUCH shorter, and the classical approach will still allow 
>>> the envelope to decay slowly.
>>> The reset clock should be set to about 100Hz? (not 8KHz).
>>> Its easy to filter the high frequencies and there is no benefit to 
>>> the circuit for short tone bursts like in the comparison paper. The 
>>> circuit is also not the best for triggering
>>> on an input signal where the lowest frequency is unknown or cannot 
>>> be specified (like wideband music etc.)? It is intended for 
>>> something like guitar or bass.
>>> Harry Bissell
>>>
>>>     ------------------------------------------------------------------------
>>>     *From: *Tom <tom at electricdruid.net <mailto:tom at electricdruid.net>>
>>>     *To: *Mike <mbryant at futurehorizons.com
>>>     <mailto:mbryant at futurehorizons.com>>
>>>     *Cc: *rburnett at richieburnett.co.uk
>>>     <mailto:rburnett at richieburnett.co.uk>
>>>     <rburnett at richieburnett.co.uk
>>>     <mailto:rburnett at richieburnett.co.uk>>; synth-diy
>>>     <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
>>>     *Date: *Wednesday, 15 December 2021 7:05 AM EST
>>>     *Subject: *Re: [sdiy] Best & fastest envelope follower
>>>     schematic.. anybody ?
>>>
>>>     Some envelope generators do feature a "Decay" pot to change the
>>>     time constant of the filter.
>>>
>>>     Depends on the use case whether that is worth it. In a bit of
>>>     studio gear where it might get used for various sources, yes, it
>>>     probably makes sense. For a stompbox where the input is going to
>>>     be a guitar, you have more knowledge about the signal and you
>>>     can optimise the design for that.
>>>
>>>
>>>     > On 15 Dec 2021, at 11:37, Mike Bryant
>>>     <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>>
>>>     wrote:
>>>     >
>>>     > Why not have both fast and slow filters, and a blend pot
>>>     between the two so you can find the best trade-off for the
>>>     incoming signal ?
>>>     >
>>>     >
>>>     > -----Original Message-----
>>>     > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org
>>>     <mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of
>>>     rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk>
>>>     > Sent: 15 December 2021 11:21
>>>     > To: Tom Wiltshire
>>>     > Cc: synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>
>>>     > Subject: Re: [sdiy] Best & fastest envelope follower
>>>     schematic.. anybody ?
>>>     >
>>>     >> With such a simple filter
>>>     >> there *will* always be a trade-off between speed and ripple.
>>>     >
>>>     > Or to put it another way... Increasing the order of the filter
>>>     gives you a more favourable trade-off between speed of response
>>>     and residual ripple.
>>>     >
>>>     > -Richie,
>>>     >
>>>     > _______________________________________________
>>>     > Synth-diy mailing list
>>>     > Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>>>     > http://synth-diy.org/mailman/listinfo/synth-diy
>>>     <http://synth-diy.org/mailman/listinfo/synth-diy>
>>>     > Selling or trading? Use marketplace at synth-diy.org
>>>     <mailto:marketplace at synth-diy.org>
>>>     >
>>>
>>>
>>>     _______________________________________________
>>>     Synth-diy mailing list
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>>
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>
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From markverbos at gmail.com  Thu Dec 16 18:15:52 2021
From: markverbos at gmail.com (mark verbos)
Date: Thu, 16 Dec 2021 18:15:52 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <f0578eb3-63fe-4eb6-f990-44cf56e0e527@pingdynasty.com>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
 <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
 <f0578eb3-63fe-4eb6-f990-44cf56e0e527@pingdynasty.com>
Message-ID: <8B8FD13A-C39C-435A-8991-F0E982C2B040@gmail.com>

In a full wave rectifier, you would have the 0 degrees and the 180 degrees (flipped over) signals run through diodes to only use the positive part. In this case, you have 4 phases. Like in a frequency shifter, you need to do phase shifters at each octave in your range, so it gets parts heavy fast. In the end, it?s probably not worth it. 

Mark




> On Dec 16, 2021, at 5:34 PM, Martin Klang <mars at pingdynasty.com> wrote:
> 
> 
> 
> Is that analogous to using a Hilbert transform (to get the analytic signal) to calculate the envelope? It works perfectly on continuous sine waves, and I believe it is used to extract amplitude modulation from a carrier wave. But not so good for audio.
> 
> 
> 
> Martin
> 
> 
> 
> On 16/12/2021 12:29, mark verbos via Synth-diy wrote:
>> The Roland SPV-355 Pitch to Voltage Synthesizer sends the signal through a simple ?dome filter? or 90 degree phase shifter before the follower. This allows the 4 phases to be diode OR?ed together and fill in the space between the umps in low frequencies. I have tried it in my pitch to voltage experiments and it didn?t help too much, but it is an interesting idea to get some frequency-decay independence.
>> 
>> Mark
>> 
>> 
>>  
>> 
>>> On Dec 16, 2021, at 1:23 AM, Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net>> wrote:
>>> 
>>> 
>>>> Begin forwarded message:
>>>> 
>>>> From: Mr&MrsAccount <hbissell at wowway.com <mailto:hbissell at wowway.com>>
>>>> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
>>>> Date: 15 December 2021 at 15:19:38 WET
>>>> To: Tom Wiltshire <tom at electricdruid.net <mailto:tom at electricdruid.net>>
>>>> 
>>>>  
>>>>  
>>>>  
>>>> The worst case for the envelope follower is at the lowest frequencies, 80Hz for guitar.  That is where the ripple is the greatest. If you make the filtering
>>>> slow enough to filter 80Hz there is a very long tail when the input signal goes away.  The normal guitar decay can be as long as seconds... but if you stop the strings
>>>> if can be MUCH shorter, and the classical approach will still allow the envelope to decay slowly.
>>>>  
>>>> The reset clock should be set to about 100Hz  (not 8KHz).   
>>>>  
>>>> Its easy to filter the high frequencies and there is no benefit to the circuit for short tone bursts like in the comparison paper. The circuit is also not the best for triggering
>>>> on an input signal where the lowest frequency is unknown or cannot be specified (like wideband music etc.)  It is intended for something like guitar or bass.
>>>>  
>>>> Harry Bissell
>>>>  
>>>> From: Tom <tom at electricdruid.net <mailto:tom at electricdruid.net>>
>>>> To: Mike <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>>
>>>> Cc: rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk> <rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk>>; synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
>>>> Date: Wednesday, 15 December 2021 7:05 AM EST
>>>> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
>>>> 
>>>> Some envelope generators do feature a "Decay" pot to change the time constant of the filter. 
>>>> 
>>>> Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that. 
>>>> 
>>>> 
>>>> > On 15 Dec 2021, at 11:37, Mike Bryant <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>> wrote: 
>>>> > 
>>>> > Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ? 
>>>> > 
>>>> > 
>>>> > -----Original Message----- 
>>>> > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org <mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of rburnett at richieburnett.co.uk <mailto:rburnett at richieburnett.co.uk> 
>>>> > Sent: 15 December 2021 11:21 
>>>> > To: Tom Wiltshire 
>>>> > Cc: synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> 
>>>> > Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? 
>>>> > 
>>>> >> With such a simple filter 
>>>> >> there *will* always be a trade-off between speed and ripple. 
>>>> > 
>>>> > Or to put it another way... Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple. 
>>>> > 
>>>> > -Richie, 
>>>> > 
>>>> > _______________________________________________ 
>>>> > Synth-diy mailing list 
>>>> > Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
>>>> > http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy> 
>>>> > Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 
>>>> > 
>>>> 
>>>> 
>>>> _______________________________________________ 
>>>> Synth-diy mailing list 
>>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
>>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy> 
>>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>>> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
>>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>> 
>> 
>> 
>> _______________________________________________
>> Synth-diy mailing list
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>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> _______________________________________________
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From rburnett at richieburnett.co.uk  Thu Dec 16 18:35:13 2021
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Thu, 16 Dec 2021 17:35:13 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <8B8FD13A-C39C-435A-8991-F0E982C2B040@gmail.com>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
 <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
 <f0578eb3-63fe-4eb6-f990-44cf56e0e527@pingdynasty.com>
 <8B8FD13A-C39C-435A-8991-F0E982C2B040@gmail.com>
Message-ID: <emiq6jts2bjgsohkqyltyo87.1639676113710@email.android.com>

>... Like in a frequency shifter, you need to do phase shifters at each octave in your range, so it gets parts heavy fast. In the end, it?s probably not worth it. 

Surely it's only the bottom few octaves that cause a problem by causing excessive ripple with their outrageously long periods. (Envelope ripple with short periods can be removed easily with a gentle filter that still has a moderately fast response time.) So does the dome filter or Hilbert transform really have to conform over the entire audio range?

I must admit I have found the Hilbert transform useful for finding the envelope of an amplitude modulated sinusoidal carrier, but it doesn't necessarily give you the "envelope" you expect when fed with signals that are spectrally more complex.

-Richie,



From tom at electricdruid.net  Thu Dec 16 19:28:18 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Thu, 16 Dec 2021 18:28:18 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <emiq6jts2bjgsohkqyltyo87.1639676113710@email.android.com>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
 <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
 <f0578eb3-63fe-4eb6-f990-44cf56e0e527@pingdynasty.com>
 <8B8FD13A-C39C-435A-8991-F0E982C2B040@gmail.com>
 <emiq6jts2bjgsohkqyltyo87.1639676113710@email.android.com>
Message-ID: <EF31DC73-5A5F-48BF-A276-44C21259A0A1@electricdruid.net>

Hiding under here somewhere is a deeper philosophical point about whether the abstraction we call the "envelope" of a signal actually exists or not.

We mostly assume it does because we explicitly create the envelope separately in our synths and then apply to a constant audio signal. But actually, synths are just about the only thing that works like that! (Theremin is the only other example I can come up with). For most instruments, the creation of the audio also creates the level of the audio, and there is no distinction between the signal and the envelope at all. The hammer on a piano creates both the audio signal and the envelope of that audio. Blowing the reed of a clarinet does the same thing. Plucking a string does the same thing. Hitting a drum, bell, gong, or vibraphone does the same thing.

Certainly, the process of multiplying a constant bipolar audio signal by a unipolar envelope and producing a shaped bipolar audio "ping" as a result is a one-way process. Information is lost, since we no longer know what both waveforms looked like, only what their product is. In its most basic form, if I give you the number "24", you don't know what two numbers I multiplied together to get that result. Might have been 3 and 8. Might have been 2 and 12...etc. That's where we are with the envelopes.

So, quite apart from the "needing to see the future" element of this being impossible, there's also the "it doesn't exist" and "not enough information even if it did" elements of this being impossible!!

Despite all this, even quite simple circuits do a usefully successful job. Have a look at the Mutron:

	http://www.generalguitargadgets.com/pdf/ggg_neutron_sc.pdf

This uses IC3b as a half-wave precision rectifier, with R14, R15, and C9 to set attack time and decay time and provide basic RC filtering. It's hard to do it in many less parts, though other designs are similarly minimal.



> On 16 Dec 2021, at 17:35, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> 
>> ... Like in a frequency shifter, you need to do phase shifters at each octave in your range, so it gets parts heavy fast. In the end, it?s probably not worth it. 
> 
> Surely it's only the bottom few octaves that cause a problem by causing excessive ripple with their outrageously long periods. (Envelope ripple with short periods can be removed easily with a gentle filter that still has a moderately fast response time.) So does the dome filter or Hilbert transform really have to conform over the entire audio range?
> 
> I must admit I have found the Hilbert transform useful for finding the envelope of an amplitude modulated sinusoidal carrier, but it doesn't necessarily give you the "envelope" you expect when fed with signals that are spectrally more complex.
> 
> -Richie,
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From hbissell at wowway.com  Thu Dec 16 19:52:50 2021
From: hbissell at wowway.com (Mr&MrsAccount)
Date: Thu, 16 Dec 2021 13:52:50 -0500 (EST)
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
References: <820296367.73662122.1639581578107.JavaMail.zimbra@wowway.com>
 <6146B124-4361-482D-8DD5-7FD14C910119@electricdruid.net>
 <91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com>
Message-ID: <245796407.75215460.1639680770515.JavaMail.zimbra@wowway.com>


Thanks Mark. I was thing about the ?SPV-355 Pitch to Voltage Synthesizer as well. The trick here is that the input waveform has been made roughly sinusoidal before we reach the "dome filter".? This dome filter is essentially a series of phase shifters which the highest peak sent to the output.? In some ways it is similar to my approach.? It does not work unless the input is a sine wave. Send a wideband signal into it nd you get junk. 
? 
  

-----Original Message-----

From: mark <synth-diy at synth-diy.org>
To: Tom <tom at electricdruid.net>
Cc: synth-diy at synth-diy.org <Synth-diy at synth-diy.org>
Date: Thursday, 16 December 2021 6:35 AM EST
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

The Roland SPV-355 Pitch to Voltage Synthesizer sends the signal through a simple ?dome filter? or 90 degree phase shifter before the follower. This allows the 4 phases to be diode OR?ed together and fill in the space between the umps in low frequencies. I have tried it in my pitch to voltage experiments and it didn?t help too much, but it is an interesting idea to get some frequency-decay independence. ? Mark ? ? ? 
  On Dec 16, 2021, at 1:23 AM, Tom Wiltshire <tom at electricdruid.net> wrote:   ?   Begin forwarded message: From: Mr&MrsAccount <hbissell at wowway.com> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? Date: 15 December 2021 at 15:19:38 WET To: Tom Wiltshire <tom at electricdruid.net>     ? ?  ? The worst case for the envelope follower is at the lowest frequencies, 80Hz for guitar.? That is where the ripple is the greatest. If you make the filtering slow enough to filter 80Hz there is a very long tail when the input signal goes away.? The normal guitar decay can be as long as seconds... but if you stop the strings if can be MUCH shorter, and the classical approach will still allow the envelope to decay slowly. ? The reset clock should be set to about 100Hz? (not 8KHz).? ? ? Its easy to filter the high frequencies and there is no benefit to the circuit for short tone bursts like in the comparison paper. The circuit is also not the best for triggering on an input signal where the lowest frequency is unknown or cannot be specified (like wideband music etc.)? It is intended for something like guitar or bass. ? Harry Bissell ?    ? 
From: Tom <tom at electricdruid.net>To: Mike <mbryant at futurehorizons.com>Cc: rburnett at richieburnett.co.uk <rburnett at richieburnett.co.uk>; synth-diy <synth-diy at synth-diy.org>Date: Wednesday, 15 December 2021 7:05 AM ESTSubject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?Some envelope generators do feature a "Decay" pot to change the time constant of the filter. Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that. > On 15 Dec 2021, at 11:37, Mike Bryant <mbryant at futurehorizons.com> wrote: > > Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ? > > > -----Original Message----- > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of rburnett at richieburnett.co.uk > Sent: 15 December 2021 11:21 > To: Tom Wiltshire > Cc: synth-diy at synth-diy.org > Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? > >> With such a simple filter >> there *will* always be a trade-off between speed and ripple. > > Or to put it another way... Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple. > > -Richie, > > _______________________________________________ > Synth-diy mailing list > Synth-diy at synth-diy.org > http://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace at synth-diy.org > _______________________________________________ Synth-diy mailing list Synth-diy at synth-diy.org http://synth-diy.org/mailman/listinfo/synth-diy Selling or trading? Use marketplace at synth-diy.org          _______________________________________________Synth-diy mailing listSynth-diy at synth-diy.orghttp://synth-diy.org/mailman/listinfo/synth-diySelling or trading? Use marketplace at synth-diy.org     
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From spirosmakris92 at gmail.com  Fri Dec 17 08:03:29 2021
From: spirosmakris92 at gmail.com (Spiros Makris)
Date: Fri, 17 Dec 2021 09:03:29 +0200
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
Message-ID: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>

Hello List,
I want to experiment with polymetric structures and create "non standard"
subdivisions within the standard ones supported by MIDI. I have only worked
with the 24ppq, using the timing messages to directly drive the sequencers.
I would like a way to multiply the clock frequency in order to increase
resolution, let's say by 10 or maybe 100 times, if that's feasible (I think
it is?).
I think this is achieved by a PLL. I understand the basic concepts of it
and have used in the analog domain, but never did it in a digital only
format. Furthermore, I suppose having an array of hardware peripherals,
such as timers and interrupts, and a fairly fast processor (teensy 3.2)
could open up other approaches that don't follow the standard PLL
configuration.
This has been on my mind for some time, but I don't really know where to
start. Any advice, or resources are greatly appreciated

Regards,
Spiros
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From brianw at audiobanshee.com  Fri Dec 17 08:25:42 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 16 Dec 2021 23:25:42 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
Message-ID: <52ACAA4B-9A83-4DF4-AF94-5E22408FC271@audiobanshee.com>

You might get the best results from a hardware DPLL compared to software. 10x is certainly feasible. Perhaps you can find an MPU with a Timer peripheral that takes an external input and has frequency multiplication from that input as well. If the Teensy (MK20DX256VLH7) doesn't have this, then maybe look for a DSP like the TMS320. In other words, pick a processor with the DPLL capabilities that you need (plus a UART for MIDI) and handle everything else in software.

Brian


On Dec 16, 2021, at 23:03, Spiros Makris wrote:
> I want to experiment with polymetric structures and create "non standard" subdivisions within the standard ones supported by MIDI. I have only worked with the 24ppq, using the timing messages to directly drive the sequencers. I would like a way to multiply the clock frequency in order to increase resolution, let's say by 10 or maybe 100 times, if that's feasible (I think it is?).
> I think this is achieved by a PLL. I understand the basic concepts of it and have used in the analog domain, but never did it in a digital only format. Furthermore, I suppose having an array of hardware peripherals, such as timers and interrupts, and a fairly fast processor (teensy 3.2) could open up other approaches that don't follow the standard PLL configuration.
> This has been on my mind for some time, but I don't really know where to start. Any advice, or resources are greatly appreciated
> 
> Regards,
> Spiros



From mbryant at futurehorizons.com  Fri Dec 17 11:05:07 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 17 Dec 2021 10:05:07 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
Message-ID: <3cf9720d43b94169b41839062fba8bc8@futurehorizons.com>

I would choose a cheap $1 ARM M0+ processor with a fast clock ? STM32G03 or RP2040 for example.  You can then run a tight loop which samples the input and modifies the increment on a software accumulator, outputting the top bit of the accumulator as the new timer.   Jitter will be clockfreq divided by looplength which should give better than 100nS with careful coding.

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Spiros Makris via Synth-diy
Sent: 17 December 2021 07:03
To: synth-diy mailing list
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?

Hello List,
I want to experiment with polymetric structures and create "non standard" subdivisions within the standard ones supported by MIDI. I have only worked with the 24ppq, using the timing messages to directly drive the sequencers. I would like a way to multiply the clock frequency in order to increase resolution, let's say by 10 or maybe 100 times, if that's feasible (I think it is?).
I think this is achieved by a PLL. I understand the basic concepts of it and have used in the analog domain, but never did it in a digital only format. Furthermore, I suppose having an array of hardware peripherals, such as timers and interrupts, and a fairly fast processor (teensy 3.2) could open up other approaches that don't follow the standard PLL configuration.
This has been on my mind for some time, but I don't really know where to start. Any advice, or resources are greatly appreciated

Regards,
Spiros
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From modular at go2.pl  Fri Dec 17 11:46:36 2021
From: modular at go2.pl (Roman Sowa)
Date: Fri, 17 Dec 2021 11:46:36 +0100
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
Message-ID: <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>

Measure incoming clock period with a timer. Then divide that measured 
timer value by the number you want to multiply the frequency. If you say 
anything between 10 and 100 is fine, then dividing by 32 sounds like 
walk in a park. And that divided value (or simply shifted in case of 32) 
is then loaded as period for another timer that outputs a pulse on overflow.
This way after each incoming clock pulse you get immediate response of 
updated frequency multiplied by 64 (or whatever other value)

Roman

W dniu 2021-12-17 o?08:03, Spiros Makris via Synth-diy pisze:
> Hello List,
> I want to experiment with polymetric structures and create "non 
> standard" subdivisions within the standard ones supported by MIDI. I 
> have only worked with the 24ppq, using the timing messages to directly 
> drive the sequencers. I would like a way to multiply the clock frequency 
> in order to increase resolution, let's say by 10 or maybe 100 times, if 
> that's feasible (I think it is?).
> I think this is achieved by a PLL. I understand the basic concepts of it 
> and have used in the analog domain, but never did it in a digital only 
> format. Furthermore, I suppose having an array of hardware peripherals, 
> such as timers and interrupts, and a fairly fast processor (teensy 3.2) 
> could open up other approaches that don't follow the standard PLL 
> configuration.
> This has been on my mind for some time, but I don't really know where to 
> start. Any advice, or resources are greatly appreciated
> 
> Regards,
> Spiros
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 


From tom at electricdruid.net  Fri Dec 17 14:36:48 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Fri, 17 Dec 2021 13:36:48 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
Message-ID: <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>

This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.


> On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com> wrote:
> 
> I think an envelope follower with no lag is called a rectifier.
> 
> Jokes aside, there are a number of options available but ultimately it comes down to filtering.
> 
> For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results.
> 
> 
> 
> best,
> 
> 
> 
> Martin
> 
> 
> 
> On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
>> Here is my goal..
>> I need a circuit that will take an AC signal and will shift level it from
>> a DC offset extracted from its min & max Peaks..
>> Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
>> The output would be the same waveform but shifted up to +5vdc. 
>> So 0 to +10vdc.
>> That final waveform would be much usable for a 0-5vdc control voltage input
>> than the original AC waveform.
>> Now the challenge is to do the same with a level changing AC signal.
>> In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
>> But here I?m looking for something that will be more versatile
>> to handle varying level waveform.
>> 
>>  
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From jpdesroc at oricom.ca  Fri Dec 17 16:33:21 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Fri, 17 Dec 2021 10:33:21 -0500
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
Message-ID: <001901d7f35b$6cc51db0$464f5910$@oricom.ca>

> This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.


So.. how can I modify the C1 section to get for example a fourth-order filter ?
To do it the way the signal flows across C1 is a bit confusing..
The signal comes from the left side but the clamping comes from D1 at right side.

I know how to implement high order filters in circuits but only
if I know the signal flow direction..

 



 

De : Synth-diy <synth-diy-bounces at synth-diy.org> De la part de Tom Wiltshire
Envoy? : 17 d?cembre 2021 08:37
? : Martin Klang <mars at pingdynasty.com>
Cc : synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

 

This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.

 





On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com <mailto:mars at pingdynasty.com> > wrote:

 

I think an envelope follower with no lag is called a rectifier.

Jokes aside, there are a number of options available but ultimately it comes down to filtering.

For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results.

 

best,

 

Martin

 

On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:

Here is my goal..

I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc. 

So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.

In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.




 

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org> 
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org> 

 

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From synthimuse at gmail.com  Fri Dec 17 18:24:32 2021
From: synthimuse at gmail.com (The SynthiMuse)
Date: Fri, 17 Dec 2021 17:24:32 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
Message-ID: <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>

The clock multiply technique I used ( just once ) is that I just outputted
multiple midi clock messages for every incoming clock message.
I measured the incoming clock period so that when I was sending multiple
clocks out, I spaced them appropriately between incoming so there was
minimum jitter in the outgoing stream.
The max practical speed I was working to was 250bpm. This would equate to a
clock pulse every 2.5mS.
I suppose I implemented a coarse DPLL and it worked ok, with the limitation
on maximum speed.
I'm afraid the code is long lost or I would happily pass it to you.
Gerry


On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:

> Measure incoming clock period with a timer. Then divide that measured
> timer value by the number you want to multiply the frequency. If you say
> anything between 10 and 100 is fine, then dividing by 32 sounds like
> walk in a park. And that divided value (or simply shifted in case of 32)
> is then loaded as period for another timer that outputs a pulse on
> overflow.
> This way after each incoming clock pulse you get immediate response of
> updated frequency multiplied by 64 (or whatever other value)
>
> Roman
>
> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
> > Hello List,
> > I want to experiment with polymetric structures and create "non
> > standard" subdivisions within the standard ones supported by MIDI. I
> > have only worked with the 24ppq, using the timing messages to directly
> > drive the sequencers. I would like a way to multiply the clock frequency
> > in order to increase resolution, let's say by 10 or maybe 100 times, if
> > that's feasible (I think it is?).
> > I think this is achieved by a PLL. I understand the basic concepts of it
> > and have used in the analog domain, but never did it in a digital only
> > format. Furthermore, I suppose having an array of hardware peripherals,
> > such as timers and interrupts, and a fairly fast processor (teensy 3.2)
> > could open up other approaches that don't follow the standard PLL
> > configuration.
> > This has been on my mind for some time, but I don't really know where to
> > start. Any advice, or resources are greatly appreciated
> >
> > Regards,
> > Spiros
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From hbissell at wowway.com  Fri Dec 17 22:41:15 2021
From: hbissell at wowway.com (Mr&MrsAccount)
Date: Fri, 17 Dec 2021 16:41:15 -0500 (EST)
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
Message-ID: <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>


Remember that high order filters don't come without their own baggage... 
? 
They suffer from greater group delay (which could be a problem) and poor transient response (also a problem). 
? 
Especially in a use where the input could start at zero or suddenly return to zero, the overshoots can be a killer. 
? 
I've been making filters to isolate the fundamental of Guitars for many (now many mnay) years.? ?The settling times are longer than the delay of the guitar signal itself, therefore the delays... 
? 
   

-----Original Message-----

From: Jean-Pierre <jpdesroc at oricom.ca>
To: 'Tom <tom at electricdruid.net>
Cc: synth-diy <synth-diy at synth-diy.org>
Date: Friday, 17 December 2021 10:39 AM EST
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

  > This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter. 
So.. how can I modify the C1 section to get for example a fourth-order filter ?
To do it the way the signal flows across C1 is a bit confusing..
The signal comes from the left side but the clamping comes from D1 at right side. I know how to implement high order filters in circuits but only
if I know the signal flow direction.. ?  ?  
  De?: Synth-diy <synth-diy-bounces at synth-diy.org> De la part de Tom Wiltshire
Envoy??: 17 d?cembre 2021 08:37
??: Martin Klang <mars at pingdynasty.com>
Cc?: synth-diy at synth-diy.org
Objet?: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?   ? This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter. 
 
 ?  
 

  
 On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com> wrote:  ? 
 I think an envelope follower with no lag is called a rectifier. Jokes aside, there are a number of options available but ultimately it comes down to filtering. For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results. ? best, ? Martin ? 
 On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:   
 Here is my goal..  
 I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc.?  
 So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.  
 In the case of a?steady waveform?this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.


  
 ?   _______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org    ?      
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From mbryant at futurehorizons.com  Sat Dec 18 00:23:10 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 17 Dec 2021 23:23:10 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
Message-ID: <c7134f002e2647c79828e49047b83722@futurehorizons.com>

If anybody is thinking of doing this digitally, you might want to read up on the Continuous Wavelet Transform.   Then once you realise your DSP isn?t up to it, have a look at the Discrete Sub Band Transform, aka Wavelet Packet Decomposition.  This gives as accurate results as the Discrete Wavelet Transform with less group delay problems, and given enough processing power is able to decompose even the human voice in real time.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Mr&MrsAccount
Sent: 17 December 2021 21:41
To: Jean-Pierre Desrochers; 'Tom Wiltshire'
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Remember that high order filters don't come without their own baggage...

They suffer from greater group delay (which could be a problem) and poor transient response (also a problem).

Especially in a use where the input could start at zero or suddenly return to zero, the overshoots can be a killer.

I've been making filters to isolate the fundamental of Guitars for many (now many mnay) years.   The settling times are longer than the delay of the guitar signal itself, therefore the delays...

________________________________
From: Jean-Pierre <jpdesroc at oricom.ca>
To: 'Tom <tom at electricdruid.net>
Cc: synth-diy <synth-diy at synth-diy.org>
Date: Friday, 17 December 2021 10:39 AM EST
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.

So.. how can I modify the C1 section to get for example a fourth-order filter ?
To do it the way the signal flows across C1 is a bit confusing..
The signal comes from the left side but the clamping comes from D1 at right side.
I know how to implement high order filters in circuits but only
if I know the signal flow direction..

[cid:image001.png at 01D7F331.833F9BD0]

De : Synth-diy <synth-diy-bounces at synth-diy.org> De la part de Tom Wiltshire
Envoy? : 17 d?cembre 2021 08:37
? : Martin Klang <mars at pingdynasty.com>
Cc : synth-diy at synth-diy.org
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.


On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com<mailto:mars at pingdynasty.com>> wrote:

I think an envelope follower with no lag is called a rectifier.
Jokes aside, there are a number of options available but ultimately it comes down to filtering.
For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results.

best,

Martin

On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
Here is my goal..
I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc.
So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.
In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.


_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>

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From synthdiy at adambaby.com  Sat Dec 18 03:49:32 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Sat, 18 Dec 2021 12:49:32 +1000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <c7134f002e2647c79828e49047b83722@futurehorizons.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
 <c7134f002e2647c79828e49047b83722@futurehorizons.com>
Message-ID: <A26AA72E-E9E9-4453-B588-1F2B0354621F@adambaby.com>



> On 18 Dec 2021, at 09:23, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> is able to decompose even the human voice in real time.


Hmm, I?m not sure I like the sound of that?

A
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From spirosmakris92 at gmail.com  Sat Dec 18 11:07:37 2021
From: spirosmakris92 at gmail.com (Spiros Makris)
Date: Sat, 18 Dec 2021 12:07:37 +0200
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
Message-ID: <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>

There are all excellent suggestions!
I happen to have a prototype with a teensy 3.2 and midi In/Out capabilities
on the bench, so I think I'm going to experiment with that first.
The counter method is an open-loop approach, pretty much, and what I'm
going to try first. I suppose if I closed the loop somehow it would become
a "proper" DPLL. Maybe if I build a software phase detector and use the
error signal in combination with the counted value to get more steady
results?
I believe going for the maximum clock speed and resolution combination for
the frequency chosen (clock frequency / counter size < max midi clock
frequency ?) is what will give the most accurate results.

Spiros

On Fri, 17 Dec 2021 at 19:24, The SynthiMuse <synthimuse at gmail.com> wrote:

> The clock multiply technique I used ( just once ) is that I just outputted
> multiple midi clock messages for every incoming clock message.
> I measured the incoming clock period so that when I was sending multiple
> clocks out, I spaced them appropriately between incoming so there was
> minimum jitter in the outgoing stream.
> The max practical speed I was working to was 250bpm. This would equate to
> a clock pulse every 2.5mS.
> I suppose I implemented a coarse DPLL and it worked ok, with the
> limitation on maximum speed.
> I'm afraid the code is long lost or I would happily pass it to you.
> Gerry
>
>
> On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:
>
>> Measure incoming clock period with a timer. Then divide that measured
>> timer value by the number you want to multiply the frequency. If you say
>> anything between 10 and 100 is fine, then dividing by 32 sounds like
>> walk in a park. And that divided value (or simply shifted in case of 32)
>> is then loaded as period for another timer that outputs a pulse on
>> overflow.
>> This way after each incoming clock pulse you get immediate response of
>> updated frequency multiplied by 64 (or whatever other value)
>>
>> Roman
>>
>> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
>> > Hello List,
>> > I want to experiment with polymetric structures and create "non
>> > standard" subdivisions within the standard ones supported by MIDI. I
>> > have only worked with the 24ppq, using the timing messages to directly
>> > drive the sequencers. I would like a way to multiply the clock
>> frequency
>> > in order to increase resolution, let's say by 10 or maybe 100 times, if
>> > that's feasible (I think it is?).
>> > I think this is achieved by a PLL. I understand the basic concepts of
>> it
>> > and have used in the analog domain, but never did it in a digital only
>> > format. Furthermore, I suppose having an array of hardware peripherals,
>> > such as timers and interrupts, and a fairly fast processor (teensy 3.2)
>> > could open up other approaches that don't follow the standard PLL
>> > configuration.
>> > This has been on my mind for some time, but I don't really know where
>> to
>> > start. Any advice, or resources are greatly appreciated
>> >
>> > Regards,
>> > Spiros
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>> >
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>
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From maohelin at gmail.com  Sat Dec 18 12:26:11 2021
From: maohelin at gmail.com (Mikko Helin)
Date: Sat, 18 Dec 2021 13:26:11 +0200
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
Message-ID: <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>

There is at least one commercial MIDI clock multiplier:
https://tubbutec.de/product/audiowerkstatt-midi-clock-multiplier/

That device does 2x - 9x multiply. I don't think MIDI clock at least
if the source is a DAW is quite stable source so multiplying more than
10x might not give expected results. Also 31.25 Kbaud is low speed
anyway, every byte takes at least 0.32 ms to transfer. Regarding
polyrhytmics which are the actual multipliers needed? Commercially
available DPLLs ("jitter attenuators" etc.) require quit high input
freq from 2kHz up or so. You might be implement slower one using FPGA,
maybe you could use something like PSoC 5LP ($10 board), see this PLL
demo: https://www.youtube.com/watch?v=ss75Jkio070

On Sat, Dec 18, 2021 at 12:11 PM Spiros Makris via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> There are all excellent suggestions!
> I happen to have a prototype with a teensy 3.2 and midi In/Out capabilities on the bench, so I think I'm going to experiment with that first.
> The counter method is an open-loop approach, pretty much, and what I'm going to try first. I suppose if I closed the loop somehow it would become a "proper" DPLL. Maybe if I build a software phase detector and use the error signal in combination with the counted value to get more steady results?
> I believe going for the maximum clock speed and resolution combination for the frequency chosen (clock frequency / counter size < max midi clock frequency ?) is what will give the most accurate results.
>
> Spiros
>
> On Fri, 17 Dec 2021 at 19:24, The SynthiMuse <synthimuse at gmail.com> wrote:
>>
>> The clock multiply technique I used ( just once ) is that I just outputted multiple midi clock messages for every incoming clock message.
>> I measured the incoming clock period so that when I was sending multiple clocks out, I spaced them appropriately between incoming so there was minimum jitter in the outgoing stream.
>> The max practical speed I was working to was 250bpm. This would equate to a clock pulse every 2.5mS.
>> I suppose I implemented a coarse DPLL and it worked ok, with the limitation on maximum speed.
>> I'm afraid the code is long lost or I would happily pass it to you.
>> Gerry
>>
>>
>> On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:
>>>
>>> Measure incoming clock period with a timer. Then divide that measured
>>> timer value by the number you want to multiply the frequency. If you say
>>> anything between 10 and 100 is fine, then dividing by 32 sounds like
>>> walk in a park. And that divided value (or simply shifted in case of 32)
>>> is then loaded as period for another timer that outputs a pulse on overflow.
>>> This way after each incoming clock pulse you get immediate response of
>>> updated frequency multiplied by 64 (or whatever other value)
>>>
>>> Roman
>>>
>>> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
>>> > Hello List,
>>> > I want to experiment with polymetric structures and create "non
>>> > standard" subdivisions within the standard ones supported by MIDI. I
>>> > have only worked with the 24ppq, using the timing messages to directly
>>> > drive the sequencers. I would like a way to multiply the clock frequency
>>> > in order to increase resolution, let's say by 10 or maybe 100 times, if
>>> > that's feasible (I think it is?).
>>> > I think this is achieved by a PLL. I understand the basic concepts of it
>>> > and have used in the analog domain, but never did it in a digital only
>>> > format. Furthermore, I suppose having an array of hardware peripherals,
>>> > such as timers and interrupts, and a fairly fast processor (teensy 3.2)
>>> > could open up other approaches that don't follow the standard PLL
>>> > configuration.
>>> > This has been on my mind for some time, but I don't really know where to
>>> > start. Any advice, or resources are greatly appreciated
>>> >
>>> > Regards,
>>> > Spiros
>>> >
>>> > _______________________________________________
>>> > Synth-diy mailing list
>>> > Synth-diy at synth-diy.org
>>> > http://synth-diy.org/mailman/listinfo/synth-diy
>>> > Selling or trading? Use marketplace at synth-diy.org
>>> >
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org
>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org



From guy.mccusker at gmail.com  Sat Dec 18 13:03:01 2021
From: guy.mccusker at gmail.com (Guy McCusker)
Date: Sat, 18 Dec 2021 12:03:01 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <c7134f002e2647c79828e49047b83722@futurehorizons.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
 <c7134f002e2647c79828e49047b83722@futurehorizons.com>
Message-ID: <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>

Can you give us a clue on how a wavelet transform would be useful in an
envelope follower? I don't know much about the area but at first glance it
does not seem like the right tool for the job.

On Fri, Dec 17, 2021 at 11:25 PM Mike Bryant <mbryant at futurehorizons.com>
wrote:

> If anybody is thinking of doing this digitally, you might want to read up
> on the Continuous Wavelet Transform.   Then once you realise your DSP isn?t
> up to it, have a look at the Discrete Sub Band Transform, aka Wavelet
> Packet Decomposition.  This gives as accurate results as the Discrete
> Wavelet Transform with less group delay problems, and given enough
> processing power is able to decompose even the human voice in real time.
>
>
>
>
>
> *From:* Synth-diy [mailto:synth-diy-bounces at synth-diy.org] *On Behalf Of *
> Mr&MrsAccount
> *Sent:* 17 December 2021 21:41
> *To:* Jean-Pierre Desrochers; 'Tom Wiltshire'
> *Cc:* synth-diy at synth-diy.org
> *Subject:* Re: [sdiy] Best & fastest envelope follower schematic..
> anybody ?
>
>
>
> Remember that high order filters don't come without their own baggage...
>
>
>
> They suffer from greater group delay (which could be a problem) and poor
> transient response (also a problem).
>
>
>
> Especially in a use where the input could start at zero or suddenly return
> to zero, the overshoots can be a killer.
>
>
>
> I've been making filters to isolate the fundamental of Guitars for many
> (now many mnay) years.   The settling times are longer than the delay of
> the guitar signal itself, therefore the delays...
>
>
>
> ------------------------------
>
> *From: *Jean-Pierre <jpdesroc at oricom.ca>
> *To: *'Tom <tom at electricdruid.net>
> *Cc: *synth-diy <synth-diy at synth-diy.org>
> *Date: *Friday, 17 December 2021 10:39 AM EST
> *Subject: *Re: [sdiy] Best & fastest envelope follower schematic..
> anybody ?
>
> > This would be the digital equivalent to the single pole RC. It should be
> possible to get better ripple suppression by using higher order filters.
> Harald showed that he got a better response using a fourth-order filter.
>
>
> So.. how can I modify the C1 section to get for example a fourth-order
> filter ?
> To do it the way the signal flows across C1 is a bit confusing..
> The signal comes from the left side but the clamping comes from D1 at
> right side.
>
> I know how to implement high order filters in circuits but only
> if I know the signal flow direction..
>
>
>
>
>
> *De :* Synth-diy <synth-diy-bounces at synth-diy.org> *De la part de* Tom
> Wiltshire
> *Envoy? :* 17 d?cembre 2021 08:37
> *? :* Martin Klang <mars at pingdynasty.com>
> *Cc :* synth-diy at synth-diy.org
> *Objet :* Re: [sdiy] Best & fastest envelope follower schematic.. anybody
> ?
>
>
>
> This would be the digital equivalent to the single pole RC. It should be
> possible to get better ripple suppression by using higher order filters.
> Harald showed that he got a better response using a fourth-order filter.
>
>
>
>
>
> On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com> wrote:
>
>
>
> I think an envelope follower with no lag is called a rectifier.
>
> Jokes aside, there are a number of options available but ultimately it
> comes down to filtering.
>
> For digital envelope followers, I like to use a simple exponential average
> (aka leaky integrator, a first-order IIR filter) on the fully rectified
> signal and tune the time constant to the expected input signal. Generally
> you want it to be fast, but not so fast as to track the waveform
> oscillations, even at say 20 Hz. This makes a computationally very
> efficient follower with predictable results.
>
>
>
> best,
>
>
>
> Martin
>
>
>
> On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
>
> Here is my goal..
>
> I need a circuit that will take an AC signal and will shift level it from
> a DC offset extracted from its min & max Peaks..
> Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
> The output would be the same waveform but shifted up to +5vdc.
>
> So 0 to +10vdc.
> That final waveform would be much usable for a 0-5vdc control voltage input
> than the original AC waveform.
> Now the challenge is to do the same with a level changing AC signal.
>
> In the case of a *steady waveform* this ?level shifter? could be an opamp
> that would add half of the peak to peak voltage as an offset DC voltage,
> But here I?m looking for something that will be more versatile
> to handle varying level waveform.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From jarander at gmail.com  Sat Dec 18 14:35:09 2021
From: jarander at gmail.com (Jared Anderson)
Date: Sat, 18 Dec 2021 14:35:09 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
 <c7134f002e2647c79828e49047b83722@futurehorizons.com>
 <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>
Message-ID: <CAEDQ4irO6QkUEssoY_unzhnWMgviBpv-zRonk8p0MOWw3RUP+Q@mail.gmail.com>

Hello All,

Seeings as different transforms have come up, I've been meaning to try
using a Hilbert Transform for doing envelope recovery as described in this
Electronotes Application Note:

https://electronotes.netfirms.com/AN355.pdf

I got as far as coding up an example iir based hilbert transformer in
Octave:

https://github.com/jazamatronic/iir_hilbert

Cheers,
Jared


On Sat, 18 Dec 2021 at 13:06, Guy McCusker via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Can you give us a clue on how a wavelet transform would be useful in an
> envelope follower? I don't know much about the area but at first glance it
> does not seem like the right tool for the job.
>
> On Fri, Dec 17, 2021 at 11:25 PM Mike Bryant <mbryant at futurehorizons.com>
> wrote:
>
>> If anybody is thinking of doing this digitally, you might want to read up
>> on the Continuous Wavelet Transform.   Then once you realise your DSP isn?t
>> up to it, have a look at the Discrete Sub Band Transform, aka Wavelet
>> Packet Decomposition.  This gives as accurate results as the Discrete
>> Wavelet Transform with less group delay problems, and given enough
>> processing power is able to decompose even the human voice in real time.
>>
>>
>>
>>
>>
>> *From:* Synth-diy [mailto:synth-diy-bounces at synth-diy.org] *On Behalf Of
>> *Mr&MrsAccount
>> *Sent:* 17 December 2021 21:41
>> *To:* Jean-Pierre Desrochers; 'Tom Wiltshire'
>> *Cc:* synth-diy at synth-diy.org
>> *Subject:* Re: [sdiy] Best & fastest envelope follower schematic..
>> anybody ?
>>
>>
>>
>> Remember that high order filters don't come without their own baggage...
>>
>>
>>
>> They suffer from greater group delay (which could be a problem) and poor
>> transient response (also a problem).
>>
>>
>>
>> Especially in a use where the input could start at zero or suddenly
>> return to zero, the overshoots can be a killer.
>>
>>
>>
>> I've been making filters to isolate the fundamental of Guitars for many
>> (now many mnay) years.   The settling times are longer than the delay of
>> the guitar signal itself, therefore the delays...
>>
>>
>>
>> ------------------------------
>>
>> *From: *Jean-Pierre <jpdesroc at oricom.ca>
>> *To: *'Tom <tom at electricdruid.net>
>> *Cc: *synth-diy <synth-diy at synth-diy.org>
>> *Date: *Friday, 17 December 2021 10:39 AM EST
>> *Subject: *Re: [sdiy] Best & fastest envelope follower schematic..
>> anybody ?
>>
>> > This would be the digital equivalent to the single pole RC. It should
>> be possible to get better ripple suppression by using higher order filters.
>> Harald showed that he got a better response using a fourth-order filter.
>>
>>
>> So.. how can I modify the C1 section to get for example a fourth-order
>> filter ?
>> To do it the way the signal flows across C1 is a bit confusing..
>> The signal comes from the left side but the clamping comes from D1 at
>> right side.
>>
>> I know how to implement high order filters in circuits but only
>> if I know the signal flow direction..
>>
>>
>>
>>
>>
>> *De :* Synth-diy <synth-diy-bounces at synth-diy.org> *De la part de* Tom
>> Wiltshire
>> *Envoy? :* 17 d?cembre 2021 08:37
>> *? :* Martin Klang <mars at pingdynasty.com>
>> *Cc :* synth-diy at synth-diy.org
>> *Objet :* Re: [sdiy] Best & fastest envelope follower schematic..
>> anybody ?
>>
>>
>>
>> This would be the digital equivalent to the single pole RC. It should be
>> possible to get better ripple suppression by using higher order filters.
>> Harald showed that he got a better response using a fourth-order filter.
>>
>>
>>
>>
>>
>> On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com> wrote:
>>
>>
>>
>> I think an envelope follower with no lag is called a rectifier.
>>
>> Jokes aside, there are a number of options available but ultimately it
>> comes down to filtering.
>>
>> For digital envelope followers, I like to use a simple exponential
>> average (aka leaky integrator, a first-order IIR filter) on the fully
>> rectified signal and tune the time constant to the expected input signal.
>> Generally you want it to be fast, but not so fast as to track the waveform
>> oscillations, even at say 20 Hz. This makes a computationally very
>> efficient follower with predictable results.
>>
>>
>>
>> best,
>>
>>
>>
>> Martin
>>
>>
>>
>> On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
>>
>> Here is my goal..
>>
>> I need a circuit that will take an AC signal and will shift level it from
>> a DC offset extracted from its min & max Peaks..
>> Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
>> The output would be the same waveform but shifted up to +5vdc.
>>
>> So 0 to +10vdc.
>> That final waveform would be much usable for a 0-5vdc control voltage
>> input
>> than the original AC waveform.
>> Now the challenge is to do the same with a level changing AC signal.
>>
>> In the case of a *steady waveform* this ?level shifter? could be an
>> opamp that would add half of the peak to peak voltage as an offset DC
>> voltage,
>> But here I?m looking for something that will be more versatile
>> to handle varying level waveform.
>>
>>
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>>
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mbryant at futurehorizons.com  Sat Dec 18 18:30:24 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 18 Dec 2021 17:30:24 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
 <c7134f002e2647c79828e49047b83722@futurehorizons.com>
 <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>
Message-ID: <ec90fbbc15cf45f4b605a37d2182d5d5@futurehorizons.com>

Well I might be misunderstanding what the OP is trying to do as the conversation did seem to go off in several directions, but I?ve seen comments that the group delay introduced by higher order filters or the output lag if using a lower order filter is a problem.

If you use wavelet decomposition you?re going to generate a moving output array of scale factors which represent the instantaneous amplitude of the wavelets the input has been decomposed into.  These won?t appear at the same time ? the lower frequencies lag the upper ones.  These can either be used separately to reconstruct something based on the incoming signal, which is how some voice synthesisers or some autotunes (but not the original) work, or the scale factors could be combined to produce a series of envelopes which is what I do in my additive synth.

But I don?t see why you couldn?t produce just a single envelope amplitude if that is what the OP wanted.  But maybe it isn?t what he wanted in which case you?re right, this isn?t the correct approach.

From: Guy McCusker [mailto:guy.mccusker at gmail.com]
Sent: 18 December 2021 12:03
To: Mike Bryant
Cc: Mr&MrsAccount; Jean-Pierre Desrochers; Tom Wiltshire; synth-diy at synth-diy.org
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Can you give us a clue on how a wavelet transform would be useful in an envelope follower? I don't know much about the area but at first glance it does not seem like the right tool for the job.

On Fri, Dec 17, 2021 at 11:25 PM Mike Bryant <mbryant at futurehorizons.com<mailto:mbryant at futurehorizons.com>> wrote:
If anybody is thinking of doing this digitally, you might want to read up on the Continuous Wavelet Transform.   Then once you realise your DSP isn?t up to it, have a look at the Discrete Sub Band Transform, aka Wavelet Packet Decomposition.  This gives as accurate results as the Discrete Wavelet Transform with less group delay problems, and given enough processing power is able to decompose even the human voice in real time.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of Mr&MrsAccount
Sent: 17 December 2021 21:41
To: Jean-Pierre Desrochers; 'Tom Wiltshire'
Cc: synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Remember that high order filters don't come without their own baggage...

They suffer from greater group delay (which could be a problem) and poor transient response (also a problem).

Especially in a use where the input could start at zero or suddenly return to zero, the overshoots can be a killer.

I've been making filters to isolate the fundamental of Guitars for many (now many mnay) years.   The settling times are longer than the delay of the guitar signal itself, therefore the delays...

________________________________
From: Jean-Pierre <jpdesroc at oricom.ca<mailto:jpdesroc at oricom.ca>>
To: 'Tom <tom at electricdruid.net<mailto:tom at electricdruid.net>>
Cc: synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>>
Date: Friday, 17 December 2021 10:39 AM EST
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.

So.. how can I modify the C1 section to get for example a fourth-order filter ?
To do it the way the signal flows across C1 is a bit confusing..
The signal comes from the left side but the clamping comes from D1 at right side.
I know how to implement high order filters in circuits but only
if I know the signal flow direction..


De : Synth-diy <synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>> De la part de Tom Wiltshire
Envoy? : 17 d?cembre 2021 08:37
? : Martin Klang <mars at pingdynasty.com<mailto:mars at pingdynasty.com>>
Cc : synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.


On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com<mailto:mars at pingdynasty.com>> wrote:

I think an envelope follower with no lag is called a rectifier.
Jokes aside, there are a number of options available but ultimately it comes down to filtering.
For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results.

best,

Martin

On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
Here is my goal..
I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc.
So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.
In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.

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From mbryant at futurehorizons.com  Sat Dec 18 18:37:07 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 18 Dec 2021 17:37:07 +0000
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <CAEDQ4irO6QkUEssoY_unzhnWMgviBpv-zRonk8p0MOWw3RUP+Q@mail.gmail.com>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
 <1325052150.76587917.1639777275346.JavaMail.zimbra@wowway.com>
 <c7134f002e2647c79828e49047b83722@futurehorizons.com>
 <CAPx-PW4=-Qu2eD5CaE8XhUJgbG_HGQwfEhRvObcVEZnWWCrkXg@mail.gmail.com>
 <CAEDQ4irO6QkUEssoY_unzhnWMgviBpv-zRonk8p0MOWw3RUP+Q@mail.gmail.com>
Message-ID: <3f63ae0e0ae444f8ace8b6d977b92232@futurehorizons.com>

Yes.  If the input signal is more random rather than a sum of a limited number of sinusoids then the Hilbert Transform is the better method.

From: Jared Anderson [mailto:jarander at gmail.com]
Sent: 18 December 2021 13:35
To: Guy McCusker
Cc: Mike Bryant; synth-diy at synth-diy.org
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Hello All,

Seeings as different transforms have come up, I've been meaning to try using a Hilbert Transform for doing envelope recovery as described in this Electronotes Application Note:

https://electronotes.netfirms.com/AN355.pdf

I got as far as coding up an example iir based hilbert transformer in Octave:

https://github.com/jazamatronic/iir_hilbert

Cheers,
Jared


On Sat, 18 Dec 2021 at 13:06, Guy McCusker via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
Can you give us a clue on how a wavelet transform would be useful in an envelope follower? I don't know much about the area but at first glance it does not seem like the right tool for the job.

On Fri, Dec 17, 2021 at 11:25 PM Mike Bryant <mbryant at futurehorizons.com<mailto:mbryant at futurehorizons.com>> wrote:
If anybody is thinking of doing this digitally, you might want to read up on the Continuous Wavelet Transform.   Then once you realise your DSP isn?t up to it, have a look at the Discrete Sub Band Transform, aka Wavelet Packet Decomposition.  This gives as accurate results as the Discrete Wavelet Transform with less group delay problems, and given enough processing power is able to decompose even the human voice in real time.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of Mr&MrsAccount
Sent: 17 December 2021 21:41
To: Jean-Pierre Desrochers; 'Tom Wiltshire'
Cc: synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

Remember that high order filters don't come without their own baggage...

They suffer from greater group delay (which could be a problem) and poor transient response (also a problem).

Especially in a use where the input could start at zero or suddenly return to zero, the overshoots can be a killer.

I've been making filters to isolate the fundamental of Guitars for many (now many mnay) years.   The settling times are longer than the delay of the guitar signal itself, therefore the delays...

________________________________
From: Jean-Pierre <jpdesroc at oricom.ca<mailto:jpdesroc at oricom.ca>>
To: 'Tom <tom at electricdruid.net<mailto:tom at electricdruid.net>>
Cc: synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>>
Date: Friday, 17 December 2021 10:39 AM EST
Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.

So.. how can I modify the C1 section to get for example a fourth-order filter ?
To do it the way the signal flows across C1 is a bit confusing..
The signal comes from the left side but the clamping comes from D1 at right side.
I know how to implement high order filters in circuits but only
if I know the signal flow direction..


De : Synth-diy <synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>> De la part de Tom Wiltshire
Envoy? : 17 d?cembre 2021 08:37
? : Martin Klang <mars at pingdynasty.com<mailto:mars at pingdynasty.com>>
Cc : synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>
Objet : Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?

This would be the digital equivalent to the single pole RC. It should be possible to get better ripple suppression by using higher order filters. Harald showed that he got a better response using a fourth-order filter.


On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com<mailto:mars at pingdynasty.com>> wrote:

I think an envelope follower with no lag is called a rectifier.
Jokes aside, there are a number of options available but ultimately it comes down to filtering.
For digital envelope followers, I like to use a simple exponential average (aka leaky integrator, a first-order IIR filter) on the fully rectified signal and tune the time constant to the expected input signal. Generally you want it to be fast, but not so fast as to track the waveform oscillations, even at say 20 Hz. This makes a computationally very efficient follower with predictable results.

best,

Martin

On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
Here is my goal..
I need a circuit that will take an AC signal and will shift level it from
a DC offset extracted from its min & max Peaks..
Ex: Suppose you have steady +/- 5v peak sine wave coming in this circuit,
The output would be the same waveform but shifted up to +5vdc.
So 0 to +10vdc.
That final waveform would be much usable for a 0-5vdc control voltage input
than the original AC waveform.
Now the challenge is to do the same with a level changing AC signal.
In the case of a steady waveform this ?level shifter? could be an opamp that would add half of the peak to peak voltage as an offset DC voltage,
But here I?m looking for something that will be more versatile
to handle varying level waveform.

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>

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From brianw at audiobanshee.com  Sat Dec 18 19:28:23 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Sat, 18 Dec 2021 10:28:23 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
Message-ID: <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>

When measuring the incoming clock period, filtering those values should smooth out the jitter. i.e. Rather than use each newly measured clock period directly, run it through a filter that averages it out with recent clock periods. The DPLL shows a 3rd order filter.

For those commercial DPLLs, do they require 2 kHz as the multiplicand, or is that a master clock?

Brian

On Dec 18, 2021, at 03:26, Mikko Helin wrote:
> There is at least one commercial MIDI clock multiplier:
> https://tubbutec.de/product/audiowerkstatt-midi-clock-multiplier/
> 
> That device does 2x - 9x multiply. I don't think MIDI clock at least
> if the source is a DAW is quite stable source so multiplying more than
> 10x might not give expected results. Also 31.25 Kbaud is low speed
> anyway, every byte takes at least 0.32 ms to transfer. Regarding
> polyrhytmics which are the actual multipliers needed? Commercially
> available DPLLs ("jitter attenuators" etc.) require quit high input
> freq from 2kHz up or so. You might be implement slower one using FPGA,
> maybe you could use something like PSoC 5LP ($10 board), see this PLL
> demo: https://www.youtube.com/watch?v=ss75Jkio070
> 
> On Sat, Dec 18, 2021 at 12:11 PM Spiros Makris wrote:
>> 
>> There are all excellent suggestions!
>> I happen to have a prototype with a teensy 3.2 and midi In/Out capabilities on the bench, so I think I'm going to experiment with that first.
>> The counter method is an open-loop approach, pretty much, and what I'm going to try first. I suppose if I closed the loop somehow it would become a "proper" DPLL. Maybe if I build a software phase detector and use the error signal in combination with the counted value to get more steady results?
>> I believe going for the maximum clock speed and resolution combination for the frequency chosen (clock frequency / counter size < max midi clock frequency ?) is what will give the most accurate results.
>> 
>> Spiros
>> 
>> On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:
>>> 
>>> Measure incoming clock period with a timer. Then divide that measured
>>> timer value by the number you want to multiply the frequency. If you say
>>> anything between 10 and 100 is fine, then dividing by 32 sounds like
>>> walk in a park. And that divided value (or simply shifted in case of 32)
>>> is then loaded as period for another timer that outputs a pulse on overflow.
>>> This way after each incoming clock pulse you get immediate response of
>>> updated frequency multiplied by 64 (or whatever other value)
>>> 
>>> Roman
>>> 
>>> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
>>>> Hello List,
>>>> I want to experiment with polymetric structures and create "non
>>>> standard" subdivisions within the standard ones supported by MIDI. I
>>>> have only worked with the 24ppq, using the timing messages to directly
>>>> drive the sequencers. I would like a way to multiply the clock frequency
>>>> in order to increase resolution, let's say by 10 or maybe 100 times, if
>>>> that's feasible (I think it is?).
>>>> I think this is achieved by a PLL. I understand the basic concepts of it
>>>> and have used in the analog domain, but never did it in a digital only
>>>> format. Furthermore, I suppose having an array of hardware peripherals,
>>>> such as timers and interrupts, and a fairly fast processor (teensy 3.2)
>>>> could open up other approaches that don't follow the standard PLL
>>>> configuration.
>>>> This has been on my mind for some time, but I don't really know where to
>>>> start. Any advice, or resources are greatly appreciated
>>>> 
>>>> Regards,
>>>> Spiros




From btremblay at me.com  Sat Dec 18 21:12:17 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Sat, 18 Dec 2021 15:12:17 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
Message-ID: <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>

Interesting topic!

I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq. 

The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.

One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.

I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.

So, two different problems. 
1) MIDI clock dropping out on groove boxes. 
2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.

> On Dec 18, 2021, at 1:28 PM, Brian Willoughby <brianw at audiobanshee.com> wrote:
> 
> When measuring the incoming clock period, filtering those values should smooth out the jitter. i.e. Rather than use each newly measured clock period directly, run it through a filter that averages it out with recent clock periods. The DPLL shows a 3rd order filter.
> 
> For those commercial DPLLs, do they require 2 kHz as the multiplicand, or is that a master clock?
> 
> Brian
> 
> On Dec 18, 2021, at 03:26, Mikko Helin wrote:
>> There is at least one commercial MIDI clock multiplier:
>> https://tubbutec.de/product/audiowerkstatt-midi-clock-multiplier/
>> 
>> That device does 2x - 9x multiply. I don't think MIDI clock at least
>> if the source is a DAW is quite stable source so multiplying more than
>> 10x might not give expected results. Also 31.25 Kbaud is low speed
>> anyway, every byte takes at least 0.32 ms to transfer. Regarding
>> polyrhytmics which are the actual multipliers needed? Commercially
>> available DPLLs ("jitter attenuators" etc.) require quit high input
>> freq from 2kHz up or so. You might be implement slower one using FPGA,
>> maybe you could use something like PSoC 5LP ($10 board), see this PLL
>> demo: https://www.youtube.com/watch?v=ss75Jkio070
>> 
>> On Sat, Dec 18, 2021 at 12:11 PM Spiros Makris wrote:
>>> 
>>> There are all excellent suggestions!
>>> I happen to have a prototype with a teensy 3.2 and midi In/Out capabilities on the bench, so I think I'm going to experiment with that first.
>>> The counter method is an open-loop approach, pretty much, and what I'm going to try first. I suppose if I closed the loop somehow it would become a "proper" DPLL. Maybe if I build a software phase detector and use the error signal in combination with the counted value to get more steady results?
>>> I believe going for the maximum clock speed and resolution combination for the frequency chosen (clock frequency / counter size < max midi clock frequency ?) is what will give the most accurate results.
>>> 
>>> Spiros
>>> 
>>> On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:
>>>> 
>>>> Measure incoming clock period with a timer. Then divide that measured
>>>> timer value by the number you want to multiply the frequency. If you say
>>>> anything between 10 and 100 is fine, then dividing by 32 sounds like
>>>> walk in a park. And that divided value (or simply shifted in case of 32)
>>>> is then loaded as period for another timer that outputs a pulse on overflow.
>>>> This way after each incoming clock pulse you get immediate response of
>>>> updated frequency multiplied by 64 (or whatever other value)
>>>> 
>>>> Roman
>>>> 
>>>> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
>>>>> Hello List,
>>>>> I want to experiment with polymetric structures and create "non
>>>>> standard" subdivisions within the standard ones supported by MIDI. I
>>>>> have only worked with the 24ppq, using the timing messages to directly
>>>>> drive the sequencers. I would like a way to multiply the clock frequency
>>>>> in order to increase resolution, let's say by 10 or maybe 100 times, if
>>>>> that's feasible (I think it is?).
>>>>> I think this is achieved by a PLL. I understand the basic concepts of it
>>>>> and have used in the analog domain, but never did it in a digital only
>>>>> format. Furthermore, I suppose having an array of hardware peripherals,
>>>>> such as timers and interrupts, and a fairly fast processor (teensy 3.2)
>>>>> could open up other approaches that don't follow the standard PLL
>>>>> configuration.
>>>>> This has been on my mind for some time, but I don't really know where to
>>>>> start. Any advice, or resources are greatly appreciated
>>>>> 
>>>>> Regards,
>>>>> Spiros
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From btremblay at me.com  Sat Dec 18 21:15:02 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Sat, 18 Dec 2021 15:15:02 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
Message-ID: <DF0B6F50-1A22-41D3-BA29-34A2CEC04DD0@me.com>

One more thing. I see a few examples online where the arduino is told to delayMicroseconds(n) to simulate the extra pulses. This seems inherently buggy because it makes the whole program only stable within a certain frequency range.

> On Dec 18, 2021, at 1:28 PM, Brian Willoughby <brianw at audiobanshee.com> wrote:
> 
> When measuring the incoming clock period, filtering those values should smooth out the jitter. i.e. Rather than use each newly measured clock period directly, run it through a filter that averages it out with recent clock periods. The DPLL shows a 3rd order filter.
> 
> For those commercial DPLLs, do they require 2 kHz as the multiplicand, or is that a master clock?
> 
> Brian
> 
> On Dec 18, 2021, at 03:26, Mikko Helin wrote:
>> There is at least one commercial MIDI clock multiplier:
>> https://tubbutec.de/product/audiowerkstatt-midi-clock-multiplier/
>> 
>> That device does 2x - 9x multiply. I don't think MIDI clock at least
>> if the source is a DAW is quite stable source so multiplying more than
>> 10x might not give expected results. Also 31.25 Kbaud is low speed
>> anyway, every byte takes at least 0.32 ms to transfer. Regarding
>> polyrhytmics which are the actual multipliers needed? Commercially
>> available DPLLs ("jitter attenuators" etc.) require quit high input
>> freq from 2kHz up or so. You might be implement slower one using FPGA,
>> maybe you could use something like PSoC 5LP ($10 board), see this PLL
>> demo: https://www.youtube.com/watch?v=ss75Jkio070
>> 
>> On Sat, Dec 18, 2021 at 12:11 PM Spiros Makris wrote:
>>> 
>>> There are all excellent suggestions!
>>> I happen to have a prototype with a teensy 3.2 and midi In/Out capabilities on the bench, so I think I'm going to experiment with that first.
>>> The counter method is an open-loop approach, pretty much, and what I'm going to try first. I suppose if I closed the loop somehow it would become a "proper" DPLL. Maybe if I build a software phase detector and use the error signal in combination with the counted value to get more steady results?
>>> I believe going for the maximum clock speed and resolution combination for the frequency chosen (clock frequency / counter size < max midi clock frequency ?) is what will give the most accurate results.
>>> 
>>> Spiros
>>> 
>>> On Fri, Dec 17, 2021 at 10:50 AM Roman Sowa <modular at go2.pl> wrote:
>>>> 
>>>> Measure incoming clock period with a timer. Then divide that measured
>>>> timer value by the number you want to multiply the frequency. If you say
>>>> anything between 10 and 100 is fine, then dividing by 32 sounds like
>>>> walk in a park. And that divided value (or simply shifted in case of 32)
>>>> is then loaded as period for another timer that outputs a pulse on overflow.
>>>> This way after each incoming clock pulse you get immediate response of
>>>> updated frequency multiplied by 64 (or whatever other value)
>>>> 
>>>> Roman
>>>> 
>>>> W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
>>>>> Hello List,
>>>>> I want to experiment with polymetric structures and create "non
>>>>> standard" subdivisions within the standard ones supported by MIDI. I
>>>>> have only worked with the 24ppq, using the timing messages to directly
>>>>> drive the sequencers. I would like a way to multiply the clock frequency
>>>>> in order to increase resolution, let's say by 10 or maybe 100 times, if
>>>>> that's feasible (I think it is?).
>>>>> I think this is achieved by a PLL. I understand the basic concepts of it
>>>>> and have used in the analog domain, but never did it in a digital only
>>>>> format. Furthermore, I suppose having an array of hardware peripherals,
>>>>> such as timers and interrupts, and a fairly fast processor (teensy 3.2)
>>>>> could open up other approaches that don't follow the standard PLL
>>>>> configuration.
>>>>> This has been on my mind for some time, but I don't really know where to
>>>>> start. Any advice, or resources are greatly appreciated
>>>>> 
>>>>> Regards,
>>>>> Spiros
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From brianw at audiobanshee.com  Sat Dec 18 21:40:42 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Sat, 18 Dec 2021 12:40:42 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
Message-ID: <60EA52EB-301D-480F-8C43-6D050095C245@audiobanshee.com>

Has anyone documented these lost clock steps from the Boss DR-202 or other groove boxes? Is it a known problem, and does anyone know why it happens? If there's an online article, I'd be curious to read about it.


One thing you might try, if you aren't already, is to write "bare metal" firmware without any of the Arduino overhead.

An important thing to consider about the MIDI Standard is that all messages involving timing are single-byte messages that can be handled immediately, with very fast code. Most MIDI messages are 2 or 3 (or more) bytes long, so the typical code collects bytes from the serial interface via an interrupt, and then runs a parser to collect together bytes into messages. Depending upon how the interrupt code and non-interrupt code is written, this parsing can create delays between the arrival of the MIDI data and the action(s) taken.

Careful code design allows the System Real Time Messages to be taken out of the parser and handled immediately by special code, which will minimize the jitter or other delays due to software. Unless someone has design a very capable MIDI interrupt handler into the Arduino system, you're not going to get the best performance without replacing that.

Depending upon the requirements, you can even write the interrupt handler in assembly language to reduce the code delays to the absolute minimum. This isn't always necessary, but some processors and compiler tools generate tons of overhead that just wastes a bunch of time (in order to make the coding "easier").


Questions:

Does the DR-202 mix Notes messages with System Real Time Messages?

Do the plain vanilla drum machines use MIDI or DIN sync?

Do any of these use MIDI Song Position Pointer (or MIDI Time Code)?


Brian

On Dec 18, 2021, at 12:12, Benjamin Tremblay <btremblay at me.com> wrote:
> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
> 
> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
> 
> So, two different problems. 
> 1) MIDI clock dropping out on groove boxes. 




From pete.hartman at gmail.com  Sat Dec 18 21:53:24 2021
From: pete.hartman at gmail.com (Pete Hartman)
Date: Sat, 18 Dec 2021 14:53:24 -0600
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
Message-ID: <CACodTR-3BYrRjM+CJLLi6httGZoC=KaVq8ZPnYgcUsieLcQoRg@mail.gmail.com>

On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <
synth-diy at synth-diy.org> wrote:

>
> 2) I wish I understood the theory of clock multipliers. I have seen code
> that measures the period between clock pulses and dead reckons the
> double-time pulse as an average of the recent periods. But why? Why can?t I
> just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event?
> Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the
> clock down to individual sequencer steps on the KPR-77. As long as the
> divided clock is coming in on the beat, what does it matter if some of the
> synthetic pulses are a little off? (They?re just shadows of the main tempo
> clock). It?s not like the KPR-77 is inferring something or trying to
> calculate BPM from the external clock? So? Anyway I just wish I knew what I
> was aiming for, and then maybe I could hit the target.
>

One suspects that most people are trying to write a general purpose
converter.  E.g. you could run those 48ppq out to some other module, like
an analog sequencer, and it would keep time.  I'm not familiar with the
KPR-77, but I'm also slightly puzzled by the idea that some piece of gear
would require 48PPQN but not care about the timing of half of the pulses.

Pete
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From btremblay at me.com  Sat Dec 18 21:56:40 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Sat, 18 Dec 2021 15:56:40 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CACodTR-3BYrRjM+CJLLi6httGZoC=KaVq8ZPnYgcUsieLcQoRg@mail.gmail.com>
References: <CACodTR-3BYrRjM+CJLLi6httGZoC=KaVq8ZPnYgcUsieLcQoRg@mail.gmail.com>
Message-ID: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>

I?m assuming all it does is divide by 12 to get a 16th note. 

Benjamin Tremblay

> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com> wrote:
> 
> ?
> 
> 
>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org> wrote:
>> 
>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
> 
> One suspects that most people are trying to write a general purpose converter.  E.g. you could run those 48ppq out to some other module, like an analog sequencer, and it would keep time.  I'm not familiar with the KPR-77, but I'm also slightly puzzled by the idea that some piece of gear would require 48PPQN but not care about the timing of half of the pulses.
> 
> Pete 
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From brianw at audiobanshee.com  Sat Dec 18 22:00:39 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Sat, 18 Dec 2021 13:00:39 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <DF0B6F50-1A22-41D3-BA29-34A2CEC04DD0@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <DF0B6F50-1A22-41D3-BA29-34A2CEC04DD0@me.com>
Message-ID: <D7FD92B8-D1D9-4E30-8B60-CD7350BBD8B7@audiobanshee.com>

Your hunch is right: Any function like delayMicroseconds() is bad design for a high performance system, unless it's used in the right places for the right reasons.

The biggest disadvantage of such software delays is that they force you to design firmware that only handles one thing at a time. In a complex system that's keeping rock-solid timing while also handling multiple features, you need a design that's handling multiple operations in the background via interrupts and hardware peripherals. Those background operations can make delayMicroseconds() take longer than it should, depending upon how it's implemented. There are ways to maintain accuracy, but not without limiting the ability to handle lots of things at the same time.


Most processors that are appropriate for handling MIDI will have several hardware timer peripherals on the chip. If you need to generate pulses, your best performance will be to select a timer peripheral that can directly drive an external pin, and just alter the period when needed. There's no way that a software pin output can compete with direct hardware timing of the pin state changes.

For situations where you're not manipulating an external pin, but have some other timing requirement, a hardware timer peripheral can generate an interrupt. Then you write an interrupt handler that immediate performs the required operation, followed by setting up the timer to trigger again (if the timer mode requires manual restart - some timer modes automatically repeat the triggers).

That said, there are sometimes cases where the CPU clock speed is too slow, and the delay is shorter than one clock cycle. Or, given that it takes several instructions of delay to handle an interrupt, the number of clock cycles needed for an interrupt handler is greater than the number of clock cycles for the delay. In these cases, you might need a "busy" wait, but that seems unlikely. What's more likely is that the Arduino interrupt handlers have way more overhead than a custom-designed piece of code might have.


delayMicroseconds() might be useful on a platform where all of the critical timing is handled directly by hardware peripherals or interrupts, leaving the slow user interface as the "top level" code running whenever the interrupts are busy and there's time left over. If you want to blink a non-timing LED, or display something and pause before displaying something else, then delayMicroseconds() would be perfectly fine. Users probably won't notice that the LCD shows text for 0.9 seconds or 1.1 seconds - that's not critical timing. This only works when 100% of the critical timing operations are handled without a delay, leaving only the non-critical operations in the leftover CPU cycles.


I haven't used Arduino, but there are a few ways to write firmware. There are big Linux systems that have lots of overhead, lots of threads, and more latency. I doubt any of the Arduino-sized platforms support Linux, but it's important to point out that Linux doesn't have the best timing performance (unless you write drivers for everything). The next option is a RTOS (Real Time Operating System) where there are still multiple threads, and performance can be a lot better than Linux, but there is still a lot of overhead in code - even the interrupts take more cycles to process. The best performance comes from a bare metal code design where there aren't really any threads. Instead of threads, the code can use interrupt handlers to run separate operations at the same time, without the typical overhead of switching the processor between threads. Once the critical pieces are handled with well-timed interrupts, the remainder of the code (user interface, non-timing-critical features) can be handled in the single foreground thread, but you just have to realize that all of the interrupts are taking time away from that foreground code.

Brian


On Dec 18, 2021, at 12:15, Benjamin Tremblay <btremblay at me.com> wrote:
> One more thing. I see a few examples online where the arduino is told to delayMicroseconds(n) to simulate the extra pulses. This seems inherently buggy because it makes the whole program only stable within a certain frequency range.




From brianw at audiobanshee.com  Sat Dec 18 22:05:01 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Sat, 18 Dec 2021 13:05:01 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
References: <CACodTR-3BYrRjM+CJLLi6httGZoC=KaVq8ZPnYgcUsieLcQoRg@mail.gmail.com>
 <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
Message-ID: <B35CFA3C-004E-41A1-815A-B0D0BF26453C@audiobanshee.com>

It's more likely that the receiver *averages* the periods between the last 12 in order to set the period for its 16th-note timer. This assumes that 32nd notes are not allowed.

If those 48 PPQ blips are not equally spaced, then they will cause the average period to rise and fall even though it should be constant.

Brian


On Dec 18, 2021, at 12:56, Benjamin Tremblay <btremblay at me.com> wrote:
> I?m assuming all it does is divide by 12 to get a 16th note. 
> 
> Benjamin Tremblay
> 
> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com> wrote:
>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org> wrote:
>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
>> 
>> One suspects that most people are trying to write a general purpose converter.  E.g. you could run those 48ppq out to some other module, like an analog sequencer, and it would keep time.  I'm not familiar with the KPR-77, but I'm also slightly puzzled by the idea that some piece of gear would require 48PPQN but not care about the timing of half of the pulses.
>> 
>> Pete 




From pete.hartman at gmail.com  Sat Dec 18 22:10:46 2021
From: pete.hartman at gmail.com (Pete Hartman)
Date: Sat, 18 Dec 2021 15:10:46 -0600
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
References: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
 <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
Message-ID: <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>

Right but where the divisions are going to fall when you're doing an odd
divisor that includes a factor of 3 is going to shift around if the pulses
being divided aren't evenly spaced.

I tried to make an ASCII representation to verify this expectation:

|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |   |      Original pulse train
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | | | | | | | | | |    evenly divided
|     |     |     |     |     |     |     |     |     |     |     |     |
  |     |     |     |     |     |     |     |     |    divide by 3
||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||
 ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||     unevenly divided
|    |      |    |      |    |      |    |      |    |      |    |      |
 |      |    |      |    |      |    |      |    |     divide by 3
|     |     |     |     |     |     |     |     |     |     |     |     |
  |     |     |     |     |     |     |     |     |    the even div/3 for
comparison

Hopefully everyone's email clients can cope with the monospace required to
make this obvious.




On Sat, Dec 18, 2021 at 3:00 PM Benjamin Tremblay <btremblay at mac.com> wrote:

> If I?m waiting around doing nothing until I count 12 pulses, all that
> matters is I construct a square wave 12 pulses long.
>
> Benjamin Tremblay
>
> On Dec 18, 2021, at 3:56 PM, Benjamin Tremblay <btremblay at me.com> wrote:
>
> ?I?m assuming all it does is divide by 12 to get a 16th note.
>
> Benjamin Tremblay
>
> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com> wrote:
>
> ?
>
>
> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>>
>> 2) I wish I understood the theory of clock multipliers. I have seen code
>> that measures the period between clock pulses and dead reckons the
>> double-time pulse as an average of the recent periods. But why? Why can?t I
>> just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event?
>> Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the
>> clock down to individual sequencer steps on the KPR-77. As long as the
>> divided clock is coming in on the beat, what does it matter if some of the
>> synthetic pulses are a little off? (They?re just shadows of the main tempo
>> clock). It?s not like the KPR-77 is inferring something or trying to
>> calculate BPM from the external clock? So? Anyway I just wish I knew what I
>> was aiming for, and then maybe I could hit the target.
>>
>
> One suspects that most people are trying to write a general purpose
> converter.  E.g. you could run those 48ppq out to some other module, like
> an analog sequencer, and it would keep time.  I'm not familiar with the
> KPR-77, but I'm also slightly puzzled by the idea that some piece of gear
> would require 48PPQN but not care about the timing of half of the pulses.
>
> Pete
>
>
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From tom at electricdruid.net  Sat Dec 18 22:23:36 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Sat, 18 Dec 2021 21:23:36 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>
References: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
 <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
 <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>
Message-ID: <F886D96B-6C25-4D5A-A194-2886A7B3A4DB@electricdruid.net>

I'm with Pete. Arguing that "we're doing timing, but it doesn't matter where the pulses fall" seems like a one-way ticket to failure.

Unless "drunk jazz drummer" is the effect you're after? ;)

> On 18 Dec 2021, at 21:10, Pete Hartman via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Right but where the divisions are going to fall when you're doing an odd divisor that includes a factor of 3 is going to shift around if the pulses being divided aren't evenly spaced.
> 
> I tried to make an ASCII representation to verify this expectation:
> 
> |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |      Original pulse train
> | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |    evenly divided
> |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |    divide by 3
> ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||     unevenly divided
> |    |      |    |      |    |      |    |      |    |      |    |      |    |      |    |      |    |      |    |      |    |     divide by 3
> |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |    the even div/3 for comparison
> 
> Hopefully everyone's email clients can cope with the monospace required to make this obvious.
> 
> 
> 
> 
> On Sat, Dec 18, 2021 at 3:00 PM Benjamin Tremblay <btremblay at mac.com <mailto:btremblay at mac.com>> wrote:
> If I?m waiting around doing nothing until I count 12 pulses, all that matters is I construct a square wave 12 pulses long.
> 
> Benjamin Tremblay
> 
>> On Dec 18, 2021, at 3:56 PM, Benjamin Tremblay <btremblay at me.com <mailto:btremblay at me.com>> wrote:
>> 
>> ?I?m assuming all it does is divide by 12 to get a 16th note. 
>> 
>> Benjamin Tremblay
>> 
>>> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com <mailto:pete.hartman at gmail.com>> wrote:
>>> 
>>> ?
>>> 
>>> 
>>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
>>> 
>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
>>> 
>>> One suspects that most people are trying to write a general purpose converter.  E.g. you could run those 48ppq out to some other module, like an analog sequencer, and it would keep time.  I'm not familiar with the KPR-77, but I'm also slightly puzzled by the idea that some piece of gear would require 48PPQN but not care about the timing of half of the pulses.
>>> 
>>> Pete 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From synthdiy at adambaby.com  Sat Dec 18 22:32:11 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Sun, 19 Dec 2021 07:32:11 +1000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>
References: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
 <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
 <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>
Message-ID: <748F8EBA-02A3-49AD-BF81-1CE9606BA213@adambaby.com>


Avoid DAW generated midi clock like the plague!

https://www.innerclocksystems.com/sync-gen-3lx <https://www.innerclocksystems.com/sync-gen-3lx>

Innerclock have addressed this problem.

They use an audio pulse generated by the DAW to produce jitter-free midi clock in hardware, with optional pulse outs of between 4 - 96ppqn.

A


btw, that KPR problem is not unique: the TR-909 has a similar bug in V1 of it?s firmware, where it would ?lose? midi clocks when being slaved. I always slave to DIN sync to get around this.





> 
> On Sat, Dec 18, 2021 at 3:00 PM Benjamin Tremblay <btremblay at mac.com <mailto:btremblay at mac.com>> wrote:
> If I?m waiting around doing nothing until I count 12 pulses, all that matters is I construct a square wave 12 pulses long.
> 
> Benjamin Tremblay
> 
>> On Dec 18, 2021, at 3:56 PM, Benjamin Tremblay <btremblay at me.com <mailto:btremblay at me.com>> wrote:
>> 
>> ?I?m assuming all it does is divide by 12 to get a 16th note. 
>> 
>> Benjamin Tremblay
>> 
>>> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com <mailto:pete.hartman at gmail.com>> wrote:
>>> 
>>> ?
>>> 
>>> 
>>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
>>> 
>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
>>> 
>>> One suspects that most people are trying to write a general purpose converter.  E.g. you could run those 48ppq out to some other module, like an analog sequencer, and it would keep time.  I'm not familiar with the KPR-77, but I'm also slightly puzzled by the idea that some piece of gear would require 48PPQN but not care about the timing of half of the pulses.
>>> 
>>> Pete 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
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From pete.hartman at gmail.com  Sat Dec 18 22:37:14 2021
From: pete.hartman at gmail.com (Pete Hartman)
Date: Sat, 18 Dec 2021 15:37:14 -0600
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <0F4904C4-DA22-43D4-A333-D37D28D73677@mac.com>
References: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
 <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
 <CACodTR9MotAH1ANxTC8Jb9xrXmsibj5FmA7Y2d0=iH_Hv2aL5g@mail.gmail.com>
 <F886D96B-6C25-4D5A-A194-2886A7B3A4DB@electricdruid.net>
 <0F4904C4-DA22-43D4-A333-D37D28D73677@mac.com>
Message-ID: <CACodTR8WKof-bBD5NJhyN82tNrpt_ogqhLRFwsDtvpdM90ecDQ@mail.gmail.com>

Right, if you have a factor of 2 in there, that may hide the problem.  But
if you want to simply divide into 32nd note triplets, you're screwed :-D

Pete

On Sat, Dec 18, 2021 at 3:35 PM Benjamin Tremblay <btremblay at mac.com> wrote:

> I was seeing it like a square wave based on 48ppq divided by 12. In that
> case, it doesn?t matter what the duty cycle of the wave is, what matters is
> the the frequency.
> The counter goes ONE 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, TWO, 2, 3, 4, 5,
> 6, 7, 8, 9, 10, 11, 12? And as long at that first pulse (which is not
> synthetic) lands on the right time, it works perfectly.
> In theory the other 11 pulses could be all bunched together and it would
> not matter.
>
> On Dec 18, 2021, at 4:23 PM, Tom Wiltshire <tom at electricdruid.net> wrote:
>
> I'm with Pete. Arguing that "we're doing timing, but it doesn't matter
> where the pulses fall" seems like a one-way ticket to failure.
>
> Unless "drunk jazz drummer" is the effect you're after? ;)
>
> On 18 Dec 2021, at 21:10, Pete Hartman via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
> Right but where the divisions are going to fall when you're doing an odd
> divisor that includes a factor of 3 is going to shift around if the pulses
> being divided aren't evenly spaced.
>
> I tried to make an ASCII representation to verify this expectation:
>
> |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
>   |   |   |   |   |   |   |   |   |   |   |   |   |      Original pulse
> train
> | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
> | | | | | | | | | | | | | | | | | | | | | | | | | | |    evenly divided
> |     |     |     |     |     |     |     |     |     |     |     |     |
>     |     |     |     |     |     |     |     |     |    divide by 3
> ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||
>  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||     unevenly divided
> |    |      |    |      |    |      |    |      |    |      |    |      |
>    |      |    |      |    |      |    |      |    |     divide by 3
> |     |     |     |     |     |     |     |     |     |     |     |     |
>     |     |     |     |     |     |     |     |     |    the even div/3 for
> comparison
>
> Hopefully everyone's email clients can cope with the monospace required to
> make this obvious.
>
>
>
>
> On Sat, Dec 18, 2021 at 3:00 PM Benjamin Tremblay <btremblay at mac.com>
> wrote:
>
>> If I?m waiting around doing nothing until I count 12 pulses, all that
>> matters is I construct a square wave 12 pulses long.
>>
>> Benjamin Tremblay
>>
>> On Dec 18, 2021, at 3:56 PM, Benjamin Tremblay <btremblay at me.com> wrote:
>>
>> ?I?m assuming all it does is divide by 12 to get a 16th note.
>>
>> Benjamin Tremblay
>>
>> On Dec 18, 2021, at 3:53 PM, Pete Hartman <pete.hartman at gmail.com> wrote:
>>
>> ?
>>
>>
>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>>
>>>
>>> 2) I wish I understood the theory of clock multipliers. I have seen code
>>> that measures the period between clock pulses and dead reckons the
>>> double-time pulse as an average of the recent periods. But why? Why can?t I
>>> just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event?
>>> Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the
>>> clock down to individual sequencer steps on the KPR-77. As long as the
>>> divided clock is coming in on the beat, what does it matter if some of the
>>> synthetic pulses are a little off? (They?re just shadows of the main tempo
>>> clock). It?s not like the KPR-77 is inferring something or trying to
>>> calculate BPM from the external clock? So? Anyway I just wish I knew what I
>>> was aiming for, and then maybe I could hit the target.
>>>
>>
>> One suspects that most people are trying to write a general purpose
>> converter.  E.g. you could run those 48ppq out to some other module, like
>> an analog sequencer, and it would keep time.  I'm not familiar with the
>> KPR-77, but I'm also slightly puzzled by the idea that some piece of gear
>> would require 48PPQN but not care about the timing of half of the pulses.
>>
>> Pete
>>
>> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
>
>
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From brianw at audiobanshee.com  Sat Dec 18 23:04:22 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Sat, 18 Dec 2021 14:04:22 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
References: <9742BBCE-45E3-42E0-98D2-0B07595166CC@me.com>
 <2C9D6598-BB0D-4153-8DA4-57B6032A6F3F@mac.com>
Message-ID: <CB108EBE-0424-43DE-BB9D-B7A4AD34334F@audiobanshee.com>

It's tempting to think of code design in (individual) human terms - as if you could shrink yourself down small enough to fit inside the processor and handle everything yourself. If that were the best approach, then you might be waiting around doing nothing but counting to 12 before taking action to flip an output pin.

The problem is: this isn't very efficient. It's like the small business that fails because the owner is trying to do everything (instead of delegating many tasks to specialists). A CPU can only execute one thing at a time, so even "waiting around doing nothing" takes a few cycles, causing delays when something finally does happen.


Instead, it's helpful to think of a team of multiple people with a manager, or a band with a band leader / conductor. How does a tight rhythm section stay in sync? Do the drummer and bassist each wait around doing nothing until the other one hits the down beat? No: each musician builds an internal tempo model, anticipates when the beat will hit, and then plays accordingly (with built-in mental compensation for internal delays between thoughts and muscle reactions).

So, a good MIDI system is going to separate the task of following incoming PPQ from generating its own music events and clock. This internal tempo is most likely going to be a timer peripheral. Incoming PPQ are all considered as contributing to the model of the actual tempo. The timer drives the musical events and clock, but there's no "waiting around doing nothing," at least not anywhere in the timing-critical code. It's not exactly a perfect analogy with a band, because the operations are divided along different lines, but the key is to think of individual pieces - each handling a very specific aspect of the overall device - but coordinated to produce the desired result.


By the way, there is one kind of processor that literally does wait, doing nothing, until something happens. This is the XMOS series of processors. They have lots of cores - at least 8 or probably 16 cores - where the code designer separates the overall features into separate parts. A single core will literally block until a particular hardware event, and then that core can start up faster even than an interrupt handler on a "normal" processor. Some processors have a "wait" opcode, but it stops everything, whereas the XMOS can stop each core independently so that things can happen.

Normally, though, you're going to have hardware peripherals driving pins directly, or (timer) interrupts driving operations with minimal latency overhead. It's all about designing around multiple "moving" parts, rather than trying to design everything into a single thread of code.

Brian


On Dec 18, 2021, at 13:00, Benjamin Tremblay wrote:
> If I?m waiting around doing nothing until I count 12 pulses, all that matters is I construct a square wave 12 pulses long.
> 
> Benjamin Tremblay
> 
> On Dec 18, 2021, at 3:56 PM, Benjamin Tremblay wrote:
>> ?I?m assuming all it does is divide by 12 to get a 16th note. 
>> 
>> Benjamin Tremblay
>> 
>> On Dec 18, 2021, at 3:53 PM, Pete Hartman wrote:
>>> On Sat, Dec 18, 2021 at 2:15 PM Benjamin Tremblay wrote:
>>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
>>>> 
>>> One suspects that most people are trying to write a general purpose converter.  E.g. you could run those 48ppq out to some other module, like an analog sequencer, and it would keep time.  I'm not familiar with the KPR-77, but I'm also slightly puzzled by the idea that some piece of gear would require 48PPQN but not care about the timing of half of the pulses.
>>> 
>>> Pete 




From gordonjcp at gjcp.net  Sun Dec 19 11:47:47 2021
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Sun, 19 Dec 2021 10:47:47 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
Message-ID: <20211219104747.GA18176@gjcp.net>

On Sat, Dec 18, 2021 at 03:12:17PM -0500, Benjamin Tremblay via Synth-diy wrote:

> So, two different problems. 
> 1) MIDI clock dropping out on groove boxes. 

Depending on how much traffic the 202 is sending it may be overwhelming the Arduino.  It's a very slow processor (16MHz) with a very small amount of RAM (2kB) even by the standards of 20 years ago.  It's pretty fast but still a pitiful amount of RAM compared to the 8-bit computers I grew up with!

The Arduino libraries are crufty as hell because they try to give the same C++ experience on a huge range of hardware, so there's a lot of steps to get from "Oh I just heard a byte come in" to "here is a clock pulse".  You'd be better off not using the Arduino serial code at all and writing your own handler that deals with the clock pulse first right there in the interrupt service routine, while it's as fresh as possible.  Given that you're only looking for MIDI Clock, Start, Stop and Continue, you don't have to care about parsing MIDI.  Systems Realtime bytes can occur anywhere in any message, even Sysex messages, and are always to be interpreted as exactly what they are, as quickly as possible.

> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.

If you just do a double pulse it'll likely work, but if it derives shuffle from that then it'll sound quite wonky.

It's something I've wondered about myself, based on the 48ppcn shuffle on the Akai MPC family starting with the MPC60.  If you want to shuffle semiquavers so that you go from ticktickticktick to more like tick titick titick ti then you have to count incoming clocks differently.  For a straight ahead feel you'd just play your note on the first clock pulse of six TICK clock clock clock clock clock TICK clock clock clock clock clock.  To shuffle that, you'd take pairs of semiquavers and count maybe seven then five, pushing the second note a little late.  The "percentage" shuffle is the count of clocks between the first and second note divided by the twelve midi clocks in two semiquavers, so for 7/5 it'd be 58%.  8/4 would be 67% shuffle (definitely lumpy sounding) and 9/3 would be 75% shuffle (Soul II Soul - Keep On Movin', Enigma - Ode to Sadeness both spring to mind).

Now on an MPC60 you can set 54% so that means it must be 48ppcn, so each semiquaver is 12 clocks and each shuffle pair is 24 clocks.  At 48ppcn 12/24 would be 50% shuffle, 13/24 would be 54%, 14/24 would be - yup - 58%, 62%, 66%, 70%, and 18/24 would be 75% shuffle.

So I guess the MPC60 must use some sort of software PLL to evenly double up the incoming clock pulses to get 48ppcn clocks.  The Roland W30 has something like 192ppcn and also responds to external MIDI clock, so it must do some very clever measurement - or, perhaps, when you get that fine you don't really notice a bit of wibbly-wobbly clocking.

-- 
Gordonjcp
 


From synthdiy at adambaby.com  Sun Dec 19 12:50:42 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Sun, 19 Dec 2021 21:50:42 +1000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <20211219104747.GA18176@gjcp.net>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
Message-ID: <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>



> On 19 Dec 2021, at 20:47, Gordonjcp <gordonjcp at gjcp.net> wrote:
> 
> So I guess the MPC60 must use some sort of software PLL to evenly double up the incoming clock pulses to get 48ppcn clocks.  The Roland W30 has something like 192ppcn and also responds to external MIDI clock, so it must do some very clever measurement - or, perhaps, when you get that fine you don't really notice a bit of wibbly-wobbly clocking.


I?ve not used a W30, but I understand it?s sequencer runs the standard Roland ?Super MRC? software that runs on the MC-300, MC-500 and MC-50 midi sequencers, and that runs at 96ppqn, not 192.
Also swing or shuffle aren?t actually even mentioned in the manual, and there is no specific setting for this, you have to do a little trick with the quantize function.
Another problem is that various companies don?t stick to a standard when it comes to using the ?percent? terminology.
Roger Linn explains it thus:

"My implementation of swing has always been very simple: I merely delay the second 16th note within each 8th note. In other words, I delay all the even-numbered 16th notes within the beat (2, 4, 6, 8, etc.) In my products I describe the swing amount in terms of the ratio of time duration between the first and second 16th notes within each 8th note. For example, 50% is no swing, meaning that both 16th notes within each 8th note are given equal timing. And 66% means perfect triplet swing, meaning that the first 16th note of each pair gets 2/3 of the time, and the second 16th note gets 1/3, so the second 16th note falls on a perfect 8th note triplet."

but Cubase has another method altogether!!

Gordon you said 67% sounds ?lumpy?? but that?s just triplets! It shouldn?t sound lumpy? unless not everyone is in sync!

I take a look at some of this stuff here
https://mezzoauto.blogspot.com/2017/08/swing-conversion.html <https://mezzoauto.blogspot.com/2017/08/swing-conversion.html>

WRT to Spiros original enquiry, I don?t understand why you need to drastically change your clock PPQN numbers in order to experiment with polymeter rhythms? but then, I?m not using modular gear. 
What you definitely do need is rock solid clocking at whatever your chosen resolution, so that any subtleties like the push and pull of swing aren?t lost in the jitter.

A
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From spirosmakris92 at gmail.com  Sun Dec 19 13:06:42 2021
From: spirosmakris92 at gmail.com (Spiros Makris)
Date: Sun, 19 Dec 2021 14:06:42 +0200
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
 <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
Message-ID: <CAGbpyReFzVydqSm4X+LxVzm05_AEhbVkMkWJ+Smqa=um1J0ADg@mail.gmail.com>

You don't *need* this kind of resolution to play around polyrhythms and
such, but musicians tend to come up with all sorts of crazy feature
requests. This particular one was the result of a discussion with a
percussionist, who has some experience in Indian percussion.
His approach, which I found rather interesting, is that you should have the
option of defining how many notes will be played within a "beat", and let
you make the "beat" equal to any of the rhythm values. So, for example,
things like 3 notes within a quarter or 5 within a dotted eight would
somehow be legit settings. Add 7 more channels to this and you have some
proper madness to play with.
Do I understand how he'd make music with this? Not really. But I think it's
a very interesting challenge from a technical standpoint.


On Sun, 19 Dec 2021 at 13:53, Adam Inglis (synthDIY) <synthdiy at adambaby.com>
wrote:

>
>
> On 19 Dec 2021, at 20:47, Gordonjcp <gordonjcp at gjcp.net> wrote:
>
> So I guess the MPC60 must use some sort of software PLL to evenly double
> up the incoming clock pulses to get 48ppcn clocks.  The Roland W30 has
> something like 192ppcn and also responds to external MIDI clock, so it must
> do some very clever measurement - or, perhaps, when you get that fine you
> don't really notice a bit of wibbly-wobbly clocking.
>
>
>
> I?ve not used a W30, but I understand it?s sequencer runs the standard
> Roland ?Super MRC? software that runs on the MC-300, MC-500 and MC-50 midi
> sequencers, and that runs at 96ppqn, not 192.
> Also swing or shuffle aren?t actually even mentioned in the manual, and
> there is no specific setting for this, you have to do a little trick with
> the quantize function.
> Another problem is that various companies don?t stick to a standard when
> it comes to using the ?percent? terminology.
> Roger Linn explains it thus:
>
> "My implementation of swing has always been very simple: I merely delay
> the second 16th note within each 8th note. In other words, I delay all the
> even-numbered 16th notes within the beat (2, 4, 6, 8, etc.) In my products
> I describe the swing amount in terms of the ratio of time duration between
> the first and second 16th notes within each 8th note. For example, 50% is
> no swing, meaning that both 16th notes within each 8th note are given equal
> timing. And 66% means perfect triplet swing, meaning that the first 16th
> note of each pair gets 2/3 of the time, and the second 16th note gets 1/3,
> so the second 16th note falls on a perfect 8th note triplet."
>
> but Cubase has another method altogether!!
>
> Gordon you said 67% sounds ?lumpy?? but that?s just triplets! It shouldn?t
> sound lumpy? unless not everyone is in sync!
>
> I take a look at some of this stuff here
> https://mezzoauto.blogspot.com/2017/08/swing-conversion.html
>
> WRT to Spiros original enquiry, I don?t understand why you need to
> drastically change your clock PPQN numbers in order to experiment with
> polymeter rhythms? but then, I?m not using modular gear.
> What you definitely do need is rock solid clocking at whatever your chosen
> resolution, so that any subtleties like the push and pull of swing aren?t
> lost in the jitter.
>
> A
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From gordonjcp at gjcp.net  Sun Dec 19 14:55:22 2021
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Sun, 19 Dec 2021 13:55:22 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
 <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
Message-ID: <20211219135522.GB18176@gjcp.net>

On Sun, Dec 19, 2021 at 09:50:42PM +1000, Adam Inglis (synthDIY) wrote:
> 
> 
> > On 19 Dec 2021, at 20:47, Gordonjcp <gordonjcp at gjcp.net> wrote:
> > 
> > So I guess the MPC60 must use some sort of software PLL to evenly double up the incoming clock pulses to get 48ppcn clocks.  The Roland W30 has something like 192ppcn and also responds to external MIDI clock, so it must do some very clever measurement - or, perhaps, when you get that fine you don't really notice a bit of wibbly-wobbly clocking.
> 
> 
> I?ve not used a W30, but I understand it?s sequencer runs the standard Roland ?Super MRC? software that runs on the MC-300, MC-500 and MC-50 midi sequencers, and that runs at 96ppqn, not 192.

It could be.  Both of mine are stored in a mate's workshop just now until I find somewhere with enough space for anything bigger than an ES1 and a pair of headphones.

> Also swing or shuffle aren?t actually even mentioned in the manual, and there is no specific setting for this, you have to do a little trick with the quantize function.

They're not, but you can nudge the timing of individual notes.  It's kind of a shame that you can't do this on-the-fly, but there you go.  The Alesis HR16 can quantise with swing but can't apply swing on playback.

The maths around applying swing to notes that might not have started out bang on the grid probably get a bit too interesting for 8-bit MCUs!

> 
> Gordon you said 67% sounds ?lumpy?? but that?s just triplets! It shouldn?t sound lumpy? unless not everyone is in sync!

Bump-dadump-dadump-da-dump, rather than "timing all over the place".  It's hard to convey in an email.

> 
> I take a look at some of this stuff here
> https://mezzoauto.blogspot.com/2017/08/swing-conversion.html <https://mezzoauto.blogspot.com/2017/08/swing-conversion.html>
> 
> WRT to Spiros original enquiry, I don?t understand why you need to drastically change your clock PPQN numbers in order to experiment with polymeter rhythms? but then, I?m not using modular gear. 
> What you definitely do need is rock solid clocking at whatever your chosen resolution, so that any subtleties like the push and pull of swing aren?t lost in the jitter.

I guess it's so that you can divide "strange" note lengths.  I've always assumed that 24ppcn was chosen because it divides nicely for 2/4, 3/4, 4/4, 6/8, and 12/8, and in both simple and compound time you can have triplet notes, and you don't have any leftovers at the end of the bar.  With 5/4 you'd have 19.2 clocks per crotchet, with a clock left over at the end making the last note in the bar a bawhair longer.  Now you could position that spare clock anywhere but I reckon you'd always hear it!  That might give a bit of a noticeable "pulse" to the bar, although if you're dicking about with polymeter are you really going to notice or care?

Dividing into 7/4 and 9/4 give increasing amounts of "leftovers" to cope with.  I guess this is where you'd use a large Euclidean sequence generator to spread the error out across the beats in the bar.  Either way the greater the number of clocks, the better the chance of dividing the bar up evenly so that four crotchets fit as well as your polymetric part.  You could also just pick meters where you have a number of clock pulses that divides evenly into both, but my maths is nowhere good enough for that.

-- 
Gordonjcp



From btremblay at me.com  Sun Dec 19 16:00:26 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Sun, 19 Dec 2021 10:00:26 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
 <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
Message-ID: <1431D00D-083F-46D7-BA20-0623437B68D0@me.com>

Thanks to all for the responses, I apologize for hijacking the thread.

> On Dec 19, 2021, at 6:50 AM, Adam Inglis (synthDIY) <synthdiy at adambaby.com> wrote:
> 
> 
> 
>> On 19 Dec 2021, at 20:47, Gordonjcp <gordonjcp at gjcp.net <mailto:gordonjcp at gjcp.net>> wrote:
>> 
>> So I guess the MPC60 must use some sort of software PLL to evenly double up the incoming clock pulses to get 48ppcn clocks.  The Roland W30 has something like 192ppcn and also responds to external MIDI clock, so it must do some very clever measurement - or, perhaps, when you get that fine you don't really notice a bit of wibbly-wobbly clocking.
> 
> 
> I?ve not used a W30, but I understand it?s sequencer runs the standard Roland ?Super MRC? software that runs on the MC-300, MC-500 and MC-50 midi sequencers, and that runs at 96ppqn, not 192.
> Also swing or shuffle aren?t actually even mentioned in the manual, and there is no specific setting for this, you have to do a little trick with the quantize function.
> Another problem is that various companies don?t stick to a standard when it comes to using the ?percent? terminology.
> Roger Linn explains it thus:
> 
> "My implementation of swing has always been very simple: I merely delay the second 16th note within each 8th note. In other words, I delay all the even-numbered 16th notes within the beat (2, 4, 6, 8, etc.) In my products I describe the swing amount in terms of the ratio of time duration between the first and second 16th notes within each 8th note. For example, 50% is no swing, meaning that both 16th notes within each 8th note are given equal timing. And 66% means perfect triplet swing, meaning that the first 16th note of each pair gets 2/3 of the time, and the second 16th note gets 1/3, so the second 16th note falls on a perfect 8th note triplet."
> 
> but Cubase has another method altogether!!
> 
> Gordon you said 67% sounds ?lumpy?? but that?s just triplets! It shouldn?t sound lumpy? unless not everyone is in sync!
> 
> I take a look at some of this stuff here
> https://mezzoauto.blogspot.com/2017/08/swing-conversion.html <https://mezzoauto.blogspot.com/2017/08/swing-conversion.html>
> 
> WRT to Spiros original enquiry, I don?t understand why you need to drastically change your clock PPQN numbers in order to experiment with polymeter rhythms? but then, I?m not using modular gear. 
> What you definitely do need is rock solid clocking at whatever your chosen resolution, so that any subtleties like the push and pull of swing aren?t lost in the jitter.
> 
> A
> _______________________________________________
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> Synth-diy at synth-diy.org
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From synthdiy at adambaby.com  Mon Dec 20 03:36:59 2021
From: synthdiy at adambaby.com (Adam Inglis (synthDIY))
Date: Mon, 20 Dec 2021 12:36:59 +1000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyReFzVydqSm4X+LxVzm05_AEhbVkMkWJ+Smqa=um1J0ADg@mail.gmail.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
 <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
 <CAGbpyReFzVydqSm4X+LxVzm05_AEhbVkMkWJ+Smqa=um1J0ADg@mail.gmail.com>
Message-ID: <5B35BCDE-4E68-48E0-80CA-060D13895065@adambaby.com>



> On 19 Dec 2021, at 22:06, Spiros Makris <spirosmakris92 at gmail.com> wrote:
> 
> You don't *need* this kind of resolution to play around polyrhythms and such, but musicians tend to come up with all sorts of crazy feature requests. This particular one was the result of a discussion with a percussionist, who has some experience in Indian percussion.
> His approach, which I found rather interesting, is that you should have the option of defining how many notes will be played within a "beat", and let you make the "beat" equal to any of the rhythm values. So, for example, things like 3 notes within a quarter or 5 within a dotted eight would somehow be legit settings. Add 7 more channels to this and you have some proper madness to play with.
> Do I understand how he'd make music with this? Not really. But I think it's a very interesting challenge from a technical standpoint.

Agree, it does sound interesting.
Certainly there is potential for ?proper madness?  !!!   ? for it to become music it will need careful control!

I?ve found when messing around, not so much with polyrhythms, but certainly with ?odd? time signatures, that it takes a good musician to show how it all makes sense. 
Play around with 7/8 on a drum machine and instrument of your choice, hmmm, hard to get a groove going? then you hear what Brubeck did with it, and you go "ah ha, now I get it!?

A


From btremblay at me.com  Mon Dec 20 04:50:17 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Sun, 19 Dec 2021 22:50:17 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <5B35BCDE-4E68-48E0-80CA-060D13895065@adambaby.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <20211219104747.GA18176@gjcp.net>
 <78FAD282-80C2-4AA9-ABCF-44D5E33AE3F4@adambaby.com>
 <CAGbpyReFzVydqSm4X+LxVzm05_AEhbVkMkWJ+Smqa=um1J0ADg@mail.gmail.com>
 <5B35BCDE-4E68-48E0-80CA-060D13895065@adambaby.com>
Message-ID: <A9910E1C-2E58-48E1-8D89-EA6840727ED2@me.com>

To me the design constraints of a MIDI clock multiplier are both tempo and accuracy.  Just achieving accuracy is enough to keep my up at night.
Obviously the very worst thing that could happen was you lose any clock pulses.
So you must get and propagate all the original pulses, because one missing pulse can ruin your whole day.
Then you must ensure that if your receiving machine needs 2 pulses for every pulse received, it gets exactly one extra pulse per pulse.

Because, I want the controlling drum machine and following drum machine to be in lock step with no audible delay between beats. I don?t want a machine that guesses the tempo and tries to keep up. I want 2 machines that are literally locked together.

Then, and that?s a tall request, you can worry about whether tempo changes are natural and divisible for polyrhythms etc. 





> On Dec 19, 2021, at 9:36 PM, Adam Inglis (synthDIY) <synthdiy at adambaby.com> wrote:
> 
> 
> 
>> On 19 Dec 2021, at 22:06, Spiros Makris <spirosmakris92 at gmail.com> wrote:
>> 
>> You don't *need* this kind of resolution to play around polyrhythms and such, but musicians tend to come up with all sorts of crazy feature requests. This particular one was the result of a discussion with a percussionist, who has some experience in Indian percussion.
>> His approach, which I found rather interesting, is that you should have the option of defining how many notes will be played within a "beat", and let you make the "beat" equal to any of the rhythm values. So, for example, things like 3 notes within a quarter or 5 within a dotted eight would somehow be legit settings. Add 7 more channels to this and you have some proper madness to play with.
>> Do I understand how he'd make music with this? Not really. But I think it's a very interesting challenge from a technical standpoint.
> 
> Agree, it does sound interesting.
> Certainly there is potential for ?proper madness?  !!!   ? for it to become music it will need careful control!
> 
> I?ve found when messing around, not so much with polyrhythms, but certainly with ?odd? time signatures, that it takes a good musician to show how it all makes sense. 
> Play around with 7/8 on a drum machine and instrument of your choice, hmmm, hard to get a groove going? then you hear what Brubeck did with it, and you go "ah ha, now I get it!?
> 
> A
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From modular at go2.pl  Mon Dec 20 11:30:49 2021
From: modular at go2.pl (Roman Sowa)
Date: Mon, 20 Dec 2021 11:30:49 +0100
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
Message-ID: <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>

When you say "complex pattern" I see a lot of MIDI messages, and then 
the clock messages like to be trapped between bytes of single note 
message. So maybe, just maybe your Arduino code, or library you've used 
are not capable to see a MIDI clock message trapped inside a note 
message, or simply get overloaded.

Is it Arduino doing or KPR itself is best to check on a scope with 
trigger set to timeout on decoded clock byte.

Roman

W dniu 2021-12-18 o?21:12, Benjamin Tremblay via Synth-diy pisze:
> Interesting topic!
> 
> I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
> 
> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.
> 
> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
> 
> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
> 
> So, two different problems.
> 1) MIDI clock dropping out on groove boxes.
> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
> 


From btremblay at me.com  Mon Dec 20 13:46:05 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Mon, 20 Dec 2021 07:46:05 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
Message-ID: <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>

@Roman
Yes I believe your theory is correct; it?s an issue with not handling a tangled bunch of messages. But I can?t prove it, and I if it?s true I don?t know what to do about.

The history of this goes back to the middle of the summer. 
I was working on MIDI interface for a Roland CR-5000 and experienced these problems while trying to generate the 24ppq clock.
This is when I first experienced this issue while testing using the DR-202.
After spending many hours twiddling the code, I decided I wanted to try this with a Teensy 4, so I could see if it was a speed issue, and also so I could get good logging over the USB port.
The issue was exactly the same on the Teensy.  I was surprised it was not an Arduino speed issue at all.
The logs showed the code I was using to measure the time between MIDI clock events was varying wildly when I played a house music or latin groove on the 202. 
As if the MIDI parser was choking on nearly-simultaneous events.
My code?s pretty simple, it looks like a boilerplate Arduino MIDI Library code example using MIDI clock, start/stop/resume.
I simply measure microseconds and generate the clock pulses when micros() exceeds the estimated clock pulse duration.

#define CLOCK_LENGTH 3333  // microseconds

void setupMidi() {
  if (USE_SERIAL) {
    Serial.println("setupMidi");
  }
  MIDI.begin(RECEIVE_CHANNEL);
  MIDI.setHandleNoteOn(handleNoteOnMidi);
  MIDI.setHandleClock(myClock);
  MIDI.setHandleStart(onClockStart);
  MIDI.setHandleContinue(onClockStart);
  MIDI.setHandleStop(onClockStop);
  if (USE_SERIAL) {
    Serial.println("setupMidi DONE");
  }
}

void myClock() {
  if (CLOCK_RUNNING) {
    digitalWrite(CLOCK_OUT, LOW);
    clockFuture = micros(); // *
  }
}

// *In previous iterations I tired to recalculate CLOCK_LENGTH by averaging, etc. It simply won?t work if its? far from 3000?s.

void loop() {
  MIDI.read();
  if (CLOCK_RUNNING) {
    if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
      digitalWrite(CLOCK_OUT, HIGH);
      clockFuture = 0;
    }
  } ? etc

// ** If I subtract micros() from clockFuture, this number goes crazy when I play a thick loop on the 202.

In spite of my avoidance of delayMicroseconds(), this code is sensitive to timing because CLOCK_LENGTH (is a constant here, but I have tried to make it dynamic in other builds) is inflexible.

I have seen some GitHub projects that use interrupts for the MIDI clock and time calculations. I have never written my own interrupt code but would gladly go that way if I was certain it could fix this problem.  But, it seems like I am hitting a hard limitation of 5 pin MIDI? The folks who write fast code with MIDI clock seem to skip ahead to using USB for real-time messages, etc.

When I was playing with the awesome cheerful.nl <http://cheerful.nl/> OPL2 Audio Board, the author provided some lean MIDI parsing code and skipped the MIDI library. (Especially a no-op for sysex.) So I forked that and tried a lean implementation. Same problem! Lag when the 202 go busy with CC messages and snare rolls.

So I reverted my code back to Arduino MIDI Library, cleaned up the source, removed dead code, and tested it using everything I learned. It runs OK when I use a dumb drum machine like an SR-16. It chokes on the floofy beats of 1998 in my DR-202. 

Finally after months, I ported the code back to Arduino Mega and runs virtually the same as on the Teensy 4.

What I don?t know is, when the 202 gets busy, how can I ditch all the MIDI events I don?t care about without waiting a long time to get the ones I do care about? As bad as the DR-202?s MIDI implementation may be, I have to assume there are many boxes (including a Yamaha QY-22 I was also testing) which send out these swooshing sweeping resonant filter CC events and sysex param tweaks in their drum-and-bass patterns.

I am assuming that someone, somewhere has mitigated this problem. I want to know how she or he did it.

Ben

> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl> wrote:
> 
> When you say "complex pattern" I see a lot of MIDI messages, and then the clock messages like to be trapped between bytes of single note message. So maybe, just maybe your Arduino code, or library you've used are not capable to see a MIDI clock message trapped inside a note message, or simply get overloaded.
> 
> Is it Arduino doing or KPR itself is best to check on a scope with trigger set to timeout on decoded clock byte.
> 
> Roman
> 
> W dniu 2021-12-18 o 21:12, Benjamin Tremblay via Synth-diy pisze:
>> Interesting topic!
>> I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
>> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.
>> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
>> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
>> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
>> So, two different problems.
>> 1) MIDI clock dropping out on groove boxes.
>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.

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From btremblay at me.com  Mon Dec 20 14:05:20 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Mon, 20 Dec 2021 08:05:20 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
Message-ID: <1F609E5C-C0D9-46E4-AA98-FBE7CD017ED8@me.com>

But wait! There?s more.

With the KPR-77 I wanted to leverage the nice HKA MIDI interface, so I put a DFRobot beetle in the clock signal path and tried to make a clock doubler.  That was a total failure, but maybe due to a lack of time to work it out.

> On Dec 20, 2021, at 7:46 AM, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> @Roman
> Yes I believe your theory is correct; it?s an issue with not handling a tangled bunch of messages. But I can?t prove it, and I if it?s true I don?t know what to do about.
> 
> The history of this goes back to the middle of the summer. 
> I was working on MIDI interface for a Roland CR-5000 and experienced these problems while trying to generate the 24ppq clock.
> This is when I first experienced this issue while testing using the DR-202.
> After spending many hours twiddling the code, I decided I wanted to try this with a Teensy 4, so I could see if it was a speed issue, and also so I could get good logging over the USB port.
> The issue was exactly the same on the Teensy.  I was surprised it was not an Arduino speed issue at all.
> The logs showed the code I was using to measure the time between MIDI clock events was varying wildly when I played a house music or latin groove on the 202. 
> As if the MIDI parser was choking on nearly-simultaneous events.
> My code?s pretty simple, it looks like a boilerplate Arduino MIDI Library code example using MIDI clock, start/stop/resume.
> I simply measure microseconds and generate the clock pulses when micros() exceeds the estimated clock pulse duration.
> 
> #define CLOCK_LENGTH 3333  // microseconds
> 
> void setupMidi() {
>   if (USE_SERIAL) {
>     Serial.println("setupMidi");
>   }
>   MIDI.begin(RECEIVE_CHANNEL);
>   MIDI.setHandleNoteOn(handleNoteOnMidi);
>   MIDI.setHandleClock(myClock);
>   MIDI.setHandleStart(onClockStart);
>   MIDI.setHandleContinue(onClockStart);
>   MIDI.setHandleStop(onClockStop);
>   if (USE_SERIAL) {
>     Serial.println("setupMidi DONE");
>   }
> }
> 
> void myClock() {
>   if (CLOCK_RUNNING) {
>     digitalWrite(CLOCK_OUT, LOW);
>     clockFuture = micros(); // *
>   }
> }
> 
> // *In previous iterations I tired to recalculate CLOCK_LENGTH by averaging, etc. It simply won?t work if its? far from 3000?s.
> 
> void loop() {
>   MIDI.read();
>   if (CLOCK_RUNNING) {
>     if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
>       digitalWrite(CLOCK_OUT, HIGH);
>       clockFuture = 0;
>     }
>   } ? etc
> 
> // ** If I subtract micros() from clockFuture, this number goes crazy when I play a thick loop on the 202.
> 
> In spite of my avoidance of delayMicroseconds(), this code is sensitive to timing because CLOCK_LENGTH (is a constant here, but I have tried to make it dynamic in other builds) is inflexible.
> 
> I have seen some GitHub projects that use interrupts for the MIDI clock and time calculations. I have never written my own interrupt code but would gladly go that way if I was certain it could fix this problem.  But, it seems like I am hitting a hard limitation of 5 pin MIDI? The folks who write fast code with MIDI clock seem to skip ahead to using USB for real-time messages, etc.
> 
> When I was playing with the awesome cheerful.nl <http://cheerful.nl/> OPL2 Audio Board, the author provided some lean MIDI parsing code and skipped the MIDI library. (Especially a no-op for sysex.) So I forked that and tried a lean implementation. Same problem! Lag when the 202 go busy with CC messages and snare rolls.
> 
> So I reverted my code back to Arduino MIDI Library, cleaned up the source, removed dead code, and tested it using everything I learned. It runs OK when I use a dumb drum machine like an SR-16. It chokes on the floofy beats of 1998 in my DR-202. 
> 
> Finally after months, I ported the code back to Arduino Mega and runs virtually the same as on the Teensy 4.
> 
> What I don?t know is, when the 202 gets busy, how can I ditch all the MIDI events I don?t care about without waiting a long time to get the ones I do care about? As bad as the DR-202?s MIDI implementation may be, I have to assume there are many boxes (including a Yamaha QY-22 I was also testing) which send out these swooshing sweeping resonant filter CC events and sysex param tweaks in their drum-and-bass patterns.
> 
> I am assuming that someone, somewhere has mitigated this problem. I want to know how she or he did it.
> 
> Ben
> 
>> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl <mailto:modular at go2.pl>> wrote:
>> 
>> When you say "complex pattern" I see a lot of MIDI messages, and then the clock messages like to be trapped between bytes of single note message. So maybe, just maybe your Arduino code, or library you've used are not capable to see a MIDI clock message trapped inside a note message, or simply get overloaded.
>> 
>> Is it Arduino doing or KPR itself is best to check on a scope with trigger set to timeout on decoded clock byte.
>> 
>> Roman
>> 
>> W dniu 2021-12-18 o 21:12, Benjamin Tremblay via Synth-diy pisze:
>>> Interesting topic!
>>> I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
>>> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.
>>> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
>>> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
>>> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
>>> So, two different problems.
>>> 1) MIDI clock dropping out on groove boxes.
>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From tom at electricdruid.net  Mon Dec 20 15:26:45 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Mon, 20 Dec 2021 14:26:45 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
Message-ID: <82143DBD-E6BF-4EE6-8B99-BA9A4888CFF1@electricdruid.net>

I'm no Arduino coder, but I just had a dig through the code for the Arduino MIDI library and couldn't see any reference to interrupts anywhere.

...which it seems to me is the root of the problem!

I very much doubt this is a "hard limitation of 5 pin MIDI" as you put it. MIDI was *designed* specifically to work on 8-bit processors running at probably only 4 or 8MHz if you were lucky. However, in order to do that, certain things were assumed. One of those assumptions was that Realtime bytes would be dealt with directly in the Rx interrupt, which is why they're easy to filter, and why it doesn't matter that they can appear anywhere: the assumption is that by the time the parser sees the string of incoming bytes, Realtime will already have been removed.

If a Z80 in 1984 can do it, there's no way it's not possible in 2021 on an Arduino. The problem is only the coding, and in this case, it seems like you're fighting against the Arduino MIDI library. The test with the Teensy basically proves that to me.

Tom


> On 20 Dec 2021, at 12:46, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> @Roman
> Yes I believe your theory is correct; it?s an issue with not handling a tangled bunch of messages. But I can?t prove it, and I if it?s true I don?t know what to do about.
> 
> The history of this goes back to the middle of the summer. 
> I was working on MIDI interface for a Roland CR-5000 and experienced these problems while trying to generate the 24ppq clock.
> This is when I first experienced this issue while testing using the DR-202.
> After spending many hours twiddling the code, I decided I wanted to try this with a Teensy 4, so I could see if it was a speed issue, and also so I could get good logging over the USB port.
> The issue was exactly the same on the Teensy.  I was surprised it was not an Arduino speed issue at all.
> The logs showed the code I was using to measure the time between MIDI clock events was varying wildly when I played a house music or latin groove on the 202. 
> As if the MIDI parser was choking on nearly-simultaneous events.
> My code?s pretty simple, it looks like a boilerplate Arduino MIDI Library code example using MIDI clock, start/stop/resume.
> I simply measure microseconds and generate the clock pulses when micros() exceeds the estimated clock pulse duration.
> 
> #define CLOCK_LENGTH 3333  // microseconds
> 
> void setupMidi() {
>   if (USE_SERIAL) {
>     Serial.println("setupMidi");
>   }
>   MIDI.begin(RECEIVE_CHANNEL);
>   MIDI.setHandleNoteOn(handleNoteOnMidi);
>   MIDI.setHandleClock(myClock);
>   MIDI.setHandleStart(onClockStart);
>   MIDI.setHandleContinue(onClockStart);
>   MIDI.setHandleStop(onClockStop);
>   if (USE_SERIAL) {
>     Serial.println("setupMidi DONE");
>   }
> }
> 
> void myClock() {
>   if (CLOCK_RUNNING) {
>     digitalWrite(CLOCK_OUT, LOW);
>     clockFuture = micros(); // *
>   }
> }
> 
> // *In previous iterations I tired to recalculate CLOCK_LENGTH by averaging, etc. It simply won?t work if its? far from 3000?s.
> 
> void loop() {
>   MIDI.read();
>   if (CLOCK_RUNNING) {
>     if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
>       digitalWrite(CLOCK_OUT, HIGH);
>       clockFuture = 0;
>     }
>   } ? etc
> 
> // ** If I subtract micros() from clockFuture, this number goes crazy when I play a thick loop on the 202.
> 
> In spite of my avoidance of delayMicroseconds(), this code is sensitive to timing because CLOCK_LENGTH (is a constant here, but I have tried to make it dynamic in other builds) is inflexible.
> 
> I have seen some GitHub projects that use interrupts for the MIDI clock and time calculations. I have never written my own interrupt code but would gladly go that way if I was certain it could fix this problem.  But, it seems like I am hitting a hard limitation of 5 pin MIDI? The folks who write fast code with MIDI clock seem to skip ahead to using USB for real-time messages, etc.
> 
> When I was playing with the awesome cheerful.nl <http://cheerful.nl/> OPL2 Audio Board, the author provided some lean MIDI parsing code and skipped the MIDI library. (Especially a no-op for sysex.) So I forked that and tried a lean implementation. Same problem! Lag when the 202 go busy with CC messages and snare rolls.
> 
> So I reverted my code back to Arduino MIDI Library, cleaned up the source, removed dead code, and tested it using everything I learned. It runs OK when I use a dumb drum machine like an SR-16. It chokes on the floofy beats of 1998 in my DR-202. 
> 
> Finally after months, I ported the code back to Arduino Mega and runs virtually the same as on the Teensy 4.
> 
> What I don?t know is, when the 202 gets busy, how can I ditch all the MIDI events I don?t care about without waiting a long time to get the ones I do care about? As bad as the DR-202?s MIDI implementation may be, I have to assume there are many boxes (including a Yamaha QY-22 I was also testing) which send out these swooshing sweeping resonant filter CC events and sysex param tweaks in their drum-and-bass patterns.
> 
> I am assuming that someone, somewhere has mitigated this problem. I want to know how she or he did it.
> 
> Ben
> 
>> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl <mailto:modular at go2.pl>> wrote:
>> 
>> When you say "complex pattern" I see a lot of MIDI messages, and then the clock messages like to be trapped between bytes of single note message. So maybe, just maybe your Arduino code, or library you've used are not capable to see a MIDI clock message trapped inside a note message, or simply get overloaded.
>> 
>> Is it Arduino doing or KPR itself is best to check on a scope with trigger set to timeout on decoded clock byte.
>> 
>> Roman
>> 
>> W dniu 2021-12-18 o 21:12, Benjamin Tremblay via Synth-diy pisze:
>>> Interesting topic!
>>> I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
>>> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.
>>> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
>>> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
>>> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
>>> So, two different problems.
>>> 1) MIDI clock dropping out on groove boxes.
>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From pete.hartman at gmail.com  Mon Dec 20 15:39:04 2021
From: pete.hartman at gmail.com (Pete Hartman)
Date: Mon, 20 Dec 2021 08:39:04 -0600
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <82143DBD-E6BF-4EE6-8B99-BA9A4888CFF1@electricdruid.net>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <82143DBD-E6BF-4EE6-8B99-BA9A4888CFF1@electricdruid.net>
Message-ID: <CACodTR-+OZEbnyB_hd+naC-XiN_joVye_+RJn2pG6pLA-fkCCA@mail.gmail.com>

It might be worth looking at other examples that don't use the library.  I
don't know absolutely that it doesn't, but Peter Kvitek's midi to CV is
well thought of, and his code is available on his website

https://midisizer.com/midi2cv-mk2/

I don't know if the alternate code for the hexinverter midi2cv ever was
published, but that would be another I'd suggest looking at is it's
available.  (But the original acx midi code had some issues, so not that ?)

Pete


On Mon, Dec 20, 2021 at 8:30 AM Tom Wiltshire <tom at electricdruid.net> wrote:

> I'm no Arduino coder, but I just had a dig through the code for the
> Arduino MIDI library and couldn't see any reference to interrupts anywhere.
>
> ...which it seems to me is the root of the problem!
>
> I very much doubt this is a "hard limitation of 5 pin MIDI" as you put it.
> MIDI was *designed* specifically to work on 8-bit processors running at
> probably only 4 or 8MHz if you were lucky. However, in order to do that,
> certain things were assumed. One of those assumptions was that Realtime
> bytes would be dealt with directly in the Rx interrupt, which is why
> they're easy to filter, and why it doesn't matter that they can appear
> anywhere: the assumption is that by the time the parser sees the string of
> incoming bytes, Realtime will already have been removed.
>
> If a Z80 in 1984 can do it, there's no way it's not possible in 2021 on an
> Arduino. The problem is only the coding, and in this case, it seems like
> you're fighting against the Arduino MIDI library. The test with the Teensy
> basically proves that to me.
>
> Tom
>
>
> On 20 Dec 2021, at 12:46, Benjamin Tremblay via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
> @Roman
> Yes I believe your theory is correct; it?s an issue with not handling a
> tangled bunch of messages. But I can?t prove it, and I if it?s true I don?t
> know what to do about.
>
> The history of this goes back to the middle of the summer.
> I was working on MIDI interface for a Roland CR-5000 and experienced these
> problems while trying to generate the 24ppq clock.
> This is when I first experienced this issue while testing using the DR-202.
> After spending many hours twiddling the code, I decided I wanted to try
> this with a Teensy 4, so I could see if it was a speed issue, and also so I
> could get good logging over the USB port.
> The issue was exactly the same on the Teensy.  I was surprised it was not
> an Arduino speed issue at all.
> The logs showed the code I was using to measure the time between MIDI
> clock events was varying wildly when I played a house music or latin groove
> on the 202.
> As if the MIDI parser was choking on nearly-simultaneous events.
> My code?s pretty simple, it looks like a boilerplate Arduino MIDI Library
> code example using MIDI clock, start/stop/resume.
> I simply measure microseconds and generate the clock pulses when micros()
> exceeds the estimated clock pulse duration.
>
> #define CLOCK_LENGTH 3333  // microseconds
>
> void setupMidi() {
>   if (USE_SERIAL) {
>     Serial.println("setupMidi");
>   }
>   MIDI.begin(RECEIVE_CHANNEL);
>   MIDI.setHandleNoteOn(handleNoteOnMidi);
>   MIDI.setHandleClock(myClock);
>   MIDI.setHandleStart(onClockStart);
>   MIDI.setHandleContinue(onClockStart);
>   MIDI.setHandleStop(onClockStop);
>   if (USE_SERIAL) {
>     Serial.println("setupMidi DONE");
>   }
> }
>
> void myClock() {
>   if (CLOCK_RUNNING) {
>     digitalWrite(CLOCK_OUT, LOW);
>     clockFuture = micros(); // *
>   }
> }
>
> // *In previous iterations I tired to recalculate CLOCK_LENGTH by
> averaging, etc. It simply won?t work if its? far from 3000?s.
>
> void loop() {
>   MIDI.read();
>   if (CLOCK_RUNNING) {
>     if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
>       digitalWrite(CLOCK_OUT, HIGH);
>       clockFuture = 0;
>     }
>   } ? etc
>
> // ** If I subtract micros() from clockFuture, this number goes crazy when
> I play a thick loop on the 202.
>
> In spite of my avoidance of delayMicroseconds(), this code is sensitive to
> timing because CLOCK_LENGTH (is a constant here, but I have tried to make
> it dynamic in other builds) is inflexible.
>
> I have seen some GitHub projects that use interrupts for the MIDI clock
> and time calculations. I have never written my own interrupt code but would
> gladly go that way if I was certain it could fix this problem.  But, it
> seems like I am hitting a hard limitation of 5 pin MIDI? The folks who
> write fast code with MIDI clock seem to skip ahead to using USB for
> real-time messages, etc.
>
> When I was playing with the awesome cheerful.nl OPL2 Audio Board, the
> author provided some lean MIDI parsing code and skipped the MIDI library.
> (Especially a no-op for sysex.) So I forked that and tried a lean
> implementation. Same problem! Lag when the 202 go busy with CC messages and
> snare rolls.
>
> So I reverted my code back to Arduino MIDI Library, cleaned up the source,
> removed dead code, and tested it using everything I learned. It runs OK
> when I use a dumb drum machine like an SR-16. It chokes on the floofy beats
> of 1998 in my DR-202.
>
> Finally after months, I ported the code back to Arduino Mega and runs
> virtually the same as on the Teensy 4.
>
> What I don?t know is, when the 202 gets busy, how can I ditch all the MIDI
> events I don?t care about without waiting a long time to get the ones I do
> care about? As bad as the DR-202?s MIDI implementation may be, I have to
> assume there are many boxes (including a Yamaha QY-22 I was also testing)
> which send out these swooshing sweeping resonant filter CC events and sysex
> param tweaks in their drum-and-bass patterns.
>
> I am assuming that someone, somewhere has mitigated this problem. I want
> to know how she or he did it.
>
> Ben
>
> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl> wrote:
>
> When you say "complex pattern" I see a lot of MIDI messages, and then the
> clock messages like to be trapped between bytes of single note message. So
> maybe, just maybe your Arduino code, or library you've used are not capable
> to see a MIDI clock message trapped inside a note message, or simply get
> overloaded.
>
> Is it Arduino doing or KPR itself is best to check on a scope with trigger
> set to timeout on decoded clock byte.
>
> Roman
>
> W dniu 2021-12-18 o 21:12, Benjamin Tremblay via Synth-diy pisze:
>
> Interesting topic!
> I have been wanting to write some code like this for a KPR-77. Goal would
> be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW
> pin state transitions per quarter note.
> One thing that discouraged me was MIDI clock coming from my Boss DR-202.
> When I play a complex pattern on that thing, I start losing clock steps. I
> could not figure out why, so I gave up on multiplying the clock.
> If I use a plain vanilla drum machine (as opposed to a groove box), it
> seems to work okay.
> I wrote this code for Arduino Mega, and then tried it with Teensy, but
> either way it has the same problems.
> So, two different problems.
> 1) MIDI clock dropping out on groove boxes.
> 2) I wish I understood the theory of clock multipliers. I have seen code
> that measures the period between clock pulses and dead reckons the
> double-time pulse as an average of the recent periods. But why? Why can?t I
> just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event?
> Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the
> clock down to individual sequencer steps on the KPR-77. As long as the
> divided clock is coming in on the beat, what does it matter if some of the
> synthetic pulses are a little off? (They?re just shadows of the main tempo
> clock). It?s not like the KPR-77 is inferring something or trying to
> calculate BPM from the external clock? So? Anyway I just wish I knew what I
> was aiming for, and then maybe I could hit the target.
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
> _______________________________________________
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From modular at go2.pl  Mon Dec 20 17:53:32 2021
From: modular at go2.pl (Roman Sowa)
Date: Mon, 20 Dec 2021 17:53:32 +0100
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
Message-ID: <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>

To make sure where the clocks are swallowed, why don't you check it on a 
scope? Reviewing code hundreds of times will not give you answers that 
single hardware test will do. Especially since you use library not 
written by yourself, so you can't really tell what's going on there.

IMHO you are not reaching hard limitation of DIN MIDI. To entirely fill 
DIN MIDI with clock it requires nearly 1000 bpm at 192ppq

If so many various platforms gave you same results, then maybe the 
DR-202 and QY-22 and KPR-77 are really skipping a few clocks here and there.

First thing I do in UART interrupt routine is to check if received byte 
is MIDI clock or whatever else. If it's clock, the program branches to 
clock handling and work is finished, clock is not needed anywhere else 
so MIDI processing is not even bothered. If received byte is not clock, 
it goes to regular full bunch of chunky MIDI processing, now obviously 
stripped from any clocks already.
This way even if MIDI is totally filled with data, back to back, 
interlaced with notes, CC and other multi-byte messages, there's not a 
single clock lost, ever. And output pulse delay appears about 45us on 
average after last bit of MIDI clock received.
BTW, it's not Arduino or Teensy, so may not be relevant.

Roman


W dniu 2021-12-20 o?13:46, Benjamin Tremblay pisze:
> @Roman
> Yes I believe your theory is correct; it?s an issue with not handling a 
> tangled bunch of messages. But I can?t prove it, and I if it?s true I 
> don?t know what to do about.
> 
> The history of this goes back to the middle of the summer.
> I was working on MIDI interface for a Roland CR-5000 and experienced 
> these problems while trying to generate the 24ppq clock.
> This is when I first experienced this issue while testing using the DR-202.
> After spending many hours twiddling the code, I decided I wanted to try 
> this with a Teensy 4, so I could see if it was a speed issue, and also 
> so I could get good logging over the USB port.
> The issue was exactly the same on the Teensy. ?I was surprised it was 
> not an Arduino speed issue at all.
> The logs showed the code I was using to measure the time between MIDI 
> clock events was varying wildly when I played a house music or latin 
> groove on the 202.
> As if the MIDI parser was choking on nearly-simultaneous events.
> My code?s pretty simple, it looks like a boilerplate Arduino MIDI 
> Library code example using MIDI clock, start/stop/resume.
> I simply measure microseconds and generate the clock pulses when 
> micros() exceeds the estimated clock pulse duration.
> 
> #define CLOCK_LENGTH 3333 ?// microseconds
> 
> void setupMidi() {
>  ? if (USE_SERIAL) {
>  ? ? Serial.println("setupMidi");
>  ? }
>  ? MIDI.begin(RECEIVE_CHANNEL);
>  ? MIDI.setHandleNoteOn(handleNoteOnMidi);
>  ? MIDI.setHandleClock(myClock);
>  ? MIDI.setHandleStart(onClockStart);
>  ? MIDI.setHandleContinue(onClockStart);
>  ? MIDI.setHandleStop(onClockStop);
>  ? if (USE_SERIAL) {
>  ? ? Serial.println("setupMidi DONE");
>  ? }
> }
> 
> void myClock() {
>  ? if (CLOCK_RUNNING) {
>  ? ? digitalWrite(CLOCK_OUT, LOW);
>  ? ? clockFuture = micros(); // *
>  ? }
> }
> 
> // *In previous iterations I tired to recalculate CLOCK_LENGTH by 
> averaging, etc. It simply won?t work if its? far from 3000?s.
> 
> void loop() {
>  ? MIDI.read();
>  ? if (CLOCK_RUNNING) {
>  ? ? if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
>  ? ? ? digitalWrite(CLOCK_OUT, HIGH);
>  ? ? ? clockFuture = 0;
>  ? ? }
>  ? } ? etc
> 
> // ** If I subtract micros() from clockFuture, this number goes crazy 
> when I play a thick loop on the 202.
> 
> In spite of my avoidance of delayMicroseconds(), this code is sensitive 
> to timing because CLOCK_LENGTH (is a constant here, but I have tried to 
> make it dynamic in other builds) is inflexible.
> 
> I have seen some GitHub projects that use interrupts for the MIDI clock 
> and time calculations. I have never written my own interrupt code but 
> would gladly go that way if I was certain it could fix this problem. 
>  ?But, it seems like I am hitting a hard limitation of 5 pin MIDI? The 
> folks who write fast code with MIDI clock seem to skip ahead to using 
> USB for real-time messages, etc.
> 
> When I was playing with the awesome cheerful.nl <http://cheerful.nl> 
> OPL2 Audio Board, the author provided some lean MIDI parsing code and 
> skipped the MIDI library. (Especially a no-op for sysex.) So I forked 
> that and tried a lean implementation. Same problem! Lag when the 202 go 
> busy with CC messages and snare rolls.
> 
> So I reverted my code back to Arduino MIDI Library, cleaned up the 
> source, removed dead code, and tested it using everything I learned. It 
> runs OK when I use a dumb drum machine like an SR-16. It chokes on the 
> floofy beats of 1998 in my DR-202.
> 
> Finally after months, I ported the code back to Arduino Mega and runs 
> virtually the same as on the Teensy 4.
> 
> What I don?t know is, when the 202 gets busy, how can I ditch all the 
> MIDI events I don?t care about without waiting a long time to get the 
> ones I do care about? As bad as the DR-202?s MIDI implementation may be, 
> I have to assume there are many boxes (including a Yamaha QY-22 I was 
> also testing) which send out these swooshing sweeping resonant filter CC 
> events and sysex param tweaks in their drum-and-bass patterns.
> 
> I am assuming that someone, somewhere has mitigated this problem. I want 
> to know how she or he did it.
> 
> Ben
> 
>> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl 
>> <mailto:modular at go2.pl>> wrote:
>>
>> When you say "complex pattern" I see a lot of MIDI messages, and then 
>> the clock messages like to be trapped between bytes of single note 
>> message. So maybe, just maybe your Arduino code, or library you've 
>> used are not capable to see a MIDI clock message trapped inside a note 
>> message, or simply get overloaded.
>>
>> Is it Arduino doing or KPR itself is best to check on a scope with 
>> trigger set to timeout on decoded clock byte.
>>
>> Roman
>>
>> W dniu 2021-12-18 o?21:12, Benjamin Tremblay via Synth-diy pisze:
>>> Interesting topic!
>>> I have been wanting to write some code like this for a KPR-77. Goal 
>>> would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
>>> The first challenge is converting 24ppq computer signals to 24 
>>> HIGH/LOW pin state transitions per quarter note.
>>> One thing that discouraged me was MIDI clock coming from my Boss 
>>> DR-202. ?When I play a complex pattern on that thing, I start losing 
>>> clock steps. I could not figure out why, so I gave up on multiplying 
>>> the clock.
>>> If I use a plain vanilla drum machine (as opposed to a groove box), 
>>> it seems to work okay.
>>> I wrote this code for Arduino Mega, and then tried it with Teensy, 
>>> but either way it has the same problems.
>>> So, two different problems.
>>> 1) MIDI clock dropping out on groove boxes.
>>> 2) I wish I understood the theory of clock multipliers. I have seen 
>>> code that measures the period between clock pulses and dead reckons 
>>> the double-time pulse as an average of the recent periods. But why? 
>>> Why can?t I just fire another extra HIGH-LOW pulse whenever I get a 
>>> MIDI clock event? Why does timing of the extra ticks matter? ?I?m 
>>> assuming 48 PPQ divides the clock down to individual sequencer steps 
>>> on the KPR-77. As long as the divided clock is coming in on the beat, 
>>> what does it matter if some of the synthetic pulses are a little off? 
>>> (They?re just shadows of the main tempo clock). It?s not like the 
>>> KPR-77 is inferring something or trying to calculate BPM from the 
>>> external clock? So? Anyway I just wish I knew what I was aiming for, 
>>> and then maybe I could hit the target.
> 


From btremblay at me.com  Mon Dec 20 17:55:49 2021
From: btremblay at me.com (Benjamin Tremblay)
Date: Mon, 20 Dec 2021 11:55:49 -0500
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
Message-ID: <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>

I finally bought a mini scope. I have no excuse not to use it.
I agree, this is not a hard limitation on 5 pin MIDI, but it?s too easy for developers interested in performance to abandon it and move to USB.


> On Dec 20, 2021, at 11:53 AM, Roman Sowa <modular at go2.pl> wrote:
> 
> To make sure where the clocks are swallowed, why don't you check it on a scope? Reviewing code hundreds of times will not give you answers that single hardware test will do. Especially since you use library not written by yourself, so you can't really tell what's going on there.
> 
> IMHO you are not reaching hard limitation of DIN MIDI. To entirely fill DIN MIDI with clock it requires nearly 1000 bpm at 192ppq
> 
> If so many various platforms gave you same results, then maybe the DR-202 and QY-22 and KPR-77 are really skipping a few clocks here and there.
> 
> First thing I do in UART interrupt routine is to check if received byte is MIDI clock or whatever else. If it's clock, the program branches to clock handling and work is finished, clock is not needed anywhere else so MIDI processing is not even bothered. If received byte is not clock, it goes to regular full bunch of chunky MIDI processing, now obviously stripped from any clocks already.
> This way even if MIDI is totally filled with data, back to back, interlaced with notes, CC and other multi-byte messages, there's not a single clock lost, ever. And output pulse delay appears about 45us on average after last bit of MIDI clock received.
> BTW, it's not Arduino or Teensy, so may not be relevant.
> 
> Roman
> 
> 
> W dniu 2021-12-20 o 13:46, Benjamin Tremblay pisze:
>> @Roman
>> Yes I believe your theory is correct; it?s an issue with not handling a tangled bunch of messages. But I can?t prove it, and I if it?s true I don?t know what to do about.
>> The history of this goes back to the middle of the summer.
>> I was working on MIDI interface for a Roland CR-5000 and experienced these problems while trying to generate the 24ppq clock.
>> This is when I first experienced this issue while testing using the DR-202.
>> After spending many hours twiddling the code, I decided I wanted to try this with a Teensy 4, so I could see if it was a speed issue, and also so I could get good logging over the USB port.
>> The issue was exactly the same on the Teensy.  I was surprised it was not an Arduino speed issue at all.
>> The logs showed the code I was using to measure the time between MIDI clock events was varying wildly when I played a house music or latin groove on the 202.
>> As if the MIDI parser was choking on nearly-simultaneous events.
>> My code?s pretty simple, it looks like a boilerplate Arduino MIDI Library code example using MIDI clock, start/stop/resume.
>> I simply measure microseconds and generate the clock pulses when micros() exceeds the estimated clock pulse duration.
>> #define CLOCK_LENGTH 3333  // microseconds
>> void setupMidi() {
>>   if (USE_SERIAL) {
>>     Serial.println("setupMidi");
>>   }
>>   MIDI.begin(RECEIVE_CHANNEL);
>>   MIDI.setHandleNoteOn(handleNoteOnMidi);
>>   MIDI.setHandleClock(myClock);
>>   MIDI.setHandleStart(onClockStart);
>>   MIDI.setHandleContinue(onClockStart);
>>   MIDI.setHandleStop(onClockStop);
>>   if (USE_SERIAL) {
>>     Serial.println("setupMidi DONE");
>>   }
>> }
>> void myClock() {
>>   if (CLOCK_RUNNING) {
>>     digitalWrite(CLOCK_OUT, LOW);
>>     clockFuture = micros(); // *
>>   }
>> }
>> // *In previous iterations I tired to recalculate CLOCK_LENGTH by averaging, etc. It simply won?t work if its? far from 3000?s.
>> void loop() {
>>   MIDI.read();
>>   if (CLOCK_RUNNING) {
>>     if (clockFuture > 0 && (micros() - clockFuture) > CLOCK_LENGTH) {
>>       digitalWrite(CLOCK_OUT, HIGH);
>>       clockFuture = 0;
>>     }
>>   } ? etc
>> // ** If I subtract micros() from clockFuture, this number goes crazy when I play a thick loop on the 202.
>> In spite of my avoidance of delayMicroseconds(), this code is sensitive to timing because CLOCK_LENGTH (is a constant here, but I have tried to make it dynamic in other builds) is inflexible.
>> I have seen some GitHub projects that use interrupts for the MIDI clock and time calculations. I have never written my own interrupt code but would gladly go that way if I was certain it could fix this problem.   But, it seems like I am hitting a hard limitation of 5 pin MIDI? The folks who write fast code with MIDI clock seem to skip ahead to using USB for real-time messages, etc.
>> When I was playing with the awesome cheerful.nl <http://cheerful.nl/> <http://cheerful.nl <http://cheerful.nl/>> OPL2 Audio Board, the author provided some lean MIDI parsing code and skipped the MIDI library. (Especially a no-op for sysex.) So I forked that and tried a lean implementation. Same problem! Lag when the 202 go busy with CC messages and snare rolls.
>> So I reverted my code back to Arduino MIDI Library, cleaned up the source, removed dead code, and tested it using everything I learned. It runs OK when I use a dumb drum machine like an SR-16. It chokes on the floofy beats of 1998 in my DR-202.
>> Finally after months, I ported the code back to Arduino Mega and runs virtually the same as on the Teensy 4.
>> What I don?t know is, when the 202 gets busy, how can I ditch all the MIDI events I don?t care about without waiting a long time to get the ones I do care about? As bad as the DR-202?s MIDI implementation may be, I have to assume there are many boxes (including a Yamaha QY-22 I was also testing) which send out these swooshing sweeping resonant filter CC events and sysex param tweaks in their drum-and-bass patterns.
>> I am assuming that someone, somewhere has mitigated this problem. I want to know how she or he did it.
>> Ben
>>> On Dec 20, 2021, at 5:30 AM, Roman Sowa <modular at go2.pl <mailto:modular at go2.pl> <mailto:modular at go2.pl <mailto:modular at go2.pl>>> wrote:
>>> 
>>> When you say "complex pattern" I see a lot of MIDI messages, and then the clock messages like to be trapped between bytes of single note message. So maybe, just maybe your Arduino code, or library you've used are not capable to see a MIDI clock message trapped inside a note message, or simply get overloaded.
>>> 
>>> Is it Arduino doing or KPR itself is best to check on a scope with trigger set to timeout on decoded clock byte.
>>> 
>>> Roman
>>> 
>>> W dniu 2021-12-18 o 21:12, Benjamin Tremblay via Synth-diy pisze:
>>>> Interesting topic!
>>>> I have been wanting to write some code like this for a KPR-77. Goal would be MIDI clock in, TTL-ish clock out. 24ppq>48ppq.
>>>> The first challenge is converting 24ppq computer signals to 24 HIGH/LOW pin state transitions per quarter note.
>>>> One thing that discouraged me was MIDI clock coming from my Boss DR-202.  When I play a complex pattern on that thing, I start losing clock steps. I could not figure out why, so I gave up on multiplying the clock.
>>>> If I use a plain vanilla drum machine (as opposed to a groove box), it seems to work okay.
>>>> I wrote this code for Arduino Mega, and then tried it with Teensy, but either way it has the same problems.
>>>> So, two different problems.
>>>> 1) MIDI clock dropping out on groove boxes.
>>>> 2) I wish I understood the theory of clock multipliers. I have seen code that measures the period between clock pulses and dead reckons the double-time pulse as an average of the recent periods. But why? Why can?t I just fire another extra HIGH-LOW pulse whenever I get a MIDI clock event? Why does timing of the extra ticks matter?  I?m assuming 48 PPQ divides the clock down to individual sequencer steps on the KPR-77. As long as the divided clock is coming in on the beat, what does it matter if some of the synthetic pulses are a little off? (They?re just shadows of the main tempo clock). It?s not like the KPR-77 is inferring something or trying to calculate BPM from the external clock? So? Anyway I just wish I knew what I was aiming for, and then maybe I could hit the target.

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From grant at musictechnologiesgroup.com  Mon Dec 20 18:26:35 2021
From: grant at musictechnologiesgroup.com (MTG)
Date: Mon, 20 Dec 2021 09:26:35 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
Message-ID: <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>

USB-MIDI is another layer (of hell). I don't think it's going to solve 
any issues that 5-pin DIN has. Maybe because the microcontrollers that 
have USB are typically many, many times faster than an old 8-bit one 
though. OTOH, some USB stacks are very poorly written.


On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
> I finally bought a mini scope. I have no excuse not to use it.
> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too easy 
> for developers interested in performance to abandon it and move to USB.
> 


From mbryant at futurehorizons.com  Mon Dec 20 18:34:41 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Mon, 20 Dec 2021 17:34:41 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
Message-ID: <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>

Totally agree some USB stacks for MIDI are useless (Linux/ALSA anybody) but that doesn't damn USB itself.   MIDI2.0 depends on using USB (or Ethernet) and even on original MIDI it gives far better performance provided you have use USB2.0.  
But USB 1 is actually worse than 5 pin DIN so make sure it isn't falling back into that.


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of MTG
Sent: 20 December 2021 17:27
To: synth-diy at synth-diy.org
Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency?

USB-MIDI is another layer (of hell). I don't think it's going to solve any issues that 5-pin DIN has. Maybe because the microcontrollers that have USB are typically many, many times faster than an old 8-bit one though. OTOH, some USB stacks are very poorly written.


On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
> I finally bought a mini scope. I have no excuse not to use it.
> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too 
> easy for developers interested in performance to abandon it and move to USB.
> 
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From mars at pingdynasty.com  Mon Dec 20 20:23:42 2021
From: mars at pingdynasty.com (mars)
Date: Mon, 20 Dec 2021 20:23:42 +0100
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
Message-ID: <202112201923.1BKJNrLs021642@dropmix.synth-diy.org>

Well in USB MIDI everything is packaged into 4 byte packets so you don't get interspersed clocks. Or running status.Martin
-------- Original message --------From: MTG <grant at musictechnologiesgroup.com> Date: 20/12/2021  18:34  (GMT+01:00) To: synth-diy at synth-diy.org Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency? USB-MIDI is another layer (of hell). I don't think it's going to solve any issues that 5-pin DIN has. Maybe because the microcontrollers that have USB are typically many, many times faster than an old 8-bit one though. OTOH, some USB stacks are very poorly written.On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:> I finally bought a mini scope. I have no excuse not to use it.> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too easy > for developers interested in performance to abandon it and move to USB.> _______________________________________________Synth-diy mailing listSynth-diy at synth-diy.orghttp://synth-diy.org/mailman/listinfo/synth-diySelling or trading? Use marketplace at synth-diy.org
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From cheater00social at gmail.com  Tue Dec 21 03:51:27 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 21 Dec 2021 03:51:27 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
Message-ID: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>

I'm looking to buy a bunch of electrolytic caps just to have some
values around. I'm looking for small to medium sizes, for audio work
and basic supply filtering (so up to, say, 30V?). Size isn't
important, this is just for messing around, but I'd like them to be
high quality, good for audio, and not dry out / drift after being
stored for 10 years, and not corrode. I don't want to buy typical "run
of the mill" since they usually end up being bad in one of a few ways.
I'd appreciate suggestions. Note I'm looking for electrolytic caps
only at this time, not polystyrene etc.

Thanks!


From spirosmakris92 at gmail.com  Tue Dec 21 08:38:01 2021
From: spirosmakris92 at gmail.com (Spiros Makris)
Date: Tue, 21 Dec 2021 09:38:01 +0200
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <202112201923.1BKJNrLs021642@dropmix.synth-diy.org>
References: <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <202112201923.1BKJNrLs021642@dropmix.synth-diy.org>
Message-ID: <CAGbpyRc_xY8hjfVei1h9kkHhbiETXyEZxb9oV+VTL1_27ZyqBQ@mail.gmail.com>

I think the biggest drawback of usb is that you can connect only one device
to each port. 5 DIN midi can be buffered and spread around the studio to 16
instruments, and there is no additional overhead for your master computer
in doing so. If you dare connect 16 USB MIDI devices...yeah, that would be
ugly.
MIDI specifies how real time messages are interleaved with the rest, and
there's some care required when making the state machine in order to fully
comply with the last version. AFAIK arduino MIDI.h handles that properly,
even without using the interrupts.

After writing the above, I decided to have a deeper look into the teensy
3.2 interrupts. Turns out you can hack an ISR in the teensyduino core.
Here's my fix:
usb_isr is the interrupt routine for USB, and is defined under
teensy3>usb_dev.c. In there you will notice a few #ifdef statements, for
the various USB device modes. We will create a function pointer, that is
called by the teensy usb_isr, and expose it to our arduino main.cpp so we
can attach whatever we need to it.
1. in teensy3>usb_dev.h add:
            void (*usbMIDI_isr)(void);
            void usbMIDI_attach_interrupt(void (*fptr)());
2. in teensy3>usb_dev.c find usb_isr and add above it:

        void usbMIDI_attach_interrupt(void (*fptr)())

{

    usbMIDI_isr = fptr;

}

3.right before the end of usb_isr() add:
           if (usbMIDI_isr)

    {
        (*usbMIDI_isr)();
    }

4. in kinetis.h locate the list of _isr functions, around line 5800. At the
end of the list, add:

extern void usbMIDI_attach_interrupt(void (*fptr)());


in my main scetch I just call usbMIDI_attach_interrupt(&readMIDI);, and run
the MIDI.h read code without any changes. It seems to work.

There is some overhead in the MIDI library that by the looks of it would be
manageable. It could do with some optimization, but I wouldn't worry too
much about it, for now.

On Mon, 20 Dec 2021 at 21:26, mars <mars at pingdynasty.com> wrote:

> Well in USB MIDI everything is packaged into 4 byte packets so you don't
> get interspersed clocks. Or running status.
>
> Martin
>
>
> -------- Original message --------
> From: MTG <grant at musictechnologiesgroup.com>
> Date: 20/12/2021 18:34 (GMT+01:00)
> To: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency?
>
> USB-MIDI is another layer (of hell). I don't think it's going to solve
> any issues that 5-pin DIN has. Maybe because the microcontrollers that
> have USB are typically many, many times faster than an old 8-bit one
> though. OTOH, some USB stacks are very poorly written.
>
>
> On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
> > I finally bought a mini scope. I have no excuse not to use it.
> > I agree, this is not a hard limitation on 5 pin MIDI, but it?s too easy
> > for developers interested in performance to abandon it and move to USB.
> >
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From rrsounds at aol.com  Tue Dec 21 09:50:41 2021
From: rrsounds at aol.com (rrsounds)
Date: Tue, 21 Dec 2021 09:50:41 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
Message-ID: <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>

A couple of specs to look for are low internal resistance, and high temperature tolerance. Buying 105?C parts usually ensures high quality and long service life. 
For audio coupling in products I have built, I have used an electrolytic paralleled with a polypropylene cap.
David Reaves



> On Dec 21, 2021, at 3:51 , cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I'm looking to buy a bunch of electrolytic caps just to have some
> values around. I'm looking for small to medium sizes, for audio work
> and basic supply filtering (so up to, say, 30V?). Size isn't
> important, this is just for messing around, but I'd like them to be
> high quality, good for audio, and not dry out / drift after being
> stored for 10 years, and not corrode. I don't want to buy typical "run
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> only at this time, not polystyrene etc.
> 
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From tom at electricdruid.net  Tue Dec 21 10:40:06 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Tue, 21 Dec 2021 09:40:06 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
Message-ID: <1DF917D6-8D6E-4064-BB4C-4DBC6DB79D99@electricdruid.net>

Nichicon have a lot of "audio grade" electrolytics, in a range of prices from merely good quality up to truly audiophile!


> On 21 Dec 2021, at 02:51, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I'm looking to buy a bunch of electrolytic caps just to have some
> values around. I'm looking for small to medium sizes, for audio work
> and basic supply filtering (so up to, say, 30V?). Size isn't
> important, this is just for messing around, but I'd like them to be
> high quality, good for audio, and not dry out / drift after being
> stored for 10 years, and not corrode. I don't want to buy typical "run
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> only at this time, not polystyrene etc.
> 
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From tom at electricdruid.net  Tue Dec 21 10:43:53 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Tue, 21 Dec 2021 09:43:53 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
Message-ID: <8B9C31C5-2DBC-4AE9-AA7C-07BB3D30B70B@electricdruid.net>

Sorry, forgot the link:

https://www.nichiconcapacitors.com



> On 21 Dec 2021, at 02:51, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I'm looking to buy a bunch of electrolytic caps just to have some
> values around. I'm looking for small to medium sizes, for audio work
> and basic supply filtering (so up to, say, 30V?). Size isn't
> important, this is just for messing around, but I'd like them to be
> high quality, good for audio, and not dry out / drift after being
> stored for 10 years, and not corrode. I don't want to buy typical "run
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> only at this time, not polystyrene etc.
> 
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From mbryant at futurehorizons.com  Tue Dec 21 10:46:48 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 21 Dec 2021 09:46:48 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <CAGbpyRc_xY8hjfVei1h9kkHhbiETXyEZxb9oV+VTL1_27ZyqBQ@mail.gmail.com>
References: <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <202112201923.1BKJNrLs021642@dropmix.synth-diy.org>
 <CAGbpyRc_xY8hjfVei1h9kkHhbiETXyEZxb9oV+VTL1_27ZyqBQ@mail.gmail.com>
Message-ID: <3a090f8dbb4a49aa9fb9fd6975a07051@futurehorizons.com>

There should be no problem with connecting lots of USB instruments provided you use a good USB hub.  Main problem is some software stacks don?t implement plug and play properly which makes things a PITA.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Spiros Makris via Synth-diy
Sent: 21 December 2021 07:38
To: mars
Cc: synth-diy mailing list
Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency?

I think the biggest drawback of usb is that you can connect only one device to each port. 5 DIN midi can be buffered and spread around the studio to 16 instruments, and there is no additional overhead for your master computer in doing so. If you dare connect 16 USB MIDI devices...yeah, that would be ugly.
MIDI specifies how real time messages are interleaved with the rest, and there's some care required when making the state machine in order to fully comply with the last version. AFAIK arduino MIDI.h handles that properly, even without using the interrupts.

After writing the above, I decided to have a deeper look into the teensy 3.2 interrupts. Turns out you can hack an ISR in the teensyduino core. Here's my fix:
usb_isr is the interrupt routine for USB, and is defined under teensy3>usb_dev.c. In there you will notice a few #ifdef statements, for the various USB device modes. We will create a function pointer, that is called by the teensy usb_isr, and expose it to our arduino main.cpp so we can attach whatever we need to it.
1. in teensy3>usb_dev.h add:
            void (*usbMIDI_isr)(void);
            void usbMIDI_attach_interrupt(void (*fptr)());
2. in teensy3>usb_dev.c find usb_isr and add above it:
        void usbMIDI_attach_interrupt(void (*fptr)())
{
    usbMIDI_isr = fptr;
}
3.right before the end of usb_isr() add:
           if (usbMIDI_isr)
    {
        (*usbMIDI_isr)();
    }
4. in kinetis.h locate the list of _isr functions, around line 5800. At the end of the list, add:
extern void usbMIDI_attach_interrupt(void (*fptr)());

in my main scetch I just call usbMIDI_attach_interrupt(&readMIDI);, and run the MIDI.h read code without any changes. It seems to work.

There is some overhead in the MIDI library that by the looks of it would be manageable. It could do with some optimization, but I wouldn't worry too much about it, for now.

On Mon, 20 Dec 2021 at 21:26, mars <mars at pingdynasty.com<mailto:mars at pingdynasty.com>> wrote:
Well in USB MIDI everything is packaged into 4 byte packets so you don't get interspersed clocks. Or running status.

Martin


-------- Original message --------
From: MTG <grant at musictechnologiesgroup.com<mailto:grant at musictechnologiesgroup.com>>
Date: 20/12/2021 18:34 (GMT+01:00)
To: synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>
Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency?

USB-MIDI is another layer (of hell). I don't think it's going to solve
any issues that 5-pin DIN has. Maybe because the microcontrollers that
have USB are typically many, many times faster than an old 8-bit one
though. OTOH, some USB stacks are very poorly written.


On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
> I finally bought a mini scope. I have no excuse not to use it.
> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too easy
> for developers interested in performance to abandon it and move to USB.
>
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
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From mbryant at futurehorizons.com  Tue Dec 21 11:29:14 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 21 Dec 2021 10:29:14 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
Message-ID: <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>

Hopefully Douglas Self won't mind me quoting him

"In subjectivist circles it is frequently asserted that electrolytic coupling capacitors (if they are
permitted at all) should be bypassed by small non-electrolytics. There is no sense in this; if the
main coupling capacitor has no signal voltage across it, the extra capacitor can have no effect."


We did a lot of work at Soundcraft on capacitors and there's far more myths than facts.   Yes they do slowly dry out especially at very high temperature with voltage applied across them, but if they are rated at 10,000 hours at 105deg C that's over a million hours (> 100 years) at a typical working temperature.  Sitting in a bag unused they will never dry out.  

The only caps that generally need replacing are in PSUs and that's more due to the stress of being turned on and off more than anything else.


As for brands, better to buy a known brand but no point in buying 'audio specials'.  They will still both sound and last the same time.



-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of rrsounds via Synth-diy
Sent: 21 December 2021 08:51
To: cheater cheater
Cc: synth-diy
Subject: Re: [sdiy] Favourite electrolytic cap brand / model?

A couple of specs to look for are low internal resistance, and high temperature tolerance. Buying 105?C parts usually ensures high quality and long service life. 
For audio coupling in products I have built, I have used an electrolytic paralleled with a polypropylene cap.
David Reaves



> On Dec 21, 2021, at 3:51 , cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I'm looking to buy a bunch of electrolytic caps just to have some 
> values around. I'm looking for small to medium sizes, for audio work 
> and basic supply filtering (so up to, say, 30V?). Size isn't 
> important, this is just for messing around, but I'd like them to be 
> high quality, good for audio, and not dry out / drift after being 
> stored for 10 years, and not corrode. I don't want to buy typical "run 
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps 
> only at this time, not polystyrene etc.
> 
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org



From modular at go2.pl  Tue Dec 21 11:33:48 2021
From: modular at go2.pl (Roman Sowa)
Date: Tue, 21 Dec 2021 11:33:48 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
Message-ID: <53f33ccf-7090-9319-8c49-bcdcb3f2d664@go2.pl>

For general use, sit-in-the-box-until-I-need-you small caps I like to 
keep Nichicon's UFW and UMW because of their extremely cool gold shell 
color. Plus, UMW are so small like someone stepped on them.
Now if I could get the green ones somewhere.

Roman

W dniu 2021-12-21 o?03:51, cheater cheater via Synth-diy pisze:
> I'm looking to buy a bunch of electrolytic caps just to have some
> values around. I'm looking for small to medium sizes, for audio work
> and basic supply filtering (so up to, say, 30V?). Size isn't
> important, this is just for messing around, but I'd like them to be
> high quality, good for audio, and not dry out / drift after being
> stored for 10 years, and not corrode. I don't want to buy typical "run
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> only at this time, not polystyrene etc.
> 
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 


From modular at go2.pl  Tue Dec 21 11:50:07 2021
From: modular at go2.pl (Roman Sowa)
Date: Tue, 21 Dec 2021 11:50:07 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
Message-ID: <25d9dc32-20b7-74b5-591a-cf9715f1efe5@go2.pl>

Once I had a switching PSU that needed recapping 5 seconds after first 
power up.

Roman

W dniu 2021-12-21 o?11:29, Mike Bryant pisze:
> 
> The only caps that generally need replacing are in PSUs and that's more due to the stress of being turned on and off more than anything else.
> 
> 
> As for brands, better to buy a known brand but no point in buying 'audio specials'.  They will still both sound and last the same time.
> 
> 


From admin at bugbrand.co.uk  Tue Dec 21 11:51:21 2021
From: admin at bugbrand.co.uk (Tom Bugs)
Date: Tue, 21 Dec 2021 10:51:21 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
Message-ID: <531746ce-9ab4-d82e-7732-072094a95115@bugbrand.co.uk>

Panasonic FC range for regular electros.

Then Nichicon UES bipolars for audio areas.

On 21/12/2021 02:51, cheater cheater via Synth-diy wrote:
> I'm looking to buy a bunch of electrolytic caps just to have some
> values around. I'm looking for small to medium sizes, for audio work
> and basic supply filtering (so up to, say, 30V?). Size isn't
> important, this is just for messing around, but I'd like them to be
> high quality, good for audio, and not dry out / drift after being
> stored for 10 years, and not corrode. I don't want to buy typical "run
> of the mill" since they usually end up being bad in one of a few ways.
> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> only at this time, not polystyrene etc.
>
> Thanks!
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

-- 
BugBrand LTD
UK company No. 07199808
VAT No. GB 988 2629 57
1 Ninetree Hill
BRISTOL BS1 3SB
United Kingdom
www.bugbrand.co.uk



From mbryant at futurehorizons.com  Tue Dec 21 11:54:47 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 21 Dec 2021 10:54:47 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <25d9dc32-20b7-74b5-591a-cf9715f1efe5@go2.pl>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
 <25d9dc32-20b7-74b5-591a-cf9715f1efe5@go2.pl>
Message-ID: <439ecdd6556648ada31e5546e9a573eb@futurehorizons.com>

They do that if you solder them in backwards :-)

But yes, some brands do suffer more early failures.  Indeed for a while HP wouldn't allow aluminium electrolytics to be used at all except in essential applications and then they had to be burnt in for about a week.   But I think that problem seemed to disappear around the early to mid 1990s.

-----Original Message-----
From: Roman Sowa [mailto:modular at go2.pl] 
Sent: 21 December 2021 10:50
To: Mike Bryant
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Favourite electrolytic cap brand / model?

Once I had a switching PSU that needed recapping 5 seconds after first power up.

Roman

W dniu 2021-12-21 o?11:29, Mike Bryant pisze:
> 
> The only caps that generally need replacing are in PSUs and that's more due to the stress of being turned on and off more than anything else.
> 
> 
> As for brands, better to buy a known brand but no point in buying 'audio specials'.  They will still both sound and last the same time.
> 
> 




From modular at go2.pl  Tue Dec 21 12:16:02 2021
From: modular at go2.pl (Roman Sowa)
Date: Tue, 21 Dec 2021 12:16:02 +0100
Subject: [sdiy] Best & fastest envelope follower schematic.. anybody ?
In-Reply-To: <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
References: <000301d7f153$dd1aa710$974ff530$@oricom.ca>
 <8509579B-D04E-4D42-9F03-FA6E7E08E2E9@electricdruid.net>
 <000901d7f1c5$39a07f70$ace17e50$@oricom.ca>
 <2F94AF82-0D54-4ADE-B1BB-E816DBC28A10@me.com>
 <CADwhBTHnRPYy5KoxpjO7HwAwuoOObX_Mu24AfHLK8KP-c_QJ5w@mail.gmail.com>
 <49C1DDF7-E748-42A6-92BA-FC6152ECA86E@adambaby.com>
 <003d01d7f215$0904e630$1b0eb290$@oricom.ca>
 <c7d237ae-1e3b-2fae-d15a-739cfa89290e@pingdynasty.com>
 <03F108B3-8949-434B-BA53-3AF784E7C534@electricdruid.net>
 <001901d7f35b$6cc51db0$464f5910$@oricom.ca>
Message-ID: <331d83c3-c3ee-e6bc-ca5e-b4c195287f43@go2.pl>

You just cant's make something a 4th order filter by modifying one 
capacitor. Besides, this will only alter DC bias, passing all AC intact, 
so any filtering should be placed after this circuit (I've attached the 
circuit you posted for reference).

So when input signal goes down, C1 is charged via diode to prevent Vo 
going below Vref. When input finally starts to go up again, the diode 
cuts off opamp from the cap, and charged voltage on C1 is added to 
rising input. But when suddenly input amplitude drops, this circuit will 
not respond immediately. AC will still pass, but the charge collected 
oat C1 during most negative peak is still there so it will have the same 
DC offset like the moment befere when amplitude was bigger. C1 must be 
discharged with external resistor connected to Vo, and this makes it 
release rate typical for 1st order RC circuit. So you're basicaly at 
square 1 again.

Roman

W dniu 2021-12-17 o?16:33, Jean-Pierre Desrochers pisze:
>>This would be the digital equivalent to the single pole RC. It should be 
> possible to get better ripple suppression by using higher order filters. 
> Harald showed that he got a better response using a fourth-order filter.
> 
> 
> So.. how can I modify the C1 section to get for example a fourth-order 
> filter ?
> To do it the way the signal flows across C1 is a bit confusing..
> The signal comes from the left side but the clamping comes from D1 at 
> right side.
> 
> I know how to implement high order filters in circuits but only
> if I know the signal flow direction..
> 
> *De?:*Synth-diy <synth-diy-bounces at synth-diy.org> *De la part de* Tom 
> Wiltshire
> *Envoy??:* 17 d?cembre 2021 08:37
> *??:* Martin Klang <mars at pingdynasty.com>
> *Cc?:* synth-diy at synth-diy.org
> *Objet?:* Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?
> 
> This would be the digital equivalent to the single pole RC. It should be 
> possible to get better ripple suppression by using higher order filters. 
> Harald showed that he got a better response using a fourth-order filter.
> 
> 
> 
>     On 16 Dec 2021, at 16:26, Martin Klang <mars at pingdynasty.com
>     <mailto:mars at pingdynasty.com>> wrote:
> 
>     I think an envelope follower with no lag is called a rectifier.
> 
>     Jokes aside, there are a number of options available but ultimately
>     it comes down to filtering.
> 
>     For digital envelope followers, I like to use a simple exponential
>     average (aka leaky integrator, a first-order IIR filter) on the
>     fully rectified signal and tune the time constant to the expected
>     input signal. Generally you want it to be fast, but not so fast as
>     to track the waveform oscillations, even at say 20 Hz. This makes a
>     computationally very efficient follower with predictable results.
> 
>     best,
> 
>     Martin
> 
>     On 16/12/2021 01:36, Jean-Pierre Desrochers wrote:
> 
>         Here is my goal..
> 
>         I need a circuit that will take an AC signal and will shift
>         level it from
>         a DC offset extracted from its min & max Peaks..
>         Ex: Suppose you have steady +/- 5v peak sine wave coming in this
>         circuit,
>         The output would be the same waveform but shifted up to +5vdc.
> 
>         So 0 to +10vdc.
>         That final waveform would be much usable for a 0-5vdc control
>         voltage input
>         than the original AC waveform.
>         Now the challenge is to do the same with a level changing AC signal.
> 
>         In the case of a_steady waveform_this ?level shifter? could be
>         an opamp that would add half of the peak to peak voltage as an
>         offset DC voltage,
>         But here I?m looking for something that will be more versatile
>         to handle varying level waveform.
> 
> 
>     _______________________________________________
>     Synth-diy mailing list
>     Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>     http://synth-diy.org/mailman/listinfo/synth-diy
>     <http://synth-diy.org/mailman/listinfo/synth-diy>
>     Selling or trading? Use marketplace at synth-diy.org
>     <mailto:marketplace at synth-diy.org>
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 
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From cheater00social at gmail.com  Tue Dec 21 13:00:20 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 21 Dec 2021 13:00:20 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
Message-ID: <CAGn5V-8=_mrje9eH7wQAAqiC2D+unNeu43iV-MbeNmH6r0mBUQ@mail.gmail.com>

Thanks for the suggestions so far everyone. As Tom figured out I'm
looking for both polar and bipolar electrolytics, so feel free to
suggest both.

On Tue, Dec 21, 2021 at 11:29 AM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> As for brands, better to buy a known brand but no point in buying 'audio specials'.  They will still both sound and last the same time.

To make this clear, I'm not looking for "audio specials" or
"audiophile capacitors", I'm just looking for high quality
electrolytics that are good for audio. Not all of them have to be, eg
due to high Q.

Low ESR and high temp ratings mean nothing, many manufacturers will
outright fake them, so I'm looking for suggestions of capacitors where
people had a capacitor in circuit for say 20 years and it was good as
new after 20 years (of course not in a situation where it's being
hammered).


From cheater00social at gmail.com  Tue Dec 21 13:18:01 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 21 Dec 2021 13:18:01 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <531746ce-9ab4-d82e-7732-072094a95115@bugbrand.co.uk>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <531746ce-9ab4-d82e-7732-072094a95115@bugbrand.co.uk>
Message-ID: <CAGn5V-8Z5aE-rDYPUGVYFKnhc+8YVsP9JkYCX+rBvfxHq+MURQ@mail.gmail.com>

Hey Tom, what values do you like to keep around for each? Thanks

On Tue, Dec 21, 2021 at 11:56 AM Tom Bugs via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Panasonic FC range for regular electros.
>
> Then Nichicon UES bipolars for audio areas.
>
> On 21/12/2021 02:51, cheater cheater via Synth-diy wrote:
> > I'm looking to buy a bunch of electrolytic caps just to have some
> > values around. I'm looking for small to medium sizes, for audio work
> > and basic supply filtering (so up to, say, 30V?). Size isn't
> > important, this is just for messing around, but I'd like them to be
> > high quality, good for audio, and not dry out / drift after being
> > stored for 10 years, and not corrode. I don't want to buy typical "run
> > of the mill" since they usually end up being bad in one of a few ways.
> > I'd appreciate suggestions. Note I'm looking for electrolytic caps
> > only at this time, not polystyrene etc.
> >
> > Thanks!
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
> --
> BugBrand LTD
> UK company No. 07199808
> VAT No. GB 988 2629 57
> 1 Ninetree Hill
> BRISTOL BS1 3SB
> United Kingdom
> www.bugbrand.co.uk
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From gordonjcp at gjcp.net  Tue Dec 21 21:29:51 2021
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Tue, 21 Dec 2021 20:29:51 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-8=_mrje9eH7wQAAqiC2D+unNeu43iV-MbeNmH6r0mBUQ@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
 <CAGn5V-8=_mrje9eH7wQAAqiC2D+unNeu43iV-MbeNmH6r0mBUQ@mail.gmail.com>
Message-ID: <20211221202951.GA27623@gjcp.net>

On Tue, Dec 21, 2021 at 01:00:20PM +0100, cheater cheater via Synth-diy wrote:
> Thanks for the suggestions so far everyone. As Tom figured out I'm
> looking for both polar and bipolar electrolytics, so feel free to
> suggest both.
> 
> On Tue, Dec 21, 2021 at 11:29 AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > As for brands, better to buy a known brand but no point in buying 'audio specials'.  They will still both sound and last the same time.
> 
> To make this clear, I'm not looking for "audio specials" or
> "audiophile capacitors", I'm just looking for high quality
> electrolytics that are good for audio. Not all of them have to be, eg
> due to high Q.

All electrolytics are equally good for audio.  Anyone that says otherwise needs piss tested because they're clearly on so much coke they can hear the individual electrons whizzing around.

-- 
Gordonjcp


From igg.debus at gmail.com  Wed Dec 22 11:57:58 2021
From: igg.debus at gmail.com (Ingo Debus)
Date: Wed, 22 Dec 2021 11:57:58 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <20211221202951.GA27623@gjcp.net>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
 <CAGn5V-8=_mrje9eH7wQAAqiC2D+unNeu43iV-MbeNmH6r0mBUQ@mail.gmail.com>
 <20211221202951.GA27623@gjcp.net>
Message-ID: <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>



> Am 21.12.2021 um 21:29 schrieb Gordonjcp <gordonjcp at gjcp.net>:
> 
> All electrolytics are equally good for audio.

In audio gear from past century?s 70s and 80s often tantalums instead of aluminium electrolytics were used for audio coupling. I always wonder why? Were they just en vogue back then? Or was this because of their (back then) smaller size? Sure they were more expensive.

Ingo
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From mbryant at futurehorizons.com  Wed Dec 22 12:03:01 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Wed, 22 Dec 2021 11:03:01 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <C87E9EFD-07AF-4921-A22E-1F2240FF5D88@aol.com>
 <800242e0d3a94875acf6528dfa981cb6@futurehorizons.com>
 <CAGn5V-8=_mrje9eH7wQAAqiC2D+unNeu43iV-MbeNmH6r0mBUQ@mail.gmail.com>
 <20211221202951.GA27623@gjcp.net>
 <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>
Message-ID: <f6daad02218047809b2face601b98125@futurehorizons.com>

Back in the 70s aluminium electrolytics were crap.  As I mentioned earlier, at HP we were only allowed to use tantalums normally and any use of aluminiums had to be burnt in for an extra long time.  I think military companies may have banned them totally.




From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Ingo Debus via Synth-diy
Sent: 22 December 2021 10:58
To: Synth-diy
Subject: Re: [sdiy] Favourite electrolytic cap brand / model?




Am 21.12.2021 um 21:29 schrieb Gordonjcp <gordonjcp at gjcp.net<mailto:gordonjcp at gjcp.net>>:

All electrolytics are equally good for audio.

In audio gear from past century?s 70s and 80s often tantalums instead of aluminium electrolytics were used for audio coupling. I always wonder why? Were they just en vogue back then? Or was this because of their (back then) smaller size? Sure they were more expensive.

Ingo
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From admin at bugbrand.co.uk  Wed Dec 22 12:11:36 2021
From: admin at bugbrand.co.uk (Tom Bugs)
Date: Wed, 22 Dec 2021 11:11:36 +0000
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <CAGn5V-8Z5aE-rDYPUGVYFKnhc+8YVsP9JkYCX+rBvfxHq+MURQ@mail.gmail.com>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <531746ce-9ab4-d82e-7732-072094a95115@bugbrand.co.uk>
 <CAGn5V-8Z5aE-rDYPUGVYFKnhc+8YVsP9JkYCX+rBvfxHq+MURQ@mail.gmail.com>
Message-ID: <7aff0388-5159-e1aa-508e-be467639438d@bugbrand.co.uk>

FC caps - well I have a drawer with 10u/22u/47u that rarely get used - 
then 100u/220u (25V) - I put a pair of 220u 25vs on the power rails of 
each module so that's prob 98% of the FCs I use

UES - 10u/22u/47u (35v ones, I think).
Yeah, I do wonder if they're worth it but they're not too pricey & I'm 
sure there were some details in Doug Self's book that made me think it 
was worth it.
I'm fairly KISS (keep it simple) so happy to have made a choice for a 
limited range of good quality parts that I know I can obtain relatively 
easily for reasonable costs.
The UES ones are quite big in size (though think in part that is due to 
bipolar) and the green does look nice ;)


On 21/12/2021 12:18, cheater cheater wrote:
> Hey Tom, what values do you like to keep around for each? Thanks
>
> On Tue, Dec 21, 2021 at 11:56 AM Tom Bugs via Synth-diy
> <synth-diy at synth-diy.org> wrote:
>> Panasonic FC range for regular electros.
>>
>> Then Nichicon UES bipolars for audio areas.
>>
>> On 21/12/2021 02:51, cheater cheater via Synth-diy wrote:
>>> I'm looking to buy a bunch of electrolytic caps just to have some
>>> values around. I'm looking for small to medium sizes, for audio work
>>> and basic supply filtering (so up to, say, 30V?). Size isn't
>>> important, this is just for messing around, but I'd like them to be
>>> high quality, good for audio, and not dry out / drift after being
>>> stored for 10 years, and not corrode. I don't want to buy typical "run
>>> of the mill" since they usually end up being bad in one of a few ways.
>>> I'd appreciate suggestions. Note I'm looking for electrolytic caps
>>> only at this time, not polystyrene etc.
>>>
>>> Thanks!
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org
>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>> --
>> BugBrand LTD
>> UK company No. 07199808
>> VAT No. GB 988 2629 57
>> 1 Ninetree Hill
>> BRISTOL BS1 3SB
>> United Kingdom
>> www.bugbrand.co.uk
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org

-- 
BugBrand LTD
UK company No. 07199808
VAT No. GB 988 2629 57
1 Ninetree Hill
BRISTOL BS1 3SB
United Kingdom
www.bugbrand.co.uk



From mec.forumreader at gmail.com  Wed Dec 22 15:52:16 2021
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Wed, 22 Dec 2021 09:52:16 -0500
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <7aff0388-5159-e1aa-508e-be467639438d@bugbrand.co.uk>
References: <CAGn5V-9gzjCRB-np75vC49pRyBnav8HtgGOPUT-OW488hsR0gw@mail.gmail.com>
 <531746ce-9ab4-d82e-7732-072094a95115@bugbrand.co.uk>
 <CAGn5V-8Z5aE-rDYPUGVYFKnhc+8YVsP9JkYCX+rBvfxHq+MURQ@mail.gmail.com>
 <7aff0388-5159-e1aa-508e-be467639438d@bugbrand.co.uk>
Message-ID: <CAAv6=UCx_3wkB7O8PMePthZqSbX_1r81k68ioDB2=S6d2wGnGA@mail.gmail.com>

You don't want to use electrolytics as the tuning elements in filters.  Too
much variance in capacitance (study the spec) and Electronotes discourages
them because they are not low leakage.

MC

On Wed, Dec 22, 2021 at 6:14 AM Tom Bugs via Synth-diy <
synth-diy at synth-diy.org> wrote:

> FC caps - well I have a drawer with 10u/22u/47u that rarely get used -
> then 100u/220u (25V) - I put a pair of 220u 25vs on the power rails of
> each module so that's prob 98% of the FCs I use
>
> UES - 10u/22u/47u (35v ones, I think).
> Yeah, I do wonder if they're worth it but they're not too pricey & I'm
> sure there were some details in Doug Self's book that made me think it
> was worth it.
> I'm fairly KISS (keep it simple) so happy to have made a choice for a
> limited range of good quality parts that I know I can obtain relatively
> easily for reasonable costs.
> The UES ones are quite big in size (though think in part that is due to
> bipolar) and the green does look nice ;)
>
>
> On 21/12/2021 12:18, cheater cheater wrote:
> > Hey Tom, what values do you like to keep around for each? Thanks
> >
> > On Tue, Dec 21, 2021 at 11:56 AM Tom Bugs via Synth-diy
> > <synth-diy at synth-diy.org> wrote:
> >> Panasonic FC range for regular electros.
> >>
> >> Then Nichicon UES bipolars for audio areas.
> >>
> >> On 21/12/2021 02:51, cheater cheater via Synth-diy wrote:
> >>> I'm looking to buy a bunch of electrolytic caps just to have some
> >>> values around. I'm looking for small to medium sizes, for audio work
> >>> and basic supply filtering (so up to, say, 30V?). Size isn't
> >>> important, this is just for messing around, but I'd like them to be
> >>> high quality, good for audio, and not dry out / drift after being
> >>> stored for 10 years, and not corrode. I don't want to buy typical "run
> >>> of the mill" since they usually end up being bad in one of a few ways.
> >>> I'd appreciate suggestions. Note I'm looking for electrolytic caps
> >>> only at this time, not polystyrene etc.
> >>>
> >>> Thanks!
> >>> _______________________________________________
> >>> Synth-diy mailing list
> >>> Synth-diy at synth-diy.org
> >>> http://synth-diy.org/mailman/listinfo/synth-diy
> >>> Selling or trading? Use marketplace at synth-diy.org
> >> --
> >> BugBrand LTD
> >> UK company No. 07199808
> >> VAT No. GB 988 2629 57
> >> 1 Ninetree Hill
> >> BRISTOL BS1 3SB
> >> United Kingdom
> >> www.bugbrand.co.uk
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
>
> --
> BugBrand LTD
> UK company No. 07199808
> VAT No. GB 988 2629 57
> 1 Ninetree Hill
> BRISTOL BS1 3SB
> United Kingdom
> www.bugbrand.co.uk
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From barryklein at cox.net  Wed Dec 22 19:24:30 2021
From: barryklein at cox.net (Barry Klein)
Date: Wed, 22 Dec 2021 10:24:30 -0800
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>
References: <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>
Message-ID: <03E42A45-E0D0-42A6-B71D-7D9982D86852@cox.net>

For guitar/amp stuff anyway it was size and life expectancy.  Good question though - I don?t remember doing audio tests between the two - just very famous people thought the tantalum products sounded great.



> On Dec 22, 2021, at 8:38 AM, Ingo Debus via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> ?
> 
>> Am 21.12.2021 um 21:29 schrieb Gordonjcp <gordonjcp at gjcp.net>:
>> 
>> All electrolytics are equally good for audio.
> 
> In audio gear from past century?s 70s and 80s often tantalums instead of aluminium electrolytics were used for audio coupling. I always wonder why? Were they just en vogue back then? Or was this because of their (back then) smaller size? Sure they were more expensive.
> 
> Ingo
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
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From rrsounds at aol.com  Wed Dec 22 20:07:32 2021
From: rrsounds at aol.com (rrsounds)
Date: Wed, 22 Dec 2021 20:07:32 +0100
Subject: [sdiy] Favourite electrolytic cap brand / model?
In-Reply-To: <03E42A45-E0D0-42A6-B71D-7D9982D86852@cox.net>
References: <AA840089-AD65-4967-8E4D-B2A1C78E8C05@gmail.com>
 <03E42A45-E0D0-42A6-B71D-7D9982D86852@cox.net>
Message-ID: <3A5FA778-3CF6-468C-907C-4B3ED786B2F0@aol.com>

I?ve always looked for articles about capacitors for audio, and have a few I can share.
The first is a two-part series by Walter Jung and Richard Marsh, ?Picking Capacitors" in Audio Magazine, from way back in February and March, 1980.
	https://vdocuments.mx/picking-capacitors.html
The second is WAN_0176 from Wolfson Microelectronics, ?A.C. Coupling Capacitor Selection?
	https://dtsheet.com/doc/1414867/wan_0176-a.c.-coupling-capacitor-selection
The third is a short treatise on how a capacitor?s type influences dielectric absorption, "On Capacitor Dielectric Materials - A Chemist's View? by Karl A. Weber, Ph.D.
	https://audience-av.com/oem-diy-parts/axo_description/a_chemistview-html/
The fourth is "Signal distortion from high-K ceramic capacitors? by John Caldwell, Analog Applications Engineer, Texas Instruments - from EDN.com, June 16, 2013
	https://www.edn.com/signal-distortion-from-high-k-ceramic-capacitors/

They all generally rank various capacitors in audibility. It?s interesting to see the types of tests and conclusions these different authors make.

David Reaves

> On Dec 22, 2021, at 19:24 , Barry Klein via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> For guitar/amp stuff anyway it was size and life expectancy.  Good question though - I don?t remember doing audio tests between the two - just very famous people thought the tantalum products sounded great.




From jpdesroc at oricom.ca  Wed Dec 22 20:47:46 2021
From: jpdesroc at oricom.ca (Jean-Pierre Desrochers)
Date: Wed, 22 Dec 2021 14:47:46 -0500
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
Message-ID: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>

Hi all,

Here is an idea (outside DIY synth) I had sometime ago..
I hope this could be of some interest for you  guys..

Tired of throwing away lots of 'end of their life' batteries
when they reached 70% or less of their original values
and you could not use them for other stuff ?
Well I accumulated a lot of AA type batteries over the years
and kept them in case of.. Happy I did so..
Here is a small project I made to re-use them and even more,
use them as a variable voltage supply..
 
http://www.arcenson.com/projects/Battery_Pack/

In this project, over time, I can spot the 'going almost dead' batteries
using the small voltmeter and comparing successive rotary switch voltages
then following the battery's chain number and remove/replace it
with another 'used' battery.

In my case this small box will be used to supply small battery operated
devices
while repairing or testing them.
This thing can supply up to 24 x 1.5vdc = 36vdc (with brand new batteries)
but this is not the primary goal of it.
Here, with used batteries installed I could reach up to 29vdc
which is not bad with 'about to be thrown away' batteries !

Merry Christmas to you all !

Jean-Pierre Desrochers

********************************************************************* 

> -----Message d'origine-----
> De?: rburnett at richieburnett.co.uk <rburnett at richieburnett.co.uk>
> Envoy??: 13 d?cembre 2021 08:02
> ??: Jean-Pierre Desrochers <jpdesroc at oricom.ca>
> Cc?: Synth-diy at synth-diy.org
> Objet?: [Polluriel d?tect?] Re: [sdiy] My good old VGA oscilloscope
plugged to
> my modular..
> Importance?: Faible
> 
> Very pretty!  The perfect use for that old 4:3 analogue VGA monitor that
> everyone still has in the cupboard gathering dust.
> 
> -Richie,
> 
> 
> 
> On 2021-12-12 21:35, Jean-Pierre Desrochers wrote:
> > Here is a short video of my 2015 open source VGA Oscilloscope project.
> > It's made out of a small Microchip PIC micro with the help of some
> > analog comparators circuitry.
> > This box produces a vertical line that follows the incoming stereo
> > audio signal connected to it.
> > It then drives an external VGA display.
> > A choice of 7 different colors can be applied to the vertical line.
> > It just needs an old 4:3 VGA screen with a 800x600 resolution.
> >
> > https://www.youtube.com/watch?v=VKMjb3CpOCE&t=135s
> >
> > Enjoy !
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org




From didierleplae at yahoo.com  Wed Dec 22 21:41:00 2021
From: didierleplae at yahoo.com (Didier Leplae)
Date: Wed, 22 Dec 2021 14:41:00 -0600
Subject: [sdiy] Battery power for eurorack
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
Message-ID: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>

I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
Plus, of course the portability would be another great benefit.

Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.

 I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.

Perhaps someone has done this that I?m not aware of.





From zac at bauermeister.com  Wed Dec 22 22:08:39 2021
From: zac at bauermeister.com (zac)
Date: Wed, 22 Dec 2021 13:08:39 -0800
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
Message-ID: <25f01587-4f9d-48d4-926e-7f0ec99e41a3@edison>

  
  
  
I've had success running 3 or 4 modules off of a USB batter plugged into this   https://modularaddict.com/eurorack-usb-power-supply-pcb-mmi
  

  
Some digital modules can go into a reset cycle on it though, since it reboots when something tries to pull too much.
  

  
Zac
  

  

  

  
  
  
  
  
>   
> On Dec 22, 2021 at 12:42 PM, Didier Leplae via Synth-diy  <synth-diy at synth-diy.org>  wrote:
>   
>   
>  I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>  I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>     
     
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From brianw at audiobanshee.com  Wed Dec 22 22:31:51 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Wed, 22 Dec 2021 13:31:51 -0800
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
Message-ID: <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>

There is at least one company making battery boosters. These are extremely thin brackets that fit around each standard size of battery, and boost the voltage from dying batteries to normal. I'm not sure what kind of supply they use, but they work with most "dead" batteries. A serious advantage is that they work with devices (such as remote controls) where external power jacks are not available.

One possible supply uses capacitive doubling to increase the voltage (drawing more than twice as much current from the battery), but this design will still fail when the dying battery drops to half the required minimum for a given device.

Another possible supply (which might not be as compact) uses an inductor to "store" current until the induced voltage matches the regulated value. This design can guarantee the desired voltage by increasing the pulse width of the PWM controlling the switcher, but in some cases the switching frequency would have to be reduced (increasing the period) to allow for longer pulse widths.

Your approach avoids the problems with switching power supplies, but it's obviously a very manual approach. Although batteries usually have the benefit of having less noise than a switching supply, the above switchers would basically automatically adjust the voltage so you can use the powered device without constantly monitoring and replacing individual batteries.

Brian


On Dec 22, 2021, at 11:47, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
> Here is an idea (outside DIY synth) I had sometime ago..
> I hope this could be of some interest for you  guys..
> 
> Tired of throwing away lots of 'end of their life' batteries
> when they reached 70% or less of their original values
> and you could not use them for other stuff ?
> Well I accumulated a lot of AA type batteries over the years
> and kept them in case of.. Happy I did so..
> Here is a small project I made to re-use them and even more,
> use them as a variable voltage supply..
> 
> http://www.arcenson.com/projects/Battery_Pack/
> 
> In this project, over time, I can spot the 'going almost dead' batteries
> using the small voltmeter and comparing successive rotary switch voltages
> then following the battery's chain number and remove/replace it
> with another 'used' battery.
> 
> In my case this small box will be used to supply small battery operated
> devices
> while repairing or testing them.
> This thing can supply up to 24 x 1.5vdc = 36vdc (with brand new batteries)
> but this is not the primary goal of it.
> Here, with used batteries installed I could reach up to 29vdc
> which is not bad with 'about to be thrown away' batteries !




From obl64 at ix.netcom.com  Wed Dec 22 22:37:31 2021
From: obl64 at ix.netcom.com (Oren Leavitt)
Date: Wed, 22 Dec 2021 15:37:31 -0600
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
Message-ID: <252c40cc-672d-64fe-fb2d-60b157db8b20@ix.netcom.com>

I've seen people use batteries to power small modular synths.

Several years ago I've ran a small synth with 10 low current analog 
modules plus an analog keyboard interface directly from two 12 volt 
DeWalt cordless drill battery packs one each for the V+ and V- rails. 
After playing on it for a few hours the V+ battery was at about 80% 
charge and the V- battery was still at full charge. This was an NiMH 
battery pack. I forget what the mAH rating was..

- Oren

On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
> I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From chromatest at azburners.org  Wed Dec 22 22:48:57 2021
From: chromatest at azburners.org (Chromatest J. Pantsmaker)
Date: Wed, 22 Dec 2021 14:48:57 -0700
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <252c40cc-672d-64fe-fb2d-60b157db8b20@ix.netcom.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
 <252c40cc-672d-64fe-fb2d-60b157db8b20@ix.netcom.com>
Message-ID: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>

I've seen people create DC-DC supplies taking power from 5V battery banks
(for charging your phone, etc.) and running entire live rigs from that.

I think having a single easily swappable battery would be better than
having one for each voltage.  You can then possibly just plug your DC-DC
supply into a large amperage 5V wall-wart.

On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I've seen people use batteries to power small modular synths.
>
> Several years ago I've ran a small synth with 10 low current analog
> modules plus an analog keyboard interface directly from two 12 volt
> DeWalt cordless drill battery packs one each for the V+ and V- rails.
> After playing on it for a few hours the V+ battery was at about 80%
> charge and the V- battery was still at full charge. This was an NiMH
> battery pack. I forget what the mAH rating was..
>
> - Oren
>
> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
> > I?m curious about the idea of using batteries for eurorack power. I am
> not an electrical engineer, so correct me if I?m wrong in thinking that
> battery power could potentially be very clean compared with the cheap power
> supplies many of us use.
> > Plus, of course the portability would be another great benefit.
> >
> > Given recent advances in rechargeable battery technology, I wonder if it
> could be practical and not terribly expensive.
> >
> >   I?m assuming you might need two or even three separate batteries to
> get the +12 , -12 and +5 volt supplies.
> >
> > Perhaps someone has done this that I?m not aware of.
> >
> >
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From ben at stuyts.nl  Wed Dec 22 22:53:45 2021
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed, 22 Dec 2021 22:53:45 +0100
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>
Message-ID: <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>



> On 22 Dec 2021, at 22:31, Brian Willoughby <brianw at audiobanshee.com> wrote:
> 
> There is at least one company making battery boosters. These are extremely thin brackets that fit around each standard size of battery, and boost the voltage from dying batteries to normal. I'm not sure what kind of supply they use, but they work with most "dead" batteries. A serious advantage is that they work with devices (such as remote controls) where external power jacks are not available.

If you are referring to the Batteriser, those have been thoroughly debunked. See https://duckduckgo.com/?q=batteriser+debunk

Ben




From synth at schmitzbits.de  Wed Dec 22 22:54:35 2021
From: synth at schmitzbits.de (=?UTF-8?Q?Ren=c3=a9_Schmitz?=)
Date: Wed, 22 Dec 2021 22:54:35 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
Message-ID: <dfc98cba-56eb-ae5e-d153-cbd5ade29d03@schmitzbits.de>

On 22.12.2021 21:41, Didier Leplae via Synth-diy wrote:
> I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.

There is an off the shelf solution for this from Polyend: 
https://polyend.com/anywhere/


Best,

 ?Ren?

-- 

synth at schmitzbits.de
http://schmitzbits.de



From grant at musictechnologiesgroup.com  Wed Dec 22 23:25:56 2021
From: grant at musictechnologiesgroup.com (MTG)
Date: Wed, 22 Dec 2021 14:25:56 -0800
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>
 <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>
Message-ID: <06982a79-2385-b88b-b70b-ffa2fa318dac@musictechnologiesgroup.com>

I think Joule Thief is the generic term. Several of my friends were 
quite annoyed that an "expired" AA lit the LED on a Joule Thief for as 
long as we cared to watch it (many many hours). They could not fathom 
why a perfectly good battery (it lit the LED didn't it!?) had to be 
removed from it's intended application (TV remote) and thrown away.

GB

On 12/22/2021 1:53 PM, Ben Stuyts wrote:
> 
> 
>> On 22 Dec 2021, at 22:31, Brian Willoughby <brianw at audiobanshee.com> wrote:
>>
>> There is at least one company making battery boosters. These are extremely thin brackets that fit around each standard size of battery, and boost the voltage from dying batteries to normal. I'm not sure what kind of supply they use, but they work with most "dead" batteries. A serious advantage is that they work with devices (such as remote controls) where external power jacks are not available.
> 
> If you are referring to the Batteriser, those have been thoroughly debunked. See https://duckduckgo.com/?q=batteriser+debunk
> 
> Ben
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> .


From ben at stuyts.nl  Thu Dec 23 00:26:00 2021
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu, 23 Dec 2021 00:26:00 +0100
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <06982a79-2385-b88b-b70b-ffa2fa318dac@musictechnologiesgroup.com>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>
 <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>
 <06982a79-2385-b88b-b70b-ffa2fa318dac@musictechnologiesgroup.com>
Message-ID: <6A0D1552-85C6-4F4E-899D-9AB1EAB34955@stuyts.nl>


> On 22 Dec 2021, at 23:25, MTG <grant at musictechnologiesgroup.com> wrote:
> 
> I think Joule Thief is the generic term. Several of my friends were quite annoyed that an "expired" AA lit the LED on a Joule Thief for as long as we cared to watch it (many many hours). They could not fathom why a perfectly good battery (it lit the LED didn't it!?) had to be removed from it's intended application (TV remote) and thrown away.

If I remember correctly, it was similar arguments that were being used for the Batteriser. Which was just a step-up DC/DC converter on top of the battery clip. So you throw away 20% efficiency or so right there.

Joule thiefs (and variants) are not very impressive: Modern LEDs will light up even at 1 mA, 2 V, which is 2 mW. Let?s say in your case it was lit for 5 hours, so the total energy during that time is 5 * 3600 * 0.002 = 36 J. A new AA battery has about 10000 J, so those 5 hours only amount to 1/277 of the initial battery capacity. 

Ben

> GB
> 
> On 12/22/2021 1:53 PM, Ben Stuyts wrote:
>>> On 22 Dec 2021, at 22:31, Brian Willoughby <brianw at audiobanshee.com> wrote:
>>> 
>>> There is at least one company making battery boosters. These are extremely thin brackets that fit around each standard size of battery, and boost the voltage from dying batteries to normal. I'm not sure what kind of supply they use, but they work with most "dead" batteries. A serious advantage is that they work with devices (such as remote controls) where external power jacks are not available.
>> If you are referring to the Batteriser, those have been thoroughly debunked. See https://duckduckgo.com/?q=batteriser+debunk
>> Ben
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>> .
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From brianw at audiobanshee.com  Thu Dec 23 00:29:40 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Wed, 22 Dec 2021 15:29:40 -0800
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <3B1481C9-3FC5-47D5-9F53-5634A476ABF2@audiobanshee.com>
 <8415C96F-F1CD-4530-B1E2-6D3B33E0E509@stuyts.nl>
Message-ID: <8459CBF7-4FC3-4949-8DC6-1E2E7EDC75A8@audiobanshee.com>



On Dec 22, 2021, at 13:53, Ben Stuyts <ben at stuyts.nl> wrote:
> On 22 Dec 2021, at 22:31, Brian Willoughby <brianw at audiobanshee.com> wrote:
>> There is at least one company making battery boosters. These are extremely thin brackets that fit around each standard size of battery, and boost the voltage from dying batteries to normal. I'm not sure what kind of supply they use, but they work with most "dead" batteries. A serious advantage is that they work with devices (such as remote controls) where external power jacks are not available.
> 
> If you are referring to the Batteriser, those have been thoroughly debunked. See https://duckduckgo.com/?q=batteriser+debunk

Well, I own a set of four of the Batteriser in AA size, and this debunking hasn't stopped them from working!

Either I missed the claim that 80% of the power of a battery remains after it's "dead" ... or I simply never believed it. I would expect that far less than 50% remains, and probably usually less than that.

Hackaday is a great site for fun, but they really are amateur. The "debunking" assumes that the device(s) they tested represent all devices, and that's far from the case. In my experience, devices vary *widely* in the minimum voltage they need from a battery in order to operate.

The most annoying variance is that some devices require a minimum voltage that's greater than rechargeable batteries. Many of the "advanced" lithium or rechargeable batteries that I buy are rated at 1.2 V on the case, where basic batteries are rated at 1.5 V. I have several devices that will not work at all with the 1.2 V batteries, so I either have to use basic 1.5 V batteries or use the Batteriser to boost the voltage.

I think that a fair "debunking" would need to survey far more real-world devices than Hackaday tested. I suspect that their example is not in the majority. That said, the "80% of your dead battery's original power is still available" is not mathematically true, except perhaps in one product design out of millions. Regardless of whether there's 80% remaining, or just a measly extra little bit remaining, the Batteriser does turn a non-working battery into a working battery.

Even though they "work" ... I wouldn't recommend the Batteriser. The biggest reason is that they fit too tightly into a battery compartment and are almost impossible to insert, much less remove. They are incredibly thin, but the whole circuit fits on the + side of the battery, adding a bit too much length for many devices. You can force them in, but it's not a good idea.

However, getting back to the OP: The only reason I brought this up was for the idea of using an automatically-self-adjusting switching supply design to extract energy from batteries with insufficient voltage. I'm thinking that you could do a lot if you circumvent the sizing constraints of the Batteriser and used a fancy inductive voltage booster that can boost more than double voltage.

Brian




From lanterma at ece.gatech.edu  Thu Dec 23 04:34:47 2021
From: lanterma at ece.gatech.edu (Lanterman, Aaron D)
Date: Thu, 23 Dec 2021 03:34:47 +0000
Subject: [sdiy] My Guitar Amplification and Effects video lectures
Message-ID: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>

I teach something music-related every spring. In the semesters that I?m not running my ?Analog Circuits for Music Synthesis? class, I run my ?Guitar Amplification and Effects? class, which I?m running this Spring

I was really really really hoping we would be done with Covid-19 by now, but it looks like it?s not done with us, so I?ll one again be recording some lecture materials and putting them on YouTube. I?m working on getting some material up ahead of time. Here are the first two lectures on triodes:

https://youtu.be/2OoL1YF7mbM

https://youtu.be/VAc9HjGsidI

I try to avoid saying annoying things like ?please like and subscribe and ring the bell to be notified when new videos are posted? in my videos since I don?t like wasting people?s time. That said? please like and subscribe and ring the bell to be notified when new videos are posted (assuming, of course, that you are into that sort of thing).

In the course I also cover the differential equations of vibrating strings, a bit of emag regarding pickups, pentodes, tone stacks, and some pedal effects circuits like distortion/overdrive, phasers, flangers, and wah wah pedals.

- Aaron
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From shawn at epicpoolsga.com  Thu Dec 23 04:59:28 2021
From: shawn at epicpoolsga.com (Shawn Rakestraw)
Date: Wed, 22 Dec 2021 22:59:28 -0500
Subject: [sdiy] My Guitar Amplification and Effects video lectures
In-Reply-To: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
References: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
Message-ID: <CA+-UNiBwkOd_=kJXDjZz1cZjsCuzdYoyBqkCc+620-BFsjm+xA@mail.gmail.com>

Thanks for letting us know. I will be sure to check it out!

On Wed, Dec 22, 2021, 10:38 PM Lanterman, Aaron D via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I teach something music-related every spring. In the semesters that I?m
> not running my ?Analog Circuits for Music Synthesis? class, I run my
> ?Guitar Amplification and Effects? class, which I?m running this Spring
>
> I was really really really hoping we would be done with Covid-19 by now,
> but it looks like it?s not done with us, so I?ll one again be recording
> some lecture materials and putting them on YouTube. I?m working on getting
> some material up ahead of time. Here are the first two lectures on triodes:
>
> https://youtu.be/2OoL1YF7mbM
>
> https://youtu.be/VAc9HjGsidI
>
> I try to avoid saying annoying things like ?please like and subscribe and
> ring the bell to be notified when new videos are posted? in my videos since
> I don?t like wasting people?s time. That said? please like and subscribe
> and ring the bell to be notified when new videos are posted (assuming, of
> course, that you are into that sort of thing).
>
> In the course I also cover the differential equations of vibrating
> strings, a bit of emag regarding pickups, pentodes, tone stacks, and some
> pedal effects circuits like distortion/overdrive, phasers, flangers, and
> wah wah pedals.
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From list at mikebeauchamp.com  Thu Dec 23 05:43:39 2021
From: list at mikebeauchamp.com (Mike Beauchamp)
Date: Wed, 22 Dec 2021 23:43:39 -0500
Subject: [sdiy] My Guitar Amplification and Effects video lectures
In-Reply-To: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
References: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
Message-ID: <96773e0b-12d0-b8a5-3c93-9dc70f301ace@mikebeauchamp.com>



On 12/22/21 10:34 PM, Lanterman, Aaron D via Synth-diy wrote:
> I teach something music-related every spring. In the semesters that I?m 
> not running my ?Analog Circuits for Music Synthesis? class, I run my 
> ?Guitar Amplification and Effects? class, which I?m running this Spring
> 

Thanks Aaron, both are being youtube-dl'd into my Lanterman Videos folder!

Mike



From modular at go2.pl  Thu Dec 23 13:02:56 2021
From: modular at go2.pl (Roman Sowa)
Date: Thu, 23 Dec 2021 13:02:56 +0100
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
Message-ID: <0c4672e0-9e43-5c6c-9782-ea23e575f5cf@go2.pl>

When one of the batteries is more dead than others, at certain current 
(it may be as low as few mA) it will be too weak to hold and becomes a 
resistor. It will actually reverse polarity and take most of stack 
voltage on itself, so entire stack will drop from say 20V to 1V.
To prevent that you might add ideal diodes over the cells. Those are 
widely used in solar panels.

And what a coincidence, few emails later I have found a spam about 
MAX17220 DC booster, it ideally matches the topic of wringing nearly 
dead batteries. It starts from 0.88V input and then works until battery 
is 0.4V dead. Only 4 external components and output adjustable from 1.8 
to 5V.

Once I got a thing from Aliexpress, basicaly a PCB with booster on it 
and battery clips. So you put a dead AAA battery in and hapily enjoy 5V 
at its output until poor battery wheeps "please let me go now...".
It was about $1 IIRC

Roman


W dniu 2021-12-22 o?20:47, Jean-Pierre Desrochers pisze:
> Hi all,
> 
> Here is an idea (outside DIY synth) I had sometime ago..
> I hope this could be of some interest for you  guys..
> 
> Tired of throwing away lots of 'end of their life' batteries
> when they reached 70% or less of their original values
> and you could not use them for other stuff ?
> Well I accumulated a lot of AA type batteries over the years
> and kept them in case of.. Happy I did so..
> Here is a small project I made to re-use them and even more,
> use them as a variable voltage supply..
>   
> http://www.arcenson.com/projects/Battery_Pack/
> 
> In this project, over time, I can spot the 'going almost dead' batteries
> using the small voltmeter and comparing successive rotary switch voltages
> then following the battery's chain number and remove/replace it
> with another 'used' battery.
> 
> In my case this small box will be used to supply small battery operated
> devices
> while repairing or testing them.
> This thing can supply up to 24 x 1.5vdc = 36vdc (with brand new batteries)
> but this is not the primary goal of it.
> Here, with used batteries installed I could reach up to 29vdc
> which is not bad with 'about to be thrown away' batteries !
> 
> Merry Christmas to you all !
> 
> Jean-Pierre Desrochers
> 
> *********************************************************************
> 
>> -----Message d'origine-----
>> De?: rburnett at richieburnett.co.uk <rburnett at richieburnett.co.uk>
>> Envoy??: 13 d?cembre 2021 08:02
>> ??: Jean-Pierre Desrochers <jpdesroc at oricom.ca>
>> Cc?: Synth-diy at synth-diy.org
>> Objet?: [Polluriel d?tect?] Re: [sdiy] My good old VGA oscilloscope
> plugged to
>> my modular..
>> Importance?: Faible
>>
>> Very pretty!  The perfect use for that old 4:3 analogue VGA monitor that
>> everyone still has in the cupboard gathering dust.
>>
>> -Richie,
>>
>>
>>
>> On 2021-12-12 21:35, Jean-Pierre Desrochers wrote:
>>> Here is a short video of my 2015 open source VGA Oscilloscope project.
>>> It's made out of a small Microchip PIC micro with the help of some
>>> analog comparators circuitry.
>>> This box produces a vertical line that follows the incoming stereo
>>> audio signal connected to it.
>>> It then drives an external VGA display.
>>> A choice of 7 different colors can be applied to the vertical line.
>>> It just needs an old 4:3 VGA screen with a 800x600 resolution.
>>>
>>> https://www.youtube.com/watch?v=VKMjb3CpOCE&t=135s
>>>
>>> Enjoy !
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org
>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 


From fanwander at mnet-online.de  Thu Dec 23 17:30:09 2021
From: fanwander at mnet-online.de (Florian Anwander)
Date: Thu, 23 Dec 2021 17:30:09 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
Message-ID: <98af899a-d010-5dbf-c2c7-c3ef1ee83a2c@mnet-online.de>

Many years ago I had a portable Doepfer A-100 theremin like System: 
http://www.florian-anwander.de/a100/portable/
I had built it for this event: 
http://www.richard-aicher.de/html/langenacht2004.html (I am on the 
second and third picture)


Am 22.12.21 um 21:41 schrieb Didier Leplae via Synth-diy:
> I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Usemarketplace at synth-diy.org
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From dschnidsky at hotmail.com  Thu Dec 23 21:56:10 2021
From: dschnidsky at hotmail.com (Darren Shorsky)
Date: Thu, 23 Dec 2021 20:56:10 +0000
Subject: [sdiy] My Guitar Amplification and Effects video lectures
In-Reply-To: <96773e0b-12d0-b8a5-3c93-9dc70f301ace@mikebeauchamp.com>
References: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
 <96773e0b-12d0-b8a5-3c93-9dc70f301ace@mikebeauchamp.com>
Message-ID: <MWHPR0501MB38340C6EAD0B290826C5EE20D17E9@MWHPR0501MB3834.namprd05.prod.outlook.com>

Thanx for this Aaron.....  i've enjoyed some of your videos & look fwd. to this set.
Happy holiday's!!

d.

________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Mike Beauchamp <list at mikebeauchamp.com>
Sent: December 23, 2021 4:43 AM
To: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: Re: [sdiy] My Guitar Amplification and Effects video lectures



On 12/22/21 10:34 PM, Lanterman, Aaron D via Synth-diy wrote:
> I teach something music-related every spring. In the semesters that I?m
> not running my ?Analog Circuits for Music Synthesis? class, I run my
> ?Guitar Amplification and Effects? class, which I?m running this Spring
>

Thanks Aaron, both are being youtube-dl'd into my Lanterman Videos folder!

Mike

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org
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From brianw at audiobanshee.com  Fri Dec 24 00:07:57 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 15:07:57 -0800
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <0c4672e0-9e43-5c6c-9782-ea23e575f5cf@go2.pl>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <0c4672e0-9e43-5c6c-9782-ea23e575f5cf@go2.pl>
Message-ID: <659C4190-896C-42ED-8DAF-BC3D5EC78E49@audiobanshee.com>

On Dec 23, 2021, at 04:02, Roman Sowa <modular at go2.pl> wrote:
> When one of the batteries is more dead than others, at certain current (it may be as low as few mA) it will be too weak to hold and becomes a resistor. It will actually reverse polarity and take most of stack voltage on itself, so entire stack will drop from say 20V to 1V.
> To prevent that you might add ideal diodes over the cells. Those are widely used in solar panels.

Thanks for passing on this technique.

I've noticed that large LED displays - the ones that include a large number of individual LEDs in a combination of series and parallel connections per segment - will often have cross connects between the parallel paths, at the nodes between individual LEDs. My understand is that this allows individual LED components to fail without stopping all current in that series path. Of course, this does require twice the current to flow through the remaining LED(s) at that stage of the series, which would result in inconsistent brightness across all LEDs, but at least it's better than the whole series path in the array going dark.

Similarly, these battery array protection diodes prevent totally dead cells from going reverse polarity, but they do consume a bit of wattage as a product of the diode drop and the total current. Like the LED array workaround, it's not ideal performance, but it postpones complete failure.

Brian


> And what a coincidence, few emails later I have found a spam about MAX17220 DC booster, it ideally matches the topic of wringing nearly dead batteries. It starts from 0.88V input and then works until battery is 0.4V dead. Only 4 external components and output adjustable from 1.8 to 5V.
> 
> Once I got a thing from Aliexpress, basicaly a PCB with booster on it and battery clips. So you put a dead AAA battery in and hapily enjoy 5V at its output until poor battery wheeps "please let me go now...".
> It was about $1 IIRC
> 
> Roman




From brianw at audiobanshee.com  Fri Dec 24 00:31:14 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 15:31:14 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
Message-ID: <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>

Are you sure about all of those details, Mike?

The USB-MIDI specification does not have any mention of USB 2. My recollection is that USB-MIDI started out as requiring Full Speed clock rates, and this was not increased when faster USB clock rates were added. There is only USB-MIDI 1.0 and it has not been improved - most likely because there is so much existing support for USB-MIDI 1.0 that any "improvements" would simply break compatibility.

Also, USB 1 includes both Low Speed and Full Speed. While you are correct that Low Speed is actually worse than Classic MIDI, there has never been a USB-MIDI specification that allowed for the use of Low Speed. So, while it's possible for some devices to "fall back" to Low Speed mode, that should not be allowed for a USB-MIDI device. I looked for this to be spelled out in the USB-MIDI 1.0 spec, but I couldn't find anything quickly - it might boil down to the use of Bulk endpoints, which aren't allowed for Low Speed, or perhaps just that USB-MIDI has too many endpoints beyond what Low Speed allows.

USB 2.0 added High Speed, which happens to be backwards-compatible with Full Speed USB 1.0 devices, including USB-MIDI. So, while a USB 2.0 hub might allow more devices to be attached, it's not actually going to make the USB-MIDI devices run any faster. At best, USB 2.0 reduces the bandwidth interference from other devices, which makes it more likely that USB-MIDI Interrupt endpoints will be serviced in a timely fashion. Since USB-MIDI doesn't use the bandwidth and latency guarantees of Isochronous endpoints, the resulting latency depends entirely upon the Host operating system scheduling of Interrupt endpoints.

I've written a few USB-MIDI firmwares, so I've experimented with what's possible here. In the early days, there were many bugs in vendor examples, but over time those have gotten a lot better. Some chips have a USB stack that's flawless, but it's difficult to know that until you use it.


On Dec 20, 2021, at 09:34, Mike Bryant <mbryant at futurehorizons.com> wrote:
> Totally agree some USB stacks for MIDI are useless (Linux/ALSA anybody) but that doesn't damn USB itself.   MIDI2.0 depends on using USB (or Ethernet) and even on original MIDI it gives far better performance provided you have use USB2.0.  
> But USB 1 is actually worse than 5 pin DIN so make sure it isn't falling back into that.
> 
> -----Original Message-----
> From: MTG
> Sent: 20 December 2021 17:27
> 
> USB-MIDI is another layer (of hell). I don't think it's going to solve any issues that 5-pin DIN has. Maybe because the microcontrollers that have USB are typically many, many times faster than an old 8-bit one though. OTOH, some USB stacks are very poorly written.
> 
> On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
>> I finally bought a mini scope. I have no excuse not to use it.
>> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too 
>> easy for developers interested in performance to abandon it and move to USB.




From brianw at audiobanshee.com  Fri Dec 24 00:37:30 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 15:37:30 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <82143DBD-E6BF-4EE6-8B99-BA9A4888CFF1@electricdruid.net>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <82143DBD-E6BF-4EE6-8B99-BA9A4888CFF1@electricdruid.net>
Message-ID: <29BE0AFE-CA3C-4B25-B945-D54045568113@audiobanshee.com>

On Dec 20, 2021, at 06:26, Tom Wiltshire <tom at electricdruid.net> wrote:
> I very much doubt this is a "hard limitation of 5 pin MIDI" as you put it. MIDI was *designed* specifically to work on 8-bit processors running at probably only 4 or 8MHz if you were lucky. However, in order to do that, certain things were assumed. One of those assumptions was that Realtime bytes would be dealt with directly in the Rx interrupt, which is why they're easy to filter, and why it doesn't matter that they can appear anywhere: the assumption is that by the time the parser sees the string of incoming bytes, Realtime will already have been removed.
> 
> If a Z80 in 1984 can do it, there's no way it's not possible in 2021 on an Arduino. The problem is only the coding, and in this case, it seems like you're fighting against the Arduino MIDI library. The test with the Teensy basically proves that to me.
> 
> Tom

You're correct, Tom. I wrote code for a 1 MHz 6502 (on an Apple ][) in the eighties that could keep up with MIDI clocks just fine. Of course, a 1 MHz 6502 accesses memory 4 times as fast as the typical 4 MHz 8-bit processor, so they're in the same ballpark. I just wanted to mention that even clock speeds as low as 1 MHz are not too slow to handle MIDI.

The challenge here is software (or firmware) development. For a 1 MHz processor, it might even be necessary to write in assembly language. In contrast, using a high-level language like C++ along with high-level function libraries like Arduino, could easily piss away the power of a 48 MHz or faster AVR processor, such that things would not work reliably. It's a real challenge to design real-time software, but it's certainly worth the effect to learn how.

Brian




From mskala at northcoastsynthesis.com  Fri Dec 24 01:00:40 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Thu, 23 Dec 2021 19:00:40 -0500 (EST)
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
Message-ID: <alpine.LNX.2.20.2112231857130.23099@kharasan.bonobo-conspiracy.ca>

On Thu, 23 Dec 2021, Brian Willoughby wrote:
> Speed. So, while it's possible for some devices to "fall back" to Low
> Speed mode, that should not be allowed for a USB-MIDI device. I looked
> for this to be spelled out in the USB-MIDI 1.0 spec, but I couldn't find
> anything quickly - it might boil down to the use of Bulk endpoints,
> which aren't allowed for Low Speed, or perhaps just that USB-MIDI has
> too many endpoints beyond what Low Speed allows.

I think the bulk endpoint thing is sufficient to prevent any "fall back"
of USB-MIDI to low speed.  Low speed devices only have interrupt and
control endpoints.  USB-MIDI requires bulk endpoints.  Even if it might be
easy to imagine ways of exchanging the same packets with an interrupt
endpoint that would normally be transferred over bulk, there'd be problems
to solve for which there's no obvious single right way to do it; and the
resulting homemade protocol would be so far from the standard that you
couldn't expect any existing hosts or devices other than your own to
support it.

I don't think number of endpoints is actually a big deal here.  I'm not
sure low-speed and full-speed actually have different numbers of endpoints
allowed, and a very basic USB-MIDI implementation doesn't need many
endpoints anyway.  A Roland UM-ONE in class compliant mode, for instance,
only has three endpoints:  one bulk in, one bulk out, and the control
endpoint.  I've certainly seen low-speed devices with that many endpoints
(because separate endpoints for "boot" and "full HID" protocols), and I
would expect that some low-speed devices with more exist.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From brianw at audiobanshee.com  Fri Dec 24 01:19:52 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 16:19:52 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <alpine.LNX.2.20.2112231857130.23099@kharasan.bonobo-conspiracy.ca>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
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 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <alpine.LNX.2.20.2112231857130.23099@kharasan.bonobo-conspiracy.ca>
Message-ID: <4D7427A1-FE67-47E3-894F-3A43E8976AEF@audiobanshee.com>

On Dec 23, 2021, at 16:00, mskala at northcoastsynthesis.com wrote:
> On Thu, 23 Dec 2021, Brian Willoughby wrote:
>> Speed. So, while it's possible for some devices to "fall back" to Low
>> Speed mode, that should not be allowed for a USB-MIDI device. I looked
>> for this to be spelled out in the USB-MIDI 1.0 spec, but I couldn't find
>> anything quickly - it might boil down to the use of Bulk endpoints,
>> which aren't allowed for Low Speed, or perhaps just that USB-MIDI has
>> too many endpoints beyond what Low Speed allows.
> 
> I think the bulk endpoint thing is sufficient to prevent any "fall back"
> of USB-MIDI to low speed.  Low speed devices only have interrupt and
> control endpoints.  USB-MIDI requires bulk endpoints.  Even if it might be
> easy to imagine ways of exchanging the same packets with an interrupt
> endpoint that would normally be transferred over bulk, there'd be problems
> to solve for which there's no obvious single right way to do it; and the
> resulting homemade protocol would be so far from the standard that you
> couldn't expect any existing hosts or devices other than your own to
> support it.

I think you nailed it, here. I had forgotten that Low Speed only allows Control and Interrupt.

> I don't think number of endpoints is actually a big deal here.  I'm not
> sure low-speed and full-speed actually have different numbers of endpoints
> allowed, and a very basic USB-MIDI implementation doesn't need many
> endpoints anyway.  A Roland UM-ONE in class compliant mode, for instance,
> only has three endpoints:  one bulk in, one bulk out, and the control
> endpoint.  I've certainly seen low-speed devices with that many endpoints
> (because separate endpoints for "boot" and "full HID" protocols), and I
> would expect that some low-speed devices with more exist.

Outside of the USB-MIDI spec, I saw one note that Low Speed allows a maximum of 2 endpoints *plus* endpoint 0, while another section of the same USB spec said that Low Speed allows a maximum of 2 endpoints *including* endpoint 0. So, I'm pretty sure that a device with 4 endpoints cannot be Low Speed.

In any case, there's a big deal in the main USB spec made about how Full Speed allows 16 endpoints compared to the vastly smaller number (2 or 3) for Low Speed. Part of the reasoning behind the design of Low Speed is to allow very cheap electronics with limited resources to be guaranteed to function as Device or Host for Low Speed operations

Your example of "boot" and "full HID" protocols probably involves multiple Interfaces. Although I don't recall whether Low Speed allows for multiple interfaces, it's certainly possible that the total number of endpoints could be greater when including all interfaces versus the number of endpoints in each single interface. I've never designed a Low Speed device, though, so there's a lot of potential restrictions that I could be missing.

I do know that multiple Interfaces are *required* for Isochronous Devices - like USB Audio Class - because there has to be a default Interface that has no active Isochronous endpoints. It's the action of selecting a non-default Interface that starts the Isochronous streams. But my first-hand familiarity with Full Speed Isochronous endpoint streams has perhaps no relation to whether Low Speed even allows for Interfaces.

Brian

> -- 
> Matthew Skala
> North Coast Synthesis Ltd.




From modular at go2.pl  Fri Dec 24 01:33:42 2021
From: modular at go2.pl (Roman Sowa)
Date: Fri, 24 Dec 2021 01:33:42 +0100
Subject: [sdiy] Outside Synth DIY topics but could be of some interest..
In-Reply-To: <659C4190-896C-42ED-8DAF-BC3D5EC78E49@audiobanshee.com>
References: <000001d7f76c$cb73ede0$625bc9a0$@oricom.ca>
 <0c4672e0-9e43-5c6c-9782-ea23e575f5cf@go2.pl>
 <659C4190-896C-42ED-8DAF-BC3D5EC78E49@audiobanshee.com>
Message-ID: <091e85cd-7492-35ec-d468-8423cbd360c3@go2.pl>

Well, I meant ideal diode, not regular or shottky diode. They are also 
called "smart bypas diode". It's basicaly a FET with charge pump, and 
it's just a few milivolts drop even at few amps current. See SM74611 for 
example. This is rather for more powerful stuff than a buch of weak 
batteries, but there are also other ideal diodes and controllers.

Roman

W dniu 2021-12-24 o?00:07, Brian Willoughby pisze:
> On Dec 23, 2021, at 04:02, Roman Sowa <modular at go2.pl> wrote:
>> When one of the batteries is more dead than others, at certain current (it may be as low as few mA) it will be too weak to hold and becomes a resistor. It will actually reverse polarity and take most of stack voltage on itself, so entire stack will drop from say 20V to 1V.
>> To prevent that you might add ideal diodes over the cells. Those are widely used in solar panels.
> Thanks for passing on this technique.
>
> I've noticed that large LED displays - the ones that include a large number of individual LEDs in a combination of series and parallel connections per segment - will often have cross connects between the parallel paths, at the nodes between individual LEDs. My understand is that this allows individual LED components to fail without stopping all current in that series path. Of course, this does require twice the current to flow through the remaining LED(s) at that stage of the series, which would result in inconsistent brightness across all LEDs, but at least it's better than the whole series path in the array going dark.
>
> Similarly, these battery array protection diodes prevent totally dead cells from going reverse polarity, but they do consume a bit of wattage as a product of the diode drop and the total current. Like the LED array workaround, it's not ideal performance, but it postpones complete failure.
>
> Brian
>
>
>> And what a coincidence, few emails later I have found a spam about MAX17220 DC booster, it ideally matches the topic of wringing nearly dead batteries. It starts from 0.88V input and then works until battery is 0.4V dead. Only 4 external components and output adjustable from 1.8 to 5V.
>>
>> Once I got a thing from Aliexpress, basicaly a PCB with booster on it and battery clips. So you put a dead AAA battery in and hapily enjoy 5V at its output until poor battery wheeps "please let me go now...".
>> It was about $1 IIRC
>>
>> Roman



From mbryant at futurehorizons.com  Fri Dec 24 01:33:49 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 24 Dec 2021 00:33:49 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
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Message-ID: <9c438414816948358e3e70cda3c68928@futurehorizons.com>

Even with the latest spec, the MIDI Association go out of their way not to specify the USB speed required even in Version 2.0 of the USB Device Class Definition for MIDI devices, but I don't think you could implement most of the features of MIDI 2.0 without USB2.0 or Ethernet. 

The 1999 spec was written assuming most people were going to multiplex DIN MIDI channels onto a USB link, but I think we've moved on from that nowadays and the high bandwidth mechanism is regularly used.  A lot of kit doesn't even come with a DIN socket on it nowadays, something I've heard Rick Wakeman ranting about :-)

I've never seen anything official saying MIDI 1.0 isn't allowed over low speed USB.  Low speed USB often implements a superset of the basic spec, including extra endpoints, and so it actually often works with a single device.  But the latency is high.

My reference to USB2.0 was about using hubs to allow lots of MIDI devices to be connected.  Ideally you need a hub with a Transaction Translator per port which retimes the MIDI data onto the USB2.0 stream.  The MIDI data obviously won't be any faster than when it left the USB MIDI device, but this allows the streams to be multiplexed more efficiently so you don't have any added latency unless you are multiplexing a pretty large number of active ports.  But cheaper hubs actually slow down to the speed of the inputs and multiplexing lots of devices becomes a bad move.  Easiest way to avoid this problem is to buy a USB3.0 hub as they always seem to do things on a per port basis.

A lot of MIDI hosts and devices nowadays are actually phones/tablets operating in MIDI mode, either over USB or BLE, and the speeds required are rising all the time as more complex messages are sent.

I tend to use a bare metal USB stack for Raspberry Pi CM4s as it handles pluging/unplugging of multiple devices well, something many stacks seem to fall over on, or at least ignore any device once it has been unplugged.



-----Original Message-----
From: Brian Willoughby [mailto:brianw at audiobanshee.com] 
Sent: 23 December 2021 23:31
To: Mike Bryant
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Techniques for Multiplying MIDI Clock frequency?

Are you sure about all of those details, Mike?

The USB-MIDI specification does not have any mention of USB 2. My recollection is that USB-MIDI started out as requiring Full Speed clock rates, and this was not increased when faster USB clock rates were added. There is only USB-MIDI 1.0 and it has not been improved - most likely because there is so much existing support for USB-MIDI 1.0 that any "improvements" would simply break compatibility.

Also, USB 1 includes both Low Speed and Full Speed. While you are correct that Low Speed is actually worse than Classic MIDI, there has never been a USB-MIDI specification that allowed for the use of Low Speed. So, while it's possible for some devices to "fall back" to Low Speed mode, that should not be allowed for a USB-MIDI device. I looked for this to be spelled out in the USB-MIDI 1.0 spec, but I couldn't find anything quickly - it might boil down to the use of Bulk endpoints, which aren't allowed for Low Speed, or perhaps just that USB-MIDI has too many endpoints beyond what Low Speed allows.

USB 2.0 added High Speed, which happens to be backwards-compatible with Full Speed USB 1.0 devices, including USB-MIDI. So, while a USB 2.0 hub might allow more devices to be attached, it's not actually going to make the USB-MIDI devices run any faster. At best, USB 2.0 reduces the bandwidth interference from other devices, which makes it more likely that USB-MIDI Interrupt endpoints will be serviced in a timely fashion. Since USB-MIDI doesn't use the bandwidth and latency guarantees of Isochronous endpoints, the resulting latency depends entirely upon the Host operating system scheduling of Interrupt endpoints.

I've written a few USB-MIDI firmwares, so I've experimented with what's possible here. In the early days, there were many bugs in vendor examples, but over time those have gotten a lot better. Some chips have a USB stack that's flawless, but it's difficult to know that until you use it.


On Dec 20, 2021, at 09:34, Mike Bryant <mbryant at futurehorizons.com> wrote:
> Totally agree some USB stacks for MIDI are useless (Linux/ALSA anybody) but that doesn't damn USB itself.   MIDI2.0 depends on using USB (or Ethernet) and even on original MIDI it gives far better performance provided you have use USB2.0.  
> But USB 1 is actually worse than 5 pin DIN so make sure it isn't falling back into that.
> 
> -----Original Message-----
> From: MTG
> Sent: 20 December 2021 17:27
> 
> USB-MIDI is another layer (of hell). I don't think it's going to solve any issues that 5-pin DIN has. Maybe because the microcontrollers that have USB are typically many, many times faster than an old 8-bit one though. OTOH, some USB stacks are very poorly written.
> 
> On 12/20/2021 8:55 AM, Benjamin Tremblay via Synth-diy wrote:
>> I finally bought a mini scope. I have no excuse not to use it.
>> I agree, this is not a hard limitation on 5 pin MIDI, but it?s too 
>> easy for developers interested in performance to abandon it and move to USB.





From mskala at northcoastsynthesis.com  Fri Dec 24 01:34:43 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Thu, 23 Dec 2021 19:34:43 -0500 (EST)
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <4D7427A1-FE67-47E3-894F-3A43E8976AEF@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
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 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
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 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <alpine.LNX.2.20.2112231857130.23099@kharasan.bonobo-conspiracy.ca>
 <4D7427A1-FE67-47E3-894F-3A43E8976AEF@audiobanshee.com>
Message-ID: <alpine.LNX.2.20.2112231927330.23099@kharasan.bonobo-conspiracy.ca>

On Thu, 23 Dec 2021, Brian Willoughby wrote:
> Your example of "boot" and "full HID" protocols probably involves
> multiple Interfaces. Although I don't recall whether Low Speed allows
> for multiple interfaces, it's certainly possible that the total number
> of endpoints could be greater when including all interfaces versus the

Yes - the one I have handy is a no-name typing keyboard that identifies
itself as "1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory" and it has
two interfaces, one for the boot protocol and one for the report protocol,
each with one interrupt in endpoint.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From brianw at audiobanshee.com  Fri Dec 24 03:19:42 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 18:19:42 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <9c438414816948358e3e70cda3c68928@futurehorizons.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
Message-ID: <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>



On Dec 23, 2021, at 16:33, Mike Bryant <mbryant at futurehorizons.com> wrote:
> Even with the latest spec, the MIDI Association go out of their way not to specify the USB speed required even in Version 2.0 of the USB Device Class Definition for MIDI devices, but I don't think you could implement most of the features of MIDI 2.0 without USB2.0 or Ethernet.

Part of not specifying the speed is that they've already defined Low Speed to not allow Bulk endpoints, and they defined USB-MIDI to require Bulk endpoints.

Another part is that High Speed did not exist when USB-MIDI was designed, so they didn't mention High Speed (and they haven't rewritten the USB-MIDI spec since).

Also, you might be surprised by the number of operating systems with default USB-MIDI drivers that simply won't acknowledge a High Speed device as USB-MIDI.

For decades, Windows would not recognize a USB-MIDI Device with non-port Entities. Thus, all USB-MIDI devices with built-in Entities like a control surface "lie" about their capabilities and report the non-port features as if they were Embedded MIDI Jacks. I know this because I implemented a Device according to the USB-MIDI Spec that Mac OS X would recognize fully, but Windows would not. Microsoft wanted to support this, but they wanted to test it first, and they couldn't find any commercial devices that implemented that part of the USB-MIDI spec. That's because nobody could successfully release a commercial device with those features because it would mean that the product is not supported on Windows. In those days, nobody could afford to be Mac-only.

In other words, the situation involves more than just USB specifications - it also involves Host support.

> The 1999 spec was written assuming most people were going to multiplex DIN MIDI channels onto a USB link, but I think we've moved on from that nowadays and the high bandwidth mechanism is regularly used.

I'm not sure what this "high bandwidth" mechanism is, other than the fact that Full Speed is a lot faster than 31.25 kbaud.

My first USB-MIDI firmware supported at least three Bulk packets per USB frame, meaning it was roughly three times the speed of Classic MIDI. This was without optimizing the firmware in any way (it probably could have been more efficient), and certainly without changing the Mac OS X driver for USB-MIDI.

If there's a distinct "high bandwidth" mode, then I'd certainly like to learn more about it.


> A lot of kit doesn't even come with a DIN socket on it nowadays, something I've heard Rick Wakeman ranting about :-)
> 
> I've never seen anything official saying MIDI 1.0 isn't allowed over low speed USB.  Low speed USB often implements a superset of the basic spec, including extra endpoints, and so it actually often works with a single device.  But the latency is high.

As M. Skala and I have been discussing, USB-MIDI 1.0 doesn't have to disallow Low Speed because USB in general disallows Bulk over Low Speed (and USB-MIDI requires Bulk).

One thing to keep in mind is that USB has several independent layers so that the generic parts can be handled by the same code. On the firmware side, some of the USB protocol is handled in hardware (different amounts for different processor designs), and some is handled in generic firmware source. Only the smallest amount of code is specific to USB-MIDI. Likewise, on the Host, an operating system will handle all USB Devices with a certain amount of generic code, and only when the Descriptors are read is the handling turned over to a specific driver like USB-MIDI.

In other words, it's highly likely that every modern operating system simply will not function with a Low Speed USB-MIDI Device, simply because the Device would be disqualified long before the USB-MIDI driver can get involved.

> My reference to USB2.0 was about using hubs to allow lots of MIDI devices to be connected.  Ideally you need a hub with a Transaction Translator per port which retimes the MIDI data onto the USB2.0 stream.  The MIDI data obviously won't be any faster than when it left the USB MIDI device, but this allows the streams to be multiplexed more efficiently so you don't have any added latency unless you are multiplexing a pretty large number of active ports.

This much is true. A good hub runs as fast as possible, except when handling the transaction with Full Speed or Low Speed Devices. The Translator could allow things to happen on multiple ports at the same time.

> But cheaper hubs actually slow down to the speed of the inputs and multiplexing lots of devices becomes a bad move.  Easiest way to avoid this problem is to buy a USB3.0 hub as they always seem to do things on a per port basis.

One thing to keep in mind is that the Host only talks to one Device at a time, and it talks to the Device at its native speed. There really isn't any support for a Host to talk to, e.g., a USB-MIDI Device at any speed other than Full Speed. The Host can't talk to the hub any faster than it could talk to the Device without the hub.

I haven't looked at the details, but it's theoretically possible that a hub with Transaction Translation could handle Interrupt endpoints without the Host and then deliver that data faster at a later time, but I've not seen any evidence of this. Other endpoint types like Isochronous literally have to be handled in real time - there's no way to run them faster between Host and Hub than they run from Hub to Device.

Also keep in mind that Full Speed Devices literally cannot communicate any faster than Full Speed, but you probably didn't say otherwise.

> I tend to use a bare metal USB stack for Raspberry Pi CM4s as it handles pluging/unplugging of multiple devices well, something many stacks seem to fall over on, or at least ignore any device once it has been unplugged.

My most recent project was to write USB Host firmware without an operating system of any kind. It was somewhat annoying because even after the Host was talking directly to the Device successfully, a lot more code had to be added to support a Hub between the Host and Device. That's because most or all Hubs are completely under control of the Host, and cannot handle anything on their own beyond the basic hardware switching and isolation. But this is a new topic for me, and there might be a few details that I missed for USB 3 Hosts. In my case, the chip only supports USB 2.0 so any newer features are irrelevant for compatibility reasons.

Brian




From mskala at northcoastsynthesis.com  Fri Dec 24 04:06:09 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Thu, 23 Dec 2021 22:06:09 -0500 (EST)
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
Message-ID: <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>

On Thu, 23 Dec 2021, Brian Willoughby wrote:
> I'm not sure what this "high bandwidth" mechanism is, other than the
> fact that Full Speed is a lot faster than 31.25 kbaud.

I've seen over 40 poll/NAK sequences per frame (maybe over 70; both
numbers are in my memory but I'm not sure the faster one was actually with
working code) between my host and USB-MIDI keyboard when the host had
nothing better to do than poll as fast as it could.  I ended up
implementing a token-bucket rate limiter because I wanted to allow it to
poll more than once per frame, but not at an unlimited rate.  PIC24 16-bit
microcontroller, 16MHz instruction clock; not a hugely powerful computer
there.  Of course, that is with no real MIDI data being sent - it couldn't
be transferring full 64-byte packets at that rate because it would exceed
the bus bandwidth, and the host would also hit some limit on how fast it
could actually do anything useful with the MIDI data.  But I was impressed
that the keyboard had no trouble keeping up with the host.

> My most recent project was to write USB Host firmware without an
> operating system of any kind. It was somewhat annoying because even

On what chip?

Right now, literally in my other terminal tab as I type this, I'm busy
writing up the documentation for my PIC24-based USB MIDI host synthesizer
module, which I'm hoping to release in the new year.  It's been quite an
adventure getting it to work, both because I had no previous USB
experience and because the hardware is only sort-of documented.
Microchip just tells people to use the C-language driver they provide.
For various reasons, I wanted to write my own in assembly language.  I'm
pleased to have that working now and that's why USB-MIDI is fresh in my
mind.

> after the Host was talking directly to the Device successfully, a lot
> more code had to be added to support a Hub between the Host and Device.

It is a hardware erratum of the PIC24 that it cannot be host for a hub
when there is a low-speed device on the bus.  Now, technically, that
wouldn't preclude using a hub with a PIC24 and USB-MIDI devices (because
USB-MIDI is never low-speed...); but it made a good excuse for me to say
that at least in the initial version of my project, I just don't support
hubs, period.  Made my life simpler, and not a huge imposition on the
intended use case of my module.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From brianw at audiobanshee.com  Fri Dec 24 06:57:28 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Thu, 23 Dec 2021 21:57:28 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
Message-ID: <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>



On Dec 23, 2021, at 19:06, mskala at northcoastsynthesis.com wrote:
> On Thu, 23 Dec 2021, Brian Willoughby wrote:
>> I'm not sure what this "high bandwidth" mechanism is, other than the
>> fact that Full Speed is a lot faster than 31.25 kbaud.
> 
> I've seen over 40 poll/NAK sequences per frame (maybe over 70; both
> numbers are in my memory but I'm not sure the faster one was actually with
> working code) between my host and USB-MIDI keyboard when the host had
> nothing better to do than poll as fast as it could.  I ended up
> implementing a token-bucket rate limiter because I wanted to allow it to
> poll more than once per frame, but not at an unlimited rate.

What operating system was serving as the USB Host?

I primarily use Mac OS X, so I have no control over how often the Host does Bulk polling because my application is designed to communicate directly with CoreMIDI instead of the USB Host driver. You can't really control the Host from your Device firmware anyway, and perhaps you don't want to try limiting things. So long as the Device responds saying "I don't have any Bulk data for you right now," then everything should work normally.

> PIC24 16-bit
> microcontroller, 16MHz instruction clock; not a hugely powerful computer
> there.

My USB-MIDI Device firmware experience is with the PIC18 8-bit MCU with a 48 MHz clock.

There are two USB firmware stacks from Microchip for the PIC18 (at the time I worked on this). One is for the normal firmware, the alternate stack is for the firmware updates that are supported over USB. The latter is slightly stripped down because it needs to fit within a finite section of Flash code memory, and it doesn't usually need to support product-specific features. I noticed that each of these two stacks had a history of bug fixes across releases, and while they were fairly well documented, it wasn't entirely clear that all bugs had been fixed in both. So, I painstakingly mapped out all of the bug fixes in the various revisions, and made sure that they were applied to both stacks. I may have also added some features to the "firmware update over USB" code because I wanted to enable switching into and out of firmware update mode without forcing the user to manually power cycle. I don't think Microchip supported the USB DFU standard at the time I was working (probably because DFU may not have even been finalized yet). So I recall spending some time implementing DFU, although I can't recall whether it was successful in a compatible way.

These Microchip USB stacks are all in C, and the chip has hardware support for the timing-critical stuff anyway. All you need to do is implement the details that make your USB Device unique compared to the average USB Device. They didn't provide a USB-MIDI driver at the time, but USB-MIDI is a very simple layer on top of the generic USB Device. Just set up Bulk endpoints for IN and OUT, group data into 4-byte USB-MIDI messages, and that's it. The rest of the code is basic MIDI (although I always thought it was a severe oversight that the USB-MIDI message has the same 4-bit command encoded twice in every message, making it rather difficult to know which one to honor if they happen to be different).

> Of course, that is with no real MIDI data being sent - it couldn't
> be transferring full 64-byte packets at that rate because it would exceed
> the bus bandwidth, and the host would also hit some limit on how fast it
> could actually do anything useful with the MIDI data.  But I was impressed
> that the keyboard had no trouble keeping up with the host.

I believe that USB allows multiple 64-byte Bulk packets per USB frame. It's up to the Host to schedule these appropriately while accounting for the minimum required Isochronous transfers plus other endpoint types. There's a table in the USB spec that shows the maximum number of Bulk transfers of various sizes, and you can see how the advertised USB bandwidth can never really be reached. It's also obvious that smaller packets reduce the bandwidth because each packet has overhead.

The way the Microchip PIC18 USB stack worked is that the Device code would queue up Bulk data ahead of time, and then whenever the Host scheduled a Bulk transfer the PIC18 firmware would set up DMA for the Bulk data. Various firmware settings made it easy to avoid going over 64 bytes per packet, or responding to a poll when there was nothing to send, and also handled Bulk packets that were shorter than the maximum (64-byte) size.

I recall doing some sort of benchmark. Either I counted packets per frame and came up with "3" or I put the frame number into the USB-MIDI data stream and noticed that there were 3 USB-MIDI messages in the same frame.

I assume that I could have optimized this by building a packet queue, where each new USB-MIDI message was added to a given packet until there were 16 USB-MIDI messages in the packet, and then moving on to fill additional packets. I could have used that table from the USB spec to see the maximum number of packets that might be needed in a single frame, plus maybe a little extra to allow queuing USB-MIDI messages for the next frame.

As it was, my code was throttled to 16 USB-MIDI messages so that the firmware was only working on one packet at a time. There was some sort of handshaking so that when a packet was sent to the Host, the queue of 16 was reset to allow more USB-MIDI messages to be added. I forget the details, but I assume that 3 messages of actual USB-MIDI data payload was probably not the actual maximum.

>> My most recent project was to write USB Host firmware without an
>> operating system of any kind. It was somewhat annoying because even
> 
> On what chip?

Texas Instruments TM4C1294 ARM, 32-bit, 120 MHz.

Texas Instruments provides several firmware examples including isochronous audio and USB Hub support. I didn't have to write the Hub support myself, but I did have to figure out how to combine multiple examples into a single piece of firmware that both supported a Hub and my Device.

My goal for supporting a Hub was to provide cheap isolation (I'd rather burn out a $4.99 Hub than my custom USB hardware), and also to allow for some way to save and restore custom settings on a USB memory stick without literally removing the controller Device from the Host USB jack.

My Device has two 384-byte Isochronous endpoints, for a total of 768 bytes per Full Speed USB frame. The TM4C1294 seems to have a hardware or firmware bug, but it may only affect Isochronous endpoints that are larger than 256 bytes. I've never seen bad data in the first 256 bytes of those Isochronous packets. Even though they "support" larger Isochronous packets, they may not have tested them very well. I haven't worked on this in a while, though.

I have not implemented USB-MIDI Host firmware on the TM4C129x, but I assume it would be easy and bug-free, given the nature of Bulk packets.

> Right now, literally in my other terminal tab as I type this, I'm busy
> writing up the documentation for my PIC24-based USB MIDI host synthesizer
> module, which I'm hoping to release in the new year.

That sounds very cool !

Given their prevalence, it seems like a very useful feature to be able to Host USB-MIDI controllers.

> It's been quite an
> adventure getting it to work, both because I had no previous USB
> experience and because the hardware is only sort-of documented.
> Microchip just tells people to use the C-language driver they provide.
> For various reasons, I wanted to write my own in assembly language.  I'm
> pleased to have that working now and that's why USB-MIDI is fresh in my
> mind.

I don't know the details of the PIC24, but if they handle enough of USB in hardware, including some DMA, then you might as well use the C Language driver. However, most processors have completely separate documentation teams for the hardware versus the firmware, so there should be enough documentation for you to provide all of the firmware ... I just wouldn't recommend working that hard.

I prefer to leverage the generic USB support - and I've never had to write it (just debug it) - and spend time on the unique aspects. Depending upon the maturity of the USB firmware stack, you can leverage the fixes for the mistakes of those who have been working with the chip longer.

>> after the Host was talking directly to the Device successfully, a lot
>> more code had to be added to support a Hub between the Host and Device.
> 
> It is a hardware erratum of the PIC24 that it cannot be host for a hub
> when there is a low-speed device on the bus.  Now, technically, that
> wouldn't preclude using a hub with a PIC24 and USB-MIDI devices (because
> USB-MIDI is never low-speed...); but it made a good excuse for me to say
> that at least in the initial version of my project, I just don't support
> hubs, period.  Made my life simpler, and not a huge imposition on the
> intended use case of my module.

I wasn't convinced that I *needed* to support a Hub, but I wanted to see how hard it would be. So, I allocated a finite amount of time to experiment. I started with examples that only worked with common USB Devices, via a Hub, and confirmed that those worked. Then I dug into the firmware source and figured out how to merge Hub support into my existing custom Device support. I turned out that this took only about a day of effort, so I added Hub support.

Of course, given that I am not running an operating system on this ARM chip, there will be no support for any Device attached to the Hub other than the two that I code for - the custom controller Device and a USB memory stick.

I think it would be fair for you to say that your product supports a Hub, but only with Devices attached that are already supported without the Hub. I guess that could be a problem if you support a mouse and/or keyboard, because then that support would go away with a Hub.

On the other hand, maybe there's a way to work around the hardware erratum in firmware? That would be some serious PIC24-fu.

> -- 
> Matthew Skala
> North Coast Synthesis Ltd.

By the way, the custom USB controller Device that I keep referring to is based on the Texas Instruments TMS320VC5506 16-bit fixed-point DSP. The two 384-byte Isochronous endpoints each send multi-touch pressure data for half of the surface, with an update rate of 1 kHz and a latency of 2 or 3 ms. This was a challenging USB Device firmware because it combines DSP assembly language to run 16,000 128-point FFT operations per second at 40-bit precision while maintaining a minimum Full Speed bandwidth of 768 KB/sec. There are additional USB endpoints for tracking pots and debugging information, but those aren't really used much. It's just amazing that everything can be squeezed into the out-of-date USB 1.0 spec with any problems. The normal Host is macOS, which doesn't have the Isochronous bugs on larger-than-256-byte Isochronous packets that the TM4C129x has.

One very interesting detail about this device is that it's native sampling rate is 125 kHz, and that works out to only a 976.5625 Hz packet rate. Although the Host USB clock is not locked to the Device sample rate, it's still true that the Host wants about 1,000 packets per second. This means that 1 out of every 42+2/3 frames has a 0-byte Isochronous packet instead of a 384-byte packet. Everything still manages to work out, because USB was designed for this.

Brian

p.s. To get back to the subject... any of these 8-bit or 16-bit or 32-bit processors should be able to handle incoming MIDI clock, lock in a Timer channel, and multiply the frequency for rock-solid output timing. Because the TM4C129x has 8 full UART peripherals, I've been tempted for several years to design an 8-input, 8-output MIDI merger than properly handles MIDI clock between everything (although that could be a mess if you don't have a way to turn off conflicting clocks).




From lofideadbeat at gmail.com  Fri Dec 24 08:47:29 2021
From: lofideadbeat at gmail.com (Jean Bender)
Date: Fri, 24 Dec 2021 08:47:29 +0100
Subject: [sdiy] My Guitar Amplification and Effects video lectures
In-Reply-To: <MWHPR0501MB38340C6EAD0B290826C5EE20D17E9@MWHPR0501MB3834.namprd05.prod.outlook.com>
References: <EFF65BE2-A1A0-4A74-BEFC-1603ABC53288@ece.gatech.edu>
 <96773e0b-12d0-b8a5-3c93-9dc70f301ace@mikebeauchamp.com>
 <MWHPR0501MB38340C6EAD0B290826C5EE20D17E9@MWHPR0501MB3834.namprd05.prod.outlook.com>
Message-ID: <CA+rzoo7j8PiANLarPXKNPxEzwcD1TQ0QU0FPwSon0ucZnBuJgQ@mail.gmail.com>

Thanks a lot for sharing this !
Happy end's year  !
J.

Le jeudi 23 d?cembre 2021, Darren Shorsky via Synth-diy <
synth-diy at synth-diy.org> a ?crit :

> Thanx for this Aaron.....  i've enjoyed some of your videos & look fwd. to
> this set.
> Happy holiday's!!
>
> d.
>
> ------------------------------
> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Mike
> Beauchamp <list at mikebeauchamp.com>
> *Sent:* December 23, 2021 4:43 AM
> *To:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] My Guitar Amplification and Effects video lectures
>
>
>
> On 12/22/21 10:34 PM, Lanterman, Aaron D via Synth-diy wrote:
> > I teach something music-related every spring. In the semesters that I?m
> > not running my ?Analog Circuits for Music Synthesis? class, I run my
> > ?Guitar Amplification and Effects? class, which I?m running this Spring
> >
>
> Thanks Aaron, both are being youtube-dl'd into my Lanterman Videos folder!
>
> Mike
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>


-- 
Jean Bender <https://hearthis.at/jean-bender/>

Hak Lofi Record <http://h.a.k.free.fr/>
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From grant at musictechnologiesgroup.com  Fri Dec 24 17:26:39 2021
From: grant at musictechnologiesgroup.com (MTG)
Date: Fri, 24 Dec 2021 08:26:39 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
Message-ID: <f9bc419d-0d2f-fe9e-ed0d-75acb1d03965@musictechnologiesgroup.com>

Hi Brian, can you explain this a bit please? Do you mean the CIN Code 
Index Number at the start of the packet (Eg. 0x8 for Note On) and then 
the first data byte that follows? I never considered that they might not 
be the same, but I suppose one uses the CIN mainly to get the length of 
data and then parse the MIDI using classic techniques.


On 12/23/2021 9:57 PM, Brian Willoughby wrote:

> (although I always thought it was a severe oversight that the USB-MIDI message has the same 4-bit command encoded twice in every message, making it rather difficult to know which one to honor if they happen to be different).




From mskala at northcoastsynthesis.com  Fri Dec 24 17:40:04 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Fri, 24 Dec 2021 11:40:04 -0500 (EST)
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
Message-ID: <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>

On Thu, 23 Dec 2021, Brian Willoughby wrote:
> On Dec 23, 2021, at 19:06, mskala at northcoastsynthesis.com wrote:
> > I've seen over 40 poll/NAK sequences per frame (maybe over 70; both
> > numbers are in my memory but I'm not sure the faster one was actually with

> What operating system was serving as the USB Host?

That was my own PIC24 host code, with no operating system as such.  The
device on the other end of the connection was an Akai "MPK mini" USB-MIDI
keyboard.

> My USB-MIDI Device firmware experience is with the PIC18 8-bit MCU with
> a 48 MHz clock.

Probably very similar hardware to what I'm working on, then; I think
Microschip uses basically the same IP block for the USB peripheral on
PIC18 and PIC24.

> I believe that USB allows multiple 64-byte Bulk packets per USB frame.

Yes, and I've seen that working in practice, although many devices will
return a whole lot of NAKs between successful packet transfers, with the
speed of actual data traffic they can support being much less than a
maxed-out bus could carry.  Flash memory sticks in particular seem to be
quite bursty - they may return a few packets at maximum bus speed, then
just NAK for a few milliseconds before waking up again.

> My goal for supporting a Hub was to provide cheap isolation (I'd rather
> burn out a $4.99 Hub than my custom USB hardware), and also to allow for
> some way to save and restore custom settings on a USB memory stick
> without literally removing the controller Device from the Host USB jack.

Interesting point about the isolation.  That's a possible advantage of
using a hub, that I hadn't thought of.

> Given their prevalence, it seems like a very useful feature to be able
> to Host USB-MIDI controllers.

I hope so!  It's also a hole in my product line - up to now I've been
having to tell customers "Well, you'll need to get a controller or
interface from someone else to play this module."

> documentation teams for the hardware versus the firmware, so there
> should be enough documentation for you to provide all of the firmware
> ... I just wouldn't recommend working that hard.

Already done, so that's no longer a big question for me.

> I wasn't convinced that I *needed* to support a Hub, but I wanted to see
> how hard it would be. So, I allocated a finite amount of time to

Seems like a sensible approach.

> I think it would be fair for you to say that your product supports a
> Hub, but only with Devices attached that are already supported without
> the Hub. I guess that could be a problem if you support a mouse and/or
> keyboard, because then that support would go away with a Hub.

I do have support for mouse and (typing) keyboard, so the limitation would
have to be a little more complicated.  But it may be something to look at
for some future firmware version.

> sampling rate is 125 kHz, and that works out to only a 976.5625 Hz
> packet rate. Although the Host USB clock is not locked to the Device
> sample rate, it's still true that the Host wants about 1,000 packets per
> second. This means that 1 out of every 42+2/3 frames has a 0-byte
> Isochronous packet instead of a 384-byte packet. Everything still
> manages to work out, because USB was designed for this.

Almost like NTSC frame drop.

> p.s. To get back to the subject... any of these 8-bit or 16-bit or
> 32-bit processors should be able to handle incoming MIDI clock, lock in
> a Timer channel, and multiply the frequency for rock-solid output
> timing. Because the TM4C129x has 8 full UART peripherals, I've been
> tempted for several years to design an 8-input, 8-output MIDI merger
> than properly handles MIDI clock between everything (although that could
> be a mess if you don't have a way to turn off conflicting clocks).

It would probably call for some kind of out-of-band control to specify
which clocks to trust and which not to.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From rburnett at richieburnett.co.uk  Fri Dec 24 18:03:56 2021
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Fri, 24 Dec 2021 17:03:56 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
Message-ID: <2lc8yw6evr56sbychmn4fsb4.1640365436864@email.android.com>

Interesting discussions about USB MIDI. Something I've been wondering about trying to implement for some time now.

Merry Christmas and happy holidays to all...

-Richie, 



---- Matthew Skala via Synth-diy wrote ----

>On Thu, 23 Dec 2021, Brian Willoughby wrote:
>> On Dec 23, 2021, at 19:06, mskala at northcoastsynthesis.com wrote:
>> > I've seen over 40 poll/NAK sequences per frame (maybe over 70; both
>> > numbers are in my memory but I'm not sure the faster one was actually with
>
>> What operating system was serving as the USB Host?
>
>That was my own PIC24 host code, with no operating system as such.  The
>device on the other end of the connection was an Akai "MPK mini" USB-MIDI
>keyboard.
>
>> My USB-MIDI Device firmware experience is with the PIC18 8-bit MCU with
>> a 48 MHz clock.
>
>Probably very similar hardware to what I'm working on, then; I think
>Microschip uses basically the same IP block for the USB peripheral on
>PIC18 and PIC24.
>
>> I believe that USB allows multiple 64-byte Bulk packets per USB frame.
>
>Yes, and I've seen that working in practice, although many devices will
>return a whole lot of NAKs between successful packet transfers, with the
>speed of actual data traffic they can support being much less than a
>maxed-out bus could carry.  Flash memory sticks in particular seem to be
>quite bursty - they may return a few packets at maximum bus speed, then
>just NAK for a few milliseconds before waking up again.
>
>> My goal for supporting a Hub was to provide cheap isolation (I'd rather
>> burn out a $4.99 Hub than my custom USB hardware), and also to allow for
>> some way to save and restore custom settings on a USB memory stick
>> without literally removing the controller Device from the Host USB jack.
>
>Interesting point about the isolation.  That's a possible advantage of
>using a hub, that I hadn't thought of.
>
>> Given their prevalence, it seems like a very useful feature to be able
>> to Host USB-MIDI controllers.
>
>I hope so!  It's also a hole in my product line - up to now I've been
>having to tell customers "Well, you'll need to get a controller or
>interface from someone else to play this module."
>
>> documentation teams for the hardware versus the firmware, so there
>> should be enough documentation for you to provide all of the firmware
>> ... I just wouldn't recommend working that hard.
>
>Already done, so that's no longer a big question for me.
>
>> I wasn't convinced that I *needed* to support a Hub, but I wanted to see
>> how hard it would be. So, I allocated a finite amount of time to
>
>Seems like a sensible approach.
>
>> I think it would be fair for you to say that your product supports a
>> Hub, but only with Devices attached that are already supported without
>> the Hub. I guess that could be a problem if you support a mouse and/or
>> keyboard, because then that support would go away with a Hub.
>
>I do have support for mouse and (typing) keyboard, so the limitation would
>have to be a little more complicated.  But it may be something to look at
>for some future firmware version.
>
>> sampling rate is 125 kHz, and that works out to only a 976.5625 Hz
>> packet rate. Although the Host USB clock is not locked to the Device
>> sample rate, it's still true that the Host wants about 1,000 packets per
>> second. This means that 1 out of every 42+2/3 frames has a 0-byte
>> Isochronous packet instead of a 384-byte packet. Everything still
>> manages to work out, because USB was designed for this.
>
>Almost like NTSC frame drop.
>
>> p.s. To get back to the subject... any of these 8-bit or 16-bit or
>> 32-bit processors should be able to handle incoming MIDI clock, lock in
>> a Timer channel, and multiply the frequency for rock-solid output
>> timing. Because the TM4C129x has 8 full UART peripherals, I've been
>> tempted for several years to design an 8-input, 8-output MIDI merger
>> than properly handles MIDI clock between everything (although that could
>> be a mess if you don't have a way to turn off conflicting clocks).
>
>It would probably call for some kind of out-of-band control to specify
>which clocks to trust and which not to.
>
>-- 
>Matthew Skala
>North Coast Synthesis Ltd.
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at synth-diy.org
>http://synth-diy.org/mailman/listinfo/synth-diy
>Selling or trading? Use marketplace at synth-diy.org



From mbryant at futurehorizons.com  Fri Dec 24 18:42:17 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 24 Dec 2021 17:42:17 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
Message-ID: <d14e4bf17d7f4f1dbdb026008f31c8bf@futurehorizons.com>

> Another part is that High Speed did not exist when USB-MIDI was designed, so they didn't mention High Speed (and they haven't rewritten the USB-MIDI spec since).

https://www.usb.org/sites/default/files/USB%20MIDI%20v2_0.pdf

This is the one everybody should be following now, not the 1999 one which is deprecated.  Adds MIDI 2.0 but subtle changes to MIDI 1.0 as well



> In those days, nobody could afford to be Mac-only.

On the contrary, most people were Mac only back then, for example Sound Designer and its successors.  It took DigiDesign to release ProTools 3.21 PCI version in 1996/7 to really establish Windows in the studio.  Cubase did support Windows earlier but most people preferred how that ran on a Mac.  Even 25 years later some DJ creation tools are Mac/iOS only.



> I'm not sure what this "high bandwidth" mechanism is, other than the fact that Full Speed is a lot faster than 31.25 kbaud.

Page 18 of the old spec, deleted in the new one as an alternate mechanism is provided



> As M. Skala and I have been discussing, USB-MIDI 1.0 doesn't have to disallow Low Speed because USB in general disallows Bulk over Low Speed (and USB-MIDI requires Bulk).

Totally agree that is what the standard says, but if you actually try it quite a lot of equipment works.  Presumably this is because their 'low speed' implementation is just the full speed implementation with a change of data rate and a few other bodges.  



> One thing to keep in mind is that the Host only talks to one Device at a time, and it talks to the Device at its native speed. There really isn't any support for a Host to talk to, e.g., a USB-MIDI Device at any speed other than Full Speed. The Host can't talk to the hub any faster than it could talk to the Device without the hub.

Sorry but that's not quite true.  If you have a good hub with a well buffered Transaction Translator per port AND a MIDI driver that supports higher rates then you can talk to many devices each at Full Speed.  Each device of course still communicates with the hub at Full Speed, they can't do anything else of course, but the Host sees data arrive from the hub at High Speed.  My driver has been tested using 16 devices all set up to continuously transmit messages at full speed without falling over or losing messages.  That's obviously far in excess of what one is ever going to see in real operation, but gives me confidence nobody will ever lose messages in real operation provided they use an approved hub.



> Other endpoint types like Isochronous literally have to be handled in real time - there's no way to run them faster between Host and Hub than they run from Hub to Device.

That's correct.  No way of speeding these up until devices support High Speed.  I really think MIDI 2.0 should have enforced or at least recommended High Speed was supported, but it didn't.  Presumably too many people still using old processors rather than moving to the STM32F73x or NXP equivalent.



> My most recent project was to write USB Host firmware without an operating system of any kind. It was somewhat annoying because even after the Host was talking directly to the Device successfully, a lot more code had to be added to support a Hub between the Host and Device. That's because most or all Hubs are completely under control of the Host, and cannot handle anything on their own beyond the basic hardware switching and isolation. But this is a new topic for me, and there might be a few details that I missed for USB 3 Hosts. In my case, the chip only supports USB 2.0 so any newer features are irrelevant for compatibility reasons.

It's not that you need the hub for USB 3, which would be pointless, just that decent USB3 hubs, usually using the VL8xx series chips, have a Transaction Translator per port, and so these are the highest performance hubs you're going to meet operating in USB2.  







From brianw at audiobanshee.com  Sat Dec 25 01:58:55 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 16:58:55 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <f9bc419d-0d2f-fe9e-ed0d-75acb1d03965@musictechnologiesgroup.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <f9bc419d-0d2f-fe9e-ed0d-75acb1d03965@musictechnologiesgroup.com>
Message-ID: <6F77212A-5B45-41EC-92FB-2C19797D7EC5@audiobanshee.com>

Yes, the first byte is unique to USB-MIDI, and combines the Cable Number and CIN. They call that byte a Packet Header. Remaining bytes are entirely defined by MIDI (except unused bytes). Given that USB-MIDI requires every 32-bit event packet to have a complete MIDI message (barring System Exclusive), it's generally possible to parse just the remaining bytes to determine the length according to standard MIDI rules, but obviously not in all cases. In particular, you could probably just look only at the second byte (the first MIDI byte) and would (almost) always know the length of the message.

The very first open-source USB-MIDI Device firmware that I saw hard-coded the CIN in such a way that it conflicted with the actual MIDI content. Apparently, all of the USB Hosts that were tested with this particular USB-MIDI Device firmware were ignoring the CIN, some or all of the time. Either that, or the firmware was completely untested (which I doubt).

I don't recall where that open source USB-MIDI firmware is, but I seem to recall that all MIDI Channel Messages were coded with CIN=8. This implied that all Channel Messages were Note Off. I guess this worked because the USB Host driver for USB-MIDI was ignoring the CIN and looking at the actual MIDI data to determine the message type and length.


That particular bug convinced me that one should never design a protocol or format with redundant information, especially if there is no rule for which piece of redundant information takes precedence in the event that they do not match. I had already been convinced that, in software, if something can be wrong with incoming data then it will be wrong at some point in time.


Granted, USB itself has redundant information in a particular byte, where the upper 4 bits appear flipped in the lower 4 bits. However, this is not strictly redundant information because it's used as a check. When those bits don't match correctly, the USB protocol states that the data should be discarded. USB-MIDI just quite assumes the redundant bits will always match, with no defined result in the cases where they do not.

Brian


On Dec 24, 2021, at 08:26, MTG <grant at musictechnologiesgroup.com> wrote:
> Hi Brian, can you explain this a bit please? Do you mean the CIN Code Index Number at the start of the packet (Eg. 0x8 for Note On) and then the first data byte that follows? I never considered that they might not be the same, but I suppose one uses the CIN mainly to get the length of data and then parse the MIDI using classic techniques.
> 
> On 12/23/2021 9:57 PM, Brian Willoughby wrote:
>> (although I always thought it was a severe oversight that the USB-MIDI message has the same 4-bit command encoded twice in every message, making it rather difficult to know which one to honor if they happen to be different).




From brianw at audiobanshee.com  Sat Dec 25 02:31:54 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 17:31:54 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
Message-ID: <2E3DE792-DD03-4BBF-B956-C05D114CF962@audiobanshee.com>



On Dec 24, 2021, at 08:40, mskala at northcoastsynthesis.com wrote:
> On Thu, 23 Dec 2021, Brian Willoughby wrote:
>> On Dec 23, 2021, at 19:06, mskala at northcoastsynthesis.com wrote:
>>> I've seen over 40 poll/NAK sequences per frame (maybe over 70; both
>>> numbers are in my memory but I'm not sure the faster one was actually with
> 
>> What operating system was serving as the USB Host?
> 
> That was my own PIC24 host code, with no operating system as such.  The
> device on the other end of the connection was an Akai "MPK mini" USB-MIDI
> keyboard.

Ah. I see. So, when you talk about throttling the rate you're talking about Host code, which is totally within the USB spec, I suppose (unless they require lots of polling somehow).

>> My USB-MIDI Device firmware experience is with the PIC18 8-bit MCU with
>> a 48 MHz clock.
> 
> Probably very similar hardware to what I'm working on, then; I think
> Microschip uses basically the same IP block for the USB peripheral on
> PIC18 and PIC24.

Maybe not. The PIC18 that I worked with is limited to Device only. It cannot be a Host. The electronics would be vastly different. I suppose it's possible that the PIC24 peripheral register set could be a strict superset, but I assume they're very different peripherals due to the additional capabilities of the PIC24.

The USB firmware stack could be very similar at the top level, though, and hide the peripheral register details deep in the code. I've noticed that Microchip has a huge number of headers - one for every chip model - describing the various memory-mapped registers.

>> I believe that USB allows multiple 64-byte Bulk packets per USB frame.
> 
> Yes, and I've seen that working in practice, although many devices will
> return a whole lot of NAKs between successful packet transfers, with the
> speed of actual data traffic they can support being much less than a
> maxed-out bus could carry.

I seems like "a whole lot of poll/NAKs" are actually required in order for everything to work. USB defines Isochronous endpoints to have guaranteed bandwidth, and then other endpoints get fit in according to opportunity. The Host is in control of the timing within each (sub)frame, but there's no way to predict how everything will fit together, especially considering a random assortment of Devices sharing the same port.

USB is designed to cater to cheap devices that have bandwidth or processing limitations, while still allowing faster devices to work.

One mystery I've never dug in to is this: What happens when a USB Host schedules a packet for a USB Device and that device responds really slowly (due to poor firmware optimization)? I know that if the delay is very long - such as when you set a breakpoint and the firmware literally stops dead in its tracks - then the Host will basically disconnect that Device. But those delays are way longer than a single USB frame. I'm wondering about within a frame.

Say a Host schedules a packet at the beginning of a frame, and the Device burns a third or a half of the frame time just getting the bytes out? Does this just ruin the total USB bandwidth, leaving little or none for other Devices on that bus?

The answer is partly made evident because most USB Device firmware stacks require the code to set up the complete data for a packet in advance, so that the hardware interrupt can immediately enable DMA to transfer the data faster than the processor could handle in code alone.

However, Control endpoints have Host query commands that switch between OUT and IN during a transaction, and I've wondered what would happen if firmware grabs a piece of data for the Control endpoint from a slow peripheral, and thus delays the Control endpoint timing.

> Flash memory sticks in particular seem to be
> quite bursty - they may return a few packets at maximum bus speed, then
> just NAK for a few milliseconds before waking up again.

I assume that this has more to do with Flash memory speed. Flash write is particularly slow, but even Flash read can be slower than USB. Also, the way USB works seems to introduce latency because data has to be prepared ahead of time and available in a buffer, rather than actually being fed across the bus in real time as it becomes available.

>> My goal for supporting a Hub was to provide cheap isolation (I'd rather
>> burn out a $4.99 Hub than my custom USB hardware), and also to allow for
>> some way to save and restore custom settings on a USB memory stick
>> without literally removing the controller Device from the Host USB jack.
> 
> Interesting point about the isolation.  That's a possible advantage of
> using a hub, that I hadn't thought of.

I've designed USB Device prototypes that burned up when the custom PCB was first attached to a computer. At least I lost something that I could easily make more of. But it was alarming enough that I worried about worse damage.

I've had clients who designed their own USB Device prototypes that were so messed up that they took out my client's laptop - or at least took out the USB ports. This had more to do with external supplies for the USB Device and grounding issues. I'd already made my mind up to use a Hub with all prototypes, but my client's experience convinced me to be particularly careful.

>> Given their prevalence, it seems like a very useful feature to be able
>> to Host USB-MIDI controllers.
> 
> I hope so!  It's also a hole in my product line - up to now I've been
> having to tell customers "Well, you'll need to get a controller or
> interface from someone else to play this module."

Personally, I think it's fair to include a MIDI input and require customers to obtain a MIDI keyboard - just like every sound module before. But adding support for USB-MIDI makes things easier these days, although it's way more complicated (and potentially more expensive).

>> I think it would be fair for you to say that your product supports a
>> Hub, but only with Devices attached that are already supported without
>> the Hub. I guess that could be a problem if you support a mouse and/or
>> keyboard, because then that support would go away with a Hub.
> 
> I do have support for mouse and (typing) keyboard, so the limitation would
> have to be a little more complicated.  But it may be something to look at
> for some future firmware version.

Ouch. I can see how mouse and keyboard would be helpful.

I hate to say it, but you may need to chose another processor - at least for the USB Host function. Either that, or get Microchip to fix the hardware errata so you can leverage the work you've already done.

>> sampling rate is 125 kHz, and that works out to only a 976.5625 Hz
>> packet rate. Although the Host USB clock is not locked to the Device
>> sample rate, it's still true that the Host wants about 1,000 packets per
>> second. This means that 1 out of every 42+2/3 frames has a 0-byte
>> Isochronous packet instead of a 384-byte packet. Everything still
>> manages to work out, because USB was designed for this.
> 
> Almost like NTSC frame drop.

I was just surprised that it worked. This isn't written down anywhere, but I think that an Apple engineer on their (now defunct) USB mailing list gave me the hints that I needed.

USB requires that the maximum packet size be defined for each endpoint. You can send "more" data than the maximum size by stringing together several packets that are exactly the maximum size, following by a packet that's less than maximum - or zero. For isochronous, if you define the endpoint maximum size to be the actual size that you want, the USB Host will always assume there's "more" data coming. The trick is to define the Isochronous endpoint to be 1 or 2 bytes larger than your actual maximum. Then, the Host won't expect "more" data, because the packet is smaller than maximum. Meanwhile, any "drop frame" packets simply have a size of zero.

It's basically the same as with Bulk except that you have a maximum of one packet per frame, or zero packets.

>> p.s. To get back to the subject... any of these 8-bit or 16-bit or
>> 32-bit processors should be able to handle incoming MIDI clock, lock in
>> a Timer channel, and multiply the frequency for rock-solid output
>> timing. Because the TM4C129x has 8 full UART peripherals, I've been
>> tempted for several years to design an 8-input, 8-output MIDI merger
>> than properly handles MIDI clock between everything (although that could
>> be a mess if you don't have a way to turn off conflicting clocks).
> 
> It would probably call for some kind of out-of-band control to specify
> which clocks to trust and which not to.

Well, out-of-band control and/or a front panel !  A display, or at least rudimentary indicators, would help. That and some buttons.

But I'm a fan of including out-of-band control for everything. Whether it's MIDI System Exclusive or tacking on Vendor commands to the Control endpoint, it's always helpful to be able to make out-of-band settings. I've even used Control endpoint Vendor commands to debug USB Device firmware by sending internal variable values across USB in near-real-time so that an application running on the USB Host could display things. This is very powerful for debugging.

> -- 
> Matthew Skala
> North Coast Synthesis Ltd.
> 




From brianw at audiobanshee.com  Sat Dec 25 02:46:50 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 17:46:50 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <d14e4bf17d7f4f1dbdb026008f31c8bf@futurehorizons.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <d14e4bf17d7f4f1dbdb026008f31c8bf@futurehorizons.com>
Message-ID: <E265092E-B96A-424A-BAA5-BB5831D664F5@audiobanshee.com>



On Dec 24, 2021, at 09:42, Mike Bryant <mbryant at futurehorizons.com> wrote:
>> Another part is that High Speed did not exist when USB-MIDI was designed, so they didn't mention High Speed (and they haven't rewritten the USB-MIDI spec since).
> 
> https://www.usb.org/sites/default/files/USB%20MIDI%20v2_0.pdf
> 
> This is the one everybody should be following now, not the 1999 one which is deprecated.  Adds MIDI 2.0 but subtle changes to MIDI 1.0 as well

I suspect that USB-MIDI 1.0 will be with us for a while. It's a *huge* market.

>> In those days, nobody could afford to be Mac-only.
> 
> On the contrary, most people were Mac only back then, for example Sound Designer and its successors.  It took DigiDesign to release ProTools 3.21 PCI version in 1996/7 to really establish Windows in the studio.  Cubase did support Windows earlier but most people preferred how that ran on a Mac.  Even 25 years later some DJ creation tools are Mac/iOS only.

I was referring only to hardware manufacturers, not software developers.

In that era, all software was Mac-only or Windows-only. You basically picked the platform and developed software exclusively for that platform. Cross-platform successes were incredibly rare.

In the hardware world - especially USB - companies basically always targeted both Windows and Mac. I can count on one hand the number of companies that designed hardware only for Mac when using an interface that was available for both Mac and Windows. Few companies could afford to ignore the potential sales to Windows users who could just plug in their hardware.

>> I'm not sure what this "high bandwidth" mechanism is, other than the fact that Full Speed is a lot faster than 31.25 kbaud.
> 
> Page 18 of the old spec, deleted in the new one as an alternate mechanism is provided

Thanks. I never noticed the Transfer Bulk endpoint option before.

Given that Windows doesn't support non-Jack MIDI Entities, and literally refuses to recognize and connect with a USB-MIDI Device that even mentions a non-Jack Entity in its Descriptors, my gut instinct is that Windows does not support Transfer Bulk endpoints, either. But I am a bit cynical.

Are you aware of any USB-MIDI Device product that implements Transfer Bulk endpoints?

If so, which operating system releases actually support this?

... and which MIDI software supports the feature?

>> As M. Skala and I have been discussing, USB-MIDI 1.0 doesn't have to disallow Low Speed because USB in general disallows Bulk over Low Speed (and USB-MIDI requires Bulk).
> 
> Totally agree that is what the standard says, but if you actually try it quite a lot of equipment works.  Presumably this is because their 'low speed' implementation is just the full speed implementation with a change of data rate and a few other bodges.

I can believe it. One of the nice things about USB is that it is neatly compartmentalized into separate layers. Even though Low Speed is "supposed" to be a separate thing, it's probably true that the OS drivers would have to go out of their way to enforce this. In other words, it might be easier to just ignore the restrictions and allow the independent layers to work together.

>> One thing to keep in mind is that the Host only talks to one Device at a time, and it talks to the Device at its native speed. There really isn't any support for a Host to talk to, e.g., a USB-MIDI Device at any speed other than Full Speed. The Host can't talk to the hub any faster than it could talk to the Device without the hub.
> 
> Sorry but that's not quite true.  If you have a good hub with a well buffered Transaction Translator per port AND a MIDI driver that supports higher rates then you can talk to many devices each at Full Speed.  Each device of course still communicates with the hub at Full Speed, they can't do anything else of course, but the Host sees data arrive from the hub at High Speed.  My driver has been tested using 16 devices all set up to continuously transmit messages at full speed without falling over or losing messages.  That's obviously far in excess of what one is ever going to see in real operation, but gives me confidence nobody will ever lose messages in real operation provided they use an approved hub.

I imagine that this would have to increase the latency, because the entire packet would have to be received by the Hub before it could be re-transmitted at the higher speed.

I have a hunch that this wouldn't work for Isochronous, but I can see how it might work quite easily with Bulk.

>> Other endpoint types like Isochronous literally have to be handled in real time - there's no way to run them faster between Host and Hub than they run from Hub to Device.
> 
> That's correct.  No way of speeding these up until devices support High Speed.  I really think MIDI 2.0 should have enforced or at least recommended High Speed was supported, but it didn't.  Presumably too many people still using old processors rather than moving to the STM32F73x or NXP equivalent.

There are *a ton* of USB-capable chips out there, and the price range goes well below what an STM costs. One of the design goals of USB was to make *cheap* possible. i.e. the larger your manufacturing quantity - think: millions of units - the more sensitive the CPU cost becomes.

Plus, if you make something require USB 3.0 then the hardware won't work on old computers. That can sometimes be a sizable market - difficult to ignore.

>> My most recent project was to write USB Host firmware without an operating system of any kind. It was somewhat annoying because even after the Host was talking directly to the Device successfully, a lot more code had to be added to support a Hub between the Host and Device. That's because most or all Hubs are completely under control of the Host, and cannot handle anything on their own beyond the basic hardware switching and isolation. But this is a new topic for me, and there might be a few details that I missed for USB 3 Hosts. In my case, the chip only supports USB 2.0 so any newer features are irrelevant for compatibility reasons.
> 
> It's not that you need the hub for USB 3, which would be pointless, just that decent USB3 hubs, usually using the VL8xx series chips, have a Transaction Translator per port, and so these are the highest performance hubs you're going to meet operating in USB2.

I need to learn about the Transaction Translator.

Thanks,

Brian




From brianw at audiobanshee.com  Sat Dec 25 02:52:58 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 17:52:58 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <2lc8yw6evr56sbychmn4fsb4.1640365436864@email.android.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
 <2lc8yw6evr56sbychmn4fsb4.1640365436864@email.android.com>
Message-ID: <74F411CD-E395-4B66-A462-04941088612B@audiobanshee.com>

Richie,

I encourage you (and others) to dive in to USB and USB-MIDI.

For the most part, USB is designed in layers, so you can almost completely ignore the vast majority of the complexity. The electronics, the hardware peripherals, and the low-level USB stack firmware will handle nearly everything locally for you.

Just learn about USB Descriptors - and that can be a serious PitA - and learn what makes USB-MIDI different from other USB Devices. At the high level, USB-MIDI is quite simple.

Granted, there are some details that aren't spelled out everywhere you might expect. So, it's often beneficial to study the other layers of USB - at least enough to get a basic understanding of how it works - and this extra knowledge will help you figure out the unwritten details that USB expert specification writers assume you already know.

Brian Willoughby

p.s. If you can, use macOS. The support for USB-MIDI is way more complete. Of course, you'll also need to test with Windows for compatibility.


On Dec 24, 2021, at 09:03, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> Interesting discussions about USB MIDI. Something I've been wondering about trying to implement for some time now.
> 
> Merry Christmas and happy holidays to all...
> 
> -Richie, 




From brianw at audiobanshee.com  Sat Dec 25 03:20:52 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 18:20:52 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <74F411CD-E395-4B66-A462-04941088612B@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
 <2lc8yw6evr56sbychmn4fsb4.1640365436864@email.android.com>
 <74F411CD-E395-4B66-A462-04941088612B@audiobanshee.com>
Message-ID: <3D7F1C2C-57C0-449C-A8AD-26389D5DCFFE@audiobanshee.com>

By the way, I designed my first USB-MIDI hardware before I had the budget for a USB Analyzer. It works perfectly.

On big advantage here is the support that Mac OS X has for USB. I used "USB Prober.app" extensively, as well as the OS support for USB debugging. Speaking of "ignoring" the lower levels, I was blissfully unaware of the data flowing across the USB for my Device. There were tons of features (some beyond USB-MIDI) and they worked seamlessly together.

Since then, I purchased a Beagle USB analyzer from Total Phase. They're expensive, but they work well. You might not need to invest that much money, though. Prior to that purchase, I sometimes borrowed client's USB analyzers. If you get into USB development, you might think about renting or borrowing, or just using macOS USB debugging capabilities.

I've definitely needed the USB analyzer for some USB product design.

Brian Willoughby


On Dec 24, 2021, at 17:52, Brian Willoughby wrote:
> Richie,
> 
> I encourage you (and others) to dive in to USB and USB-MIDI.
> 
> For the most part, USB is designed in layers, so you can almost completely ignore the vast majority of the complexity. The electronics, the hardware peripherals, and the low-level USB stack firmware will handle nearly everything locally for you.
> 
> Just learn about USB Descriptors - and that can be a serious PitA - and learn what makes USB-MIDI different from other USB Devices. At the high level, USB-MIDI is quite simple.
> 
> Granted, there are some details that aren't spelled out everywhere you might expect. So, it's often beneficial to study the other layers of USB - at least enough to get a basic understanding of how it works - and this extra knowledge will help you figure out the unwritten details that USB expert specification writers assume you already know.
> 
> Brian Willoughby
> 
> p.s. If you can, use macOS. The support for USB-MIDI is way more complete. Of course, you'll also need to test with Windows for compatibility.
> 
> 
> On Dec 24, 2021, at 09:03, Richie Burnett wrote:
>> Interesting discussions about USB MIDI. Something I've been wondering about trying to implement for some time now.
>> 
>> Merry Christmas and happy holidays to all...
>> 
>> -Richie, 




From mskala at northcoastsynthesis.com  Sat Dec 25 03:33:09 2021
From: mskala at northcoastsynthesis.com (mskala at northcoastsynthesis.com)
Date: Fri, 24 Dec 2021 21:33:09 -0500 (EST)
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <2E3DE792-DD03-4BBF-B956-C05D114CF962@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
 <2E3DE792-DD03-4BBF-B956-C05D114CF962@audiobanshee.com>
Message-ID: <alpine.LNX.2.20.2112242039060.21546@kharasan.bonobo-conspiracy.ca>

On Fri, 24 Dec 2021, Brian Willoughby wrote:
> On Dec 24, 2021, at 08:40, mskala at northcoastsynthesis.com wrote:
> > That was my own PIC24 host code, with no operating system as such.  The
> > device on the other end of the connection was an Akai "MPK mini" USB-MIDI
> > keyboard.
>
> Ah. I see. So, when you talk about throttling the rate you're talking
> about Host code, which is totally within the USB spec, I suppose (unless
> they require lots of polling somehow).

Sure - I don't think the host is ever *required* to poll a bulk endpoint,
let alone more than once per frame.

> Maybe not. The PIC18 that I worked with is limited to Device only. It
> cannot be a Host. The electronics would be vastly different. I suppose
> it's possible that the PIC24 peripheral register set could be a strict
> superset, but I assume they're very different peripherals due to the
> additional capabilities of the PIC24.

Interesting.  I several times found answers to questions in the PIC18
discussion forums that seemed applicable to the PIC24 also, but I guess
that could simply be because of similar design philosophy, and
similarities in the driver software at the higher level.

> One mystery I've never dug in to is this: What happens when a USB Host
> schedules a packet for a USB Device and that device responds really
> slowly (due to poor firmware optimization)? I know that if the delay is

I think this is in section 7.1.18 of the USB 2.0 standard.  The device is
expected to reply pretty much immediately, if it's going to reply at all.
For low and full speed, the maximum allowed is either 6.5 or 7.5 bit times
depending on whether the device has a detachable cable.  Many more bit
times, but still a small amount of real time, for high speed.  If the
device takes longer than allowed, it runs the risk of colliding with the
host's next packet, and would be better off to keep silent (which *will*
be an error).

> The answer is partly made evident because most USB Device firmware
> stacks require the code to set up the complete data for a packet in
> advance, so that the hardware interrupt can immediately enable DMA to
> transfer the data faster than the processor could handle in code alone.

Bearing in mind that the signalling is synchronous, there can't be a delay
in the middle of a packet without corruption.  It's not like a UART
connection that resynchronizes on every byte and could potentially have
arbitrary pauses between bytes.  Once the device starts sending a packet,
then whatever voltages exist on the bus over the next however many
microseconds *are* the contents of the packet whether the device was
driving those voltages or not.  And if it doesn't start sending the packet
at all when the host was expecting it to, I guess that depends on the host
but it seems like a standards-compliant host should have given up almost
immediately.  The whole bus can't wait for one device.  Devices that
cannot send data on schedule are supposed to send NAKs on schedule, not
send nothing or break the schedule.

> However, Control endpoints have Host query commands that switch between
> OUT and IN during a transaction, and I've wondered what would happen if
> firmware grabs a piece of data for the Control endpoint from a slow
> peripheral, and thus delays the Control endpoint timing.

That seems like it should be a delay at a different level.  The control
in transfer looks something like this:

host        device

SETUP
DATA
            ACK
IN
            DATA
ACK
OUT
DATA (0 length)
            ACK

If the device needs more time to prepare the data for the IN, it is
allowed to send NAK to indicate it's not ready, but the NAKs themselves
have to be sent promptly:

host        device

SETUP
DATA
            ACK
IN
            NAK
IN
            NAK
IN
            DATA
ACK
OUT
DATA (0 length)
            ACK

I would expect most devices nowadays to handle this with hardware
that will automatically send the NAK if the firmware has not yet
instructed it to give a different response.  7.5 bit times at full speed
is not a lot of time for a microcontroller to handle an interrupt and
decide whether to start sending data.

At the higher level, I think the number of NAKs allowed may be unlimited.
The standard says this phase of the control transaction is handled like a
bulk transfer, in which NAKs would be unlimited.

> I've had clients who designed their own USB Device prototypes that were
> so messed up that they took out my client's laptop - or at least took
> out the USB ports. This had more to do with external supplies for the

A straightforward power short on the USB port will often shut down a
laptop.  Usually, they can boot up again afterward.

-- 
Matthew Skala
North Coast Synthesis Ltd.


From brianw at audiobanshee.com  Sat Dec 25 07:23:44 2021
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Fri, 24 Dec 2021 22:23:44 -0800
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <alpine.LNX.2.20.2112242039060.21546@kharasan.bonobo-conspiracy.ca>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <alpine.LNX.2.20.2112232134560.23099@kharasan.bonobo-conspiracy.ca>
 <DC5553F2-B900-4D84-88D1-1AB0E2210F23@audiobanshee.com>
 <alpine.LNX.2.20.2112241103210.21546@kharasan.bonobo-conspiracy.ca>
 <2E3DE792-DD03-4BBF-B956-C05D114CF962@audiobanshee.com>
 <alpine.LNX.2.20.2112242039060.21546@kharasan.bonobo-conspiracy.ca>
Message-ID: <F507928C-927D-4DA9-95A5-EBD4F550E262@audiobanshee.com>

On Dec 24, 2021, at 18:33, Matthew Skala wrote:
> On Fri, 24 Dec 2021, Brian Willoughby wrote:
>> On Dec 24, 2021, at 08:40, mskala at northcoastsynthesis.com wrote:
>>> That was my own PIC24 host code, with no operating system as such.  The
>>> device on the other end of the connection was an Akai "MPK mini" USB-MIDI
>>> keyboard.
>> 
>> Ah. I see. So, when you talk about throttling the rate you're talking
>> about Host code, which is totally within the USB spec, I suppose (unless
>> they require lots of polling somehow).
> 
> Sure - I don't think the host is ever *required* to poll a bulk endpoint,
> let alone more than once per frame.

Since you're writing the Host code, it seems like all you have to do is ensure that all Devices are polled enough to allow sufficient bandwidth. If there is bandwidth to spare, it seems like there would be no reason to throttle Bulk packets. Unless the Host has something else to do with the USB, then it might as well "over" poll the Bulk Device endpoints.

Once you get to the point where you can support a Hub with a mouse, (typing) keyboard, *and* MIDI controller, then I think your Host code will have to make sure to service all Devices according to their minimum requirements. That said, you may find that you get better performance if you poll the Bulk endpoints for USB-MIDI as much as possible, so long as other duties aren't neglected.

>> Maybe not. The PIC18 that I worked with is limited to Device only. It
>> cannot be a Host. The electronics would be vastly different. I suppose
>> it's possible that the PIC24 peripheral register set could be a strict
>> superset, but I assume they're very different peripherals due to the
>> additional capabilities of the PIC24.
> 
> Interesting.  I several times found answers to questions in the PIC18
> discussion forums that seemed applicable to the PIC24 also, but I guess
> that could simply be because of similar design philosophy, and
> similarities in the driver software at the higher level.

As I dug deeper into the various USB stacks, I noticed that the vast majority of the design is taken directly from the USB specifications. In that sense, I would expect many different USB stacks could be supported with the same Q&A. As I mentioned, Apple actually helped me with my Isochronous Device, without any idea of which processor I was using or which firmware stack.

I've written USB firmware for four product families. Two for PIC18, one for TMS320VC5506, and Host firmware for the TM4C1294. Unfortunately, every one of them has been a different Device Class, so I didn't get a chance to see how much there was in common between the different USB stacks when solving the exact same problem. Of course, the two PIC18 firmwares used the same USB stack, albeit different releases, but the second product was not USB-MIDI.

>> One mystery I've never dug in to is this: What happens when a USB Host
>> schedules a packet for a USB Device and that device responds really
>> slowly (due to poor firmware optimization)? I know that if the delay is
> 
> I think this is in section 7.1.18 of the USB 2.0 standard.  The device is
> expected to reply pretty much immediately, if it's going to reply at all.
> For low and full speed, the maximum allowed is either 6.5 or 7.5 bit times
> depending on whether the device has a detachable cable.  Many more bit
> times, but still a small amount of real time, for high speed.  If the
> device takes longer than allowed, it runs the risk of colliding with the
> host's next packet, and would be better off to keep silent (which *will*
> be an error).

Thanks. This makes sense. I suppose I'm only thinking about Control. Custom Vendor extensions to Control transfers is the only place where I've coded any sort of just-in-time response. Everything else has been prepared buffers of data for future packets.

>> The answer is partly made evident because most USB Device firmware
>> stacks require the code to set up the complete data for a packet in
>> advance, so that the hardware interrupt can immediately enable DMA to
>> transfer the data faster than the processor could handle in code alone.
> 
> Bearing in mind that the signalling is synchronous, there can't be a delay
> in the middle of a packet without corruption.  It's not like a UART
> connection that resynchronizes on every byte and could potentially have
> arbitrary pauses between bytes.  Once the device starts sending a packet,
> then whatever voltages exist on the bus over the next however many
> microseconds *are* the contents of the packet whether the device was
> driving those voltages or not.  And if it doesn't start sending the packet
> at all when the host was expecting it to, I guess that depends on the host
> but it seems like a standards-compliant host should have given up almost
> immediately.  The whole bus can't wait for one device.  Devices that
> cannot send data on schedule are supposed to send NAKs on schedule, not
> send nothing or break the schedule.

I should have said something like "transfer" instead of packet. The Control transactions involve multiple bidirectional packets. Each packet is consistently timed, from beginning to end, but between the packets of a Control transfer there might be gaps.

As far as I recall, every kind of endpoint *besides* Control has involved collecting buffered data in advance, sending it to the USB stack as a whole packet, and then allowing the USB peripheral to time the transfer when the Host asks for it, based on Descriptors.

>> However, Control endpoints have Host query commands that switch between
>> OUT and IN during a transaction, and I've wondered what would happen if
>> firmware grabs a piece of data for the Control endpoint from a slow
>> peripheral, and thus delays the Control endpoint timing.
> 
> That seems like it should be a delay at a different level.  The control
> in transfer looks something like this:
> 
> host        device
> 
> SETUP
> DATA
>            ACK
> IN
>            DATA
> ACK
> OUT
> DATA (0 length)
>            ACK
> 
> If the device needs more time to prepare the data for the IN, it is
> allowed to send NAK to indicate it's not ready, but the NAKs themselves
> have to be sent promptly:
> 
> host        device
> 
> SETUP
> DATA
>            ACK
> IN
>            NAK
> IN
>            NAK
> IN
>            DATA
> ACK
> OUT
> DATA (0 length)
>            ACK
> 
> I would expect most devices nowadays to handle this with hardware
> that will automatically send the NAK if the firmware has not yet
> instructed it to give a different response.  7.5 bit times at full speed
> is not a lot of time for a microcontroller to handle an interrupt and
> decide whether to start sending data.

In my case, I coded the firmware to send ACK, NAK, or STALL, depending upon the request in SETUP. I use the Vendor Type in the Control Request plus the 8-bit Request, 16-bit Index, and 16-bit Value to allow a huge array of queries. Values larger than 16 bits can be handled with the 16-bit Length (although I've never gone beyond 32-bit or maybe 64-bit). That's for writing values from Host to Device. For reading values, the Length must always specify the size of the value to be returned.

I use STALL to confirm that a given Request and/or Index is completely invalid. Technically, this shouldn't be necessary if the Host application is based on the latest product protocol documentation, but when other developers are writing Host software it helps to be able to force the OS USB driver to return a meaningful error for bad requests, rather than mysteriously fail to provide meaningful data.

I can't recall whether NAK is used, but I do recall that some Values come from EEPROM storage that's slow, and I worried that reading the value might take too long for USB.

Control transfers, a.k.a. Device Requests, seem to be the only USB transfers where one packet selects the data that will be returned in the very next packet. So, I was worried that a slow EEPROM access might be "too slow." I can't recall whether I ended up using NAK and some sort of asynchronous technique. I seem to recall that the PIC18 USB stack has some sort of callback mechanism so that the stack can call the custom code when it needs the value.

e.g. A lot of the product settings were stored in EEPROM. Device Requests allow writing and reading those values from the Host application. Writing is easy, because the firmware can cache the value to be written and handle the actual EEPROM write after the Control transfer is completed. Reading is slightly challenging because the Device Request specifies which setting is desired by using the Index, and then the firmware has to read the value from the EEPROM using slower-than-RAM accesses (the PIC18 model is archaic, to say the least). Anyway, I guess it doesn't matter because the product is done, and the final firmware seems to work.

Brian Willoughby

p.s. When your USB-MIDI Host synth is ready to be announced, please drop me an email ... or just let this whole list know.




From mbryant at futurehorizons.com  Sat Dec 25 12:21:46 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 25 Dec 2021 11:21:46 +0000
Subject: [sdiy] Techniques for Multiplying MIDI Clock frequency?
In-Reply-To: <E265092E-B96A-424A-BAA5-BB5831D664F5@audiobanshee.com>
References: <CAGbpyRfw7BW8Nkx57Lqz3r_9M98DfkGwaqiBery+5xSOuKsCAw@mail.gmail.com>
 <2e95aecd-a7b1-2307-4b87-bcd5837393d4@go2.pl>
 <CAJ-kJoC6YrLOVAEvNEh5ZSxgn1d_nK_7Q73R7dGqZq86cveeZw@mail.gmail.com>
 <CAGbpyRc7=bQ1M7X5933Hd0sCc8EmZDkc0kGZ9vrwHE=OUmf+Mw@mail.gmail.com>
 <CAJ5nAj5jC4tfTRdN7v4PdmAdQzDfTvDp9tU75rRWhaHTeu46DQ@mail.gmail.com>
 <9FB018D4-341A-4AA3-9069-7CC0419B38FC@audiobanshee.com>
 <279ADB50-F95C-4BEF-9471-58CAD52F8DDB@me.com>
 <038039f7-6891-ef8f-4980-0cb376dc80bc@go2.pl>
 <254DEE13-BE7B-4F12-B3AF-21CC944E1456@me.com>
 <c50065c1-a57b-c8e2-ea3e-1282a32c69aa@go2.pl>
 <27755DB4-23CE-4D8E-A47B-7B78683A1757@me.com>
 <a2d3bdd7-6e84-4dee-7415-72a3a093a1eb@musictechnologiesgroup.com>
 <7a3634624af94d9983c19a1ecf7b1b15@futurehorizons.com>
 <B643EB4D-26B6-449E-86BD-ED14ED8C2F4E@audiobanshee.com>
 <9c438414816948358e3e70cda3c68928@futurehorizons.com>
 <5EC65D78-A0F7-4E20-AA5F-4CA729966BDD@audiobanshee.com>
 <d14e4bf17d7f4f1dbdb026008f31c8bf@futurehorizons.com>
 <E265092E-B96A-424A-BAA5-BB5831D664F5@audiobanshee.com>
Message-ID: <19a99f24a71c4c2997d9ba449a07786d@futurehorizons.com>

> I was referring only to hardware manufacturers, not software developers.
DigiDesign were a hardware manufacturer.  The ProTools software came free back then :-)


> In that era, all software was Mac-only or Windows-only. You basically picked the platform and developed software exclusively for that platform. Cross-platform successes were incredibly rare.
Agreed.  DigiDesign only changed that once Apple adopted PCI bus so the same accelerator board plugged into the newest Macs and Windows PCs.  But I'd say even now Windows is a minority thing in studios.



>> I'm not sure what this "high bandwidth" mechanism is, other than the fact that Full Speed is a lot faster than 31.25 kbaud.
>> Page 18 of the old spec, deleted in the new one as an alternate mechanism is provided

> Thanks. I never noticed the Transfer Bulk endpoint option before.
> Given that Windows doesn't support non-Jack MIDI Entities, and literally refuses to recognize and connect with a USB-MIDI Device that even mentions a non-Jack Entity in its Descriptors, my gut instinct is that Windows does not support Transfer Bulk  > endpoints, either. But I am a bit cynical. Are you aware of any USB-MIDI Device product that implements Transfer Bulk endpoints?
> If so, which operating system releases actually support this?
> ... and which MIDI software supports the feature?

Windows indeed doesn't.  A few sampling devices use it and they mention Mac only, but as I said it's been removed from the latest spec and replaced by better solutions in MIDI 2.0 



>> If you have a good hub with a well buffered Transaction Translator per port AND a MIDI driver that supports higher rates then you can talk to many devices each at Full Speed.  Each device of course still communicates with the hub at Full Speed, they can't do anything else of course, but the Host sees data arrive from the hub at High Speed.  My driver has been tested using 16 devices all set up to continuously transmit messages at full speed without falling over or losing messages.  That's obviously far in excess of what one is ever going to see in real operation, but gives me confidence nobody will ever lose messages in real operation provided they use an approved hub.

> I imagine that this would have to increase the latency, because the entire packet would have to be received by the Hub before it could be re-transmitted at the higher speed.

In theory it could start transmitting at the point where it knows the rest of the packet will arrive in time, but I've never timed anything that accurately.


> I have a hunch that this wouldn't work for Isochronous, but I can see how it might work quite easily with Bulk.
That was my next comment :-)   Isochronous indeed doesn't.



>>  I really think MIDI 2.0 should have enforced or at least recommended High Speed was supported, but it didn't.  Presumably too many people still using old processors rather than moving to the STM32F73x or NXP equivalent.
> There are *a ton* of USB-capable chips out there, and the price range goes well below what an STM costs. One of the design goals of USB was to make *cheap* possible. i.e. the larger your manufacturing quantity - think: millions of units - the more sensitive the CPU cost becomes.

STM32F730 is $2 and is quite quickly replacing the STM32F103 as the standard MCU in high volume pro-audio equipment as it can take on much of the DSP as well so you can often avoid the cost of a SHARC.  Harman Group and Music Tribe are both starting to use it a lot so usage spreads to their contract designers and spin-offs pretty quickly.  And when the F73x runs out of steam the H75x series start at only $1.50 more for 2.5 times the performance.  I used three F730s and one H750 in a design I did for a client last year.  NXP meanwhile seem to have tied up the Alexa-type and home security markets with their versions. 
Below that the STM32G03, the equivalent NXP, and the new RP2040 are all under $1 if you really only need full speed USB, but give far more performance than older devices.  G03 is useful as so far it does seem to be uncrackable unless you use an electron beam scanner, so it keeps your code secure if you need that feature.



> Plus, if you make something require USB 3.0 then the hardware won't work on old computers. That can sometimes be a sizable market - difficult to ignore.

I said make high speed a requirement, not super speed :-)    USB3 is actually a major problem in audio as it can wipe out some forms of wireless communication so I think most people are sticking with USB2.0.   My clients have never asked for 3.0 anyway, and I don't suggest it even though the VL805 is now under $1.

Mike




From cheater00social at gmail.com  Sun Dec 26 03:53:11 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Sun, 26 Dec 2021 03:53:11 +0100
Subject: [sdiy] Cooling in modular synths
Message-ID: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>

Hi all, I was wondering how people approach cooling in modular synths.
Specifically larger systems. Do you find that having free convection
or even forced cooling is necessary?

Also, what sort of power draw do your synths have?

Thanks


From fluxmonk at gmail.com  Sun Dec 26 04:36:56 2021
From: fluxmonk at gmail.com (bbob)
Date: Sat, 25 Dec 2021 22:36:56 -0500
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
Message-ID: <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>

Just the power supplies, i've never noticed any individual modules running
hot.  I use mostly power-one or condor PSs, which have substantial aluminum
frames that do a good job as heat sinks, as long as there's free
convective  air movement around them they seem fine without fans.  imy main
DIY has 3 cabinets with 4 or 5 frac racks @ - i haven't measured individual
module current draw, but each cabinet has it's own 3amp supply, seems fine.

flxmnky


On Sat, Dec 25, 2021 at 9:57 PM cheater cheater via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Hi all, I was wondering how people approach cooling in modular synths.
> Specifically larger systems. Do you find that having free convection
> or even forced cooling is necessary?
>
> Also, what sort of power draw do your synths have?
>
> Thanks
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From cheater00social at gmail.com  Sun Dec 26 14:26:12 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Sun, 26 Dec 2021 14:26:12 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
Message-ID: <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>

That would mean each cabinet is up to, what, 36W? 45W? Given the
outside area of the cabinet I wouldn't think that it needs cooling,
yeah.

So why do older polysynths need cooling? Was semiconductor technology
just loads more inefficient?

On Sun, Dec 26, 2021 at 4:37 AM bbob <fluxmonk at gmail.com> wrote:
>
> Just the power supplies, i've never noticed any individual modules running hot.  I use mostly power-one or condor PSs, which have substantial aluminum frames that do a good job as heat sinks, as long as there's free convective  air movement around them they seem fine without fans.  imy main DIY has 3 cabinets with 4 or 5 frac racks @ - i haven't measured individual module current draw, but each cabinet has it's own 3amp supply, seems fine.
>
> flxmnky
>
>
> On Sat, Dec 25, 2021 at 9:57 PM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> Hi all, I was wondering how people approach cooling in modular synths.
>> Specifically larger systems. Do you find that having free convection
>> or even forced cooling is necessary?
>>
>> Also, what sort of power draw do your synths have?
>>
>> Thanks
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org



From mr at analogue.org  Sun Dec 26 16:14:13 2021
From: mr at analogue.org (Mattias Rickardsson)
Date: Sun, 26 Dec 2021 16:14:13 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
Message-ID: <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>

On Sun, 26 Dec 2021 at 14:27, cheater cheater via Synth-diy <
synth-diy at synth-diy.org> wrote:

> So why do older polysynths need cooling? Was semiconductor technology
> just loads more inefficient?


More temperature-sensitive circuitry on horizontal boards hidden under
other boards in a low flat casing.

/mr
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From peter at synquanon.com  Sun Dec 26 19:08:50 2021
From: peter at synquanon.com (Peter Knoot)
Date: Sun, 26 Dec 2021 11:08:50 -0700 (MST)
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
Message-ID: <22982265.507349.1640542130862@email.ionos.com>

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From electrocontinuo at gmail.com  Sun Dec 26 20:04:52 2021
From: electrocontinuo at gmail.com (Peter Pearson)
Date: Sun, 26 Dec 2021 14:04:52 -0500
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
Message-ID: <CA+qbVc9MFPHNXVFmQp5x912BRMb7hhUG_WN0OkWQq_GG91vzvQ@mail.gmail.com>

I remember Malcolm Cecil talking about how he had wanted to run liquid
nitrogen through the Faraday cage in the back of TONTO.  You could try
going that route.

On Sun, Dec 26, 2021 at 8:30 AM cheater cheater via Synth-diy <
synth-diy at synth-diy.org> wrote:

> That would mean each cabinet is up to, what, 36W? 45W? Given the
> outside area of the cabinet I wouldn't think that it needs cooling,
> yeah.
>
> So why do older polysynths need cooling? Was semiconductor technology
> just loads more inefficient?
>
> On Sun, Dec 26, 2021 at 4:37 AM bbob <fluxmonk at gmail.com> wrote:
> >
> > Just the power supplies, i've never noticed any individual modules
> running hot.  I use mostly power-one or condor PSs, which have substantial
> aluminum frames that do a good job as heat sinks, as long as there's free
> convective  air movement around them they seem fine without fans.  imy main
> DIY has 3 cabinets with 4 or 5 frac racks @ - i haven't measured individual
> module current draw, but each cabinet has it's own 3amp supply, seems fine.
> >
> > flxmnky
> >
> >
> > On Sat, Dec 25, 2021 at 9:57 PM cheater cheater via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >>
> >> Hi all, I was wondering how people approach cooling in modular synths.
> >> Specifically larger systems. Do you find that having free convection
> >> or even forced cooling is necessary?
> >>
> >> Also, what sort of power draw do your synths have?
> >>
> >> Thanks
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From cheater00social at gmail.com  Sun Dec 26 20:49:19 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Sun, 26 Dec 2021 20:49:19 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
 <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>
Message-ID: <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>

Would you say current designs are less temp sensitive?

What was the most temp sensitive part in things like a Jupiter 8,
CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
especially are said to have been very difficult to keep in tune...


On Sun, Dec 26, 2021 at 4:14 PM Mattias Rickardsson <mr at analogue.org> wrote:
>
> On Sun, 26 Dec 2021 at 14:27, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> So why do older polysynths need cooling? Was semiconductor technology
>> just loads more inefficient?
>
>
> More temperature-sensitive circuitry on horizontal boards hidden under other boards in a low flat casing.
>
> /mr
>


From cheater00social at gmail.com  Sun Dec 26 20:51:03 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Sun, 26 Dec 2021 20:51:03 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CA+qbVc9MFPHNXVFmQp5x912BRMb7hhUG_WN0OkWQq_GG91vzvQ@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
 <CA+qbVc9MFPHNXVFmQp5x912BRMb7hhUG_WN0OkWQq_GG91vzvQ@mail.gmail.com>
Message-ID: <CAGn5V-8vR930J4qyHJ92npRLcrk2+DJu1SOv3CFHix2xSJDbVw@mail.gmail.com>

That's it - I should do that. Thanks Peter.

On Sun, Dec 26, 2021 at 8:04 PM Peter Pearson <electrocontinuo at gmail.com> wrote:
>
> I remember Malcolm Cecil talking about how he had wanted to run liquid nitrogen through the Faraday cage in the back of TONTO.  You could try going that route.
>
> On Sun, Dec 26, 2021 at 8:30 AM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> That would mean each cabinet is up to, what, 36W? 45W? Given the
>> outside area of the cabinet I wouldn't think that it needs cooling,
>> yeah.
>>
>> So why do older polysynths need cooling? Was semiconductor technology
>> just loads more inefficient?
>>
>> On Sun, Dec 26, 2021 at 4:37 AM bbob <fluxmonk at gmail.com> wrote:
>> >
>> > Just the power supplies, i've never noticed any individual modules running hot.  I use mostly power-one or condor PSs, which have substantial aluminum frames that do a good job as heat sinks, as long as there's free convective  air movement around them they seem fine without fans.  imy main DIY has 3 cabinets with 4 or 5 frac racks @ - i haven't measured individual module current draw, but each cabinet has it's own 3amp supply, seems fine.
>> >
>> > flxmnky
>> >
>> >
>> > On Sat, Dec 25, 2021 at 9:57 PM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>> >>
>> >> Hi all, I was wondering how people approach cooling in modular synths.
>> >> Specifically larger systems. Do you find that having free convection
>> >> or even forced cooling is necessary?
>> >>
>> >> Also, what sort of power draw do your synths have?
>> >>
>> >> Thanks
>> >> _______________________________________________
>> >> Synth-diy mailing list
>> >> Synth-diy at synth-diy.org
>> >> http://synth-diy.org/mailman/listinfo/synth-diy
>> >> Selling or trading? Use marketplace at synth-diy.org
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org



From gordonjcp at gjcp.net  Sun Dec 26 23:30:18 2021
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Sun, 26 Dec 2021 22:30:18 +0000
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
 <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>
 <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>
Message-ID: <20211226223018.GD16028@gjcp.net>

On Sun, Dec 26, 2021 at 08:49:19PM +0100, cheater cheater via Synth-diy wrote:
> Would you say current designs are less temp sensitive?
> 
> What was the most temp sensitive part in things like a Jupiter 8,
> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
> especially are said to have been very difficult to keep in tune...
> 

It's always going to be the expo converters, which is why they're hard to keep in tune.

-- 
Gordonjcp



From mr at analogue.org  Mon Dec 27 14:02:10 2021
From: mr at analogue.org (Mattias Rickardsson)
Date: Mon, 27 Dec 2021 14:02:10 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
 <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>
 <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>
Message-ID: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>

Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com> skrev:

> Would you say current designs are less temp sensitive?
>

Yes, and put in other words you could say that there have been advances in
tuning and temperature compensation since 45 years ago. :-)

Temperature-dependent deviations have become better understood, temp
sensing and compensation can be done closer to the error source - on chip
level with less problematic factors, clever microprocessor control can be
used, etc.

What was the most temp sensitive part in things like a Jupiter 8,
> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
> especially are said to have been very difficult to keep in tune...
>

As said before, exponential converters are the most sensitive (but luckily
also the most consistent and relatively easy to compensate) in three of the
above.

For the CS-80 with its linear VCOs I don't really know what would be the
main cause of tuning problems, apart for trimpots moving while touring...
and my CS-50 has never ever needed a re-tuning, so it feels quite robust at
least in moderate temperature variations.

Some traditionally tricky areas can be avoided by going linear, but I'm
currently fighting with some research understanding the other less famous
factors that then show up as temperature dependencies with more stochastic
variations between units. Both CV generation and basic analog circuits can
have some temperature dependencies due to resistors, caps, diodes, op-amps,
comparators and DACs not being perfectly perfect. :-)

/mr
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From johnspeth at yahoo.com  Mon Dec 27 14:37:46 2021
From: johnspeth at yahoo.com (John Speth)
Date: Mon, 27 Dec 2021 13:37:46 +0000 (UTC)
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <20211226223018.GD16028@gjcp.net>
References: <CAGn5V-_NigDdTPR3RB99JEAQU-Gzhvgxv+Cv39-Ru5DS7ZF2HQ@mail.gmail.com>
 <CABbX2d9rba75hvNtWfQUw+WX1O72d2OAhqSvx8XVuKb8Y6zjxw@mail.gmail.com>
 <CAGn5V-8DL=ax_VdX7-bo25Oh22zb4Kppa9PvvcPzrvBaKz_Tcg@mail.gmail.com>
 <CAP92RBXHWBcuUQPJ1MwvWjPnccKXwh0tV_1dYW+X=QnXkcKdhA@mail.gmail.com>
 <CAGn5V--P3ArzL-k1g5GHZO0ZOtb9LNDCnpt4qo0SANGMU0vF5g@mail.gmail.com>
 <20211226223018.GD16028@gjcp.net>
Message-ID: <1514313659.1292057.1640612266557@mail.yahoo.com>

 I have an original Prophet-5 (Curtis chips inside). It has a one-touch tuning button that works great. It always succeeded in tuning for me. So it was never difficult to tune my P5. It does drift as the system warms up after a cold start but it eventually stabilizes. Pressing the tune button again fixes tuning very well. One trick to get a fat P5 sound is to avoid tuning (and hope for the best).
I know all 10 VCOs were tuned. I don't know about the filters but I strongly doubt they were tuned (only important if the VCFs are set to self oscillate). VCOs are clearly the most temp sensitive components.
    On Sunday, December 26, 2021, 02:38:44 PM PST, Gordonjcp <gordonjcp at gjcp.net> wrote:  
 
 On Sun, Dec 26, 2021 at 08:49:19PM +0100, cheater cheater via Synth-diy wrote:
> Would you say current designs are less temp sensitive?
> 
> What was the most temp sensitive part in things like a Jupiter 8,
> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
> especially are said to have been very difficult to keep in tune...
> 

It's always going to be the expo converters, which is why they're hard to keep in tune.

-- 
Gordonjcp

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org
  
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From rrsounds at aol.com  Mon Dec 27 14:39:36 2021
From: rrsounds at aol.com (rrsounds (null))
Date: Mon, 27 Dec 2021 14:39:36 +0100
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
References: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
Message-ID: <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>

The analog conversion between linear and logarithmic (and vice-versa) scaling using semiconductors often depended upon tightly-coupled (physically) compensating thermistors that were themselves highly temperature-sensitive, and of variable quality. Keeping a steady temperature in the equipment?s environment was often vitally-related to keeping in tune.
As Mattias writes, these problems have been more or less solved in today?s equipment.

I suspect that, like many other generally negative anomalies, the serendipitous effects of temperature drift were, however, seen as beneficial to some people?s art. 

David Reaves

Sent from my iPad

> On Dec 27, 2021, at 2:03 PM, Mattias Rickardsson <mr at analogue.org> wrote:
> 
> ?
> Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com> skrev:
>> Would you say current designs are less temp sensitive?
> 
> 
> Yes, and put in other words you could say that there have been advances in tuning and temperature compensation since 45 years ago. :-)
> 
> Temperature-dependent deviations have become better understood, temp sensing and compensation can be done closer to the error source - on chip level with less problematic factors, clever microprocessor control can be used, etc.
> 
>> What was the most temp sensitive part in things like a Jupiter 8,
>> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
>> especially are said to have been very difficult to keep in tune...
> 
> 
> As said before, exponential converters are the most sensitive (but luckily also the most consistent and relatively easy to compensate) in three of the above.
> 
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From mec.forumreader at gmail.com  Mon Dec 27 16:24:25 2021
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Mon, 27 Dec 2021 10:24:25 -0500
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>
References: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
 <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>
Message-ID: <CAAv6=UDKJ3sH8srWcnce5ZMZrF_Q2Wexuo=oPzKB=Dz8EJMr1A@mail.gmail.com>

I have solved tuning problems with corrections in power distribution.  I
learned some tricks in my career as systems engineer.

When I first got my Minimoog (very early serial #) it was hopelessly
unstable.  Things like modern BiFET opamps in the CV summers helped, but
the biggest contributor was modifying the power distribution.  Not just the
oscillator card but the pitch wheel and front panel tuning pots.  I gigged
that Minimoog; I tuned it before the show started, and never had to retune
it the next four hours.

The biggest contributor to Memorymoog tuning issues is also power
distribution.  I restored two Memorymoogs, including my own.  My fix with
replacing interconnects with gold plated contacts is well known (including
the PSU), the last restore I reflowed the flaky solder joints on the DMUX
board which receives the power harness from the PSU.  The DMUX power
harness is obviously a manual process at the factory and was not done very
well.  After my restoration work was done, I demonstrated it to the
customer and was surprised to find that the MM booted up cold and was
perfectly in tune.

Another cause of tuning problems is incorrect dielectric of the charging
cap in the VCO.  The tempco of the dielectric of the cap is a factor in the
accuracy of the expo conversion, and its tuning stability.  Memorymoogs and
Oberheims equipped with CEM3340s use the wrong cap.  The CEM spec calls out
the correct dielectric (it is NOT a polystyrene).  When I corrected the
caps on my 3340-based synths, the tuning was much better.  I bought a Moog
Voyager SE when they first came out and it has been rock solid tuning;
years later I acquired a Voyager RME and the tuning drifted.  Study of the
schematic and comparing the two boards revealed that the RME had the
incorrect dielectric cap; when that was corrected it was much better.  I
bought the RME at the Moog Store where it was a bench unit; it is possible
that at some point of Voyager production there was a supply problem and
they substituted the cap with the same value, but wrong dielectric.

MC

On Mon, Dec 27, 2021 at 8:42 AM rrsounds (null) via Synth-diy <
synth-diy at synth-diy.org> wrote:

> The analog conversion between linear and logarithmic (and vice-versa)
> scaling using semiconductors often depended upon tightly-coupled
> (physically) compensating thermistors that were themselves highly
> temperature-sensitive, and of variable quality. Keeping a steady
> temperature in the equipment?s environment was often vitally-related to
> keeping in tune.
> As Mattias writes, these problems have been more or less solved in today?s
> equipment.
>
> I suspect that, like many other generally negative anomalies, the
> serendipitous effects of temperature drift were, however, seen as
> beneficial to some people?s art.
>
> David Reaves
>
> Sent from my iPad
>
> On Dec 27, 2021, at 2:03 PM, Mattias Rickardsson <mr at analogue.org> wrote:
>
> ?
> Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com>
> skrev:
>
>> Would you say current designs are less temp sensitive?
>>
>
> Yes, and put in other words you could say that there have been advances in
> tuning and temperature compensation since 45 years ago. :-)
>
> Temperature-dependent deviations have become better understood, temp
> sensing and compensation can be done closer to the error source - on chip
> level with less problematic factors, clever microprocessor control can be
> used, etc.
>
> What was the most temp sensitive part in things like a Jupiter 8,
>> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
>> especially are said to have been very difficult to keep in tune...
>>
>
> As said before, exponential converters are the most sensitive (but luckily
> also the most consistent and relatively easy to compensate) in three of the
> above.
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From tom at electricdruid.net  Mon Dec 27 16:55:01 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Mon, 27 Dec 2021 15:55:01 +0000
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <CAAv6=UDKJ3sH8srWcnce5ZMZrF_Q2Wexuo=oPzKB=Dz8EJMr1A@mail.gmail.com>
References: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
 <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>
 <CAAv6=UDKJ3sH8srWcnce5ZMZrF_Q2Wexuo=oPzKB=Dz8EJMr1A@mail.gmail.com>
Message-ID: <480186F2-EE28-4CBD-BC54-3A271BC72C2D@electricdruid.net>

For other people who are wondering, the CEM3340 long datasheet says:

"a low leakage, low tempco capacitor, such as mica, should be used for Cf".


> On 27 Dec 2021, at 15:24, Michael E Caloroso via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I have solved tuning problems with corrections in power distribution.  I learned some tricks in my career as systems engineer.
> 
> When I first got my Minimoog (very early serial #) it was hopelessly unstable.  Things like modern BiFET opamps in the CV summers helped, but the biggest contributor was modifying the power distribution.  Not just the oscillator card but the pitch wheel and front panel tuning pots.  I gigged that Minimoog; I tuned it before the show started, and never had to retune it the next four hours.
> 
> The biggest contributor to Memorymoog tuning issues is also power distribution.  I restored two Memorymoogs, including my own.  My fix with replacing interconnects with gold plated contacts is well known (including the PSU), the last restore I reflowed the flaky solder joints on the DMUX board which receives the power harness from the PSU.  The DMUX power harness is obviously a manual process at the factory and was not done very well.  After my restoration work was done, I demonstrated it to the customer and was surprised to find that the MM booted up cold and was perfectly in tune.
> 
> Another cause of tuning problems is incorrect dielectric of the charging cap in the VCO.  The tempco of the dielectric of the cap is a factor in the accuracy of the expo conversion, and its tuning stability.  Memorymoogs and Oberheims equipped with CEM3340s use the wrong cap.  The CEM spec calls out the correct dielectric (it is NOT a polystyrene).  When I corrected the caps on my 3340-based synths, the tuning was much better.  I bought a Moog Voyager SE when they first came out and it has been rock solid tuning; years later I acquired a Voyager RME and the tuning drifted.  Study of the schematic and comparing the two boards revealed that the RME had the incorrect dielectric cap; when that was corrected it was much better.  I bought the RME at the Moog Store where it was a bench unit; it is possible that at some point of Voyager production there was a supply problem and they substituted the cap with the same value, but wrong dielectric.
> 
> MC
> 
> On Mon, Dec 27, 2021 at 8:42 AM rrsounds (null) via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
> The analog conversion between linear and logarithmic (and vice-versa) scaling using semiconductors often depended upon tightly-coupled (physically) compensating thermistors that were themselves highly temperature-sensitive, and of variable quality. Keeping a steady temperature in the equipment?s environment was often vitally-related to keeping in tune.
> As Mattias writes, these problems have been more or less solved in today?s equipment.
> 
> I suspect that, like many other generally negative anomalies, the serendipitous effects of temperature drift were, however, seen as beneficial to some people?s art. 
> 
> David Reaves
> 
> Sent from my iPad
> 
>> On Dec 27, 2021, at 2:03 PM, Mattias Rickardsson <mr at analogue.org <mailto:mr at analogue.org>> wrote:
>> 
>> ?
>> Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com <mailto:cheater00social at gmail.com>> skrev:
>> Would you say current designs are less temp sensitive?
>> 
>> Yes, and put in other words you could say that there have been advances in tuning and temperature compensation since 45 years ago. :-)
>> 
>> Temperature-dependent deviations have become better understood, temp sensing and compensation can be done closer to the error source - on chip level with less problematic factors, clever microprocessor control can be used, etc.
>> 
>> What was the most temp sensitive part in things like a Jupiter 8,
>> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
>> especially are said to have been very difficult to keep in tune...
>> 
>> As said before, exponential converters are the most sensitive (but luckily also the most consistent and relatively easy to compensate) in three of the above.
>> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy <http://synth-diy.org/mailman/listinfo/synth-diy>
> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From mbryant at futurehorizons.com  Mon Dec 27 18:18:39 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Mon, 27 Dec 2021 17:18:39 +0000
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <480186F2-EE28-4CBD-BC54-3A271BC72C2D@electricdruid.net>
References: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
 <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>
 <CAAv6=UDKJ3sH8srWcnce5ZMZrF_Q2Wexuo=oPzKB=Dz8EJMr1A@mail.gmail.com>
 <480186F2-EE28-4CBD-BC54-3A271BC72C2D@electricdruid.net>
Message-ID: <a56968fe0a1b428886f28a09a9caf807@futurehorizons.com>

Careful or you?ll you start a trend for people ripping out perfectly good capacitors and replacing them with mica :-)

The designers of the CEM3340 probably either designed or tested the temperature coefficient of their prototype ICs and looked up which capacitors balanced this out best.  Other VCOs/VCFs may be more suited to other types of capacitor.
As you have both have done, but many others don?t ? RTFM !   Bit disappointing that Moog didn?t, but possible R&D originally specified the correct component but then someone cost-reduced the product.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom Wiltshire
Sent: 27 December 2021 15:55
To: Michael E Caloroso
Cc: synth-diy
Subject: Re: [sdiy] Cooling in modular synths

For other people who are wondering, the CEM3340 long datasheet says:

"a low leakage, low tempco capacitor, such as mica, should be used for Cf".



On 27 Dec 2021, at 15:24, Michael E Caloroso via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:

I have solved tuning problems with corrections in power distribution.  I learned some tricks in my career as systems engineer.

When I first got my Minimoog (very early serial #) it was hopelessly unstable.  Things like modern BiFET opamps in the CV summers helped, but the biggest contributor was modifying the power distribution.  Not just the oscillator card but the pitch wheel and front panel tuning pots.  I gigged that Minimoog; I tuned it before the show started, and never had to retune it the next four hours.

The biggest contributor to Memorymoog tuning issues is also power distribution.  I restored two Memorymoogs, including my own.  My fix with replacing interconnects with gold plated contacts is well known (including the PSU), the last restore I reflowed the flaky solder joints on the DMUX board which receives the power harness from the PSU.  The DMUX power harness is obviously a manual process at the factory and was not done very well.  After my restoration work was done, I demonstrated it to the customer and was surprised to find that the MM booted up cold and was perfectly in tune.

Another cause of tuning problems is incorrect dielectric of the charging cap in the VCO.  The tempco of the dielectric of the cap is a factor in the accuracy of the expo conversion, and its tuning stability.  Memorymoogs and Oberheims equipped with CEM3340s use the wrong cap.  The CEM spec calls out the correct dielectric (it is NOT a polystyrene).  When I corrected the caps on my 3340-based synths, the tuning was much better.  I bought a Moog Voyager SE when they first came out and it has been rock solid tuning; years later I acquired a Voyager RME and the tuning drifted.  Study of the schematic and comparing the two boards revealed that the RME had the incorrect dielectric cap; when that was corrected it was much better.  I bought the RME at the Moog Store where it was a bench unit; it is possible that at some point of Voyager production there was a supply problem and they substituted the cap with the same value, but wrong dielectric.

MC

On Mon, Dec 27, 2021 at 8:42 AM rrsounds (null) via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
The analog conversion between linear and logarithmic (and vice-versa) scaling using semiconductors often depended upon tightly-coupled (physically) compensating thermistors that were themselves highly temperature-sensitive, and of variable quality. Keeping a steady temperature in the equipment?s environment was often vitally-related to keeping in tune.
As Mattias writes, these problems have been more or less solved in today?s equipment.

I suspect that, like many other generally negative anomalies, the serendipitous effects of temperature drift were, however, seen as beneficial to some people?s art.

David Reaves
Sent from my iPad


On Dec 27, 2021, at 2:03 PM, Mattias Rickardsson <mr at analogue.org<mailto:mr at analogue.org>> wrote:
?
Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com<mailto:cheater00social at gmail.com>> skrev:
Would you say current designs are less temp sensitive?

Yes, and put in other words you could say that there have been advances in tuning and temperature compensation since 45 years ago. :-)

Temperature-dependent deviations have become better understood, temp sensing and compensation can be done closer to the error source - on chip level with less problematic factors, clever microprocessor control can be used, etc.

What was the most temp sensitive part in things like a Jupiter 8,
CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
especially are said to have been very difficult to keep in tune...

As said before, exponential converters are the most sensitive (but luckily also the most consistent and relatively easy to compensate) in three of the above.

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
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Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>

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From mec.forumreader at gmail.com  Mon Dec 27 18:33:55 2021
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Mon, 27 Dec 2021 12:33:55 -0500
Subject: [sdiy] Cooling in modular synths
In-Reply-To: <a56968fe0a1b428886f28a09a9caf807@futurehorizons.com>
References: <CAP92RBVuUx=R55gFOBC8cxu0Fo-JL7TQVhLgk-40KUPybV5rig@mail.gmail.com>
 <206E6E03-EA54-4271-8EB0-140AC51DF8A3@aol.com>
 <CAAv6=UDKJ3sH8srWcnce5ZMZrF_Q2Wexuo=oPzKB=Dz8EJMr1A@mail.gmail.com>
 <480186F2-EE28-4CBD-BC54-3A271BC72C2D@electricdruid.net>
 <a56968fe0a1b428886f28a09a9caf807@futurehorizons.com>
Message-ID: <CAAv6=UAP2xyQzUse5UTr_-dgGzZyB4LfsEeH+1eaYTMXkdBcuw@mail.gmail.com>

Yeah, mica caps are not the universal charging element for every VCO.
Other designs use polystyrene for a reason.

Sadly a lot of engineers/techs do not RTFM.

MC

On Mon, Dec 27, 2021 at 12:18 PM Mike Bryant <mbryant at futurehorizons.com>
wrote:

> Careful or you?ll you start a trend for people ripping out perfectly good
> capacitors and replacing them with mica :-)
>
>
>
> The designers of the CEM3340 probably either designed or tested the
> temperature coefficient of their prototype ICs and looked up which
> capacitors balanced this out best.  Other VCOs/VCFs may be more suited to
> other types of capacitor.
>
> As you have both have done, but many others don?t ? RTFM !   Bit
> disappointing that Moog didn?t, but possible R&D originally specified the
> correct component but then someone cost-reduced the product.
>
>
>
>
>
> *From:* Synth-diy [mailto:synth-diy-bounces at synth-diy.org] *On Behalf Of *Tom
> Wiltshire
> *Sent:* 27 December 2021 15:55
> *To:* Michael E Caloroso
> *Cc:* synth-diy
> *Subject:* Re: [sdiy] Cooling in modular synths
>
>
>
> For other people who are wondering, the CEM3340 long datasheet says:
>
>
>
> "a low leakage, low tempco capacitor, such as mica, should be used for Cf".
>
>
>
>
>
> On 27 Dec 2021, at 15:24, Michael E Caloroso via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>
>
> I have solved tuning problems with corrections in power distribution.  I
> learned some tricks in my career as systems engineer.
>
>
>
> When I first got my Minimoog (very early serial #) it was hopelessly
> unstable.  Things like modern BiFET opamps in the CV summers helped, but
> the biggest contributor was modifying the power distribution.  Not just the
> oscillator card but the pitch wheel and front panel tuning pots.  I gigged
> that Minimoog; I tuned it before the show started, and never had to retune
> it the next four hours.
>
>
>
> The biggest contributor to Memorymoog tuning issues is also power
> distribution.  I restored two Memorymoogs, including my own.  My fix with
> replacing interconnects with gold plated contacts is well known (including
> the PSU), the last restore I reflowed the flaky solder joints on the DMUX
> board which receives the power harness from the PSU.  The DMUX power
> harness is obviously a manual process at the factory and was not done very
> well.  After my restoration work was done, I demonstrated it to the
> customer and was surprised to find that the MM booted up cold and was
> perfectly in tune.
>
>
>
> Another cause of tuning problems is incorrect dielectric of the charging
> cap in the VCO.  The tempco of the dielectric of the cap is a factor in the
> accuracy of the expo conversion, and its tuning stability.  Memorymoogs and
> Oberheims equipped with CEM3340s use the wrong cap.  The CEM spec calls out
> the correct dielectric (it is NOT a polystyrene).  When I corrected the
> caps on my 3340-based synths, the tuning was much better.  I bought a Moog
> Voyager SE when they first came out and it has been rock solid tuning;
> years later I acquired a Voyager RME and the tuning drifted.  Study of the
> schematic and comparing the two boards revealed that the RME had the
> incorrect dielectric cap; when that was corrected it was much better.  I
> bought the RME at the Moog Store where it was a bench unit; it is possible
> that at some point of Voyager production there was a supply problem and
> they substituted the cap with the same value, but wrong dielectric.
>
>
>
> MC
>
>
>
> On Mon, Dec 27, 2021 at 8:42 AM rrsounds (null) via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
> The analog conversion between linear and logarithmic (and vice-versa)
> scaling using semiconductors often depended upon tightly-coupled
> (physically) compensating thermistors that were themselves highly
> temperature-sensitive, and of variable quality. Keeping a steady
> temperature in the equipment?s environment was often vitally-related to
> keeping in tune.
>
> As Mattias writes, these problems have been more or less solved in today?s
> equipment.
>
>
>
> I suspect that, like many other generally negative anomalies, the
> serendipitous effects of temperature drift were, however, seen as
> beneficial to some people?s art.
>
>
>
> David Reaves
>
> Sent from my iPad
>
>
>
> On Dec 27, 2021, at 2:03 PM, Mattias Rickardsson <mr at analogue.org> wrote:
>
> ?
>
> Den s?n 26 dec. 2021 20:50cheater cheater <cheater00social at gmail.com>
> skrev:
>
> Would you say current designs are less temp sensitive?
>
>
>
> Yes, and put in other words you could say that there have been advances in
> tuning and temperature compensation since 45 years ago. :-)
>
>
>
> Temperature-dependent deviations have become better understood, temp
> sensing and compensation can be done closer to the error source - on chip
> level with less problematic factors, clever microprocessor control can be
> used, etc.
>
>
>
> What was the most temp sensitive part in things like a Jupiter 8,
> CS-80, or a Memorymoog? Or even an original Prophet-10? The last two
> especially are said to have been very difficult to keep in tune...
>
>
>
> As said before, exponential converters are the most sensitive (but luckily
> also the most consistent and relatively easy to compensate) in three of the
> above.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
>
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From Simon.Wheaton at cit.edu.au  Tue Dec 28 02:21:29 2021
From: Simon.Wheaton at cit.edu.au (Wheaton, Simon)
Date: Tue, 28 Dec 2021 01:21:29 +0000
Subject: [sdiy] Looking for 2 x Genuine SSM2044?
In-Reply-To: <MEYPR01MB6504D8A61A22990BC39E2673D2439@MEYPR01MB6504.ausprd01.prod.outlook.com>
References: <MEYPR01MB6504D8A61A22990BC39E2673D2439@MEYPR01MB6504.ausprd01.prod.outlook.com>
Message-ID: <MEYPR01MB650411C9AF4A43FE0C75189CD2439@MEYPR01MB6504.ausprd01.prod.outlook.com>

UNOFFICIAL

I need a pair of genuine SSM2044 chips, preferably from the same year of manufacture.

Can anyone advise where to try, to ensure they are genuine and at a decent price?

Would prefer SSM to SSI, as I have read they are not exactly the same.

Thanks,
Simon
Canberra
AUSTRALIA
________________________________
This email, and any attachments, may be confidential and also privileged. If you are not the intended recipient, please notify the sender and delete all copies of this transmission along with any attachments immediately. You should not copy or use it for any purpose, nor disclose its contents to any other person.
________________________________
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From cheater00social at gmail.com  Tue Dec 28 20:47:27 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 28 Dec 2021 20:47:27 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
Message-ID: <CAGn5V-_aSM-wW+zrHV77nEpoiEqq9VBPKdWGyLZAP9+VwXu9jw@mail.gmail.com>

battery power is not cleaner than a regulated psu, especially a
linearly regulated one. you will still want a linear regulator, as
well as a filtering stage.

On Wed, Dec 22, 2021 at 9:44 PM Didier Leplae via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>  I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org



From mbryant at futurehorizons.com  Tue Dec 28 20:57:18 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 28 Dec 2021 19:57:18 +0000
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CAGn5V-_aSM-wW+zrHV77nEpoiEqq9VBPKdWGyLZAP9+VwXu9jw@mail.gmail.com>
References: <4193B371-58E2-43A6-A906-1161692F3FC0.ref@yahoo.com>
 <4193B371-58E2-43A6-A906-1161692F3FC0@yahoo.com>
 <CAGn5V-_aSM-wW+zrHV77nEpoiEqq9VBPKdWGyLZAP9+VwXu9jw@mail.gmail.com>
Message-ID: <44372c8ccfe04935a9dc2e64f1ead46e@futurehorizons.com>

Well I've never met a 5V battery, and 12V batteries are often 13.x volts so you're going to need some sort of voltage regulator.  And to avoid them discharging unequally you'd be far better off with a single battery and switch-mode boost converters to get the outputs you need.  

I think anybody having problems with 'dirty' power supplies is just buying cheap crap.  Decent ones are very clean nowadays, and most come with a suggested external circuit if you really need even less noise.  Conversely batteries actually produce constant noise at all frequencies due to their method of generating power - put some headphones via a capacitor across one to see how bad some are.


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of cheater cheater via Synth-diy
Sent: 28 December 2021 19:47
To: Didier Leplae
Cc: synth-diy mailing list
Subject: Re: [sdiy] Battery power for eurorack

battery power is not cleaner than a regulated psu, especially a linearly regulated one. you will still want a linear regulator, as well as a filtering stage.

On Wed, Dec 22, 2021 at 9:44 PM Didier Leplae via Synth-diy <synth-diy at synth-diy.org> wrote:
>
> I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
> Plus, of course the portability would be another great benefit.
>
> Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>
>  I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>
> Perhaps someone has done this that I?m not aware of.
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org



From fanwander at mnet-online.de  Wed Dec 29 14:14:34 2021
From: fanwander at mnet-online.de (Florian Anwander)
Date: Wed, 29 Dec 2021 14:14:34 +0100
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
Message-ID: <b496e16c-9937-5c9a-6c33-cce370468df5@mnet-online.de>

Hi,

I offer on my website custom made transformers for the typical analog 
synth supplies like 15V/15V/5V or so.... I order those in small 
quantities from a local transformer winding service. 
(http://www.florian-anwander.de/roland_jx3p/jx3p_transformer.html)

At least once a month I get a request from the US, for such a 
transformer, but each time I have to show them that the shipping costs 
are ridiculously high and/or the duration of the shipping is insanely long.

I think there should be a lot of similar transformer winding services in 
the US. Can anyone of you recommend such a service in the US? Preferably 
in California, but recommendations for other continental states are welcome.

Florian

-- 
http://www.florian-anwander.de/
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From fanwander at mnet-online.de  Wed Dec 29 15:17:18 2021
From: fanwander at mnet-online.de (Florian Anwander)
Date: Wed, 29 Dec 2021 15:17:18 +0100
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
In-Reply-To: <20211229151012.2ZedniFRPRKxd2ZednISaK@smtp1.tb.mail.iss.as9143.net>
References: <20211229151012.2ZedniFRPRKxd2ZednISaK@smtp1.tb.mail.iss.as9143.net>
Message-ID: <a28f7e62-db77-86e1-a1c9-9225c477f585@mnet-online.de>

Hi Jarno

Am 29.12.21 um 15:10 schrieb jarno.verhoeven:
> Edcor?
It looks like they don't do toroidal transformers. Nevertheless thanks!

Florian
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From cheater00social at gmail.com  Wed Dec 29 22:01:14 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Wed, 29 Dec 2021 22:01:14 +0100
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
In-Reply-To: <a28f7e62-db77-86e1-a1c9-9225c477f585@mnet-online.de>
References: <20211229151012.2ZedniFRPRKxd2ZednISaK@smtp1.tb.mail.iss.as9143.net>
 <a28f7e62-db77-86e1-a1c9-9225c477f585@mnet-online.de>
Message-ID: <CAGn5V-82+f0h1-+Y+bTSR1Wj6wUrUijyaTCFiuGv0Yz4aRguZg@mail.gmail.com>

Just a guess, but do Hammond do custom transformers?

On Wed, Dec 29, 2021 at 3:21 PM Florian Anwander
<fanwander at mnet-online.de> wrote:
>
> Hi Jarno
>
> Am 29.12.21 um 15:10 schrieb jarno.verhoeven:
>
> Edcor?
>
> It looks like they don't do toroidal transformers. Nevertheless thanks!
>
> Florian
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From obl64 at ix.netcom.com  Wed Dec 29 22:38:02 2021
From: obl64 at ix.netcom.com (Oren Leavitt)
Date: Wed, 29 Dec 2021 15:38:02 -0600
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
In-Reply-To: <b496e16c-9937-5c9a-6c33-cce370468df5@mnet-online.de>
References: <b496e16c-9937-5c9a-6c33-cce370468df5@mnet-online.de>
Message-ID: <90aff0af-e9d0-0d88-af10-588470524c84@ix.netcom.com>

I've bought toroidal power transformers from these folks for many years.

https://toroid.com/

They do custom, and also sell toroid kits pre-wound with primary-only if 
you want to roll your own secondaries.

https://toroid.com/transformer-kits/

They're in Maryland, USA

- Oren


On 12/29/21 7:14 AM, Florian Anwander wrote:
> Hi,
>
> I offer on my website custom made transformers for the typical analog 
> synth supplies like 15V/15V/5V or so.... I order those in small 
> quantities from a local transformer winding service. 
> (http://www.florian-anwander.de/roland_jx3p/jx3p_transformer.html)
>
> At least once a month I get a request from the US, for such a 
> transformer, but each time I have to show them that the shipping costs 
> are ridiculously high and/or the duration of the shipping is insanely 
> long.
>
> I think there should be a lot of similar transformer winding services 
> in the US. Can anyone of you recommend such a service in the US? 
> Preferably in California, but recommendations for other continental 
> states are welcome.
>
> Florian
> -- 
> http://www.florian-anwander.de/
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From thx1138 at earthlink.net  Wed Dec 29 23:31:23 2021
From: thx1138 at earthlink.net (Terry Shultz)
Date: Wed, 29 Dec 2021 14:31:23 -0800
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
In-Reply-To: <90aff0af-e9d0-0d88-af10-588470524c84@ix.netcom.com>
References: <90aff0af-e9d0-0d88-af10-588470524c84@ix.netcom.com>
Message-ID: <09337F4C-7E33-423C-9B61-FAA9FDBDBF75@earthlink.net>

I have been using Signal transformers since mid 1970?s clear back to my E-my days 

Terry

Sent from my iPhone

> On Dec 29, 2021, at 1:40 PM, Oren Leavitt via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> ?I've bought toroidal power transformers from these folks for many years.
> 
> https://toroid.com/
> 
> They do custom, and also sell toroid kits pre-wound with primary-only if you want to roll your own secondaries.
> 
> https://toroid.com/transformer-kits/
> 
> They're in Maryland, USA
> 
> - Oren
> 
> 
>> On 12/29/21 7:14 AM, Florian Anwander wrote:
>> Hi,
>> 
>> I offer on my website custom made transformers for the typical analog synth supplies like 15V/15V/5V or so.... I order those in small quantities from a local transformer winding service. (http://www.florian-anwander.de/roland_jx3p/jx3p_transformer.html)
>> 
>> At least once a month I get a request from the US, for such a transformer, but each time I have to show them that the shipping costs are ridiculously high and/or the duration of the shipping is insanely long.
>> 
>> I think there should be a lot of similar transformer winding services in the US. Can anyone of you recommend such a service in the US? Preferably in California, but recommendations for other continental states are welcome.
>> 
>> Florian
>> -- 
>> http://www.florian-anwander.de/
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org



From cheater00social at gmail.com  Thu Dec 30 19:18:32 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 30 Dec 2021 19:18:32 +0100
Subject: [sdiy] Which transistors for synth circuits?
Message-ID: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>

Hi all,
I was wondering how you pick out transistors (as well as diodes) for
synth circuits like filters. For example moog filter, 303 filter, etc.
Do you look for anything in specific? I'm talking about a situation
where you don't want to use the exact part in the schematic, but want
to play around with parts and see what comes out of it.

Best regards


From gordonjcp at gjcp.net  Thu Dec 30 21:30:51 2021
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Thu, 30 Dec 2021 20:30:51 +0000
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
Message-ID: <20211230203051.GA22542@gjcp.net>

On Thu, Dec 30, 2021 at 07:18:32PM +0100, cheater cheater via Synth-diy wrote:
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation
> where you don't want to use the exact part in the schematic, but want
> to play around with parts and see what comes out of it.

Any two transistors you pull out of a bag of a thousand from some dude in China totally at random will be more closely matched than the "super matched pairs" we spent so much money on in the 80s.

The big difficulty these days is that random pick'n'mix from some Chinese dude on eBay is going to be so much higher quality than the parts used in vintage synths that they won't be "wrong" enough to work for some applications.  While a reversed transistor makes a good noise source even now, you may have to try a few to get enough noise out of it!

With a very few exceptions none of the components used in vintage synth circuits are especially finicky and almost any transistor will work.  I tend to keep a very large stock of BC548/BC558, 1N4148, and TL07x, and of course LM13700s.  With that I reckon I could build pretty much any part of an analogue synth voice, to any one of a few dozen designs.  If you want to get crazy with it, throw in some LM3900s (ARP "patent buster" filter, among others) and CD4069UBE (EDP Wasp/Gnat SVF and absolutely *gorgeous* "valve sound" distortion).

-- 
Gordonjcp
  


From modular at go2.pl  Thu Dec 30 22:02:36 2021
From: modular at go2.pl (Roman)
Date: Thu, 30 Dec 2021 22:02:36 +0100
Subject: [sdiy] ODP:  Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
Message-ID: <sdqjdgc1fsob5nioq0ire0r1.1640898039811@email.android.com>

I pick transistors based on their package. As long as it comes in SC75, or DFN1010, it's good. Luckily BC847/857 come in every package ever invented.
Unless I want something specific. That's why my BJT stock holds around 30 types or so. 
There are also dual transistors, more available models to choose from than there were singles not so long ago. And everyone of them is better matched than famous classic 2SC1583

Roman 

---- U?ytkownik cheater cheater via Synth-diy napisa? ----

>Hi all,
>I was wondering how you pick out transistors (as well as diodes) for
>synth circuits like filters. For example moog filter, 303 filter, etc.
>Do you look for anything in specific? I'm talking about a situation
>where you don't want to use the exact part in the schematic, but want
>to play around with parts and see what comes out of it.
>
>Best regards
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at synth-diy.org
>http://synth-diy.org/mailman/listinfo/synth-diy
>Selling or trading? Use marketplace at synth-diy.org
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From mbryant at futurehorizons.com  Thu Dec 30 22:33:26 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Thu, 30 Dec 2021 21:33:26 +0000
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
Message-ID: <b40e254cf4314638a3e5dbd14c9f1eb4@futurehorizons.com>

I mostly use MMBT5401 (PNP), MMBT5551 (NPN) and BAV99 (dual diode, even for singles).   Keeps volumes up and stocks down.

2SA1312 is my low noise transistor but going obsolete.

TBH, if changing transistors randomly changes the sound then the design needs some improving.  Far better to design in a particular 'sound' so it's repeatable.


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of cheater cheater via Synth-diy
Sent: 30 December 2021 18:19
To: synth-diy
Subject: [sdiy] Which transistors for synth circuits?

Hi all,
I was wondering how you pick out transistors (as well as diodes) for synth circuits like filters. For example moog filter, 303 filter, etc.
Do you look for anything in specific? I'm talking about a situation where you don't want to use the exact part in the schematic, but want to play around with parts and see what comes out of it.

Best regards
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org




From fanwander at mnet-online.de  Thu Dec 30 22:42:35 2021
From: fanwander at mnet-online.de (Florian Anwander)
Date: Thu, 30 Dec 2021 22:42:35 +0100
Subject: [sdiy] looking for custom transformer service in the US,
 preferred California
In-Reply-To: <09337F4C-7E33-423C-9B61-FAA9FDBDBF75@earthlink.net>
References: <90aff0af-e9d0-0d88-af10-588470524c84@ix.netcom.com>
 <09337F4C-7E33-423C-9B61-FAA9FDBDBF75@earthlink.net>
Message-ID: <63f7c969-4911-0da2-e511-db0e41a50084@mnet-online.de>

Hello Terry,

Am 29.12.21 um 23:31 schrieb Terry Shultz via Synth-diy:
> Signal transformers
Do they offer single piece custom manufacturing?

Florian
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From tom at electricdruid.net  Thu Dec 30 23:55:17 2021
From: tom at electricdruid.net (Tom Wiltshire)
Date: Thu, 30 Dec 2021 22:55:17 +0000
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
Message-ID: <786413BE-2736-4DB2-9251-1D87AA8B2D8E@electricdruid.net>

I don't.

I'm a lame-arse about stuff like that. I use 2N3904 and 2N3906 for basically everything unless there's some absolutely fundamental reason why not. It's amazing what you can get away with. If you were *really* concerned you could match them, but to be honest if you grab a few from the same bag you probably won't notice.

Previously I used to use BC547/557 the same way. I don't even remember why I swapped over. It might have been the pinout rather than anything more important.

> On 30 Dec 2021, at 18:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation
> where you don't want to use the exact part in the schematic, but want
> to play around with parts and see what comes out of it.
> 
> Best regards
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From obl64 at ix.netcom.com  Fri Dec 31 00:08:03 2021
From: obl64 at ix.netcom.com (Oren Leavitt)
Date: Thu, 30 Dec 2021 17:08:03 -0600
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
Message-ID: <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>

Some transistors in my general stock and what scenario I use them in:

2N3904/BC847 (NPN), 2N3906/BC857 (PNP), and 2N3819 (N ch JFET), 1N4148 
(Si diode) - most general purpose "jelly bean" stuff.

BCM847 (dual NPN) and BCM857 (dual PNP) - small SMD matched pairs for 
discrete OTA/ladder filters, current mirrors, expo converters, etc.

SSM2212 (dual NPN) - precision, low rbe expo converter for VCOs.

MPSA42 (NPN) and MPSA92 (PNP) - high voltage 300V.

2N5088/5089 (NPN) and 2N5087 (PNP) - high hFE.

2N4402/4403 (PNP) and 2N4857/4391/4393 (N ch JFET) - Discharge switches, 
choppers.

Other small signal and power transistors for occasional hi-fi/power 
amplifier projects.

- Oren

On 12/30/21 12:18 PM, cheater cheater via Synth-diy wrote:
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation
> where you don't want to use the exact part in the schematic, but want
> to play around with parts and see what comes out of it.
>
> Best regards
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From didierleplae at yahoo.com  Fri Dec 31 02:39:03 2021
From: didierleplae at yahoo.com (Didier Leplae)
Date: Fri, 31 Dec 2021 02:39:03 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
Message-ID: <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>

Thanks. I think these last two responses put this idea to rest for me, as my main objective was cleaner power. 

> On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <chromatest at azburners.org> wrote:
> 
> ?
> I've seen people create DC-DC supplies taking power from 5V battery banks (for charging your phone, etc.) and running entire live rigs from that.
> 
> I think having a single easily swappable battery would be better than having one for each voltage.  You can then possibly just plug your DC-DC supply into a large amperage 5V wall-wart.
> 
>> On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <synth-diy at synth-diy.org> wrote:
>> I've seen people use batteries to power small modular synths.
>> 
>> Several years ago I've ran a small synth with 10 low current analog 
>> modules plus an analog keyboard interface directly from two 12 volt 
>> DeWalt cordless drill battery packs one each for the V+ and V- rails. 
>> After playing on it for a few hours the V+ battery was at about 80% 
>> charge and the V- battery was still at full charge. This was an NiMH 
>> battery pack. I forget what the mAH rating was..
>> 
>> - Oren
>> 
>> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
>> > I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
>> > Plus, of course the portability would be another great benefit.
>> >
>> > Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>> >
>> >   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>> >
>> > Perhaps someone has done this that I?m not aware of.
>> >
>> >
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
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From cheater00social at gmail.com  Fri Dec 31 04:03:04 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Fri, 31 Dec 2021 04:03:04 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
Message-ID: <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>

If you want really very clean power, use a full-sine UPS to power a
toroid based power supply.

On Fri, Dec 31, 2021 at 2:42 AM Didier Leplae via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Thanks. I think these last two responses put this idea to rest for me, as my main objective was cleaner power.
>
> On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <chromatest at azburners.org> wrote:
>
> ?
> I've seen people create DC-DC supplies taking power from 5V battery banks (for charging your phone, etc.) and running entire live rigs from that.
>
> I think having a single easily swappable battery would be better than having one for each voltage.  You can then possibly just plug your DC-DC supply into a large amperage 5V wall-wart.
>
> On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> I've seen people use batteries to power small modular synths.
>>
>> Several years ago I've ran a small synth with 10 low current analog
>> modules plus an analog keyboard interface directly from two 12 volt
>> DeWalt cordless drill battery packs one each for the V+ and V- rails.
>> After playing on it for a few hours the V+ battery was at about 80%
>> charge and the V- battery was still at full charge. This was an NiMH
>> battery pack. I forget what the mAH rating was..
>>
>> - Oren
>>
>> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
>> > I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
>> > Plus, of course the portability would be another great benefit.
>> >
>> > Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>> >
>> >   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>> >
>> > Perhaps someone has done this that I?m not aware of.
>> >
>> >
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org



From bjostarmark at yahoo.se  Fri Dec 31 04:05:25 2021
From: bjostarmark at yahoo.se (=?utf-8?Q?Bj=C3=B6rn_Starmark?=)
Date: Fri, 31 Dec 2021 04:05:25 +0100
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>
Message-ID: <751132268.134146.1640919926104@yahoo.se>

Some more transistors:

PMP4201 (NPN), PMP5201 (PNP) matched dual BJT transistors, for expo and ladder filter. Used in Moog Werkstatt.

J113, MMBFJ113  NJFET for reset switch in saw VCO

/Bjorn
Skickades fr?n E-post f?r Windows

Fr?n: Oren Leavitt via Synth-diy
Skickat: den 31 december 2021 00:14
Till: synth-diy at synth-diy.org
?mne: Re: [sdiy] Which transistors for synth circuits?

Some transistors in my general stock and what scenario I use them in:

2N3904/BC847 (NPN), 2N3906/BC857 (PNP), and 2N3819 (N ch JFET), 1N4148 
(Si diode) - most general purpose "jelly bean" stuff.

BCM847 (dual NPN) and BCM857 (dual PNP) - small SMD matched pairs for 
discrete OTA/ladder filters, current mirrors, expo converters, etc.

SSM2212 (dual NPN) - precision, low rbe expo converter for VCOs.

MPSA42 (NPN) and MPSA92 (PNP) - high voltage 300V.

2N5088/5089 (NPN) and 2N5087 (PNP) - high hFE.

2N4402/4403 (PNP) and 2N4857/4391/4393 (N ch JFET) - Discharge switches, 
choppers.

Other small signal and power transistors for occasional hi-fi/power 
amplifier projects.

- Oren

On 12/30/21 12:18 PM, cheater cheater via Synth-diy wrote:
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation
> where you don't want to use the exact part in the schematic, but want
> to play around with parts and see what comes out of it.
>
> Best regards
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org

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From cheater00social at gmail.com  Fri Dec 31 04:07:51 2021
From: cheater00social at gmail.com (cheater cheater)
Date: Fri, 31 Dec 2021 04:07:51 +0100
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>
Message-ID: <CAGn5V-_QHbOAG9_THM8svw6TMQVyhGWZoYwCGC2ggqXxZ11a1g@mail.gmail.com>

Thanks all, do any of you also every mess around with germanium or
GaAs based transistors? Is there a reason to get a bunch to play
around with? Not for production, just for own fun.


On Fri, Dec 31, 2021 at 12:11 AM Oren Leavitt via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Some transistors in my general stock and what scenario I use them in:
>
> 2N3904/BC847 (NPN), 2N3906/BC857 (PNP), and 2N3819 (N ch JFET), 1N4148
> (Si diode) - most general purpose "jelly bean" stuff.
>
> BCM847 (dual NPN) and BCM857 (dual PNP) - small SMD matched pairs for
> discrete OTA/ladder filters, current mirrors, expo converters, etc.
>
> SSM2212 (dual NPN) - precision, low rbe expo converter for VCOs.
>
> MPSA42 (NPN) and MPSA92 (PNP) - high voltage 300V.
>
> 2N5088/5089 (NPN) and 2N5087 (PNP) - high hFE.
>
> 2N4402/4403 (PNP) and 2N4857/4391/4393 (N ch JFET) - Discharge switches,
> choppers.
>
> Other small signal and power transistors for occasional hi-fi/power
> amplifier projects.
>
> - Oren
>
> On 12/30/21 12:18 PM, cheater cheater via Synth-diy wrote:
> > Hi all,
> > I was wondering how you pick out transistors (as well as diodes) for
> > synth circuits like filters. For example moog filter, 303 filter, etc.
> > Do you look for anything in specific? I'm talking about a situation
> > where you don't want to use the exact part in the schematic, but want
> > to play around with parts and see what comes out of it.
> >
> > Best regards
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From quincas at gmail.com  Fri Dec 31 05:19:57 2021
From: quincas at gmail.com (Quincas Moreira)
Date: Thu, 30 Dec 2021 22:19:57 -0600
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
Message-ID: <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>

I use this battery on any of my cases with great results! Of course my
cases no longer use linear supplies, those require bipolar power and waste
tons of current. DCDC converters for the win!
https://www.amazon.com.mx/gp/product/B00ME3ZH7C/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1


On Thu, Dec 30, 2021 at 9:07 PM cheater cheater via Synth-diy <
synth-diy at synth-diy.org> wrote:

> If you want really very clean power, use a full-sine UPS to power a
> toroid based power supply.
>
> On Fri, Dec 31, 2021 at 2:42 AM Didier Leplae via Synth-diy
> <synth-diy at synth-diy.org> wrote:
> >
> > Thanks. I think these last two responses put this idea to rest for me,
> as my main objective was cleaner power.
> >
> > On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <
> chromatest at azburners.org> wrote:
> >
> > ?
> > I've seen people create DC-DC supplies taking power from 5V battery
> banks (for charging your phone, etc.) and running entire live rigs from
> that.
> >
> > I think having a single easily swappable battery would be better than
> having one for each voltage.  You can then possibly just plug your DC-DC
> supply into a large amperage 5V wall-wart.
> >
> > On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >>
> >> I've seen people use batteries to power small modular synths.
> >>
> >> Several years ago I've ran a small synth with 10 low current analog
> >> modules plus an analog keyboard interface directly from two 12 volt
> >> DeWalt cordless drill battery packs one each for the V+ and V- rails.
> >> After playing on it for a few hours the V+ battery was at about 80%
> >> charge and the V- battery was still at full charge. This was an NiMH
> >> battery pack. I forget what the mAH rating was..
> >>
> >> - Oren
> >>
> >> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
> >> > I?m curious about the idea of using batteries for eurorack power. I
> am not an electrical engineer, so correct me if I?m wrong in thinking that
> battery power could potentially be very clean compared with the cheap power
> supplies many of us use.
> >> > Plus, of course the portability would be another great benefit.
> >> >
> >> > Given recent advances in rechargeable battery technology, I wonder if
> it could be practical and not terribly expensive.
> >> >
> >> >   I?m assuming you might need two or even three separate batteries to
> get the +12 , -12 and +5 volt supplies.
> >> >
> >> > Perhaps someone has done this that I?m not aware of.
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > Synth-diy mailing list
> >> > Synth-diy at synth-diy.org
> >> > http://synth-diy.org/mailman/listinfo/synth-diy
> >> > Selling or trading? Use marketplace at synth-diy.org
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>


-- 
[image: QMA]

Quincas Moreira
Director | QMA
mobile:  5534988825
site:  quincasmoreira.com
email:  quincas at gmail.com
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From lanterma at ece.gatech.edu  Fri Dec 31 12:00:44 2021
From: lanterma at ece.gatech.edu (Lanterman, Aaron D)
Date: Fri, 31 Dec 2021 11:00:44 +0000
Subject: [sdiy] Support for my synth circuit lecture videos
Message-ID: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>

Dear DIYers,

I hope it isn?t out of line for me to post this here...

Over a decade ago, I put some rough recordings of lectures from my music synthesis class and posted them on blip.tv. That service went away, but some kind folks archived and reuploaded those videos (which was very useful since I lost the original files). Partially inspired by the enthusiastic response those old videos received, when Covid hit, I redid all my lectures in a more polished format and put them on YouTube: 

https://www.youtube.com/playlist?list=PLOunECWxELQS5bMdWo9VhmZtsCjhjYNcV

Over the years people who have found benefit from my lecture videos have occasionally asked if I had a Patreon or similar service they could contribute to. Since the videos were created as part of my job at Georgia Tech for which I?m paid by Georgia Tech, ethically I can?t really set up something like that which would put money directly in my bank account.

But, I worked out a deal with the Powers that Be at Tech such that people could make a *targeted* donation to the Georgia Tech Foundation earmarked to support my work with my students. Instructions are given here: https://youtu.be/VBu-LST1p9c

In particular, it's important that Lantertronics/GTF210000920 goes the ?special purpose? field so your donation doesn?t go to building another football stadium or something like that. ;)

(Some year ago I worked out something similar, but it required people to mail a paper check. Now you can type in a credit card number.)

This goes a long way towards helping me show my fellow faculty, in particularly my superiors, that there is a hunger for this kind of material.

And it?s tax deductible. :)

Aaron Lanterman, Prof. of ECE, Georgia Tech
My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
My blog on Electronics and Programming: https://lantertronics.blogspot.com
My YouTube channel on Electronics and Programming: https://www.youtube.com/c/lantertronics






From mbryant at futurehorizons.com  Fri Dec 31 12:27:25 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 31 Dec 2021 11:27:25 +0000
Subject: [sdiy] Support for my synth circuit lecture videos
In-Reply-To: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
References: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
Message-ID: <d91e2fb2bc6b46aea18cd5eb4e88d3ab@futurehorizons.com>

Definitely not out of line to my mind.

An awful lot of knowledge on specialist subjects doesn't get passed down as most students tend to focus on mainstream topics, and of course there are fewer to pass down that knowledge in the first place.  For instance much of the early knowledge on music synthesis gained at Cardiff University has probably been lost by now.  Six years ago I was treated for a medical condition which took fifteen minutes to fix, but five years to find one of only three consultants in the world who understood the condition.  I asked the consultant why this wasn't taught to medical students and he said there's already too much for them to learn.  If he'd posted a video I might have found him far earlier.


-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Lanterman, Aaron D via Synth-diy
Sent: 31 December 2021 11:01
To: Synth Diy
Subject: [sdiy] Support for my synth circuit lecture videos

Dear DIYers,

I hope it isn?t out of line for me to post this here...

Over a decade ago, I put some rough recordings of lectures from my music synthesis class and posted them on blip.tv. That service went away, but some kind folks archived and reuploaded those videos (which was very useful since I lost the original files). Partially inspired by the enthusiastic response those old videos received, when Covid hit, I redid all my lectures in a more polished format and put them on YouTube: 

https://www.youtube.com/playlist?list=PLOunECWxELQS5bMdWo9VhmZtsCjhjYNcV

Over the years people who have found benefit from my lecture videos have occasionally asked if I had a Patreon or similar service they could contribute to. Since the videos were created as part of my job at Georgia Tech for which I?m paid by Georgia Tech, ethically I can?t really set up something like that which would put money directly in my bank account.

But, I worked out a deal with the Powers that Be at Tech such that people could make a *targeted* donation to the Georgia Tech Foundation earmarked to support my work with my students. Instructions are given here: https://youtu.be/VBu-LST1p9c

In particular, it's important that Lantertronics/GTF210000920 goes the ?special purpose? field so your donation doesn?t go to building another football stadium or something like that. ;)

(Some year ago I worked out something similar, but it required people to mail a paper check. Now you can type in a credit card number.)

This goes a long way towards helping me show my fellow faculty, in particularly my superiors, that there is a hunger for this kind of material.

And it?s tax deductible. :)

Aaron Lanterman, Prof. of ECE, Georgia Tech My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
My blog on Electronics and Programming: https://lantertronics.blogspot.com
My YouTube channel on Electronics and Programming: https://www.youtube.com/c/lantertronics




_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org



From mbryant at futurehorizons.com  Fri Dec 31 12:31:44 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 31 Dec 2021 11:31:44 +0000
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
 <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
Message-ID: <7603fe198e29440db55ad0baab8fd099@futurehorizons.com>

Most batteries like that have a dc-dc convertor inside them anyway :-)

I don?t know why people think switchers have to be noisy.  To me there?s nothing worse than 50/100Hz still leaking through umpteen thousand microfarads of smoothing.    Apply that much smoothing to a >50kHz switcher and the noise would be below the cosmic background noise level.

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Quincas Moreira via Synth-diy
Sent: 31 December 2021 04:20
To: cheater cheater
Cc: SDIY
Subject: Re: [sdiy] Battery power for eurorack

I use this battery on any of my cases with great results! Of course my cases no longer use linear supplies, those require bipolar power and waste tons of current. DCDC converters for the win!
https://www.amazon.com.mx/gp/product/B00ME3ZH7C/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

On Thu, Dec 30, 2021 at 9:07 PM cheater cheater via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
If you want really very clean power, use a full-sine UPS to power a
toroid based power supply.

On Fri, Dec 31, 2021 at 2:42 AM Didier Leplae via Synth-diy
<synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
>
> Thanks. I think these last two responses put this idea to rest for me, as my main objective was cleaner power.
>
> On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <chromatest at azburners.org<mailto:chromatest at azburners.org>> wrote:
>
> ?
> I've seen people create DC-DC supplies taking power from 5V battery banks (for charging your phone, etc.) and running entire live rigs from that.
>
> I think having a single easily swappable battery would be better than having one for each voltage.  You can then possibly just plug your DC-DC supply into a large amperage 5V wall-wart.
>
> On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
>>
>> I've seen people use batteries to power small modular synths.
>>
>> Several years ago I've ran a small synth with 10 low current analog
>> modules plus an analog keyboard interface directly from two 12 volt
>> DeWalt cordless drill battery packs one each for the V+ and V- rails.
>> After playing on it for a few hours the V+ battery was at about 80%
>> charge and the V- battery was still at full charge. This was an NiMH
>> battery pack. I forget what the mAH rating was..
>>
>> - Oren
>>
>> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
>> > I?m curious about the idea of using batteries for eurorack power. I am not an electrical engineer, so correct me if I?m wrong in thinking that battery power could potentially be very clean compared with the cheap power supplies many of us use.
>> > Plus, of course the portability would be another great benefit.
>> >
>> > Given recent advances in rechargeable battery technology, I wonder if it could be practical and not terribly expensive.
>> >
>> >   I?m assuming you might need two or even three separate batteries to get the +12 , -12 and +5 volt supplies.
>> >
>> > Perhaps someone has done this that I?m not aware of.
>> >
>> >
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>


--
[QMA]

Quincas Moreira

Director | QMA

mobile:  5534988825<tel:5534988825>

site:  quincasmoreira.com<http://quincasmoreira.com/>

email:  quincas at gmail.com<mailto:quincas at gmail.com>







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From ben at stuyts.nl  Fri Dec 31 13:27:13 2021
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri, 31 Dec 2021 13:27:13 +0100
Subject: [sdiy] Support for my synth circuit lecture videos
In-Reply-To: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
References: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
Message-ID: <1B96F44C-5A41-4F2A-99A5-E015FBC2C2DB@stuyts.nl>

Hi Aaron,

Two remarks:

First: I have no problem with posts like this.
Second: Thanks for making all those videos available.

? Oops, our *three* remarks are: fear, surprise and: 
Third: donated. ?

Best,
Ben


> On 31 Dec 2021, at 12:00, Lanterman, Aaron D via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Dear DIYers,
> 
> I hope it isn?t out of line for me to post this here...
> 
> Over a decade ago, I put some rough recordings of lectures from my music synthesis class and posted them on blip.tv. That service went away, but some kind folks archived and reuploaded those videos (which was very useful since I lost the original files). Partially inspired by the enthusiastic response those old videos received, when Covid hit, I redid all my lectures in a more polished format and put them on YouTube: 
> 
> https://www.youtube.com/playlist?list=PLOunECWxELQS5bMdWo9VhmZtsCjhjYNcV
> 
> Over the years people who have found benefit from my lecture videos have occasionally asked if I had a Patreon or similar service they could contribute to. Since the videos were created as part of my job at Georgia Tech for which I?m paid by Georgia Tech, ethically I can?t really set up something like that which would put money directly in my bank account.
> 
> But, I worked out a deal with the Powers that Be at Tech such that people could make a *targeted* donation to the Georgia Tech Foundation earmarked to support my work with my students. Instructions are given here: https://youtu.be/VBu-LST1p9c
> 
> In particular, it's important that Lantertronics/GTF210000920 goes the ?special purpose? field so your donation doesn?t go to building another football stadium or something like that. ;)
> 
> (Some year ago I worked out something similar, but it required people to mail a paper check. Now you can type in a credit card number.)
> 
> This goes a long way towards helping me show my fellow faculty, in particularly my superiors, that there is a hunger for this kind of material.
> 
> And it?s tax deductible. :)
> 
> Aaron Lanterman, Prof. of ECE, Georgia Tech
> My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
> My blog on Electronics and Programming: https://lantertronics.blogspot.com
> My YouTube channel on Electronics and Programming: https://www.youtube.com/c/lantertronics
> 
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 




From mr at analogue.org  Fri Dec 31 14:44:51 2021
From: mr at analogue.org (Mattias Rickardsson)
Date: Fri, 31 Dec 2021 14:44:51 +0100
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <7603fe198e29440db55ad0baab8fd099@futurehorizons.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
 <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
 <7603fe198e29440db55ad0baab8fd099@futurehorizons.com>
Message-ID: <CAP92RBXVx8LKmnKwJkOc2oTaJS9CBv1T5En05azweYKOBmZfrg@mail.gmail.com>

Mike Bryant <mbryant at futurehorizons.com>:

> I don?t know why people think switchers have to be noisy.  To me there?s
nothing worse than 50/100Hz still leaking through umpteen thousand
microfarads of smoothing.    Apply that much smoothing to a >50kHz switcher
and the noise would be below the cosmic background noise level.

Low audible noise, but perhaps that's not the only aspect. The RF energy
from switchers is often clearly visible on a scope, in repetitive spikes at
frequencies and amplitudes that vary a bit with temperature and current
draw.
What happens when these spikes are added to a comparator threshold level in
a VCO core designed with only linear power supplies in mind? :-)

/mr
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From mbryant at futurehorizons.com  Fri Dec 31 14:52:38 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 31 Dec 2021 13:52:38 +0000
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CAP92RBXVx8LKmnKwJkOc2oTaJS9CBv1T5En05azweYKOBmZfrg@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
 <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
 <7603fe198e29440db55ad0baab8fd099@futurehorizons.com>
 <CAP92RBXVx8LKmnKwJkOc2oTaJS9CBv1T5En05azweYKOBmZfrg@mail.gmail.com>
Message-ID: <3ef675b372914a5b8e9813bc48a17486@futurehorizons.com>


If you?ve got visible RF spikes you need a better PSU arrangement !   The problem is people are happy to spend money and space on adding linear smoothing but not on adding the equivalent components to a switcher, which includes decent screening for the PSU and smoothing components.   I stopped using linears in the 1980s because switchers overtook linear around then, and they?ve only got even better ever since.


From: Mattias Rickardsson [mailto:mr at analogue.org]
Sent: 31 December 2021 13:45
To: Mike Bryant
Cc: Quincas Moreira; cheater cheater; Synth DIY
Subject: Re: [sdiy] Battery power for eurorack

Mike Bryant <mbryant at futurehorizons.com<mailto:mbryant at futurehorizons.com>>:

> I don?t know why people think switchers have to be noisy.  To me there?s nothing worse than 50/100Hz still leaking through umpteen thousand microfarads of smoothing.    Apply that much smoothing to a >50kHz switcher and the noise would be below the cosmic background noise level.

Low audible noise, but perhaps that's not the only aspect. The RF energy from switchers is often clearly visible on a scope, in repetitive spikes at frequencies and amplitudes that vary a bit with temperature and current draw.
What happens when these spikes are added to a comparator threshold level in a VCO core designed with only linear power supplies in mind? :-)

/mr

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From usenet at teply.info  Fri Dec 31 16:15:50 2021
From: usenet at teply.info (usenet at teply.info)
Date: Fri, 31 Dec 2021 16:15:50 +0100
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAGn5V-_QHbOAG9_THM8svw6TMQVyhGWZoYwCGC2ggqXxZ11a1g@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <a40a36ee-ab13-e969-bc75-059d6c9680b3@ix.netcom.com>
 <CAGn5V-_QHbOAG9_THM8svw6TMQVyhGWZoYwCGC2ggqXxZ11a1g@mail.gmail.com>
Message-ID: <3e5312ae-5b4e-5947-5442-bf297ebdf2f6@teply.info>

These days, I'd say IF there was a need for a germanium or GaAs 
transistor you'd already know.
Yes, there are a few corner cases where one could use properties of 
III/V devices, say, high power/ high linearity microwave circuits, or 
some ultra low noise RF.
The only reasons to use germanium I could see is their lower forward 
drop of their base-emitter diode. But this hardly matters in practical 
circuit implementations. Or you'd want to use them as photosensitive 
devices in the medium infrared range (roughly 1000-1900nm wavelength).

As I said, if any of these applications play a role in your experiments, 
you'll most likely know already. Otherwise I wouldn't care. It's good to 
know they exist in case they are useful to meet specific needs, but 
apart from that very few electronics experimenters actually could use 
their properties.

HTH,
Florian

On 31.12.21 04:07, cheater cheater via Synth-diy wrote:
> Thanks all, do any of you also every mess around with germanium or
> GaAs based transistors? Is there a reason to get a bunch to play
> around with? Not for production, just for own fun.
> 
> 
> On Fri, Dec 31, 2021 at 12:11 AM Oren Leavitt via Synth-diy
> <synth-diy at synth-diy.org> wrote:
>>
>> Some transistors in my general stock and what scenario I use them in:
>>
>> 2N3904/BC847 (NPN), 2N3906/BC857 (PNP), and 2N3819 (N ch JFET), 1N4148
>> (Si diode) - most general purpose "jelly bean" stuff.
>>
>> BCM847 (dual NPN) and BCM857 (dual PNP) - small SMD matched pairs for
>> discrete OTA/ladder filters, current mirrors, expo converters, etc.
>>
>> SSM2212 (dual NPN) - precision, low rbe expo converter for VCOs.
>>
>> MPSA42 (NPN) and MPSA92 (PNP) - high voltage 300V.
>>
>> 2N5088/5089 (NPN) and 2N5087 (PNP) - high hFE.
>>
>> 2N4402/4403 (PNP) and 2N4857/4391/4393 (N ch JFET) - Discharge switches,
>> choppers.
>>
>> Other small signal and power transistors for occasional hi-fi/power
>> amplifier projects.
>>
>> - Oren
>>
>> On 12/30/21 12:18 PM, cheater cheater via Synth-diy wrote:
>>> Hi all,
>>> I was wondering how you pick out transistors (as well as diodes) for
>>> synth circuits like filters. For example moog filter, 303 filter, etc.
>>> Do you look for anything in specific? I'm talking about a situation
>>> where you don't want to use the exact part in the schematic, but want
>>> to play around with parts and see what comes out of it.
>>>
>>> Best regards
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org
>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From dixon at mail.ubc.ca  Fri Dec 31 18:52:19 2021
From: dixon at mail.ubc.ca (David G Dixon)
Date: Fri, 31 Dec 2021 09:52:19 -0800
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <786413BE-2736-4DB2-9251-1D87AA8B2D8E@electricdruid.net>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <786413BE-2736-4DB2-9251-1D87AA8B2D8E@electricdruid.net>
Message-ID: <FE730B2103314E86992317AA076BF473@david78c70950b>

Same. 

-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom
Wiltshire
Sent: Thursday, December 30, 2021 2:55 PM
To: cheater cheater
Cc: synth-diy
Subject: Re: [sdiy] Which transistors for synth circuits?

[CAUTION: Non-UBC Email]

I don't.

I'm a lame-arse about stuff like that. I use 2N3904 and 2N3906 for basically
everything unless there's some absolutely fundamental reason why not. It's
amazing what you can get away with. If you were *really* concerned you could
match them, but to be honest if you grab a few from the same bag you
probably won't notice.

Previously I used to use BC547/557 the same way. I don't even remember why I
swapped over. It might have been the pinout rather than anything more
important.

> On 30 Dec 2021, at 18:18, cheater cheater via Synth-diy
<synth-diy at synth-diy.org> wrote:
> 
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for 
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation 
> where you don't want to use the exact part in the schematic, but want 
> to play around with parts and see what comes out of it.
> 
> Best regards
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


_______________________________________________
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Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org



From mec.forumreader at gmail.com  Fri Dec 31 19:47:15 2021
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Fri, 31 Dec 2021 13:47:15 -0500
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <FE730B2103314E86992317AA076BF473@david78c70950b>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <786413BE-2736-4DB2-9251-1D87AA8B2D8E@electricdruid.net>
 <FE730B2103314E86992317AA076BF473@david78c70950b>
Message-ID: <CAAv6=UAtW1D46UvRF-iAdEropzDU1TLRDMTCq-_TL_rvcdq7PA@mail.gmail.com>

Designers have the freedom to use their favored transistors.

For substitution in existing devices, some circuits are sensitive to
transistor selection.

In vintage synths, the voltage to current converter for the iABC input of
the OTA based SVF is one of them.  Scott Rider was designing an OBX
voicecard clone and when it was installed in my OBX the filter sounded
different.  We thought it was the 13700 in place of the 3080 but study of
the databook spec showed the control law was the same (the 13700 was
configured the same as the 3080).  Scott substituted the 2N3906 in place of
the 2N3905 on the original, so that was my next suspicion.  When I compared
the '06 against the '05 specs in my Fairchild databook, I found that the
'05 had a lower HFE range than the '06.  Sure enough, when the 2N3905 was
put in the voicecard clone now sounded the same.  The 2N3906 caused the SVF
cutoff scaling to change because the higher HFE range resulted a
steeper current/volt response, thus it was putting out higher current to
iABC for the cutoff control voltage.   That's why the filter sounded
different.

Other crucial parameters are max iC, min vCE, etc.  You need to know the
limits of your circuit, no single transistor substitutes in every circuit.
There are some VCA designs out there that rely on high beta PNP
transistors, which are not easy to acquire.

MC

On Fri, Dec 31, 2021 at 12:56 PM David G Dixon via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Same.
>
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom
> Wiltshire
> Sent: Thursday, December 30, 2021 2:55 PM
> To: cheater cheater
> Cc: synth-diy
> Subject: Re: [sdiy] Which transistors for synth circuits?
>
> [CAUTION: Non-UBC Email]
>
> I don't.
>
> I'm a lame-arse about stuff like that. I use 2N3904 and 2N3906 for
> basically
> everything unless there's some absolutely fundamental reason why not. It's
> amazing what you can get away with. If you were *really* concerned you
> could
> match them, but to be honest if you grab a few from the same bag you
> probably won't notice.
>
> Previously I used to use BC547/557 the same way. I don't even remember why
> I
> swapped over. It might have been the pinout rather than anything more
> important.
>
> > On 30 Dec 2021, at 18:18, cheater cheater via Synth-diy
> <synth-diy at synth-diy.org> wrote:
> >
> > Hi all,
> > I was wondering how you pick out transistors (as well as diodes) for
> > synth circuits like filters. For example moog filter, 303 filter, etc.
> > Do you look for anything in specific? I'm talking about a situation
> > where you don't want to use the exact part in the schematic, but want
> > to play around with parts and see what comes out of it.
> >
> > Best regards
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From chromatest at azburners.org  Fri Dec 31 20:55:12 2021
From: chromatest at azburners.org (Chromatest J. Pantsmaker)
Date: Fri, 31 Dec 2021 12:55:12 -0700
Subject: [sdiy] Support for my synth circuit lecture videos
In-Reply-To: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
References: <45052243-D6E5-4AAE-9458-1C7FE44D7BA0@ece.gatech.edu>
Message-ID: <CADpm=3G-kygvAe-6i9vzhWP4fFt8H2SVrbBEvoufrnx8-aQ4gw@mail.gmail.com>

I don't feel like watching the video.  Can you post a link to the donation
page?

On Fri, Dec 31, 2021 at 4:02 AM Lanterman, Aaron D via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Dear DIYers,
>
> I hope it isn?t out of line for me to post this here...
>
> Over a decade ago, I put some rough recordings of lectures from my music
> synthesis class and posted them on blip.tv. That service went away, but
> some kind folks archived and reuploaded those videos (which was very useful
> since I lost the original files). Partially inspired by the enthusiastic
> response those old videos received, when Covid hit, I redid all my lectures
> in a more polished format and put them on YouTube:
>
> https://www.youtube.com/playlist?list=PLOunECWxELQS5bMdWo9VhmZtsCjhjYNcV
>
> Over the years people who have found benefit from my lecture videos have
> occasionally asked if I had a Patreon or similar service they could
> contribute to. Since the videos were created as part of my job at Georgia
> Tech for which I?m paid by Georgia Tech, ethically I can?t really set up
> something like that which would put money directly in my bank account.
>
> But, I worked out a deal with the Powers that Be at Tech such that people
> could make a *targeted* donation to the Georgia Tech Foundation earmarked
> to support my work with my students. Instructions are given here:
> https://youtu.be/VBu-LST1p9c
>
> In particular, it's important that Lantertronics/GTF210000920 goes the
> ?special purpose? field so your donation doesn?t go to building another
> football stadium or something like that. ;)
>
> (Some year ago I worked out something similar, but it required people to
> mail a paper check. Now you can type in a credit card number.)
>
> This goes a long way towards helping me show my fellow faculty, in
> particularly my superiors, that there is a hunger for this kind of material.
>
> And it?s tax deductible. :)
>
> Aaron Lanterman, Prof. of ECE, Georgia Tech
> My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
> My blog on Electronics and Programming: https://lantertronics.blogspot.com
> My YouTube channel on Electronics and Programming:
> https://www.youtube.com/c/lantertronics
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From chromatest at azburners.org  Fri Dec 31 20:58:01 2021
From: chromatest at azburners.org (Chromatest J. Pantsmaker)
Date: Fri, 31 Dec 2021 12:58:01 -0700
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
 <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
Message-ID: <CADpm=3FP19Cb3QJXz8T0k6hAr6VDcZ1h+4TB+BXFGsrViG3pAw@mail.gmail.com>

I clicked on that link and saw the price!  What kind of battery is this?????
Then I changed the domain to .com
https://www.amazon.com/gp/product/B00ME3ZH7C

Quincas, what do you use to convert that battery to your module voltages?

On Thu, Dec 30, 2021 at 9:21 PM Quincas Moreira via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I use this battery on any of my cases with great results! Of course my
> cases no longer use linear supplies, those require bipolar power and waste
> tons of current. DCDC converters for the win!
>
> https://www.amazon.com.mx/gp/product/B00ME3ZH7C/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
>
>
> On Thu, Dec 30, 2021 at 9:07 PM cheater cheater via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>> If you want really very clean power, use a full-sine UPS to power a
>> toroid based power supply.
>>
>> On Fri, Dec 31, 2021 at 2:42 AM Didier Leplae via Synth-diy
>> <synth-diy at synth-diy.org> wrote:
>> >
>> > Thanks. I think these last two responses put this idea to rest for me,
>> as my main objective was cleaner power.
>> >
>> > On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <
>> chromatest at azburners.org> wrote:
>> >
>> > ?
>> > I've seen people create DC-DC supplies taking power from 5V battery
>> banks (for charging your phone, etc.) and running entire live rigs from
>> that.
>> >
>> > I think having a single easily swappable battery would be better than
>> having one for each voltage.  You can then possibly just plug your DC-DC
>> supply into a large amperage 5V wall-wart.
>> >
>> > On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>> >>
>> >> I've seen people use batteries to power small modular synths.
>> >>
>> >> Several years ago I've ran a small synth with 10 low current analog
>> >> modules plus an analog keyboard interface directly from two 12 volt
>> >> DeWalt cordless drill battery packs one each for the V+ and V- rails.
>> >> After playing on it for a few hours the V+ battery was at about 80%
>> >> charge and the V- battery was still at full charge. This was an NiMH
>> >> battery pack. I forget what the mAH rating was..
>> >>
>> >> - Oren
>> >>
>> >> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
>> >> > I?m curious about the idea of using batteries for eurorack power. I
>> am not an electrical engineer, so correct me if I?m wrong in thinking that
>> battery power could potentially be very clean compared with the cheap power
>> supplies many of us use.
>> >> > Plus, of course the portability would be another great benefit.
>> >> >
>> >> > Given recent advances in rechargeable battery technology, I wonder
>> if it could be practical and not terribly expensive.
>> >> >
>> >> >   I?m assuming you might need two or even three separate batteries
>> to get the +12 , -12 and +5 volt supplies.
>> >> >
>> >> > Perhaps someone has done this that I?m not aware of.
>> >> >
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > Synth-diy mailing list
>> >> > Synth-diy at synth-diy.org
>> >> > http://synth-diy.org/mailman/listinfo/synth-diy
>> >> > Selling or trading? Use marketplace at synth-diy.org
>> >> _______________________________________________
>> >> Synth-diy mailing list
>> >> Synth-diy at synth-diy.org
>> >> http://synth-diy.org/mailman/listinfo/synth-diy
>> >> Selling or trading? Use marketplace at synth-diy.org
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>
>
> --
> [image: QMA]
>
> Quincas Moreira
> Director | QMA
> mobile:  5534988825
> site:  quincasmoreira.com
> email:  quincas at gmail.com
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mbryant at futurehorizons.com  Fri Dec 31 22:09:30 2021
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Fri, 31 Dec 2021 21:09:30 +0000
Subject: [sdiy] Which transistors for synth circuits?
In-Reply-To: <CAAv6=UAtW1D46UvRF-iAdEropzDU1TLRDMTCq-_TL_rvcdq7PA@mail.gmail.com>
References: <CAGn5V-_X224NNoNRAEzqfmVyJWUjUeJ9zLWuNyTfA1+38U53vg@mail.gmail.com>
 <786413BE-2736-4DB2-9251-1D87AA8B2D8E@electricdruid.net>
 <FE730B2103314E86992317AA076BF473@david78c70950b>
 <CAAv6=UAtW1D46UvRF-iAdEropzDU1TLRDMTCq-_TL_rvcdq7PA@mail.gmail.com>
Message-ID: <5855f4b9a0ba4e209a7d33a45be7bc41@futurehorizons.com>

?  When I compared the '06 against the '05 specs in my Fairchild databook, I found that the '05 had a lower HFE range than the '06.  Sure enough, when the 2N3905 was put in the voicecard clone now sounded the same.  The 2N3906 caused the SVF cutoff scaling to change because the higher HFE range resulted a steeper current/volt response, thus it was putting out higher current to iABC for the cutoff control voltage.   That's why the filter sounded different.

Isn?t that more an indication of a poor design ?  If the current/volt response is critical then it should have been reduced with an emitter resistor.



From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Michael E Caloroso via Synth-diy
Sent: 31 December 2021 18:47
To: David G Dixon
Cc: synth-diy
Subject: Re: [sdiy] Which transistors for synth circuits?

Designers have the freedom to use their favored transistors.

For substitution in existing devices, some circuits are sensitive to transistor selection.

In vintage synths, the voltage to current converter for the iABC input of the OTA based SVF is one of them.  Scott Rider was designing an OBX voicecard clone and when it was installed in my OBX the filter sounded different.  We thought it was the 13700 in place of the 3080 but study of the databook spec showed the control law was the same (the 13700 was configured the same as the 3080).  Scott substituted the 2N3906 in place of the 2N3905 on the original, so that was my next suspicion.  When I compared the '06 against the '05 specs in my Fairchild databook, I found that the '05 had a lower HFE range than the '06.  Sure enough, when the 2N3905 was put in the voicecard clone now sounded the same.  The 2N3906 caused the SVF cutoff scaling to change because the higher HFE range resulted a steeper current/volt response, thus it was putting out higher current to iABC for the cutoff control voltage.   That's why the filter sounded different.

Other crucial parameters are max iC, min vCE, etc.  You need to know the limits of your circuit, no single transistor substitutes in every circuit.  There are some VCA designs out there that rely on high beta PNP transistors, which are not easy to acquire.

MC

On Fri, Dec 31, 2021 at 12:56 PM David G Dixon via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
Same.

-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>] On Behalf Of Tom
Wiltshire
Sent: Thursday, December 30, 2021 2:55 PM
To: cheater cheater
Cc: synth-diy
Subject: Re: [sdiy] Which transistors for synth circuits?

[CAUTION: Non-UBC Email]

I don't.

I'm a lame-arse about stuff like that. I use 2N3904 and 2N3906 for basically
everything unless there's some absolutely fundamental reason why not. It's
amazing what you can get away with. If you were *really* concerned you could
match them, but to be honest if you grab a few from the same bag you
probably won't notice.

Previously I used to use BC547/557 the same way. I don't even remember why I
swapped over. It might have been the pinout rather than anything more
important.

> On 30 Dec 2021, at 18:18, cheater cheater via Synth-diy
<synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
>
> Hi all,
> I was wondering how you pick out transistors (as well as diodes) for
> synth circuits like filters. For example moog filter, 303 filter, etc.
> Do you look for anything in specific? I'm talking about a situation
> where you don't want to use the exact part in the schematic, but want
> to play around with parts and see what comes out of it.
>
> Best regards
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>


_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
http://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org<mailto:marketplace at synth-diy.org>
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From quincas at gmail.com  Fri Dec 31 23:48:06 2021
From: quincas at gmail.com (Quincas Moreira)
Date: Fri, 31 Dec 2021 16:48:06 -0600
Subject: [sdiy] Battery power for eurorack
In-Reply-To: <CADpm=3FP19Cb3QJXz8T0k6hAr6VDcZ1h+4TB+BXFGsrViG3pAw@mail.gmail.com>
References: <CADpm=3Eo40oiv1F9Ub95-uTK6F-6pqy4Ay9f9XJ1-tYpYKHDcw@mail.gmail.com>
 <DE75A1FD-C343-4E06-B7AC-BD9BA9827EF7@yahoo.com>
 <CAGn5V-939Myz0tm30dPYtGfs1z33R3oiFWoC7piRpSrBdYVRxg@mail.gmail.com>
 <CA+u0Jt=o8MJoMdT38ptJLEx8eQBUeMP1uZNOX69SRbda97PTTA@mail.gmail.com>
 <CADpm=3FP19Cb3QJXz8T0k6hAr6VDcZ1h+4TB+BXFGsrViG3pAw@mail.gmail.com>
Message-ID: <CA+u0Jtkd+B+xqH6+JcnK+dmYvort4=26vVGr_VVK_MqSvb=Hqg@mail.gmail.com>

Chromatest, since my PSUs are hybrid, there is no conversion needed. The
cases themselves use switchers, caps and regulators to generate the clean
modular voltages, all they ask for is about 12v DC, which you can get from
any Laptop PSU or battery.  Just plug and play.  In particular I use the
battery with my Erica Synths Travel case, and my small DIY case which uses
the Befaco Lunch Bus power system, but with the beefier Meanwell DC
DC brick as found in their Excalibus board.
The battery lasts well over an hour with the big 104hp 12U case, and up to
three on the little blue one. I also use it with my LXR-02 drum machine
which is fun to carry around the house :)

Quincas

On Fri, Dec 31, 2021 at 1:58 PM Chromatest J. Pantsmaker <
chromatest at azburners.org> wrote:

> I clicked on that link and saw the price!  What kind of battery is
> this?????
> Then I changed the domain to .com
> https://www.amazon.com/gp/product/B00ME3ZH7C
>
> Quincas, what do you use to convert that battery to your module voltages?
>
> On Thu, Dec 30, 2021 at 9:21 PM Quincas Moreira via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>> I use this battery on any of my cases with great results! Of course my
>> cases no longer use linear supplies, those require bipolar power and waste
>> tons of current. DCDC converters for the win!
>>
>> https://www.amazon.com.mx/gp/product/B00ME3ZH7C/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
>>
>>
>> On Thu, Dec 30, 2021 at 9:07 PM cheater cheater via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>>
>>> If you want really very clean power, use a full-sine UPS to power a
>>> toroid based power supply.
>>>
>>> On Fri, Dec 31, 2021 at 2:42 AM Didier Leplae via Synth-diy
>>> <synth-diy at synth-diy.org> wrote:
>>> >
>>> > Thanks. I think these last two responses put this idea to rest for me,
>>> as my main objective was cleaner power.
>>> >
>>> > On Dec 22, 2021, at 10:54 PM, Chromatest J. Pantsmaker <
>>> chromatest at azburners.org> wrote:
>>> >
>>> > ?
>>> > I've seen people create DC-DC supplies taking power from 5V battery
>>> banks (for charging your phone, etc.) and running entire live rigs from
>>> that.
>>> >
>>> > I think having a single easily swappable battery would be better than
>>> having one for each voltage.  You can then possibly just plug your DC-DC
>>> supply into a large amperage 5V wall-wart.
>>> >
>>> > On Wed, Dec 22, 2021 at 2:38 PM Oren Leavitt via Synth-diy <
>>> synth-diy at synth-diy.org> wrote:
>>> >>
>>> >> I've seen people use batteries to power small modular synths.
>>> >>
>>> >> Several years ago I've ran a small synth with 10 low current analog
>>> >> modules plus an analog keyboard interface directly from two 12 volt
>>> >> DeWalt cordless drill battery packs one each for the V+ and V- rails.
>>> >> After playing on it for a few hours the V+ battery was at about 80%
>>> >> charge and the V- battery was still at full charge. This was an NiMH
>>> >> battery pack. I forget what the mAH rating was..
>>> >>
>>> >> - Oren
>>> >>
>>> >> On 12/22/21 2:41 PM, Didier Leplae via Synth-diy wrote:
>>> >> > I?m curious about the idea of using batteries for eurorack power. I
>>> am not an electrical engineer, so correct me if I?m wrong in thinking that
>>> battery power could potentially be very clean compared with the cheap power
>>> supplies many of us use.
>>> >> > Plus, of course the portability would be another great benefit.
>>> >> >
>>> >> > Given recent advances in rechargeable battery technology, I wonder
>>> if it could be practical and not terribly expensive.
>>> >> >
>>> >> >   I?m assuming you might need two or even three separate batteries
>>> to get the +12 , -12 and +5 volt supplies.
>>> >> >
>>> >> > Perhaps someone has done this that I?m not aware of.
>>> >> >
>>> >> >
>>> >> >
>>> >> > _______________________________________________
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>>> >> _______________________________________________
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>>> >
>>> > _______________________________________________
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>>> >
>>> > _______________________________________________
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>>>
>>> _______________________________________________
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>>
>>
>> --
>> [image: QMA]
>>
>> Quincas Moreira
>> Director | QMA
>> mobile:  5534988825
>> site:  quincasmoreira.com
>> email:  quincas at gmail.com
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>

-- 
[image: QMA]

Quincas Moreira
Director | QMA
mobile:  5534988825
site:  quincasmoreira.com
email:  quincas at gmail.com
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