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CGS 58 - Utility LFO minimum rate mod

CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Stephen Richards

Hi Ken

I wanted to make the LFO rate slower so i choose Method 2 as per your build page.

I replaced the 47n with a 100n to reduce the rate of the LFO (didn't change the resistor to reclaim the max. speed yet).
It's still not really slow enough for my liking , so i'm going to keep experimenting.

I was going to try a 1uF probably.

I just wanted to ask , is there a point that the relationship between the capacitor between pins 1 and 2 of the TL074 and the resistor in series with the Speed Pot becomes unworkable ; as far as reducing speed but keeping max. speed ?

[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by sasami@hotkey.net.au

>I just wanted to ask , is there a point that the relationship between
the capacitor between pins 1 and 2 of the TL074 and the resistor in series
with the Speed Pot becomes unworkable ; as far as reducing speed but
keeping max. speed ?

I've not tried it myself so I don't know, but I have heard of some pretty
extreme mods being done by others with respect to this. Ultimately your
limit would come when the leakage through the cap is greater than the
current through the resistor, and that is only likely to be an issue if you
start using electrolytics.

Ken

_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Richarius Molindarius

For the integrator cap. as well keep in mind, if I'm not mistaken, you
can't go with a polarized cap, like an electrolytic; tantalum; etc. Try
going up to a 0.47.
Also - in NON-waveform changing LFOs, I had always used at least a 1 meg
size for the speed pot. That helps to give a much wider range though,
lesser resolution for speeds.
I remember when I had built my first variable waveform LFO back in the 90's
that my larger pot size for speed, did cause interaction with the waveshape
of the waveshape changing pot. Your milage may vary.

I myself have recently given up on LFOs and VCLFOs specifically moving
completely to Serge modules instead. Far more power. Look at those that
Ken has available. Tons and tons of modulation power that in my opinion,
blows away the functionality of LFOs/VCLFOs. :)

--
Take care,
Warmth and Peace,
Rich


[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Stephen Richards

Thanks Richard

I'm working on the CGS58 that is in the Best of CGS 'BOG' panel. Serge/CGS is my favourite format and what i do all of my live shows on.

It's funny but i find myself wanting to make this LFO uber slow like the envelopes on the DUSG which is right next to it in the same panel.



________________________________
Show quoted textHide quoted text
From: Richarius Molindarius <richmolindarius@...>
To: cgs_synth@yahoogroups.com
Sent: Friday, December 14, 2012 6:00 PM
Subject: Re: [cgs_synth] CGS 58 - Utility LFO minimum rate mod



For the integrator cap. as well keep in mind, if I'm not mistaken, you
can't go with a polarized cap, like an electrolytic; tantalum; etc. Try
going up to a 0.47.
Also - in NON-waveform changing LFOs, I had always used at least a 1 meg
size for the speed pot. That helps to give a much wider range though,
lesser resolution for speeds.
I remember when I had built my first variable waveform LFO back in the 90's
that my larger pot size for speed, did cause interaction with the waveshape
of the waveshape changing pot. Your milage may vary.

I myself have recently given up on LFOs and VCLFOs specifically moving
completely to Serge modules instead. Far more power. Look at those that
Ken has available. Tons and tons of modulation power that in my opinion,
blows away the functionality of LFOs/VCLFOs. :)

--
Take care,
Warmth and Peace,
Rich

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Richarius Molindarius

Ohhhhh kay. Unnerstannable. :) Serge/CGS mentions on Muffwiggler just
over a year ago, is what started by divebombing into almost complete
Serge/CGS-Serge conversion. :)
Ken's 58 IS a cool module. There's some nice functionality in there that
will NOT tie up a USG. I'm addicted though. All my ADSRs and LFOs are
gone as of a few weeks ago. But ... that's just me having lusted after
Serge stuff for 20 years almost exactly until I found that Ken was
offering things. Duh. Lol. Should have realized that earlier. :D


On Fri, Dec 14, 2012 at 2:18 AM, Stephen Richards <okayjustalittle@...
Show quoted textHide quoted text
> wrote:

> **
>
>
> Thanks Richard
>
> I'm working on the CGS58 that is in the Best of CGS 'BOG' panel. Serge/CGS
> is my favourite format and what i do all of my live shows on.
>
> It's funny but i find myself wanting to make this LFO uber slow like the
> envelopes on the DUSG which is right next to it in the same panel.
>
> ________________________________
> From: Richarius Molindarius <richmolindarius@...>
> To: cgs_synth@yahoogroups.com
> Sent: Friday, December 14, 2012 6:00 PM
> Subject: Re: [cgs_synth] CGS 58 - Utility LFO minimum rate mod
>
>
>
>
> For the integrator cap. as well keep in mind, if I'm not mistaken, you
> can't go with a polarized cap, like an electrolytic; tantalum; etc. Try
> going up to a 0.47.
> Also - in NON-waveform changing LFOs, I had always used at least a 1 meg
> size for the speed pot. That helps to give a much wider range though,
> lesser resolution for speeds.
> I remember when I had built my first variable waveform LFO back in the 90's
> that my larger pot size for speed, did cause interaction with the waveshape
> of the waveshape changing pot. Your milage may vary.
>
> I myself have recently given up on LFOs and VCLFOs specifically moving
> completely to Serge modules instead. Far more power. Look at those that
> Ken has available. Tons and tons of modulation power that in my opinion,
> blows away the functionality of LFOs/VCLFOs. :)
>
> --
> Take care,
> Warmth and Peace,
> Rich
>
> [Non-text portions of this message have been removed]
>
> [Non-text portions of this message have been removed]
>
>
>



--
Take care,
Warmth and Peace,
Rich

http://www.damian.deathlehem.com/ - my modular synth
http://www.soundcloud.com/Richarius - my latest composition snippets
http://www.youtube.com/dolphinicus/ - various module videos of mine / etc.


[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Dave Kendall

Hi.

Like Mr Richarius said - there is an interaction between the cap and
the resistor (10K on the schemo) if values are much changed from the
original.

If the cap gets bigger and the resistor stays the same, I have had odd
waveshapes at extremes of speed (at higher rates I *think*)
1 meg or more for the resistor, and 1uF or bigger for the cap works
well for slow stuff.
Rapid electronics in the UK stock poly (MKT/WIMA - type) non-polarized
caps up to 3.3uF, and they don't have a huge range in stock, so these
size caps should be quite easy to find around the world.
If you use a multi-pole toggle or rotary for a range control, switching
both cap and resistor, you should be able to minimise undesirable
waveshape changes.

Experimenting with values is the way to go - the magic smoke risk is
relatively low ;-)

Good luck with it!

cheers,
Dave
Show quoted textHide quoted text
On 14 Dec 2012, at 07:26, Richarius Molindarius wrote:

> Ohhhhh kay. Unnerstannable. :) Serge/CGS mentions on Muffwiggler just
> over a year ago, is what started by divebombing into almost complete
> Serge/CGS-Serge conversion. :)
> Ken's 58 IS a cool module. There's some nice functionality in there
> that
> will NOT tie up a USG. I'm addicted though. All my ADSRs and LFOs are
> gone as of a few weeks ago. But ... that's just me having lusted after
> Serge stuff for 20 years almost exactly until I found that Ken was
> offering things. Duh. Lol. Should have realized that earlier. :D
>
>
> On Fri, Dec 14, 2012 at 2:18 AM, Stephen Richards
> <okayjustalittle@...
>> wrote:
>
>> **
>>
>>
>> Thanks Richard
>>
>> I'm working on the CGS58 that is in the Best of CGS 'BOG' panel.
>> Serge/CGS
>> is my favourite format and what i do all of my live shows on.
>>
>> It's funny but i find myself wanting to make this LFO uber slow like
>> the
>> envelopes on the DUSG which is right next to it in the same panel.
>>
>> ________________________________
>> From: Richarius Molindarius <richmolindarius@...>
>> To: cgs_synth@yahoogroups.com
>> Sent: Friday, December 14, 2012 6:00 PM
>> Subject: Re: [cgs_synth] CGS 58 - Utility LFO minimum rate mod
>>
>>
>>
>>
>> For the integrator cap. as well keep in mind, if I'm not mistaken, you
>> can't go with a polarized cap, like an electrolytic; tantalum; etc.
>> Try
>> going up to a 0.47.
>> Also - in NON-waveform changing LFOs, I had always used at least a 1
>> meg
>> size for the speed pot. That helps to give a much wider range though,
>> lesser resolution for speeds.
>> I remember when I had built my first variable waveform LFO back in
>> the 90's
>> that my larger pot size for speed, did cause interaction with the
>> waveshape
>> of the waveshape changing pot. Your milage may vary.
>>
>> I myself have recently given up on LFOs and VCLFOs specifically moving
>> completely to Serge modules instead. Far more power. Look at those
>> that
>> Ken has available. Tons and tons of modulation power that in my
>> opinion,
>> blows away the functionality of LFOs/VCLFOs. :)
>>
>> --
>> Take care,
>> Warmth and Peace,
>> Rich
>>
>> [Non-text portions of this message have been removed]
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
>
>
>
> --
> Take care,
> Warmth and Peace,
> Rich
>
> http://www.damian.deathlehem.com/ - my modular synth
> http://www.soundcloud.com/Richarius - my latest composition snippets
> http://www.youtube.com/dolphinicus/ - various module videos of mine /
> etc.
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>
>
>

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by David Holt

So, I wired my double Utility LFO per Fonik's (admittedly) untested schematic on his website with a switch to change speeds, and I've noticed that when in audio range, the saw and ramp are a little "laggy" and "filtered" sounding. Also, the pitch changes along the full sweep of the shape pot. Could this be the culprit?

[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Richarius Molindarius

Right. The frequency change when adjusting the waveshape. That's what I
had found with a similar variable waveshape LFO that I had made from Barry
Klein's book back in the 90's. It's just something that you'll have to
live with, if I'm not mistaken.
I know that both Serge and Buchla have changable waveshapes in VCOs of
their's, but I'm not familiar with how to do it for sure, outside of a
manually adjusted pot with different waveshapes coming into either side of
it.
Show quoted textHide quoted text
On Fri, Dec 14, 2012 at 10:59 AM, David Holt <dave_3283@...>wrote:

> **
>
>
> So, I wired my double Utility LFO per Fonik's (admittedly) untested
> schematic on his website with a switch to change speeds, and I've
> noticed that when in audio range, the saw and ramp are a little "laggy" and
> "filtered" sounding. Also, the pitch changes along the full sweep of the
> shape pot. Could this be the culprit?
>
>
> [Non-text portions of this message have been removed]
>
>
>



--
Take care,
Warmth and Peace,
Rich

http://www.damian.deathlehem.com/ - my modular synth
http://www.soundcloud.com/Richarius - my latest composition snippets
http://www.youtube.com/dolphinicus/ - various module videos of mine / etc.


[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Joachim

Hi Stephen,

there is a bit of reading here regarding minimum rate speed mod:
http://electro-music.com/forum/viewtopic.php?p=258870#258870

Here are my mods (and some embarrassing n00b errors):
http://electro-music.com/forum/viewtopic.php?p=365448#365448

If you read until my last posts I would suggest to use a 5K 25-turn trimmer
instead of the 4K7 resistor. You are then able to set the minimum rate to your
liking without the need to desolder anything.

Cheers
Joachim

Am 14.12.2012 06:52, schrieb Stephen Richards:
Show quoted textHide quoted text
> Hi Ken
>
> I wanted to make the LFO rate slower so i choose Method 2 as per your build page.
>
> I replaced the 47n with a 100n to reduce the rate of the LFO (didn't change the resistor to reclaim the max. speed yet).
> It's still not really slow enough for my liking , so i'm going to keep experimenting.
>
> I was going to try a 1uF probably.
>
> I just wanted to ask , is there a point that the relationship between the capacitor between pins 1 and 2 of the TL074 and the resistor in series with the Speed Pot becomes unworkable ; as far as reducing speed but keeping max. speed ?
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>
>
>
>

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-14 by Stephen Richards

Cheers Joachim

A 5k trimmer was how i was going to go. In that case would you be using a 1uF or 3.3uF cap ?


________________________________
Show quoted textHide quoted text
From: Joachim <sonicwarrior@...>
To: cgs_synth@yahoogroups.com
Sent: Saturday, December 15, 2012 7:47 AM
Subject: Re: [cgs_synth] CGS 58 - Utility LFO minimum rate mod



Hi Stephen,

there is a bit of reading here regarding minimum rate speed mod:
http://electro-music.com/forum/viewtopic.php?p=258870#258870

Here are my mods (and some embarrassing n00b errors):
http://electro-music.com/forum/viewtopic.php?p=365448#365448

If you read until my last posts I would suggest to use a 5K 25-turn trimmer
instead of the 4K7 resistor. You are then able to set the minimum rate to your
liking without the need to desolder anything.

Cheers
Joachim

Am 14.12.2012 06:52, schrieb Stephen Richards:
> Hi Ken
>
> I wanted to make the LFO rate slower so i choose Method 2 as per your build page.
>
> I replaced the 47n with a 100n to reduce the rate of the LFO (didn't change the resistor to reclaim the max. speed yet).
> It's still not really slow enough for my liking , so i'm going to keep experimenting.
>
> I was going to try a 1uF probably.
>
> I just wanted to ask , is there a point that the relationship between the capacitor between pins 1 and 2 of the TL074 and the resistor in series with the Speed Pot becomes unworkable ; as far as reducing speed but keeping max. speed ?
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>
>
>
>




[Non-text portions of this message have been removed]

Re: CGS 58 - Utility LFO minimum rate mod

2012-12-15 by Joachim

In that case 1 uF is definitely enough.


Am 14.12.2012 22:53, schrieb Stephen Richards:
Show quoted textHide quoted text
> Cheers Joachim
>
> A 5k trimmer was how i was going to go. In that case would you be using a 1uF or 3.3uF cap ?
>
>
> ________________________________
> From: Joachim <sonicwarrior@...>
> To: cgs_synth@yahoogroups.com
> Sent: Saturday, December 15, 2012 7:47 AM
> Subject: Re: [cgs_synth] CGS 58 - Utility LFO minimum rate mod
>
>
>
> Hi Stephen,
>
> there is a bit of reading here regarding minimum rate speed mod:
> http://electro-music.com/forum/viewtopic.php?p=258870#258870
>
> Here are my mods (and some embarrassing n00b errors):
> http://electro-music.com/forum/viewtopic.php?p=365448#365448
>
> If you read until my last posts I would suggest to use a 5K 25-turn trimmer
> instead of the 4K7 resistor. You are then able to set the minimum rate to your
> liking without the need to desolder anything.
>
> Cheers
> Joachim
>
> Am 14.12.2012 06:52, schrieb Stephen Richards:
>> Hi Ken
>>
>> I wanted to make the LFO rate slower so i choose Method 2 as per your build page.
>>
>> I replaced the 47n with a 100n to reduce the rate of the LFO (didn't change the resistor to reclaim the max. speed yet).
>> It's still not really slow enough for my liking , so i'm going to keep experimenting.
>>
>> I was going to try a 1uF probably.
>>
>> I just wanted to ask , is there a point that the relationship between the capacitor between pins 1 and 2 of the TL074 and the resistor in series with the Speed Pot becomes unworkable ; as far as reducing speed but keeping max. speed ?
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
>> ------------------------------------
>>
>> The CGS Modular Synth home page: http://www.cgs.synth.net/
>> Yahoo! Groups Links
>>
>>
>>
>>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>
>
>
>

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