From commodorejohn at gmail.com  Thu Jul  2 01:03:21 2026
From: commodorejohn at gmail.com (John)
Date: Wed, 1 Jul 2026 16:03:21 -0700
Subject: [sdiy] TTSH - part/substitution questions
Message-ID: <20260701160321.00002ab1@gmail.com>

I'm in the process of speccing out a TTSH build, and there's a couple
things I'm curious about and hoping that someone more knowledgeable
than myself might be able to offer some insight on:

First, both the TTSH and the gate-boost BOM list ferrite beads with a
part # of FB_226 - but I cannot for the life of me find any such thing
online. Even a quoted-literal search returns nothing but results point-
ing right back to these BOMs. Is this some understood shorthand for the
specs on a generic ferrite bead? How does one read that?

Second, I'm sure I'm not remotely the first person to note that some of
the transistors required are, erm, unicorn poop, either completely un-
available outside of eBay or just wildly expensive :/ I'm curious, has
anyone worked out alternatives for these?

The 2N4392s are in the electronic switch, and go straight to the jacks;
AFAICT, they're just there to alternately restrict current flow on one
of the two paths?

The 2N3954 is a dual JFET used in the sine shaper; can two JFETs of
equivalent specs be used in its place, or is it important that they be
inna-can for tempco/symmetry purposes?

The 2N3958s go to what were discrete modules on the original. Per what
I can find, one is a buffer for the filter circuit; from my amateur
guesswork, it looks like it uses the ladder's output voltage to control
current flow between +15V and the offset trimmer (which I assume goes
to ground or -15V?) The other is in the S&H, and it looks like it may
serve *almost* the same function, except that it has source & drain for
one JFET reversed, where the filter has them both going the same way.
Is tempco/symmetry also important for these? If they're not matched &
coupled, would that manifest as asymmetric output, or a gap around 0V?

The BOM lists MJE182 and MJE172, which appear from what I can find to
be power transistors, but I don't see them in the power-supply section
and can't spot them anywhere else on the board diagrams I've found. If
I'm using a separate PSU, can I omit them?

From pete.hartman at gmail.com  Thu Jul  2 03:59:31 2026
From: pete.hartman at gmail.com (Pete Hartman)
Date: Wed, 1 Jul 2026 20:59:31 -0500
Subject: [sdiy] TTSH - part/substitution questions
In-Reply-To: <20260701160321.00002ab1@gmail.com>
References: <20260701160321.00002ab1@gmail.com>
Message-ID: <CACodTR95h26RKZPSsY+rdA-dtm+rNYyx_1R2Fk5STmxTHMEbDg@mail.gmail.com>

On Wed, Jul 1, 2026 at 6:11?PM John via Synth-diy
<synth-diy at synth-diy.org> wrote:
> First, both the TTSH and the gate-boost BOM list ferrite beads with a
> part # of FB_226 - but I cannot for the life of me find any such thing
> online. Even a quoted-literal search returns nothing but results point-
> ing right back to these BOMs. Is this some understood shorthand for the
> specs on a generic ferrite bead? How does one read that?

I'm not sure if it's a generic shorthand, but I don't think the
ferrites for these are intended to be anything fussy.  I have a drawer
full of this type of ferrite bead:
https://www.mouser.com/ProductDetail/Fair-Rite/2743002112?qs=X2DWwR3nihDJfxeTNAhF3w%3D%3D
and I just pulled from my own stock on hand.

BTW I looked at my images of rev1, rev2 and rev3 TTSH boards and I
could only find the beads on the rev1.... is that what you're
building?


> Second, I'm sure I'm not remotely the first person to note that some of
> the transistors required are, erm, unicorn poop, either completely un-
> available outside of eBay or just wildly expensive :/ I'm curious, has
> anyone worked out alternatives for these?

I built it with the Transistors as spec'd but then again, I bought a
rare parts kit from Thonk in the UK, so I didn't have to fuss about
with that.  I don't think they're still selling those :(


> The 2N3954 is a dual JFET used in the sine shaper; can two JFETs of
> equivalent specs be used in its place, or is it important that they be
> inna-can for tempco/symmetry purposes?

I would expect they need to be *matched* to each other, but aside from
that, I can't see any reason why the can makes it special


> The BOM lists MJE182 and MJE172, which appear from what I can find to
> be power transistors, but I don't see them in the power-supply section
> and can't spot them anywhere else on the board diagrams I've found. If
> I'm using a separate PSU, can I omit them?

Based on this I guess you're building a rev2 (or maybe later?).  On my
rev1 bom I have
 BD236 and BD237 which were power transistors for the amplifiers that
drove the speakers.
That's where I'd recommend to look, though I haven't dug into this
stuff in a long time now.


From commodorejohn at gmail.com  Thu Jul  2 08:44:50 2026
From: commodorejohn at gmail.com (John Ames)
Date: Wed, 1 Jul 2026 23:44:50 -0700
Subject: [sdiy] TTSH - part/substitution questions
In-Reply-To: <CACodTR95h26RKZPSsY+rdA-dtm+rNYyx_1R2Fk5STmxTHMEbDg@mail.gmail.com>
References: <20260701160321.00002ab1@gmail.com>
 <CACodTR95h26RKZPSsY+rdA-dtm+rNYyx_1R2Fk5STmxTHMEbDg@mail.gmail.com>
Message-ID: <20260701234450.313e13cd@coppelia.commodorejohn.com>

On Wed, 1 Jul 2026 20:59:31 -0500
Pete Hartman <pete.hartman at gmail.com> wrote:

> I'm not sure if it's a generic shorthand, but I don't think the
> ferrites for these are intended to be anything fussy.

Thanks, I kinda figured but this is more than a little beyond me.

> BTW I looked at my images of rev1, rev2 and rev3 TTSH boards and I
> could only find the beads on the rev1.... is that what you're
> building?

V.4, per the SynthCube product listing. BOM is at
https://product-downloads.freshclick.co.uk/uploads/187269622300ec56c723fa76ec709111.pdf
if you're curious.

> I built it with the Transistors as spec'd but then again, I bought a
> rare parts kit from Thonk in the UK, so I didn't have to fuss about
> with that.  I don't think they're still selling those :(

TBH I hadn't checked if they were, since Stupid Circumstances have made
international shipping stupid expensive :/

> I would expect they need to be *matched* to each other, but aside from
> that, I can't see any reason why the can makes it special

That's kinda what I'd guessed, but good to have some backup on this.
Curious what you'd be matching for - resistance? Switching time?

(On which note, obvious newbie question, but: since the ideal JFET is
open at 0V, is it a reasonable first-order approximation of "matching"
to compare resistance across a totally disconnected transistor, or is
it important to note variance in resistance across a range of gate
voltages...?)

> Based on this I guess you're building a rev2 (or maybe later?).  On my
> rev1 bom I have BD236 and BD237 which were power transistors for the
> amplifiers that drove the speakers.

Good to know, I'll have another look. If it's the speakers I'm omitting
those as well, but it'd be nice to minimize complications for the time
being.

From commodorejohn at gmail.com  Thu Jul  2 16:12:28 2026
From: commodorejohn at gmail.com (John Ames)
Date: Thu, 2 Jul 2026 07:12:28 -0700
Subject: [sdiy] TTSH - part/substitution questions
In-Reply-To: <SE2P216MB1508ACB6A852DE8E91F23457F7F52@SE2P216MB1508.KORP216.PROD.OUTLOOK.COM>
References: <20260701160321.00002ab1@gmail.com>
 <CACodTR95h26RKZPSsY+rdA-dtm+rNYyx_1R2Fk5STmxTHMEbDg@mail.gmail.com>
 <20260701234450.313e13cd@coppelia.commodorejohn.com>
 <SE2P216MB1508ACB6A852DE8E91F23457F7F52@SE2P216MB1508.KORP216.PROD.OUTLOOK.COM>
Message-ID: <20260702071228.7c4d112b@coppelia.commodorejohn.com>

On Thu, 2 Jul 2026 07:30:48 +0000
geoff james <minimoog1 at hotmail.com> wrote:

> Hi, Try this for your JFET matching.
> http://www.geofex.com/article_folders/fetmatch/fetmatch.htm

Oh bless you, that's massively useful.

From guatis at gmail.com  Fri Jul  3 18:43:11 2026
From: guatis at gmail.com (=?UTF-8?Q?Benjam=C3=ADn_Velasco?=)
Date: Fri, 3 Jul 2026 12:43:11 -0400
Subject: [sdiy] GRP Genesi
Message-ID: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>

I recently noticed this Arp Prosoloist clone:
https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html

Does anyone know anything about it? Is it a part by part clone (sans
keyboard)? How does it compare to the original? I'm curious about the
implementation of the VCO since the one in the Prosoloist/Pro DGX is
quite unique.

I've sent a couple of emails to the company with no answer.

Cheers

-- 
*Benjam?n Velasco Ossand?n*
Cel. +56 9 96344468
Casa. +56 2 27162400
Oficina. +56 2 29254154
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From synthdiy at adambaby.com  Sat Jul  4 00:19:18 2026
From: synthdiy at adambaby.com (Adam (synthDIY))
Date: Sat, 4 Jul 2026 08:19:18 +1000
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
Message-ID: <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>

The YT video is 3 years old, yet the website isn't finished or very helpful - something tells me this didn't get very far...


A

> On 4 Jul 2026, at 02:43, Benjam?n Velasco via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I recently noticed this Arp Prosoloist clone:
> https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html
> 
> Does anyone know anything about it? Is it a part by part clone (sans keyboard)? How does it compare to the original? I'm curious about the implementation of the VCO since the one in the Prosoloist/Pro DGX is quite unique.
> 
> I've sent a couple of emails to the company with no answer.
> 
> Cheers
> 
> --
> Benjam?n Velasco Ossand?n
> Cel. +56 9 96344468
> Casa. +56 2 27162400
> Oficina. +56 2 29254154
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

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From guatis at gmail.com  Sat Jul  4 00:22:38 2026
From: guatis at gmail.com (=?UTF-8?Q?Benjam=C3=ADn_Velasco?=)
Date: Fri, 3 Jul 2026 18:22:38 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
Message-ID: <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>

I became aware of these when recently some units started popping on Ebay,
Reverb, etc....Maybe leftovers? I'm intrigued...

El vie, 3 jul 2026 a las 18:19, Adam (synthDIY) (<synthdiy at adambaby.com>)
escribi?:

> The YT video is 3 years old, yet the website isn't finished or very
> helpful - something tells me this didn't get very far...
>
>
> A
>
> On 4 Jul 2026, at 02:43, Benjam?n Velasco via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
> I recently noticed this Arp Prosoloist clone:
> https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html
>
> Does anyone know anything about it? Is it a part by part clone (sans
> keyboard)? How does it compare to the original? I'm curious about the
> implementation of the VCO since the one in the Prosoloist/Pro DGX is
> quite unique.
>
> I've sent a couple of emails to the company with no answer.
>
> Cheers
>
> --
> *Benjam?n Velasco Ossand?n*
> Cel. +56 9 96344468
> Casa. +56 2 27162400
> Oficina. +56 2 29254154
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
>

-- 
*Benjam?n Velasco Ossand?n*
Cel. +56 9 96344468
Casa. +56 2 27162400
Oficina. +56 2 29254154
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From mec.forumreader at gmail.com  Sat Jul  4 05:42:47 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Fri, 3 Jul 2026 23:42:47 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
Message-ID: <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>

One was on display at Superbooth 2026.  A german magazine (Synmag) has a
review in an upcoming issue.

MC

On Fri, Jul 3, 2026 at 6:29?PM Benjam?n Velasco via Synth-diy <
synth-diy at synth-diy.org> wrote:

> I became aware of these when recently some units started popping on Ebay,
> Reverb, etc....Maybe leftovers? I'm intrigued...
>
> El vie, 3 jul 2026 a las 18:19, Adam (synthDIY) (<synthdiy at adambaby.com>)
> escribi?:
>
>> The YT video is 3 years old, yet the website isn't finished or very
>> helpful - something tells me this didn't get very far...
>>
>>
>> A
>>
>> On 4 Jul 2026, at 02:43, Benjam?n Velasco via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>>
>> I recently noticed this Arp Prosoloist clone:
>>
>> https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html
>>
>> Does anyone know anything about it? Is it a part by part clone (sans
>> keyboard)? How does it compare to the original? I'm curious about the
>> implementation of the VCO since the one in the Prosoloist/Pro DGX is
>> quite unique.
>>
>> I've sent a couple of emails to the company with no answer.
>>
>> Cheers
>>
>> --
>> *Benjam?n Velasco Ossand?n*
>> Cel. +56 9 96344468
>> Casa. +56 2 27162400
>> Oficina. +56 2 29254154
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>>
>>
>
> --
> *Benjam?n Velasco Ossand?n*
> Cel. +56 9 96344468
> Casa. +56 2 27162400
> Oficina. +56 2 29254154
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mec.forumreader at gmail.com  Sat Jul  4 05:45:21 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Fri, 3 Jul 2026 23:45:21 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
Message-ID: <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>

Yes the VCO in the ProSoloist/DGX is often misunderstood as digital, it is
actually analog.  The patent explains it much better.  Definitely unique
and very very stable.

MC

On Fri, Jul 3, 2026 at 11:42?PM Michael E Caloroso <
mec.forumreader at gmail.com> wrote:

> One was on display at Superbooth 2026.  A german magazine (Synmag) has a
> review in an upcoming issue.
>
> MC
>
> On Fri, Jul 3, 2026 at 6:29?PM Benjam?n Velasco via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>> I became aware of these when recently some units started popping on Ebay,
>> Reverb, etc....Maybe leftovers? I'm intrigued...
>>
>> El vie, 3 jul 2026 a las 18:19, Adam (synthDIY) (<synthdiy at adambaby.com>)
>> escribi?:
>>
>>> The YT video is 3 years old, yet the website isn't finished or very
>>> helpful - something tells me this didn't get very far...
>>>
>>>
>>> A
>>>
>>> On 4 Jul 2026, at 02:43, Benjam?n Velasco via Synth-diy <
>>> synth-diy at synth-diy.org> wrote:
>>>
>>> I recently noticed this Arp Prosoloist clone:
>>>
>>> https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html
>>>
>>> Does anyone know anything about it? Is it a part by part clone (sans
>>> keyboard)? How does it compare to the original? I'm curious about the
>>> implementation of the VCO since the one in the Prosoloist/Pro DGX is
>>> quite unique.
>>>
>>> I've sent a couple of emails to the company with no answer.
>>>
>>> Cheers
>>>
>>> --
>>> *Benjam?n Velasco Ossand?n*
>>> Cel. +56 9 96344468
>>> Casa. +56 2 27162400
>>> Oficina. +56 2 29254154
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>>>
>>>
>>>
>>
>> --
>> *Benjam?n Velasco Ossand?n*
>> Cel. +56 9 96344468
>> Casa. +56 2 27162400
>> Oficina. +56 2 29254154
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://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  Sat Jul  4 11:25:14 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 11:25:14 +0200
Subject: [sdiy] Converting rack mount to DC input?
Message-ID: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>

Hi all,
Beside my head I have my mic processing rack with a bunch of preamps,
voice strips, EQs, etc. I'm in a very quiet room, and the transformer
buzz is audible, which is undesirable for my kind of work. I've been
wondering if anyone ever tried converting their analog racks to DC
input, and how that went. All the racks I'm talking about are
internally running at +15,0,-15V rails, so I could just have a single
linear (or even high quality SMPS) power supply, distribute it via XT
or XLR style connectors, and have simple filter boards inside each
unit that filter the incoming DC, with switch to disconnect the mains
PSU and connect the DC board. I was wondering if this is a good idea
in general and in particular how this relates to issues like ground
loops and EMI pickup. My run from the DC power supply to the rack
would be about 2-3 meters long, but it would be running parallel to
some digital cabling. I would also be interested in suggestions on
connectors to use, especially if I want to make daisy chain cables
that go from device to device.

I would appreciate suggestions / experiences on the topic.

Thanks!

From mbryant at futurehorizons.com  Sat Jul  4 11:36:27 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 09:36:27 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
Message-ID: <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.

Here is a typical one :  https://www.ebay.co.uk/itm/257443162756

As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?

I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
Sent: 04 July 2026 10:25
To: synth-diy <synth-diy at synth-diy.org>
Subject: [sdiy] Converting rack mount to DC input?

Hi all,
Beside my head I have my mic processing rack with a bunch of preamps,
voice strips, EQs, etc. I'm in a very quiet room, and the transformer
buzz is audible, which is undesirable for my kind of work. I've been
wondering if anyone ever tried converting their analog racks to DC
input, and how that went. All the racks I'm talking about are
internally running at +15,0,-15V rails, so I could just have a single
linear (or even high quality SMPS) power supply, distribute it via XT
or XLR style connectors, and have simple filter boards inside each
unit that filter the incoming DC, with switch to disconnect the mains
PSU and connect the DC board. I was wondering if this is a good idea
in general and in particular how this relates to issues like ground
loops and EMI pickup. My run from the DC power supply to the rack
would be about 2-3 meters long, but it would be running parallel to
some digital cabling. I would also be interested in suggestions on
connectors to use, especially if I want to make daisy chain cables
that go from device to device.

I would appreciate suggestions / experiences on the topic.

Thanks!
________________________________________________________
This is the Synth-diy mailing list
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From mbryant at futurehorizons.com  Sat Jul  4 11:37:30 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 09:37:30 +0000
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
Message-ID: <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Do you have a link to the patent ?  I found an interesting article about the feedback counters but it wasn't detailed enough to say exactly how it worked.
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Michael E Caloroso via Synth-diy <synth-diy at synth-diy.org>
Sent: 04 July 2026 04:45
To: Benjam?n Velasco <guatis at gmail.com>
Cc: SYNTH DIY <synth-diy at synth-diy.org>
Subject: Re: [sdiy] GRP Genesi

Yes the VCO in the ProSoloist/DGX is often misunderstood as digital, it is actually analog.  The patent explains it much better.  Definitely unique and very very stable.

MC

On Fri, Jul 3, 2026 at 11:42?PM Michael E Caloroso <mec.forumreader at gmail.com<mailto:mec.forumreader at gmail.com>> wrote:
One was on display at Superbooth 2026.  A german magazine (Synmag) has a review in an upcoming issue.

MC

On Fri, Jul 3, 2026 at 6:29?PM Benjam?n Velasco via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:
I became aware of these when recently some units started popping on Ebay, Reverb, etc....Maybe leftovers? I'm intrigued...

El vie, 3 jul 2026 a las 18:19, Adam (synthDIY) (<synthdiy at adambaby.com<mailto:synthdiy at adambaby.com>>) escribi?:
The YT video is 3 years old, yet the website isn't finished or very helpful - something tells me this didn't get very far...


A

On 4 Jul 2026, at 02:43, Benjam?n Velasco via Synth-diy <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>> wrote:

I recently noticed this Arp Prosoloist clone:
https://www.grpsynthesizer.it/index.php/en/products/grp-vintage-genesi.html

Does anyone know anything about it? Is it a part by part clone (sans keyboard)? How does it compare to the original? I'm curious about the implementation of the VCO since the one in the Prosoloist/Pro DGX is quite unique.

I've sent a couple of emails to the company with no answer.

Cheers

--
Benjam?n Velasco Ossand?n
Cel. +56 9 96344468
Casa. +56 2 27162400
Oficina. +56 2 29254154
________________________________________________________
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Submit email to: Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
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--
Benjam?n Velasco Ossand?n
Cel. +56 9 96344468
Casa. +56 2 27162400
Oficina. +56 2 29254154
________________________________________________________
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From cheater00social at gmail.com  Sat Jul  4 11:44:02 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 11:44:02 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>

Thanks Mike. Do you think sharing one large PSU across many rack items
will be fine? I mean the whole stack currently takes less than 100W
mains. My guess would be to short the kelvin sensing pins to the rails
where I get close to the first rack item and then just distribute the
three rails (+V, -V, 0) without any sense wires.

On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
>
> Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
>
> As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
>
> I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> ________________________________
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> Sent: 04 July 2026 10:25
> To: synth-diy <synth-diy at synth-diy.org>
> Subject: [sdiy] Converting rack mount to DC input?
>
> Hi all,
> Beside my head I have my mic processing rack with a bunch of preamps,
> voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> buzz is audible, which is undesirable for my kind of work. I've been
> wondering if anyone ever tried converting their analog racks to DC
> input, and how that went. All the racks I'm talking about are
> internally running at +15,0,-15V rails, so I could just have a single
> linear (or even high quality SMPS) power supply, distribute it via XT
> or XLR style connectors, and have simple filter boards inside each
> unit that filter the incoming DC, with switch to disconnect the mains
> PSU and connect the DC board. I was wondering if this is a good idea
> in general and in particular how this relates to issues like ground
> loops and EMI pickup. My run from the DC power supply to the rack
> would be about 2-3 meters long, but it would be running parallel to
> some digital cabling. I would also be interested in suggestions on
> connectors to use, especially if I want to make daisy chain cables
> that go from device to device.
>
> I would appreciate suggestions / experiences on the topic.
>
> Thanks!
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From mbryant at futurehorizons.com  Sat Jul  4 11:48:32 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 09:48:32 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
Message-ID: <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?

They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?

You'll also find the power line noise on these units is probably better than your present supplies.
________________________________
From: cheater cheater <cheater00social at gmail.com>
Sent: 04 July 2026 10:44
To: Mike Bryant <mbryant at futurehorizons.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Thanks Mike. Do you think sharing one large PSU across many rack items
will be fine? I mean the whole stack currently takes less than 100W
mains. My guess would be to short the kelvin sensing pins to the rails
where I get close to the first rack item and then just distribute the
three rails (+V, -V, 0) without any sense wires.

On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
>
> Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
>
> As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
>
> I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> ________________________________
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> Sent: 04 July 2026 10:25
> To: synth-diy <synth-diy at synth-diy.org>
> Subject: [sdiy] Converting rack mount to DC input?
>
> Hi all,
> Beside my head I have my mic processing rack with a bunch of preamps,
> voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> buzz is audible, which is undesirable for my kind of work. I've been
> wondering if anyone ever tried converting their analog racks to DC
> input, and how that went. All the racks I'm talking about are
> internally running at +15,0,-15V rails, so I could just have a single
> linear (or even high quality SMPS) power supply, distribute it via XT
> or XLR style connectors, and have simple filter boards inside each
> unit that filter the incoming DC, with switch to disconnect the mains
> PSU and connect the DC board. I was wondering if this is a good idea
> in general and in particular how this relates to issues like ground
> loops and EMI pickup. My run from the DC power supply to the rack
> would be about 2-3 meters long, but it would be running parallel to
> some digital cabling. I would also be interested in suggestions on
> connectors to use, especially if I want to make daisy chain cables
> that go from device to device.
>
> I would appreciate suggestions / experiences on the topic.
>
> Thanks!
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://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 Jul  4 12:59:13 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 10:59:13 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
Message-ID: <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

They usually have an adjuster so you can set them back to 15V.

No idea on second-tier brands ?

Yes 950 is back-breaking - needs to be on wheels.  Not what you need.

________________________________
From: cheater cheater <cheater00social at gmail.com>
Sent: 04 July 2026 11:03
To: Mike Bryant <mbryant at futurehorizons.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

That's cool & interesting!

Two questions

1. The rack units (mostly dbx / behringer stuff since those go real
cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
linked to provides 17V rails. What would I do?

2. Could you suggest power supplies for other mixer brands if you have
any suggestions please? Soundcraft are just a little difficult to find
here.

Jeez that CPS-950 is a hog :)

Oh, it reminds me I might probably need the 48V too. Good call...

On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
>
> They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
>
> You'll also find the power line noise on these units is probably better than your present supplies.
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 10:44
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Thanks Mike. Do you think sharing one large PSU across many rack items
> will be fine? I mean the whole stack currently takes less than 100W
> mains. My guess would be to short the kelvin sensing pins to the rails
> where I get close to the first rack item and then just distribute the
> three rails (+V, -V, 0) without any sense wires.
>
> On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> >
> > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> >
> > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> >
> > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > ________________________________
> > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > Sent: 04 July 2026 10:25
> > To: synth-diy <synth-diy at synth-diy.org>
> > Subject: [sdiy] Converting rack mount to DC input?
> >
> > Hi all,
> > Beside my head I have my mic processing rack with a bunch of preamps,
> > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > buzz is audible, which is undesirable for my kind of work. I've been
> > wondering if anyone ever tried converting their analog racks to DC
> > input, and how that went. All the racks I'm talking about are
> > internally running at +15,0,-15V rails, so I could just have a single
> > linear (or even high quality SMPS) power supply, distribute it via XT
> > or XLR style connectors, and have simple filter boards inside each
> > unit that filter the incoming DC, with switch to disconnect the mains
> > PSU and connect the DC board. I was wondering if this is a good idea
> > in general and in particular how this relates to issues like ground
> > loops and EMI pickup. My run from the DC power supply to the rack
> > would be about 2-3 meters long, but it would be running parallel to
> > some digital cabling. I would also be interested in suggestions on
> > connectors to use, especially if I want to make daisy chain cables
> > that go from device to device.
> >
> > I would appreciate suggestions / experiences on the topic.
> >
> > Thanks!
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://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  Sat Jul  4 13:23:57 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 13:23:57 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>

Heh, ok!

A few more questions if you feel like it:
1. Is the CPS 150 still as low noise / rejection as the larger ones? I
think I have one of those in storage somewhere actually, now that I
think about it!
2. The 150 doesn't seem to have sensing pins in its output cable - do
you know what the smallest one is that does?
3. Do you think the separate circuits of the rack devices might couple
to each other via the power rails, producing crosstalk between them?

Thanks...

On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> They usually have an adjuster so you can set them back to 15V.
>
> No idea on second-tier brands ?
>
> Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 11:03
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> That's cool & interesting!
>
> Two questions
>
> 1. The rack units (mostly dbx / behringer stuff since those go real
> cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> linked to provides 17V rails. What would I do?
>
> 2. Could you suggest power supplies for other mixer brands if you have
> any suggestions please? Soundcraft are just a little difficult to find
> here.
>
> Jeez that CPS-950 is a hog :)
>
> Oh, it reminds me I might probably need the 48V too. Good call...
>
> On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> >
> > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> >
> > You'll also find the power line noise on these units is probably better than your present supplies.
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 10:44
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > Thanks Mike. Do you think sharing one large PSU across many rack items
> > will be fine? I mean the whole stack currently takes less than 100W
> > mains. My guess would be to short the kelvin sensing pins to the rails
> > where I get close to the first rack item and then just distribute the
> > three rails (+V, -V, 0) without any sense wires.
> >
> > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > >
> > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > >
> > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > >
> > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > ________________________________
> > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > Sent: 04 July 2026 10:25
> > > To: synth-diy <synth-diy at synth-diy.org>
> > > Subject: [sdiy] Converting rack mount to DC input?
> > >
> > > Hi all,
> > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > buzz is audible, which is undesirable for my kind of work. I've been
> > > wondering if anyone ever tried converting their analog racks to DC
> > > input, and how that went. All the racks I'm talking about are
> > > internally running at +15,0,-15V rails, so I could just have a single
> > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > or XLR style connectors, and have simple filter boards inside each
> > > unit that filter the incoming DC, with switch to disconnect the mains
> > > PSU and connect the DC board. I was wondering if this is a good idea
> > > in general and in particular how this relates to issues like ground
> > > loops and EMI pickup. My run from the DC power supply to the rack
> > > would be about 2-3 meters long, but it would be running parallel to
> > > some digital cabling. I would also be interested in suggestions on
> > > connectors to use, especially if I want to make daisy chain cables
> > > that go from device to device.
> > >
> > > I would appreciate suggestions / experiences on the topic.
> > >
> > > Thanks!
> > > ________________________________________________________
> > > This is the Synth-diy mailing list
> > > Submit email to: Synth-diy at synth-diy.org
> > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > Selling or trading? Use marketplace at synth-diy.org


From mbryant at futurehorizons.com  Sat Jul  4 13:41:21 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 11:41:21 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
Message-ID: <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.

As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.

________________________________
From: cheater cheater <cheater00social at gmail.com>
Sent: 04 July 2026 12:23
To: Mike Bryant <mbryant at futurehorizons.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Heh, ok!

A few more questions if you feel like it:
1. Is the CPS 150 still as low noise / rejection as the larger ones? I
think I have one of those in storage somewhere actually, now that I
think about it!
2. The 150 doesn't seem to have sensing pins in its output cable - do
you know what the smallest one is that does?
3. Do you think the separate circuits of the rack devices might couple
to each other via the power rails, producing crosstalk between them?

Thanks...

On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> They usually have an adjuster so you can set them back to 15V.
>
> No idea on second-tier brands ?
>
> Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 11:03
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> That's cool & interesting!
>
> Two questions
>
> 1. The rack units (mostly dbx / behringer stuff since those go real
> cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> linked to provides 17V rails. What would I do?
>
> 2. Could you suggest power supplies for other mixer brands if you have
> any suggestions please? Soundcraft are just a little difficult to find
> here.
>
> Jeez that CPS-950 is a hog :)
>
> Oh, it reminds me I might probably need the 48V too. Good call...
>
> On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> >
> > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> >
> > You'll also find the power line noise on these units is probably better than your present supplies.
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 10:44
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > Thanks Mike. Do you think sharing one large PSU across many rack items
> > will be fine? I mean the whole stack currently takes less than 100W
> > mains. My guess would be to short the kelvin sensing pins to the rails
> > where I get close to the first rack item and then just distribute the
> > three rails (+V, -V, 0) without any sense wires.
> >
> > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > >
> > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > >
> > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > >
> > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > ________________________________
> > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > Sent: 04 July 2026 10:25
> > > To: synth-diy <synth-diy at synth-diy.org>
> > > Subject: [sdiy] Converting rack mount to DC input?
> > >
> > > Hi all,
> > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > buzz is audible, which is undesirable for my kind of work. I've been
> > > wondering if anyone ever tried converting their analog racks to DC
> > > input, and how that went. All the racks I'm talking about are
> > > internally running at +15,0,-15V rails, so I could just have a single
> > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > or XLR style connectors, and have simple filter boards inside each
> > > unit that filter the incoming DC, with switch to disconnect the mains
> > > PSU and connect the DC board. I was wondering if this is a good idea
> > > in general and in particular how this relates to issues like ground
> > > loops and EMI pickup. My run from the DC power supply to the rack
> > > would be about 2-3 meters long, but it would be running parallel to
> > > some digital cabling. I would also be interested in suggestions on
> > > connectors to use, especially if I want to make daisy chain cables
> > > that go from device to device.
> > >
> > > I would appreciate suggestions / experiences on the topic.
> > >
> > > Thanks!
> > > ________________________________________________________
> > > This is the Synth-diy mailing list
> > > Submit email to: Synth-diy at synth-diy.org
> > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > Check your settings at: https://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  Sat Jul  4 13:56:52 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 13:56:52 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>

Would I separately earth the chassis of each rack device to mains PE,
or would I just rely on the power supply 0V as grounding?

Thanks...

On Sat, Jul 4, 2026 at 1:41?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.
>
> As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 12:23
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Heh, ok!
>
> A few more questions if you feel like it:
> 1. Is the CPS 150 still as low noise / rejection as the larger ones? I
> think I have one of those in storage somewhere actually, now that I
> think about it!
> 2. The 150 doesn't seem to have sensing pins in its output cable - do
> you know what the smallest one is that does?
> 3. Do you think the separate circuits of the rack devices might couple
> to each other via the power rails, producing crosstalk between them?
>
> Thanks...
>
> On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > They usually have an adjuster so you can set them back to 15V.
> >
> > No idea on second-tier brands ?
> >
> > Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
> >
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 11:03
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > That's cool & interesting!
> >
> > Two questions
> >
> > 1. The rack units (mostly dbx / behringer stuff since those go real
> > cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> > linked to provides 17V rails. What would I do?
> >
> > 2. Could you suggest power supplies for other mixer brands if you have
> > any suggestions please? Soundcraft are just a little difficult to find
> > here.
> >
> > Jeez that CPS-950 is a hog :)
> >
> > Oh, it reminds me I might probably need the 48V too. Good call...
> >
> > On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> > >
> > > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> > >
> > > You'll also find the power line noise on these units is probably better than your present supplies.
> > > ________________________________
> > > From: cheater cheater <cheater00social at gmail.com>
> > > Sent: 04 July 2026 10:44
> > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > Thanks Mike. Do you think sharing one large PSU across many rack items
> > > will be fine? I mean the whole stack currently takes less than 100W
> > > mains. My guess would be to short the kelvin sensing pins to the rails
> > > where I get close to the first rack item and then just distribute the
> > > three rails (+V, -V, 0) without any sense wires.
> > >
> > > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > >
> > > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > > >
> > > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > > >
> > > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > > >
> > > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > > ________________________________
> > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > > Sent: 04 July 2026 10:25
> > > > To: synth-diy <synth-diy at synth-diy.org>
> > > > Subject: [sdiy] Converting rack mount to DC input?
> > > >
> > > > Hi all,
> > > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > > buzz is audible, which is undesirable for my kind of work. I've been
> > > > wondering if anyone ever tried converting their analog racks to DC
> > > > input, and how that went. All the racks I'm talking about are
> > > > internally running at +15,0,-15V rails, so I could just have a single
> > > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > > or XLR style connectors, and have simple filter boards inside each
> > > > unit that filter the incoming DC, with switch to disconnect the mains
> > > > PSU and connect the DC board. I was wondering if this is a good idea
> > > > in general and in particular how this relates to issues like ground
> > > > loops and EMI pickup. My run from the DC power supply to the rack
> > > > would be about 2-3 meters long, but it would be running parallel to
> > > > some digital cabling. I would also be interested in suggestions on
> > > > connectors to use, especially if I want to make daisy chain cables
> > > > that go from device to device.
> > > >
> > > > I would appreciate suggestions / experiences on the topic.
> > > >
> > > > Thanks!
> > > > ________________________________________________________
> > > > This is the Synth-diy mailing list
> > > > Submit email to: Synth-diy at synth-diy.org
> > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > Selling or trading? Use marketplace at synth-diy.org


From fanwander at mnet-online.de  Sat Jul  4 14:22:19 2026
From: fanwander at mnet-online.de (Florian Anwander)
Date: Sat, 4 Jul 2026 14:22:19 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
Message-ID: <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>

Maybe, it's a stupid thought, but...: could it be that a device relies 
on beeing galvanical separated from other devices. I this case the 
common supply might clash with the devices concept.


Am 04.07.26 um 11:25 schrieb cheater cheater via Synth-diy:
> Hi all,
> Beside my head I have my mic processing rack with a bunch of preamps,
> voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> buzz is audible, which is undesirable for my kind of work. I've been
> wondering if anyone ever tried converting their analog racks to DC
> input, and how that went. All the racks I'm talking about are
> internally running at +15,0,-15V rails, so I could just have a single
> linear (or even high quality SMPS) power supply, distribute it via XT
> or XLR style connectors, and have simple filter boards inside each
> unit that filter the incoming DC, with switch to disconnect the mains
> PSU and connect the DC board. I was wondering if this is a good idea
> in general and in particular how this relates to issues like ground
> loops and EMI pickup. My run from the DC power supply to the rack
> would be about 2-3 meters long, but it would be running parallel to
> some digital cabling. I would also be interested in suggestions on
> connectors to use, especially if I want to make daisy chain cables
> that go from device to device.
>
> I would appreciate suggestions / experiences on the topic.
>
> Thanks!
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to:Synth-diy at synth-diy.org
> View archive at:https://synth-diy.org/pipermail/synth-diy/
> Check your settings at:https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Usemarketplace at synth-diy.org
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From mbryant at futurehorizons.com  Sat Jul  4 15:17:08 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 13:17:08 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
Message-ID: <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Power supply ground is normally pretty hefty.

But if you use one of those modern switchers with just L and N then you need to route ground separately.

The gospel :
https://www.ranecommercial.com/legacy/library.html

Wiring, Interconnection and Grounding section.




________________________________
From: cheater cheater <cheater00social at gmail.com>
Sent: 04 July 2026 12:56
To: Mike Bryant <mbryant at futurehorizons.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Would I separately earth the chassis of each rack device to mains PE,
or would I just rely on the power supply 0V as grounding?

Thanks...

On Sat, Jul 4, 2026 at 1:41?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.
>
> As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 12:23
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Heh, ok!
>
> A few more questions if you feel like it:
> 1. Is the CPS 150 still as low noise / rejection as the larger ones? I
> think I have one of those in storage somewhere actually, now that I
> think about it!
> 2. The 150 doesn't seem to have sensing pins in its output cable - do
> you know what the smallest one is that does?
> 3. Do you think the separate circuits of the rack devices might couple
> to each other via the power rails, producing crosstalk between them?
>
> Thanks...
>
> On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > They usually have an adjuster so you can set them back to 15V.
> >
> > No idea on second-tier brands ?
> >
> > Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
> >
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 11:03
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > That's cool & interesting!
> >
> > Two questions
> >
> > 1. The rack units (mostly dbx / behringer stuff since those go real
> > cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> > linked to provides 17V rails. What would I do?
> >
> > 2. Could you suggest power supplies for other mixer brands if you have
> > any suggestions please? Soundcraft are just a little difficult to find
> > here.
> >
> > Jeez that CPS-950 is a hog :)
> >
> > Oh, it reminds me I might probably need the 48V too. Good call...
> >
> > On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> > >
> > > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> > >
> > > You'll also find the power line noise on these units is probably better than your present supplies.
> > > ________________________________
> > > From: cheater cheater <cheater00social at gmail.com>
> > > Sent: 04 July 2026 10:44
> > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > Thanks Mike. Do you think sharing one large PSU across many rack items
> > > will be fine? I mean the whole stack currently takes less than 100W
> > > mains. My guess would be to short the kelvin sensing pins to the rails
> > > where I get close to the first rack item and then just distribute the
> > > three rails (+V, -V, 0) without any sense wires.
> > >
> > > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > >
> > > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > > >
> > > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > > >
> > > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > > >
> > > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > > ________________________________
> > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > > Sent: 04 July 2026 10:25
> > > > To: synth-diy <synth-diy at synth-diy.org>
> > > > Subject: [sdiy] Converting rack mount to DC input?
> > > >
> > > > Hi all,
> > > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > > buzz is audible, which is undesirable for my kind of work. I've been
> > > > wondering if anyone ever tried converting their analog racks to DC
> > > > input, and how that went. All the racks I'm talking about are
> > > > internally running at +15,0,-15V rails, so I could just have a single
> > > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > > or XLR style connectors, and have simple filter boards inside each
> > > > unit that filter the incoming DC, with switch to disconnect the mains
> > > > PSU and connect the DC board. I was wondering if this is a good idea
> > > > in general and in particular how this relates to issues like ground
> > > > loops and EMI pickup. My run from the DC power supply to the rack
> > > > would be about 2-3 meters long, but it would be running parallel to
> > > > some digital cabling. I would also be interested in suggestions on
> > > > connectors to use, especially if I want to make daisy chain cables
> > > > that go from device to device.
> > > >
> > > > I would appreciate suggestions / experiences on the topic.
> > > >
> > > > Thanks!
> > > > ________________________________________________________
> > > > This is the Synth-diy mailing list
> > > > Submit email to: Synth-diy at synth-diy.org
> > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > Check your settings at: https://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  Sat Jul  4 15:51:09 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 15:51:09 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
Message-ID: <CAGn5V--7GtzuE6wNs1g5ROZk+bhyvG3tNqCPpswxagJM-Db9-A@mail.gmail.com>

On Sat, Jul 4, 2026 at 2:28?PM Florian Anwander via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.

Wouldn't that require input and output transformers too? (none of my
equipment has those)

>
> Am 04.07.26 um 11:25 schrieb cheater cheater via Synth-diy:
>
> Hi all,
> Beside my head I have my mic processing rack with a bunch of preamps,
> voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> buzz is audible, which is undesirable for my kind of work. I've been
> wondering if anyone ever tried converting their analog racks to DC
> input, and how that went. All the racks I'm talking about are
> internally running at +15,0,-15V rails, so I could just have a single
> linear (or even high quality SMPS) power supply, distribute it via XT
> or XLR style connectors, and have simple filter boards inside each
> unit that filter the incoming DC, with switch to disconnect the mains
> PSU and connect the DC board. I was wondering if this is a good idea
> in general and in particular how this relates to issues like ground
> loops and EMI pickup. My run from the DC power supply to the rack
> would be about 2-3 meters long, but it would be running parallel to
> some digital cabling. I would also be interested in suggestions on
> connectors to use, especially if I want to make daisy chain cables
> that go from device to device.
>
> I would appreciate suggestions / experiences on the topic.
>
> Thanks!
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Sat Jul  4 15:54:43 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 15:54:43 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
 <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V-9JHq3QhTy4xuHq2u5iLjfHA3aFUihvwwtOE8Wio=+dJw@mail.gmail.com>

On Sat, Jul 4, 2026 at 3:17?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Power supply ground is normally pretty hefty.
>
> But if you use one of those modern switchers with just L and N then you need to route ground separately.
>
> The gospel :
> https://www.ranecommercial.com/legacy/library.html
>
> Wiring, Interconnection and Grounding section.

Oh, yeah, definitely.

I was just wondering:

- If I have a linear PSU with -15, 0, 15V
- and the 0V is earth referenced (i.e. shorted to mains protective earth)
- and the rails (-15 and +15V) have kelvin leads

THEN
is it fine to just ground the devices via the 0V
OR
should I also earth those devices directly to mains PE via an IEC
cable that only has the PE lead and no L/N lead?

>
>
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 12:56
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Would I separately earth the chassis of each rack device to mains PE,
> or would I just rely on the power supply 0V as grounding?
>
> Thanks...
>
> On Sat, Jul 4, 2026 at 1:41?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.
> >
> > As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.
> >
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 12:23
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > Heh, ok!
> >
> > A few more questions if you feel like it:
> > 1. Is the CPS 150 still as low noise / rejection as the larger ones? I
> > think I have one of those in storage somewhere actually, now that I
> > think about it!
> > 2. The 150 doesn't seem to have sensing pins in its output cable - do
> > you know what the smallest one is that does?
> > 3. Do you think the separate circuits of the rack devices might couple
> > to each other via the power rails, producing crosstalk between them?
> >
> > Thanks...
> >
> > On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > They usually have an adjuster so you can set them back to 15V.
> > >
> > > No idea on second-tier brands ?
> > >
> > > Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
> > >
> > > ________________________________
> > > From: cheater cheater <cheater00social at gmail.com>
> > > Sent: 04 July 2026 11:03
> > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > That's cool & interesting!
> > >
> > > Two questions
> > >
> > > 1. The rack units (mostly dbx / behringer stuff since those go real
> > > cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> > > linked to provides 17V rails. What would I do?
> > >
> > > 2. Could you suggest power supplies for other mixer brands if you have
> > > any suggestions please? Soundcraft are just a little difficult to find
> > > here.
> > >
> > > Jeez that CPS-950 is a hog :)
> > >
> > > Oh, it reminds me I might probably need the 48V too. Good call...
> > >
> > > On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > >
> > > > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> > > >
> > > > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> > > >
> > > > You'll also find the power line noise on these units is probably better than your present supplies.
> > > > ________________________________
> > > > From: cheater cheater <cheater00social at gmail.com>
> > > > Sent: 04 July 2026 10:44
> > > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > > >
> > > > Thanks Mike. Do you think sharing one large PSU across many rack items
> > > > will be fine? I mean the whole stack currently takes less than 100W
> > > > mains. My guess would be to short the kelvin sensing pins to the rails
> > > > where I get close to the first rack item and then just distribute the
> > > > three rails (+V, -V, 0) without any sense wires.
> > > >
> > > > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > > >
> > > > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > > > >
> > > > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > > > >
> > > > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > > > >
> > > > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > > > ________________________________
> > > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > > > Sent: 04 July 2026 10:25
> > > > > To: synth-diy <synth-diy at synth-diy.org>
> > > > > Subject: [sdiy] Converting rack mount to DC input?
> > > > >
> > > > > Hi all,
> > > > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > > > buzz is audible, which is undesirable for my kind of work. I've been
> > > > > wondering if anyone ever tried converting their analog racks to DC
> > > > > input, and how that went. All the racks I'm talking about are
> > > > > internally running at +15,0,-15V rails, so I could just have a single
> > > > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > > > or XLR style connectors, and have simple filter boards inside each
> > > > > unit that filter the incoming DC, with switch to disconnect the mains
> > > > > PSU and connect the DC board. I was wondering if this is a good idea
> > > > > in general and in particular how this relates to issues like ground
> > > > > loops and EMI pickup. My run from the DC power supply to the rack
> > > > > would be about 2-3 meters long, but it would be running parallel to
> > > > > some digital cabling. I would also be interested in suggestions on
> > > > > connectors to use, especially if I want to make daisy chain cables
> > > > > that go from device to device.
> > > > >
> > > > > I would appreciate suggestions / experiences on the topic.
> > > > >
> > > > > Thanks!
> > > > > ________________________________________________________
> > > > > This is the Synth-diy mailing list
> > > > > Submit email to: Synth-diy at synth-diy.org
> > > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > > Selling or trading? Use marketplace at synth-diy.org


From mbryant at futurehorizons.com  Sat Jul  4 16:36:20 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sat, 4 Jul 2026 14:36:20 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-9JHq3QhTy4xuHq2u5iLjfHA3aFUihvwwtOE8Wio=+dJw@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CWLP265MB7132ACD53F64DF5D188BC6D1DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V--MxBdBsp8__najLgpEbxmvqdVH4Q7vVuxO9MyO2n2wGQ@mail.gmail.com>
 <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
 <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-9JHq3QhTy4xuHq2u5iLjfHA3aFUihvwwtOE8Wio=+dJw@mail.gmail.com>
Message-ID: <CWLP265MB7132E7B93A7BF2A3331B400CDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

You now come down to national rules and what your set up is.

In the UK, all permanently installed bare metalwork racks (e.g. effects racks or Eurorack synth racks) have to be permanently hardwire connected to mains ground, not just via an IEC.  Large studios usually have a ground distribution screw-block on most walls.  But that doesn't mean the effects units or synth modules in those racks have to be grounded through the metal rack.

And of course many racks are moveable so provided they are grounded via the IEC providing L and N that should suffice.

________________________________
- If I have a linear PSU with -15, 0, 15V
- and the 0V is earth referenced (i.e. shorted to mains protective earth)
- and the rails (-15 and +15V) have kelvin leads

THEN
is it fine to just ground the devices via the 0V
OR
should I also earth those devices directly to mains PE via an IEC
cable that only has the PE lead and no L/N lead?

>
>
>
> ________________________________
> From: cheater cheater <cheater00social at gmail.com>
> Sent: 04 July 2026 12:56
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Would I separately earth the chassis of each rack device to mains PE,
> or would I just rely on the power supply 0V as grounding?
>
> Thanks...
>
> On Sat, Jul 4, 2026 at 1:41?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.
> >
> > As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.
> >
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 12:23
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > Heh, ok!
> >
> > A few more questions if you feel like it:
> > 1. Is the CPS 150 still as low noise / rejection as the larger ones? I
> > think I have one of those in storage somewhere actually, now that I
> > think about it!
> > 2. The 150 doesn't seem to have sensing pins in its output cable - do
> > you know what the smallest one is that does?
> > 3. Do you think the separate circuits of the rack devices might couple
> > to each other via the power rails, producing crosstalk between them?
> >
> > Thanks...
> >
> > On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > They usually have an adjuster so you can set them back to 15V.
> > >
> > > No idea on second-tier brands ?
> > >
> > > Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
> > >
> > > ________________________________
> > > From: cheater cheater <cheater00social at gmail.com>
> > > Sent: 04 July 2026 11:03
> > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > That's cool & interesting!
> > >
> > > Two questions
> > >
> > > 1. The rack units (mostly dbx / behringer stuff since those go real
> > > cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> > > linked to provides 17V rails. What would I do?
> > >
> > > 2. Could you suggest power supplies for other mixer brands if you have
> > > any suggestions please? Soundcraft are just a little difficult to find
> > > here.
> > >
> > > Jeez that CPS-950 is a hog :)
> > >
> > > Oh, it reminds me I might probably need the 48V too. Good call...
> > >
> > > On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > >
> > > > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> > > >
> > > > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> > > >
> > > > You'll also find the power line noise on these units is probably better than your present supplies.
> > > > ________________________________
> > > > From: cheater cheater <cheater00social at gmail.com>
> > > > Sent: 04 July 2026 10:44
> > > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > > >
> > > > Thanks Mike. Do you think sharing one large PSU across many rack items
> > > > will be fine? I mean the whole stack currently takes less than 100W
> > > > mains. My guess would be to short the kelvin sensing pins to the rails
> > > > where I get close to the first rack item and then just distribute the
> > > > three rails (+V, -V, 0) without any sense wires.
> > > >
> > > > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > > >
> > > > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > > > >
> > > > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > > > >
> > > > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > > > >
> > > > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > > > ________________________________
> > > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > > > Sent: 04 July 2026 10:25
> > > > > To: synth-diy <synth-diy at synth-diy.org>
> > > > > Subject: [sdiy] Converting rack mount to DC input?
> > > > >
> > > > > Hi all,
> > > > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > > > buzz is audible, which is undesirable for my kind of work. I've been
> > > > > wondering if anyone ever tried converting their analog racks to DC
> > > > > input, and how that went. All the racks I'm talking about are
> > > > > internally running at +15,0,-15V rails, so I could just have a single
> > > > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > > > or XLR style connectors, and have simple filter boards inside each
> > > > > unit that filter the incoming DC, with switch to disconnect the mains
> > > > > PSU and connect the DC board. I was wondering if this is a good idea
> > > > > in general and in particular how this relates to issues like ground
> > > > > loops and EMI pickup. My run from the DC power supply to the rack
> > > > > would be about 2-3 meters long, but it would be running parallel to
> > > > > some digital cabling. I would also be interested in suggestions on
> > > > > connectors to use, especially if I want to make daisy chain cables
> > > > > that go from device to device.
> > > > >
> > > > > I would appreciate suggestions / experiences on the topic.
> > > > >
> > > > > Thanks!
> > > > > ________________________________________________________
> > > > > This is the Synth-diy mailing list
> > > > > Submit email to: Synth-diy at synth-diy.org
> > > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > Check your settings at: https://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  Sat Jul  4 17:38:26 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Sat, 4 Jul 2026 17:38:26 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB7132E7B93A7BF2A3331B400CDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
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 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
 <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-9JHq3QhTy4xuHq2u5iLjfHA3aFUihvwwtOE8Wio=+dJw@mail.gmail.com>
 <CWLP265MB7132E7B93A7BF2A3331B400CDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V-9gby+Vk0u_2Zx-=3emGya89mLCws33KC5-nb2OL95zag@mail.gmail.com>

oh, i'm not concerned with like national rules or whatever, just
what's good for audio :)

On Sat, Jul 4, 2026 at 4:36?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> You now come down to national rules and what your set up is.
>
> In the UK, all permanently installed bare metalwork racks (e.g. effects racks or Eurorack synth racks) have to be permanently hardwire connected to mains ground, not just via an IEC.  Large studios usually have a ground distribution screw-block on most walls.  But that doesn't mean the effects units or synth modules in those racks have to be grounded through the metal rack.
>
> And of course many racks are moveable so provided they are grounded via the IEC providing L and N that should suffice.
>
> ________________________________
> - If I have a linear PSU with -15, 0, 15V
> - and the 0V is earth referenced (i.e. shorted to mains protective earth)
> - and the rails (-15 and +15V) have kelvin leads
>
> THEN
> is it fine to just ground the devices via the 0V
> OR
> should I also earth those devices directly to mains PE via an IEC
> cable that only has the PE lead and no L/N lead?
>
> >
> >
> >
> > ________________________________
> > From: cheater cheater <cheater00social at gmail.com>
> > Sent: 04 July 2026 12:56
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > Would I separately earth the chassis of each rack device to mains PE,
> > or would I just rely on the power supply 0V as grounding?
> >
> > Thanks...
> >
> > On Sat, Jul 4, 2026 at 1:41?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > > Sorry yes you're correct, the CPS150 is a much simpler PSU than the others.  But I'm sure it will still be more than good enough for what you are doing.
> > >
> > > As for crosstalk between devices, that usually happens through the ground lead, not the +/- leads.  So make sure everything is earthed as much as possible.
> > >
> > > ________________________________
> > > From: cheater cheater <cheater00social at gmail.com>
> > > Sent: 04 July 2026 12:23
> > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > Heh, ok!
> > >
> > > A few more questions if you feel like it:
> > > 1. Is the CPS 150 still as low noise / rejection as the larger ones? I
> > > think I have one of those in storage somewhere actually, now that I
> > > think about it!
> > > 2. The 150 doesn't seem to have sensing pins in its output cable - do
> > > you know what the smallest one is that does?
> > > 3. Do you think the separate circuits of the rack devices might couple
> > > to each other via the power rails, producing crosstalk between them?
> > >
> > > Thanks...
> > >
> > > On Sat, Jul 4, 2026 at 12:59?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > >
> > > > They usually have an adjuster so you can set them back to 15V.
> > > >
> > > > No idea on second-tier brands ?
> > > >
> > > > Yes 950 is back-breaking - needs to be on wheels.  Not what you need.
> > > >
> > > > ________________________________
> > > > From: cheater cheater <cheater00social at gmail.com>
> > > > Sent: 04 July 2026 11:03
> > > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > > >
> > > > That's cool & interesting!
> > > >
> > > > Two questions
> > > >
> > > > 1. The rack units (mostly dbx / behringer stuff since those go real
> > > > cheap nowadays for a lot of function) use 15V rails. The CPS 950 you
> > > > linked to provides 17V rails. What would I do?
> > > >
> > > > 2. Could you suggest power supplies for other mixer brands if you have
> > > > any suggestions please? Soundcraft are just a little difficult to find
> > > > here.
> > > >
> > > > Jeez that CPS-950 is a hog :)
> > > >
> > > > Oh, it reminds me I might probably need the 48V too. Good call...
> > > >
> > > > On Sat, Jul 4, 2026 at 11:48?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > > >
> > > > > Yes that would be fine - it's effectively what happens in a large mixer.  It's a long way from one end to the other of a 48 channel analogue console ?
> > > > >
> > > > > They are also designed so you can put two in parallel so providing fail-safe operation for live use.  Being out in the middle of a concert hall mixing can be a precarious place to be when the sound dies, but you probably don't need that ?
> > > > >
> > > > > You'll also find the power line noise on these units is probably better than your present supplies.
> > > > > ________________________________
> > > > > From: cheater cheater <cheater00social at gmail.com>
> > > > > Sent: 04 July 2026 10:44
> > > > > To: Mike Bryant <mbryant at futurehorizons.com>
> > > > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > > > >
> > > > > Thanks Mike. Do you think sharing one large PSU across many rack items
> > > > > will be fine? I mean the whole stack currently takes less than 100W
> > > > > mains. My guess would be to short the kelvin sensing pins to the rails
> > > > > where I get close to the first rack item and then just distribute the
> > > > > three rails (+V, -V, 0) without any sense wires.
> > > > >
> > > > > On Sat, Jul 4, 2026 at 11:36?AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > > > > >
> > > > > > Yes this is a well known problem, and older top-end professional mixers with linear power supplies always put the power supply in a remote box.
> > > > > >
> > > > > > Here is a typical one :  https://www.ebay.co.uk/itm/257443162756
> > > > > >
> > > > > > As well as thick wires for the supplies and ground, they also had return wires so that the PSU compensated for any voltage loss in the cable, which was often tens of metres long.  I've even seen them dumped in the studio's reception to keep the receptionist warm ?
> > > > > >
> > > > > > I think the CPS-150 was the smallest we did, but there will be equivalent small external PSUs from Midas and so on.
> > > > > > ________________________________
> > > > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> > > > > > Sent: 04 July 2026 10:25
> > > > > > To: synth-diy <synth-diy at synth-diy.org>
> > > > > > Subject: [sdiy] Converting rack mount to DC input?
> > > > > >
> > > > > > Hi all,
> > > > > > Beside my head I have my mic processing rack with a bunch of preamps,
> > > > > > voice strips, EQs, etc. I'm in a very quiet room, and the transformer
> > > > > > buzz is audible, which is undesirable for my kind of work. I've been
> > > > > > wondering if anyone ever tried converting their analog racks to DC
> > > > > > input, and how that went. All the racks I'm talking about are
> > > > > > internally running at +15,0,-15V rails, so I could just have a single
> > > > > > linear (or even high quality SMPS) power supply, distribute it via XT
> > > > > > or XLR style connectors, and have simple filter boards inside each
> > > > > > unit that filter the incoming DC, with switch to disconnect the mains
> > > > > > PSU and connect the DC board. I was wondering if this is a good idea
> > > > > > in general and in particular how this relates to issues like ground
> > > > > > loops and EMI pickup. My run from the DC power supply to the rack
> > > > > > would be about 2-3 meters long, but it would be running parallel to
> > > > > > some digital cabling. I would also be interested in suggestions on
> > > > > > connectors to use, especially if I want to make daisy chain cables
> > > > > > that go from device to device.
> > > > > >
> > > > > > I would appreciate suggestions / experiences on the topic.
> > > > > >
> > > > > > Thanks!
> > > > > > ________________________________________________________
> > > > > > This is the Synth-diy mailing list
> > > > > > Submit email to: Synth-diy at synth-diy.org
> > > > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > > > Selling or trading? Use marketplace at synth-diy.org


From mec.forumreader at gmail.com  Sat Jul  4 18:38:59 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Sat, 4 Jul 2026 12:38:59 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>

US 3,930,429

MC

On Sat, Jul 4, 2026 at 5:37?AM Mike Bryant <mbryant at futurehorizons.com>
wrote:

> Do you have a link to the patent ?  I found an interesting article about
> the feedback counters but it wasn't detailed enough to say exactly how it
> worked.
> ------------------------------
> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Michael
> E Caloroso via Synth-diy <synth-diy at synth-diy.org>
> *Sent:* 04 July 2026 04:45
> *To:* Benjam?n Velasco <guatis at gmail.com>
> *Cc:* SYNTH DIY <synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] GRP Genesi
>
> Yes the VCO in the ProSoloist/DGX is often misunderstood as digital, it is
> actually analog.  The patent explains it much better.  Definitely unique
> and very very stable.
>
> MC
>
>
>
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From mr at analogue.org  Sat Jul  4 23:19:39 2026
From: mr at analogue.org (Mattias Rickardsson)
Date: Sat, 4 Jul 2026 23:19:39 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
Message-ID: <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>

Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <
synth-diy at synth-diy.org> skrev:

> Maybe, it's a stupid thought, but...: could it be that a device relies on
> beeing galvanical separated from other devices. I this case the common
> supply might clash with the devices concept.
>

This reminds me of a somewhat similar issue I had many years ago:

I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck.
(Swedish-sold old Korgs had a big external power transformer to step down
from 220 V AC to 16 V AC, which is then what the instrument then accepts
via a plug with 2 flat prongs that doesn't seem roadworthy with European
electrical standards.)

So I made a short splitter Y cable on the 16 V AC side and attached both
instruments and turned them on. But then I connected an audio cable between
them (or audio cables from both units to the same mixer) and I had a blown
fuse! It was apparently not okay to connect those two grounds together when
running off the same AC supply.

/mr

>
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From neil.johnson71 at gmail.com  Sun Jul  5 11:26:43 2026
From: neil.johnson71 at gmail.com (Neil Johnson)
Date: Sun, 5 Jul 2026 10:26:43 +0100
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
Message-ID: <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>

Michael E Caloroso wrote:

> US 3,930,429
>

Don did a write-up of it here:
https://till.com/articles/arp/patents.html#US03930429
Very weird architecture indeed!

Neil
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From gordonjcp at gjcp.net  Sun Jul  5 15:39:14 2026
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Sun, 5 Jul 2026 14:39:14 +0100
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-9gby+Vk0u_2Zx-=3emGya89mLCws33KC5-nb2OL95zag@mail.gmail.com>
References: <CWLP265MB7132A32EFAA23F11BAAFA0CDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_PFfmu2bnagGbG6bZdyTzaScWMz3_8oQ0RSKK+VdJYhQ@mail.gmail.com>
 <CWLP265MB71325B17A5DE406B11A5CD0EDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-8-Zi1wNniLPo3yO4yCrFMPff+Su=GGk10pdQH43uq7rQ@mail.gmail.com>
 <CWLP265MB7132EDF286AAF3C212DBA0BDDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-_-sZ87+3b3FVPkDWeRnQi3YhnbbNoXPiNm_FNLBtr1VQ@mail.gmail.com>
 <CWLP265MB7132A00C2814F483FF6D5365DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAGn5V-9JHq3QhTy4xuHq2u5iLjfHA3aFUihvwwtOE8Wio=+dJw@mail.gmail.com>
 <CWLP265MB7132E7B93A7BF2A3331B400CDBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
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Message-ID: <20260705133914.GA28814@gjcp.net>

On Sat, Jul 04, 2026 at 05:38:26PM +0200, cheater cheater via Synth-diy wrote:
> oh, i'm not concerned with like national rules or whatever, just
> what's good for audio :)

Your insurance company is, though ;-)

-- 
Gordonjcp


From mbryant at futurehorizons.com  Sun Jul  5 16:01:38 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Sun, 5 Jul 2026 14:01:38 +0000
Subject: [sdiy] GRP Genesi
In-Reply-To: <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
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Message-ID: <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Does it really even need the linear to exp convertor ?  The feedback loop will force it to the correct frequency.  Portamento could just use a different charging function on the capacitor.

________________________________
From: Neil Johnson <neil.johnson71 at gmail.com>
Sent: 05 July 2026 10:26
To: Michael E Caloroso <mec.forumreader at gmail.com>
Cc: Mike Bryant <mbryant at futurehorizons.com>; SYNTH DIY <synth-diy at synth-diy.org>
Subject: Re: [sdiy] GRP Genesi

Michael E Caloroso wrote:
US 3,930,429

Don did a write-up of it here: https://till.com/articles/arp/patents.html#US03930429
Very weird architecture indeed!

Neil
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From mec.forumreader at gmail.com  Sun Jul  5 20:57:09 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Sun, 5 Jul 2026 14:57:09 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAAv6=UBWX=s4c3t9PF2wtDSHgxBb48r_A23D+-F-gu5tv4JROQ@mail.gmail.com>

On the ProSoloist, a ten octave range is required for the VCO charged cap
core, which is not in the feedback loop.  You can't achieve that with a
v/hz architecture.  With a v/hz system, the control voltage doubles for
every octave and you quickly reach the power rail.  Thus the CV for top
pitch is defined just below the power rail (opamps back then were not
rail-to-rail opamps).

There's two problems with a v/hz system.  One, the pitch range is limited.
For a top pitch CV set at 14VDC, a ten octave range would have a descending
CV scale of 14V, 7V, 3.5V, 1.75V, 0.875V, 0.4375V, 0.21875V, 0.109375V, uh
oh.  We have a problem and have only reached eight octaves. The CVs for the
lower pitches descend into the inherent limitation of the opamp - the
microvolt error domain.  The offset error voltages are now a significant
contributor to the pitch CV, causing tuning problems that are impossible to
trim out because the errors drift with temperature.  So a realistic
range for a v/hz system is actually six octaves.

Problem two is modulation CV.  A fixed modulation CV will not produce the
same modulation depth across the entire range of a v/hz system.  If you
scale the gain of the modulation CV with pitch you run into another
problem; as the pitch CV ascends toward maximum pitch CV, the sum of pitch
and modulation CV must not exceed the maximum or you risk opamp latchup or
phase inversion.

That's why v/hz instruments - Moog Taurus I, Taurus III, Minitaur, Sirius,
Korg MS series, etc - have a limited pitch range.

So yes it does need the linear to expo converter for a v/oct system.  The
beauty of the PS VCO is that no tempco resistor is needed, although the
exponential DAC does require a custom resistor array of precision
non-standard values.

MC

On Sun, Jul 5, 2026 at 10:01?AM Mike Bryant <mbryant at futurehorizons.com>
wrote:

> Does it really even need the linear to exp convertor ?  The feedback loop
> will force it to the correct frequency.  Portamento could just use a
> different charging function on the capacitor.
>
> ------------------------------
> *From:* Neil Johnson <neil.johnson71 at gmail.com>
> *Sent:* 05 July 2026 10:26
> *To:* Michael E Caloroso <mec.forumreader at gmail.com>
> *Cc:* Mike Bryant <mbryant at futurehorizons.com>; SYNTH DIY <
> synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] GRP Genesi
>
> Michael E Caloroso wrote:
>
> US 3,930,429
>
>
> Don did a write-up of it here:
> https://till.com/articles/arp/patents.html#US03930429
> Very weird architecture indeed!
>
> Neil
>
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From mec.forumreader at gmail.com  Sun Jul  5 20:58:52 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Sun, 5 Jul 2026 14:58:52 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAAv6=UBnpuEOW52Sr4uPa1RmhtmM+Qzd6vbdh0o==wFD-utWMw@mail.gmail.com>

My error - the VCO charged cap core is inside the feedback loop.

It is indeed a weird architecture - Jeremy Hill was really thinking outside
the box!

MC

On Sun, Jul 5, 2026 at 10:01?AM Mike Bryant <mbryant at futurehorizons.com>
wrote:

> Does it really even need the linear to exp convertor ?  The feedback loop
> will force it to the correct frequency.  Portamento could just use a
> different charging function on the capacitor.
>
> ------------------------------
> *From:* Neil Johnson <neil.johnson71 at gmail.com>
> *Sent:* 05 July 2026 10:26
> *To:* Michael E Caloroso <mec.forumreader at gmail.com>
> *Cc:* Mike Bryant <mbryant at futurehorizons.com>; SYNTH DIY <
> synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] GRP Genesi
>
> Michael E Caloroso wrote:
>
> US 3,930,429
>
>
> Don did a write-up of it here:
> https://till.com/articles/arp/patents.html#US03930429
> Very weird architecture indeed!
>
> Neil
>
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From spridley1 at gmail.com  Mon Jul  6 10:03:07 2026
From: spridley1 at gmail.com (S Ridley)
Date: Mon, 6 Jul 2026 09:03:07 +0100
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UBnpuEOW52Sr4uPa1RmhtmM+Qzd6vbdh0o==wFD-utWMw@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <CWLP265MB71320544D64A5F96310A2180DBF22@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBnpuEOW52Sr4uPa1RmhtmM+Qzd6vbdh0o==wFD-utWMw@mail.gmail.com>
Message-ID: <CAPgGCkJAxpmh-sb0NvuOcj2owxSWcGc5Bx+CTt7Wg9mm_4Uc9A@mail.gmail.com>

Jeremy Hill talks about designing the ARP Pro Soloist on namm org:

https://www.namm.org/library/oral-history/jeremy-hill


Steve


On Sun, 5 Jul 2026 at 20:03, Michael E Caloroso via Synth-diy <
synth-diy at synth-diy.org> wrote:

> My error - the VCO charged cap core is inside the feedback loop.
>
> It is indeed a weird architecture - Jeremy Hill was really thinking
> outside the box!
>
> MC
>
> On Sun, Jul 5, 2026 at 10:01?AM Mike Bryant <mbryant at futurehorizons.com>
> wrote:
>
>> Does it really even need the linear to exp convertor ?  The feedback loop
>> will force it to the correct frequency.  Portamento could just use a
>> different charging function on the capacitor.
>>
>> ------------------------------
>> *From:* Neil Johnson <neil.johnson71 at gmail.com>
>> *Sent:* 05 July 2026 10:26
>> *To:* Michael E Caloroso <mec.forumreader at gmail.com>
>> *Cc:* Mike Bryant <mbryant at futurehorizons.com>; SYNTH DIY <
>> synth-diy at synth-diy.org>
>> *Subject:* Re: [sdiy] GRP Genesi
>>
>> Michael E Caloroso wrote:
>>
>> US 3,930,429
>>
>>
>> Don did a write-up of it here:
>> https://till.com/articles/arp/patents.html#US03930429
>> Very weird architecture indeed!
>>
>> Neil
>>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://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 Jul  6 13:06:14 2026
From: modular at go2.pl (Roman Sowa)
Date: Mon, 6 Jul 2026 13:06:14 +0200
Subject: [sdiy] GRP Genesi
In-Reply-To: <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
Message-ID: <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>

At first glimpse, just looking at block diagram, it looks like typical 
PLL, but instead of phase comparator it uses F-to-V conversion and 
voltage comparator. Same divider ratio is used in the feedback as in the 
vaweform output, so the VCO works only within 1 octave while overall 
output spans over many octaves.

Roman

W dniu 2026-07-05 o?11:26, Neil Johnson via Synth-diy pisze:
> Michael E Caloroso wrote:
> 
>     US 3,930,429
> 
> 
> Don did a write-up of it here: 
> https://till.com/articles/arp/patents.html#US03930429 
> <https://till.com/articles/arp/patents.html#US03930429>
> Very?weird architecture indeed!
> 
> Neil
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

From mbryant at futurehorizons.com  Mon Jul  6 14:01:38 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Mon, 6 Jul 2026 12:01:38 +0000
Subject: [sdiy] GRP Genesi
In-Reply-To: <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
Message-ID: <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Actually one of the cleverest bits is probably converting the down-scaled squarewaves to sawtooths whilst keeping the levels consistent across the whole frequency range.  No mention of how they did they - presumably by programming a constant current source with the key and octave number ?
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Roman Sowa via Synth-diy <synth-diy at synth-diy.org>
Sent: 06 July 2026 12:06
To: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: Re: [sdiy] GRP Genesi

At first glimpse, just looking at block diagram, it looks like typical
PLL, but instead of phase comparator it uses F-to-V conversion and
voltage comparator. Same divider ratio is used in the feedback as in the
vaweform output, so the VCO works only within 1 octave while overall
output spans over many octaves.

Roman

W dniu 2026-07-05 o 11:26, Neil Johnson via Synth-diy pisze:
> Michael E Caloroso wrote:
>
>     US 3,930,429
>
>
> Don did a write-up of it here:
> https://till.com/articles/arp/patents.html#US03930429
> <https://till.com/articles/arp/patents.html#US03930429>
> Very weird architecture indeed!
>
> Neil
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org
View archive at: https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://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  Mon Jul  6 18:05:33 2026
From: ben at stuyts.nl (Ben Stuyts)
Date: Mon, 6 Jul 2026 18:05:33 +0200
Subject: [sdiy] [ADMIN] Read this if you suddenly received a ton of
 synth-diy messages
Message-ID: <03DC10E5-E80D-400E-8A2C-0F1A226C7666@stuyts.nl>

Hi,

There are a few accounts which have just received a metric ton of synth-diy messages.

If this was you, they were back-logged because our mail server refused to negotiate a secure connection with your mail server.

- Our mail server now refuses to connect to servers with outdated TLS negotiation. Only supports STARTTLS.
- Or your server only supports legacy sigalg (typically SHA-1 or another obsolete algorithm).

I have now added exceptions for these domains, so they do not use any TLS at all.

All hail the server OS upgrades.

Ben



From tmowbray at ihug.com.au  Mon Jul  6 22:02:48 2026
From: tmowbray at ihug.com.au (Tony Mowbray)
Date: Tue, 7 Jul 2026 06:02:48 +1000
Subject: [sdiy] [ADMIN] Read this if you suddenly received a ton of
 synth-diy messages
In-Reply-To: <03DC10E5-E80D-400E-8A2C-0F1A226C7666@stuyts.nl>
References: <03DC10E5-E80D-400E-8A2C-0F1A226C7666@stuyts.nl>
Message-ID: <023601dd0d82$6e14f640$4a3ee2c0$@ihug.com.au>

Indeed, all hail server upgrades...



Kind Regards

Tony Mowbray

-----Original Message-----
From: Synth-diy <synth-diy-bounces at synth-diy.org> On Behalf Of Ben Stuyts
via Synth-diy
Sent: Tuesday, 7 July 2026 2:06 AM
To: SDIY List <synth-diy at synth-diy.org>
Subject: [sdiy] [ADMIN] Read this if you suddenly received a ton of
synth-diy messages

Hi,

There are a few accounts which have just received a metric ton of synth-diy
messages.

If this was you, they were back-logged because our mail server refused to
negotiate a secure connection with your mail server.

- Our mail server now refuses to connect to servers with outdated TLS
negotiation. Only supports STARTTLS.
- Or your server only supports legacy sigalg (typically SHA-1 or another
obsolete algorithm).

I have now added exceptions for these domains, so they do not use any TLS at
all.

All hail the server OS upgrades.

Ben


________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org View archive at:
https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org


From tom at electricdruid.net  Tue Jul  7 00:25:30 2026
From: tom at electricdruid.net (Tom Wiltshire)
Date: Mon, 6 Jul 2026 23:25:30 +0100
Subject: [sdiy] GRP Genesi
In-Reply-To: <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>

Isn't it just the typical adding-up-a-load-of-octave-squarewaves to make a staircase "ramp" waveform? 6 bits in this case, iirc.

Ah, yes, here it is, from the service manual:



> On 6 Jul 2026, at 13:01, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> Actually one of the cleverest bits is probably converting the down-scaled squarewaves to sawtooths whilst keeping the levels consistent across the whole frequency range.  No mention of how they did they - presumably by programming a constant current source with the key and octave number ?
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Roman Sowa via Synth-diy <synth-diy at synth-diy.org>
> Sent: 06 July 2026 12:06
> To: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] GRP Genesi
>  
> At first glimpse, just looking at block diagram, it looks like typical 
> PLL, but instead of phase comparator it uses F-to-V conversion and 
> voltage comparator. Same divider ratio is used in the feedback as in the 
> vaweform output, so the VCO works only within 1 octave while overall 
> output spans over many octaves.
> 
> Roman
> 
> W dniu 2026-07-05 o 11:26, Neil Johnson via Synth-diy pisze:
> > Michael E Caloroso wrote:
> > 
> >     US 3,930,429
> > 
> > 
> > Don did a write-up of it here: 
> > https://till.com/articles/arp/patents.html#US03930429 <https://till.com/articles/arp/patents.html#US03930429> 
> > <https://till.com/articles/arp/patents.html#US03930429 <https://till.com/articles/arp/patents.html#US03930429>>
> > Very weird architecture indeed!
> > 
> > Neil
> > 
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://synth-diy.org/mailman/listinfo/synth-diy>
> > Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://synth-diy.org/mailman/listinfo/synth-diy>
> Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
> View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://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 tom at electricdruid.net  Tue Jul  7 01:16:22 2026
From: tom at electricdruid.net (Tom Wiltshire)
Date: Tue, 7 Jul 2026 00:16:22 +0100
Subject: [sdiy] GRP Genesi
In-Reply-To: <CWLP265MB7132D4C8CAC706998A2AB773DBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CWLP265MB7132D4C8CAC706998A2AB773DBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <A2EB3A92-92F3-44FD-A0D3-31F8F5F1DA72@electricdruid.net>

Missing the 64th, 128th, 192nd, 256th harmonic (etc) but otherwise identical. The 64th harmonic is -36dB down so it's probably audible but hardly a big deal. In my view, it's close enough for synthesis - this is raw material, not a pure test signal. Is it rich and does it provide plenty to work with? Yep!
The Roland Alpha Juno "DCO" chip (NCO really) does the same thing, but manages to produce an 8-bit staircase, which reduces the errors even further. No-one ever complained the "Hoover" synth wasn't producing a rich enough waveform!


> On 6 Jul 2026, at 23:27, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> Ah right.  Not really a proper sawtooth then.  Thanks
> 
> From: Tom Wiltshire <tom at electricdruid.net>
> Sent: 06 July 2026 23:25
> To: Mike Bryant <mbryant at futurehorizons.com>
> Cc: synth-diy at synth-diy.org <synth-diy at synth-diy.org>; Roman Sowa <modular at go2.pl>
> Subject: Re: [sdiy] GRP Genesi
>  
> Isn't it just the typical adding-up-a-load-of-octave-squarewaves to make a staircase "ramp" waveform? 6 bits in this case, iirc.
> 
> Ah, yes, here it is, from the service manual:
> 
> <PastedGraphic-8.png>
> 
>> On 6 Jul 2026, at 13:01, Mike Bryant <mbryant at futurehorizons.com <mailto:mbryant at futurehorizons.com>> wrote:
>> 
>> Actually one of the cleverest bits is probably converting the down-scaled squarewaves to sawtooths whilst keeping the levels consistent across the whole frequency range.  No mention of how they did they - presumably by programming a constant current source with the key and octave number ?
>>   
>> From: Synth-diy <synth-diy-bounces at synth-diy.org <mailto:synth-diy-bounces at synth-diy.org>> on behalf of Roman Sowa via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
>> Sent: 06 July 2026 12:06
>> To: synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org> <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
>> Subject: Re: [sdiy] GRP Genesi
>>  
>> At first glimpse, just looking at block diagram, it looks like typical 
>> PLL, but instead of phase comparator it uses F-to-V conversion and 
>> voltage comparator. Same divider ratio is used in the feedback as in the 
>> vaweform output, so the VCO works only within 1 octave while overall 
>> output spans over many octaves.
>> 
>> Roman
>> 
>> W dniu 2026-07-05 o 11:26, Neil Johnson via Synth-diy pisze:
>> > Michael E Caloroso wrote:
>> > 
>> >     US 3,930,429
>> > 
>> > 
>> > Don did a write-up of it here: 
>> > https://till.com/articles/arp/patents.html#US03930429 <https://till.com/articles/arp/patents.html#US03930429> 
>> > <https://till.com/articles/arp/patents.html#US03930429 <https://till.com/articles/arp/patents.html#US03930429>>
>> > Very weird architecture indeed!
>> > 
>> > Neil
>> > 
>> > ________________________________________________________
>> > This is the Synth-diy mailing list
>> > Submit email to: Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> > View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
>> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://synth-diy.org/mailman/listinfo/synth-diy>
>> > Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://synth-diy.org/mailman/listinfo/synth-diy>
>> Selling or trading? Use marketplace at synth-diy.org <mailto:marketplace at synth-diy.org>
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org <mailto:Synth-diy at synth-diy.org>
>> View archive at: https://synth-diy.org/pipermail/synth-diy/ <https://synth-diy.org/pipermail/synth-diy/>
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy <https://synth-diy.org/mailman/listinfo/synth-diy>
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From mec.forumreader at gmail.com  Tue Jul  7 02:25:51 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Mon, 6 Jul 2026 20:25:51 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
Message-ID: <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>

"...the first read only memories ...64 bits"

The ProSoloist used the 7488 OTP PROM - made by TI - for instant patch
changes.  The 7488 had a capacity of 256 bits (not KB or MB!) in an 8x32
matrix - each PROM had 8 control lines for the 30 ProSoloist/ProDGX presets
(two addresses were unused "off"), and there were eight of these PROMs in
the PS.  Access time was a snappy 26ns (compared to 2-300 millisecond
access of later 27xxx EPROMs).  Jeremy exploited the open collector output
feature of those PROMs to enable or disable ProSoloist circuits by shorting
control lines to ground through the PROM output when the OC output was a
logic '1'.

I don't think any programmer had a profile for those old PROMs.  They
last appeared in a 1977 databook, yet ARP kept using them to make Pro/DGXs
into 1981...!

That novel feature was covered in the patent.  Other competitors - Moog,
Roland, Yamaha, etc - had their preset synths but none lasted as long as
the PS, and I don't think any of them could use PROMs for preset control
without infringing the patent.  I know that the Moog Satellite used a
matrix of fixed resistors for preset configuration, which ARP had abandoned
with the unreliable Soloist.

Woe for the 1970s repair tech who had to fix a malfunctioning ProSoloist
VCO... few if any understood what made it tick.  I asked a tech from those
days if he had fixed ARPs - "Woah... Evil..." (sign of the cross) :D

MC

On Mon, Jul 6, 2026 at 6:35?PM Tom Wiltshire <tom at electricdruid.net> wrote:

> Isn't it just the typical adding-up-a-load-of-octave-squarewaves to make a
> staircase "ramp" waveform? 6 bits in this case, iirc.
>
> Ah, yes, here it is, from the service manual:
>
>
>
> On 6 Jul 2026, at 13:01, Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> Actually one of the cleverest bits is probably converting the down-scaled
> squarewaves to sawtooths whilst keeping the levels consistent across the
> whole frequency range.  No mention of how they did they - presumably by
> programming a constant current source with the key and octave number ?
> ------------------------------
> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Roman
> Sowa via Synth-diy <synth-diy at synth-diy.org>
> *Sent:* 06 July 2026 12:06
> *To:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] GRP Genesi
>
> At first glimpse, just looking at block diagram, it looks like typical
> PLL, but instead of phase comparator it uses F-to-V conversion and
> voltage comparator. Same divider ratio is used in the feedback as in the
> vaweform output, so the VCO works only within 1 octave while overall
> output spans over many octaves.
>
> Roman
>
> W dniu 2026-07-05 o 11:26, Neil Johnson via Synth-diy pisze:
> > Michael E Caloroso wrote:
> >
> >     US 3,930,429
> >
> >
> > Don did a write-up of it here:
> > https://till.com/articles/arp/patents.html#US03930429
> > <https://till.com/articles/arp/patents.html#US03930429>
> > Very weird architecture indeed!
> >
> > Neil
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://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  Tue Jul  7 04:53:02 2026
From: synthdiy at adambaby.com (Adam (synthDIY))
Date: Tue, 7 Jul 2026 12:53:02 +1000
Subject: [sdiy] GRP Genesi
In-Reply-To: <A2EB3A92-92F3-44FD-A0D3-31F8F5F1DA72@electricdruid.net>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CWLP265MB7132D4C8CAC706998A2AB773DBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <A2EB3A92-92F3-44FD-A0D3-31F8F5F1DA72@electricdruid.net>
Message-ID: <C9EB0BAA-8BA3-4761-AAA2-DC005A0DC1D1@adambaby.com>



> On 7 Jul 2026, at 09:16, Tom Wiltshire <tom at electricdruid.net> wrote:
> 
> No-one ever complained the "Hoover" synth wasn't producing a rich enough waveform!


LOL!!

The Roland SH-2000 is another preset synth with stair-step waveforms. Rich waveforms for that great filter to chew on.

A
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From don at till.com  Tue Jul  7 05:24:36 2026
From: don at till.com (Donald Tillman)
Date: Mon, 6 Jul 2026 20:24:36 -0700
Subject: [sdiy] GRP Genesi
In-Reply-To: <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
Message-ID: <DC7A91DF-5F23-4E0C-BADB-8A3AA9B37E29@till.com>

On Jul 5, 2026, at 2:26?AM, Neil Johnson via Synth-diy <synth-diy at synth-diy.org> wrote:

> Michael E Caloroso wrote:
> US 3,930,429
> 
> Don did a write-up of it here: https://till.com/articles/arp/patents.html#US03930429
> Very weird architecture indeed!

Hiya,

My memory is telling me that there may be significant differences between the patent and the actual product.  (I'm not in the mood to check at the moment; there's a lot to go through there.)


  -- Don
--
Donald Tillman, Palo Alto, California
https://till.com

From don at till.com  Tue Jul  7 05:33:55 2026
From: don at till.com (Donald Tillman)
Date: Mon, 6 Jul 2026 20:33:55 -0700
Subject: [sdiy] GRP Genesi
In-Reply-To: <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
Message-ID: <C7B42582-9AED-493B-9014-6D803C96E166@till.com>

Yeah, building a sawtooth wave by summing the square waves from the higher divide-down octaves was standard practice for many electronic organs back in the day.  The Schober organs for sure.  

There are fewer octaves to sum on the higher notes, sure, but that's okay.

  -- Don
--
Donald Tillman, Palo Alto, California
https://till.com

> On Jul 6, 2026, at 3:25?PM, Tom Wiltshire <tom at electricdruid.net> wrote:
> 
> Isn't it just the typical adding-up-a-load-of-octave-squarewaves to make a staircase "ramp" waveform? 6 bits in this case, iirc.
> 
> Ah, yes, here it is, from the service manual:
> 
> 
>> On 6 Jul 2026, at 13:01, Mike Bryant <mbryant at futurehorizons.com> wrote:
>> 
>> Actually one of the cleverest bits is probably converting the down-scaled squarewaves to sawtooths whilst keeping the levels consistent across the whole frequency range.


From don at till.com  Tue Jul  7 05:36:58 2026
From: don at till.com (Donald Tillman)
Date: Mon, 6 Jul 2026 20:36:58 -0700
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
Message-ID: <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>

On Jul 6, 2026, at 5:25?PM, Michael E Caloroso via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> 
> 
> Other competitors - Moog, Roland, Yamaha, etc - had their preset synths but none lasted as long as the PS [...]

Nobody else had the Tony Banks solo from Genesis' "Cinema Show".

  -- Don
--
Donald Tillman, Palo Alto, California
https://till.com



From cheater00social at gmail.com  Tue Jul  7 06:39:58 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 7 Jul 2026 06:39:58 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
Message-ID: <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>

Don't you think this may have had something to do with you
distributing AC power, rather than DC with 0V potential?

On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>
> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>
>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>
>
> This reminds me of a somewhat similar issue I had many years ago:
>
> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>
> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>
> /mr
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From oleavitt at proton.me  Tue Jul  7 07:14:28 2026
From: oleavitt at proton.me (Oren Leavitt)
Date: Tue, 07 Jul 2026 05:14:28 +0000
Subject: [sdiy] [ADMIN] Read this if you suddenly received a ton of
 synth-diy messages
In-Reply-To: <03DC10E5-E80D-400E-8A2C-0F1A226C7666@stuyts.nl>
References: <03DC10E5-E80D-400E-8A2C-0F1A226C7666@stuyts.nl>
Message-ID: <e402ea6b-6908-4922-a904-f31efb0f4620@proton.me>

Should be good for another 30 years!

Thanks for keeping Synth-diy going!

On 7/6/26 11:05 AM, Ben Stuyts via Synth-diy wrote:
> Hi,
> 
> There are a few accounts which have just received a metric ton of synth-diy messages.
> 
> If this was you, they were back-logged because our mail server refused to negotiate a secure connection with your mail server.
> 
> - Our mail server now refuses to connect to servers with outdated TLS negotiation. Only supports STARTTLS.
> - Or your server only supports legacy sigalg (typically SHA-1 or another obsolete algorithm).
> 
> I have now added exceptions for these domains, so they do not use any TLS at all.
> 
> All hail the server OS upgrades.
> 
> Ben
> 
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org




From neil.johnson71 at gmail.com  Thu Jul  9 10:01:57 2026
From: neil.johnson71 at gmail.com (Neil Johnson)
Date: Thu, 9 Jul 2026 09:01:57 +0100
Subject: [sdiy] Microchip compilers now all free
Message-ID: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>

Hi all,

I see Microchip has finally made all of their compilers completely free:

https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers

Hopefully a good sign, rather than a bad one....

Neil
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From cheater00social at gmail.com  Thu Jul  9 10:15:15 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 10:15:15 +0200
Subject: [sdiy] 7815 / 7915, "vintage sound", and modern replacements
Message-ID: <CAGn5V-_HYonm5p8DB0QyWxDJN9B8+XbNnSVLjq2-gVHyPPB8yQ@mail.gmail.com>

(this email seems to have been eaten by gmail... so I have to type it
all out from memory)



INTRO / BACKGROUND

Hi all,

I'm looking further into my project to modify rack devices to run on
DC rather than AC. Looks like most of them use a 7815/7915 combo with
a full-wave rectifier. Pretty much like the first circuit here:

https://www.eleccircuit.com/power-supply-regulator-15v-15v-1a-by-ic-7815-7915/



So the idea is to put a 4P2T switch (V, -V, phantom, 0V) or some
jumpers, right after the rectifier but before the regulators, in order
to either power the regulators from the internal power supply, or from
the remote DC supply. I would feed DC in, and let the rack unit do its
final volt or so regulation itself, to prevent sag and voltage rail
based crosstalk from other rack devices (10-20 units) that live on the
same DC distribution bus.

It seems like most of those racks are below the 10W mark, meaning at
30V, we're talking about less than 0.5A being delivered by the
regulators total.



VOLTAGE REGULATOR QUESTIONS

I've had a couple questions:

1. What is the best DC voltage to run to the 7815 / 7915 so they
create the least dissipation, have the best regulation, and produce
the least noise?

2. Are there any better modern replacement linear regulators for
audio? (I'm assuming linear regulators are still what's recommended)
Something with considerably better noise and regulation performance,
no more than say $5 a pop, though that's not a fixed price. I'll be
happy with something that's cents too if that's the go-to part. I
don't need an exact pin for pin replacement, but being able to use
something that doesn't require a massive amount of modification to the
existing circuit would be nice. Although I might just bypass the
existing internal power supplies completely, and build new ones, so
feel free to suggest anything. Noise performance and ripple rejection
are the most important thing here. I'm specifically not looking for
any sort of "vintage sound".


I would appreciate any info on the questions above. Thanks.



P.S. "VINTAGE" SOUND

I've also noticed something interesting when looking at 7815
datasheets. Specifically the output impedance, which I found plotted
in an older datasheet, on page 6 in the top left corner here:

https://www.alldatasheet.com/datasheet-pdf/view/9046/NSC/7815.html

The output impedance goes from 0.008 Ohm at 1 kHz to 0.03-0.04 Ohm at
20 kHz, even if bypassed with 1uF tantalum caps as the plot indicates.

It's common to find that older synths sound darker and modern ones
sound very bright (meaning older synths have lowered high frequency
reproduction). I wonder if between this nature of the most popular
linear regulators, and caps that were never good enough to bypass
those frequencies when they were new (let alone after decades), that
could explain some of that. Simply power supply sag in the higher
registers, creating a compounding loss of gain. What do you guys
think? I assume earlier voltage regulators were even worse than that
plot.

From cheater00social at gmail.com  Thu Jul  9 10:18:23 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 10:18:23 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
Message-ID: <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>

One way to have DC input, but retain the capability of using the
internal power supply, is to have a 4P2T switch for configuration.

It seems that 4P2T switches are super expensive, especially if they're
supposed to withstand, say, 1A.

So I started looking around. TLDR: classic pcie 8-pin power connectors
are probably the best, and also the cheapest.

My first thought was to look at PCIE x1 slots. The cheapest advanced
connector on earth, for 0.4 Euro at unit price, you get a connector
that handles 1.1A per pin as per eg this document, page 6, 4.4

https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf

> 4.4 CONTACT CURRENT RATING
> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.

The connector has 36 pins, so while I don't think it would handle 36A,
I'm sure it would handle something like 2A, especially if you share
pins. You can even leave pins empty to prevent shorts during
insertion.

You could put the connector out the back, and either insert a plug-in
"card" (really just a small edge connector with wires soldered on)
that provides DC, or a pass-through "card" that shorts some pins
together to carry power from the internal power supply. And now
instead of $20-30 per unit, this costs $1 per unit. My main question
is how I would fix the connector, but maybe a simple screw hole in the
connector that mates with a threaded hole in the case could do the
trick.

A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
rack unit, which is 45mm, so it doesn't take up much space either.

The cheapest one that can be found at Mouser currently and can be
bought in low volumes is roughly 0.4 Euro.

https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D

Qty.  Unit Price  Ext. Price
1     ? 0,439     ? 0,44
10    ? 0,372     ? 3,72
25    ? 0,332     ? 8,30
100   ? 0,316     ? 31,60

By making the connector require a dummy plug to connect the internal
power supply into the circuit, it makes it impossible to connect both
DC power and mains AC, so that makes the design intrinsically safe
without using switches.

Alternatively to a PCIE connector I could use some panel mount plug
with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
power from the internal power supply, and similarly use a shorting
plug to use the internal power supply.

Circular DIN connectors start at about 8 Euro per pair of socket and plug.
Circular metric aren't better.
MIL Spec connectors seem to be cheaper. But the mouser search sucks,
so I can't find them by number of pins.

PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
They're latching (no need for screws and stuff). There doesn't seem to
be a panel mount version, but one could mount a through-hole connector
to a pcb, and have the pcb have screw holes for mounting to the rear
panel. They handle high power - 150W meaning 3A per pin (half the pins
are return pins). Seems like a winner to me. They're also tiny so they
will easily fit in the back of a 1U unit even vertically. The biggest
pain here might be making the rectangular hole and having it look any
good. might be a case for custom die, maybe a small steel job that
uses two bolts to screw together the two cutting parts through the
sheet metal.

"Pin and socket" connectors are the same kind of thing, just not
specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
useful alternative if more than 4 rails are necessary.

D-sub connectors carry up to 3A... and are very cheap and can do panel
mount of some sort. But I'll be damned if I use one of those cursed
things for power.

Automotive connectors seem inexpensive too, but I haven't really
looked into them much other than a quick parametric search.

I wonder what everyone thinks of this.

On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
<cheater00social at gmail.com> wrote:
>
> Don't you think this may have had something to do with you
> distributing AC power, rather than DC with 0V potential?
>
> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >
> > Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>
> >> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >
> >
> > This reminds me of a somewhat similar issue I had many years ago:
> >
> > I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >
> > So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >
> > /mr
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Thu Jul  9 10:18:46 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 10:18:46 +0200
Subject: [sdiy] Microchip compilers now all free
In-Reply-To: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
References: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
Message-ID: <CAGn5V-87Phw+uPwr1PVvenG=M2D64UXkqg-Nwg7jmZe2n2F1-Q@mail.gmail.com>

Free as in freedom?

On Thu, Jul 9, 2026 at 10:17?AM Neil Johnson via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Hi all,
>
> I see Microchip has finally made all of their compilers completely free:
>
> https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers
>
> Hopefully a good sign, rather than a bad one....
>
> Neil
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From synthdiy at adambaby.com  Thu Jul  9 10:30:30 2026
From: synthdiy at adambaby.com (Adam (synthDIY))
Date: Thu, 9 Jul 2026 18:30:30 +1000
Subject: [sdiy] Microchip compilers now all free
In-Reply-To: <CAGn5V-87Phw+uPwr1PVvenG=M2D64UXkqg-Nwg7jmZe2n2F1-Q@mail.gmail.com>
References: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
 <CAGn5V-87Phw+uPwr1PVvenG=M2D64UXkqg-Nwg7jmZe2n2F1-Q@mail.gmail.com>
Message-ID: <4BF11EF6-9857-42E5-9DB8-23286B18EC41@adambaby.com>

Free.. as in beer.

> On 9 Jul 2026, at 18:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Free as in freedom?
> 
> On Thu, Jul 9, 2026 at 10:17?AM Neil Johnson via Synth-diy
> <synth-diy at synth-diy.org> wrote:
>> 
>> Hi all,
>> 
>> I see Microchip has finally made all of their compilers completely free:
>> 
>> https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers
>> 
>> Hopefully a good sign, rather than a bad one....
>> 
>> Neil
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org



From neil.johnson71 at gmail.com  Thu Jul  9 10:33:29 2026
From: neil.johnson71 at gmail.com (Neil Johnson)
Date: Thu, 9 Jul 2026 09:33:29 +0100
Subject: [sdiy] Microchip compilers now all free
In-Reply-To: <4BF11EF6-9857-42E5-9DB8-23286B18EC41@adambaby.com>
References: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
 <CAGn5V-87Phw+uPwr1PVvenG=M2D64UXkqg-Nwg7jmZe2n2F1-Q@mail.gmail.com>
 <4BF11EF6-9857-42E5-9DB8-23286B18EC41@adambaby.com>
Message-ID: <CACZGMxKhY=AtgA3neUYtEFZu+W6JZCmjADhhUu9+MF_kLduNrw@mail.gmail.com>

For the 8-bitters there is already AVR-GCC, and for the ARM 32-bitters
there's ARM-GCC.  It's only really the 16-bit dsPICs that don't have a
clean GCC toolchain.

On Thu, 9 Jul 2026 at 09:30, Adam (synthDIY) <synthdiy at adambaby.com> wrote:

> Free.. as in beer.
>
> > On 9 Jul 2026, at 18:18, cheater cheater via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >
> > Free as in freedom?
> >
> > On Thu, Jul 9, 2026 at 10:17?AM Neil Johnson via Synth-diy
> > <synth-diy at synth-diy.org> wrote:
> >>
> >> Hi all,
> >>
> >> I see Microchip has finally made all of their compilers completely free:
> >>
> >>
> https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers
> >>
> >> Hopefully a good sign, rather than a bad one....
> >>
> >> Neil
> >> ________________________________________________________
> >> This is the Synth-diy mailing list
> >> Submit email to: Synth-diy at synth-diy.org
> >> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >> Check your settings at:
> https://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://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  Thu Jul  9 13:40:46 2026
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu, 9 Jul 2026 13:40:46 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
Message-ID: <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>

Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.

Ben

> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> One way to have DC input, but retain the capability of using the
> internal power supply, is to have a 4P2T switch for configuration.
> 
> It seems that 4P2T switches are super expensive, especially if they're
> supposed to withstand, say, 1A.
> 
> So I started looking around. TLDR: classic pcie 8-pin power connectors
> are probably the best, and also the cheapest.
> 
> My first thought was to look at PCIE x1 slots. The cheapest advanced
> connector on earth, for 0.4 Euro at unit price, you get a connector
> that handles 1.1A per pin as per eg this document, page 6, 4.4
> 
> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> 
>> 4.4 CONTACT CURRENT RATING
>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> 
> The connector has 36 pins, so while I don't think it would handle 36A,
> I'm sure it would handle something like 2A, especially if you share
> pins. You can even leave pins empty to prevent shorts during
> insertion.
> 
> You could put the connector out the back, and either insert a plug-in
> "card" (really just a small edge connector with wires soldered on)
> that provides DC, or a pass-through "card" that shorts some pins
> together to carry power from the internal power supply. And now
> instead of $20-30 per unit, this costs $1 per unit. My main question
> is how I would fix the connector, but maybe a simple screw hole in the
> connector that mates with a threaded hole in the case could do the
> trick.
> 
> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> rack unit, which is 45mm, so it doesn't take up much space either.
> 
> The cheapest one that can be found at Mouser currently and can be
> bought in low volumes is roughly 0.4 Euro.
> 
> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> 
> Qty.  Unit Price  Ext. Price
> 1     ? 0,439     ? 0,44
> 10    ? 0,372     ? 3,72
> 25    ? 0,332     ? 8,30
> 100   ? 0,316     ? 31,60
> 
> By making the connector require a dummy plug to connect the internal
> power supply into the circuit, it makes it impossible to connect both
> DC power and mains AC, so that makes the design intrinsically safe
> without using switches.
> 
> Alternatively to a PCIE connector I could use some panel mount plug
> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> power from the internal power supply, and similarly use a shorting
> plug to use the internal power supply.
> 
> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> Circular metric aren't better.
> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> so I can't find them by number of pins.
> 
> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> They're latching (no need for screws and stuff). There doesn't seem to
> be a panel mount version, but one could mount a through-hole connector
> to a pcb, and have the pcb have screw holes for mounting to the rear
> panel. They handle high power - 150W meaning 3A per pin (half the pins
> are return pins). Seems like a winner to me. They're also tiny so they
> will easily fit in the back of a 1U unit even vertically. The biggest
> pain here might be making the rectangular hole and having it look any
> good. might be a case for custom die, maybe a small steel job that
> uses two bolts to screw together the two cutting parts through the
> sheet metal.
> 
> "Pin and socket" connectors are the same kind of thing, just not
> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> useful alternative if more than 4 rails are necessary.
> 
> D-sub connectors carry up to 3A... and are very cheap and can do panel
> mount of some sort. But I'll be damned if I use one of those cursed
> things for power.
> 
> Automotive connectors seem inexpensive too, but I haven't really
> looked into them much other than a quick parametric search.
> 
> I wonder what everyone thinks of this.
> 
> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> <cheater00social at gmail.com> wrote:
>> 
>> Don't you think this may have had something to do with you
>> distributing AC power, rather than DC with 0V potential?
>> 
>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>> 
>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>> 
>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>> 
>>> 
>>> This reminds me of a somewhat similar issue I had many years ago:
>>> 
>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>> 
>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>> 
>>> /mr
>>> 
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
> 



From spridley1 at gmail.com  Thu Jul  9 14:03:18 2026
From: spridley1 at gmail.com (S Ridley)
Date: Thu, 9 Jul 2026 13:03:18 +0100
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
Message-ID: <CAPgGCkK+P2iMkTbE_Njpp6XBv9BnmfK3CkVrpApuQWmXAMqtPQ@mail.gmail.com>

Molex Mini-Fit Jr?



On Thu, 9 Jul 2026 at 12:43, Ben Stuyts via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Perhaps a 4 or 5 pin XLR connector is an option? They are not that
> expensive, and lots of ready-made cables are available.
>
> Ben
>
> > On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >
> > One way to have DC input, but retain the capability of using the
> > internal power supply, is to have a 4P2T switch for configuration.
> >
> > It seems that 4P2T switches are super expensive, especially if they're
> > supposed to withstand, say, 1A.
> >
> > So I started looking around. TLDR: classic pcie 8-pin power connectors
> > are probably the best, and also the cheapest.
> >
> > My first thought was to look at PCIE x1 slots. The cheapest advanced
> > connector on earth, for 0.4 Euro at unit price, you get a connector
> > that handles 1.1A per pin as per eg this document, page 6, 4.4
> >
> >
> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >
> >> 4.4 CONTACT CURRENT RATING
> >> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express
> Connector High Speed Electrical Test Procedure. The temperature rise shall
> not exceed 30 degree C. Ambient condition is still air at 25?C.
> >
> > The connector has 36 pins, so while I don't think it would handle 36A,
> > I'm sure it would handle something like 2A, especially if you share
> > pins. You can even leave pins empty to prevent shorts during
> > insertion.
> >
> > You could put the connector out the back, and either insert a plug-in
> > "card" (really just a small edge connector with wires soldered on)
> > that provides DC, or a pass-through "card" that shorts some pins
> > together to carry power from the internal power supply. And now
> > instead of $20-30 per unit, this costs $1 per unit. My main question
> > is how I would fix the connector, but maybe a simple screw hole in the
> > connector that mates with a threaded hole in the case could do the
> > trick.
> >
> > A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > rack unit, which is 45mm, so it doesn't take up much space either.
> >
> > The cheapest one that can be found at Mouser currently and can be
> > bought in low volumes is roughly 0.4 Euro.
> >
> >
> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >
> > Qty.  Unit Price  Ext. Price
> > 1     ? 0,439     ? 0,44
> > 10    ? 0,372     ? 3,72
> > 25    ? 0,332     ? 8,30
> > 100   ? 0,316     ? 31,60
> >
> > By making the connector require a dummy plug to connect the internal
> > power supply into the circuit, it makes it impossible to connect both
> > DC power and mains AC, so that makes the design intrinsically safe
> > without using switches.
> >
> > Alternatively to a PCIE connector I could use some panel mount plug
> > with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > power from the internal power supply, and similarly use a shorting
> > plug to use the internal power supply.
> >
> > Circular DIN connectors start at about 8 Euro per pair of socket and
> plug.
> > Circular metric aren't better.
> > MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > so I can't find them by number of pins.
> >
> > PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > They're latching (no need for screws and stuff). There doesn't seem to
> > be a panel mount version, but one could mount a through-hole connector
> > to a pcb, and have the pcb have screw holes for mounting to the rear
> > panel. They handle high power - 150W meaning 3A per pin (half the pins
> > are return pins). Seems like a winner to me. They're also tiny so they
> > will easily fit in the back of a 1U unit even vertically. The biggest
> > pain here might be making the rectangular hole and having it look any
> > good. might be a case for custom die, maybe a small steel job that
> > uses two bolts to screw together the two cutting parts through the
> > sheet metal.
> >
> > "Pin and socket" connectors are the same kind of thing, just not
> > specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > useful alternative if more than 4 rails are necessary.
> >
> > D-sub connectors carry up to 3A... and are very cheap and can do panel
> > mount of some sort. But I'll be damned if I use one of those cursed
> > things for power.
> >
> > Automotive connectors seem inexpensive too, but I haven't really
> > looked into them much other than a quick parametric search.
> >
> > I wonder what everyone thinks of this.
> >
> > On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > <cheater00social at gmail.com> wrote:
> >>
> >> Don't you think this may have had something to do with you
> >> distributing AC power, rather than DC with 0V potential?
> >>
> >> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org>
> wrote:
> >>>
> >>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <
> synth-diy at synth-diy.org> skrev:
> >>>>
> >>>> Maybe, it's a stupid thought, but...: could it be that a device
> relies on beeing galvanical separated from other devices. I this case the
> common supply might clash with the devices concept.
> >>>
> >>>
> >>> This reminds me of a somewhat similar issue I had many years ago:
> >>>
> >>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power
> puck. (Swedish-sold old Korgs had a big external power transformer to step
> down from 220 V AC to 16 V AC, which is then what the instrument then
> accepts via a plug with 2 flat prongs that doesn't seem roadworthy with
> European electrical standards.)
> >>>
> >>> So I made a short splitter Y cable on the 16 V AC side and attached
> both instruments and turned them on. But then I connected an audio cable
> between them (or audio cables from both units to the same mixer) and I had
> a blown fuse! It was apparently not okay to connect those two grounds
> together when running off the same AC supply.
> >>>
> >>> /mr
> >>>
> >>> ________________________________________________________
> >>> This is the Synth-diy mailing list
> >>> Submit email to: Synth-diy at synth-diy.org
> >>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>> Check your settings at:
> https://synth-diy.org/mailman/listinfo/synth-diy
> >>> Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://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 Jul  9 15:02:07 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Thu, 9 Jul 2026 13:02:07 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
Message-ID: <CWLP265MB71320362D18697E50597757ADBFE2@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

The 6 pin XLR is the standard for +/- power transmission.  See last entry on :

https://www.clarkwire.com/pinouts/xlr-audio-pinouts

________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
Sent: 09 July 2026 12:40
To: cheater cheater <cheater00social at gmail.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.

Ben

> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>
> One way to have DC input, but retain the capability of using the
> internal power supply, is to have a 4P2T switch for configuration.
>
> It seems that 4P2T switches are super expensive, especially if they're
> supposed to withstand, say, 1A.
>
> So I started looking around. TLDR: classic pcie 8-pin power connectors
> are probably the best, and also the cheapest.
>
> My first thought was to look at PCIE x1 slots. The cheapest advanced
> connector on earth, for 0.4 Euro at unit price, you get a connector
> that handles 1.1A per pin as per eg this document, page 6, 4.4
>
> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>
>> 4.4 CONTACT CURRENT RATING
>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>
> The connector has 36 pins, so while I don't think it would handle 36A,
> I'm sure it would handle something like 2A, especially if you share
> pins. You can even leave pins empty to prevent shorts during
> insertion.
>
> You could put the connector out the back, and either insert a plug-in
> "card" (really just a small edge connector with wires soldered on)
> that provides DC, or a pass-through "card" that shorts some pins
> together to carry power from the internal power supply. And now
> instead of $20-30 per unit, this costs $1 per unit. My main question
> is how I would fix the connector, but maybe a simple screw hole in the
> connector that mates with a threaded hole in the case could do the
> trick.
>
> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> rack unit, which is 45mm, so it doesn't take up much space either.
>
> The cheapest one that can be found at Mouser currently and can be
> bought in low volumes is roughly 0.4 Euro.
>
> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>
> Qty.  Unit Price  Ext. Price
> 1     ? 0,439     ? 0,44
> 10    ? 0,372     ? 3,72
> 25    ? 0,332     ? 8,30
> 100   ? 0,316     ? 31,60
>
> By making the connector require a dummy plug to connect the internal
> power supply into the circuit, it makes it impossible to connect both
> DC power and mains AC, so that makes the design intrinsically safe
> without using switches.
>
> Alternatively to a PCIE connector I could use some panel mount plug
> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> power from the internal power supply, and similarly use a shorting
> plug to use the internal power supply.
>
> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> Circular metric aren't better.
> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> so I can't find them by number of pins.
>
> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> They're latching (no need for screws and stuff). There doesn't seem to
> be a panel mount version, but one could mount a through-hole connector
> to a pcb, and have the pcb have screw holes for mounting to the rear
> panel. They handle high power - 150W meaning 3A per pin (half the pins
> are return pins). Seems like a winner to me. They're also tiny so they
> will easily fit in the back of a 1U unit even vertically. The biggest
> pain here might be making the rectangular hole and having it look any
> good. might be a case for custom die, maybe a small steel job that
> uses two bolts to screw together the two cutting parts through the
> sheet metal.
>
> "Pin and socket" connectors are the same kind of thing, just not
> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> useful alternative if more than 4 rails are necessary.
>
> D-sub connectors carry up to 3A... and are very cheap and can do panel
> mount of some sort. But I'll be damned if I use one of those cursed
> things for power.
>
> Automotive connectors seem inexpensive too, but I haven't really
> looked into them much other than a quick parametric search.
>
> I wonder what everyone thinks of this.
>
> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> <cheater00social at gmail.com> wrote:
>>
>> Don't you think this may have had something to do with you
>> distributing AC power, rather than DC with 0V potential?
>>
>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>
>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>
>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>
>>>
>>> This reminds me of a somewhat similar issue I had many years ago:
>>>
>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>
>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>
>>> /mr
>>>
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>


________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org
View archive at: https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://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  Thu Jul  9 15:15:02 2026
From: modular at go2.pl (Roman Sowa)
Date: Thu, 9 Jul 2026 15:15:02 +0200
Subject: [sdiy] Microchip compilers now all free
In-Reply-To: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
References: <CACZGMx+nLx1Eu29ZJqksiSdmVTq-nLhAy-EseK6V3cCexHeqew@mail.gmail.com>
Message-ID: <3a543e1c-62f7-45d7-b3d3-cd94b02d0da5@go2.pl>

Trying to convince people to use their useless, terrible, stupid and 
slow  MPLAB-X.

I'd rather welcome an update to MPLAB-IDE v8, just to include new 
microcontrollers massively introduced during last 10 years, but that's 
not gonna happen, as all their good programmers are retired now.

Roman

W dniu 2026-07-09 o?10:01, Neil Johnson via Synth-diy pisze:
> Hi all,
> 
> I see Microchip has finally made all of their compilers completely free:
> 
> https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers <https://www.microchip.com/en-us/tools-resources/develop/mplab-xc-compilers>
> 
> Hopefully a good sign, rather than a bad one....
> 
> Neil
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org

From ben at stuyts.nl  Thu Jul  9 15:37:25 2026
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu, 9 Jul 2026 15:37:25 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CWLP265MB71320362D18697E50597757ADBFE2@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CWLP265MB71320362D18697E50597757ADBFE2@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <24576AE7-D624-4E60-A460-B3270D131E41@stuyts.nl>

With respect, but is that really *the* standard? A bit of duckduckgo-ing shows me this:

https://pinoutguide.com/Audio-Video-Hardware/xlr6_pinout.shtml

and then there is this?

https://pinoutguide.com/Audio-Video-Hardware/xlr4_pinout.shtml

and of course:

https://xkcd.com/927/

Ben


> On 9 Jul 2026, at 15:02, Mike Bryant <mbryant at futurehorizons.com> wrote:
> 
> The 6 pin XLR is the standard for +/- power transmission.  See last entry on :
> 
> https://www.clarkwire.com/pinouts/xlr-audio-pinouts
> 
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> Sent: 09 July 2026 12:40
> To: cheater cheater <cheater00social at gmail.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>  
> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> 
> Ben
> 
> > On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >
> > One way to have DC input, but retain the capability of using the
> > internal power supply, is to have a 4P2T switch for configuration.
> >
> > It seems that 4P2T switches are super expensive, especially if they're
> > supposed to withstand, say, 1A.
> >
> > So I started looking around. TLDR: classic pcie 8-pin power connectors
> > are probably the best, and also the cheapest.
> >
> > My first thought was to look at PCIE x1 slots. The cheapest advanced
> > connector on earth, for 0.4 Euro at unit price, you get a connector
> > that handles 1.1A per pin as per eg this document, page 6, 4.4
> >
> > https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >
> >> 4.4 CONTACT CURRENT RATING
> >> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >
> > The connector has 36 pins, so while I don't think it would handle 36A,
> > I'm sure it would handle something like 2A, especially if you share
> > pins. You can even leave pins empty to prevent shorts during
> > insertion.
> >
> > You could put the connector out the back, and either insert a plug-in
> > "card" (really just a small edge connector with wires soldered on)
> > that provides DC, or a pass-through "card" that shorts some pins
> > together to carry power from the internal power supply. And now
> > instead of $20-30 per unit, this costs $1 per unit. My main question
> > is how I would fix the connector, but maybe a simple screw hole in the
> > connector that mates with a threaded hole in the case could do the
> > trick.
> >
> > A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > rack unit, which is 45mm, so it doesn't take up much space either.
> >
> > The cheapest one that can be found at Mouser currently and can be
> > bought in low volumes is roughly 0.4 Euro.
> >
> > https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >
> > Qty.  Unit Price  Ext. Price
> > 1     ? 0,439     ? 0,44
> > 10    ? 0,372     ? 3,72
> > 25    ? 0,332     ? 8,30
> > 100   ? 0,316     ? 31,60
> >
> > By making the connector require a dummy plug to connect the internal
> > power supply into the circuit, it makes it impossible to connect both
> > DC power and mains AC, so that makes the design intrinsically safe
> > without using switches.
> >
> > Alternatively to a PCIE connector I could use some panel mount plug
> > with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > power from the internal power supply, and similarly use a shorting
> > plug to use the internal power supply.
> >
> > Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > Circular metric aren't better.
> > MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > so I can't find them by number of pins.
> >
> > PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > They're latching (no need for screws and stuff). There doesn't seem to
> > be a panel mount version, but one could mount a through-hole connector
> > to a pcb, and have the pcb have screw holes for mounting to the rear
> > panel. They handle high power - 150W meaning 3A per pin (half the pins
> > are return pins). Seems like a winner to me. They're also tiny so they
> > will easily fit in the back of a 1U unit even vertically. The biggest
> > pain here might be making the rectangular hole and having it look any
> > good. might be a case for custom die, maybe a small steel job that
> > uses two bolts to screw together the two cutting parts through the
> > sheet metal.
> >
> > "Pin and socket" connectors are the same kind of thing, just not
> > specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > useful alternative if more than 4 rails are necessary.
> >
> > D-sub connectors carry up to 3A... and are very cheap and can do panel
> > mount of some sort. But I'll be damned if I use one of those cursed
> > things for power.
> >
> > Automotive connectors seem inexpensive too, but I haven't really
> > looked into them much other than a quick parametric search.
> >
> > I wonder what everyone thinks of this.
> >
> > On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > <cheater00social at gmail.com> wrote:
> >>
> >> Don't you think this may have had something to do with you
> >> distributing AC power, rather than DC with 0V potential?
> >>
> >> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>
> >>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>
> >>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>
> >>>
> >>> This reminds me of a somewhat similar issue I had many years ago:
> >>>
> >>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>
> >>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>
> >>> /mr
> >>>
> >>> ________________________________________________________
> >>> This is the Synth-diy mailing list
> >>> Submit email to: Synth-diy at synth-diy.org
> >>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>> Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
> 
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://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 Jul  9 15:44:25 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Thu, 9 Jul 2026 13:44:25 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <24576AE7-D624-4E60-A460-B3270D131E41@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CWLP265MB71320362D18697E50597757ADBFE2@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <24576AE7-D624-4E60-A460-B3270D131E41@stuyts.nl>
Message-ID: <CWLP265MB713227A8A4B15FFA339BD99BDBFE2@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>

Yes it is ... for audio ... which is what the OP wanted.

Your 6 pin is the standard for lighting systems.

________________________________
From: Ben Stuyts <ben at stuyts.nl>
Sent: 09 July 2026 14:37
To: Mike Bryant <mbryant at futurehorizons.com>
Cc: cheater cheater <cheater00social at gmail.com>; synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

With respect, but is that really *the* standard? A bit of duckduckgo-ing shows me this:

https://pinoutguide.com/Audio-Video-Hardware/xlr6_pinout.shtml

and then there is this?

https://pinoutguide.com/Audio-Video-Hardware/xlr4_pinout.shtml

and of course:

https://xkcd.com/927/

Ben


On 9 Jul 2026, at 15:02, Mike Bryant <mbryant at futurehorizons.com> wrote:

The 6 pin XLR is the standard for +/- power transmission.  See last entry on :

https://www.clarkwire.com/pinouts/xlr-audio-pinouts

________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
Sent: 09 July 2026 12:40
To: cheater cheater <cheater00social at gmail.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.

Ben

> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>
> One way to have DC input, but retain the capability of using the
> internal power supply, is to have a 4P2T switch for configuration.
>
> It seems that 4P2T switches are super expensive, especially if they're
> supposed to withstand, say, 1A.
>
> So I started looking around. TLDR: classic pcie 8-pin power connectors
> are probably the best, and also the cheapest.
>
> My first thought was to look at PCIE x1 slots. The cheapest advanced
> connector on earth, for 0.4 Euro at unit price, you get a connector
> that handles 1.1A per pin as per eg this document, page 6, 4.4
>
> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>
>> 4.4 CONTACT CURRENT RATING
>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>
> The connector has 36 pins, so while I don't think it would handle 36A,
> I'm sure it would handle something like 2A, especially if you share
> pins. You can even leave pins empty to prevent shorts during
> insertion.
>
> You could put the connector out the back, and either insert a plug-in
> "card" (really just a small edge connector with wires soldered on)
> that provides DC, or a pass-through "card" that shorts some pins
> together to carry power from the internal power supply. And now
> instead of $20-30 per unit, this costs $1 per unit. My main question
> is how I would fix the connector, but maybe a simple screw hole in the
> connector that mates with a threaded hole in the case could do the
> trick.
>
> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> rack unit, which is 45mm, so it doesn't take up much space either.
>
> The cheapest one that can be found at Mouser currently and can be
> bought in low volumes is roughly 0.4 Euro.
>
> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>
> Qty.  Unit Price  Ext. Price
> 1     ? 0,439     ? 0,44
> 10    ? 0,372     ? 3,72
> 25    ? 0,332     ? 8,30
> 100   ? 0,316     ? 31,60
>
> By making the connector require a dummy plug to connect the internal
> power supply into the circuit, it makes it impossible to connect both
> DC power and mains AC, so that makes the design intrinsically safe
> without using switches.
>
> Alternatively to a PCIE connector I could use some panel mount plug
> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> power from the internal power supply, and similarly use a shorting
> plug to use the internal power supply.
>
> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> Circular metric aren't better.
> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> so I can't find them by number of pins.
>
> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> They're latching (no need for screws and stuff). There doesn't seem to
> be a panel mount version, but one could mount a through-hole connector
> to a pcb, and have the pcb have screw holes for mounting to the rear
> panel. They handle high power - 150W meaning 3A per pin (half the pins
> are return pins). Seems like a winner to me. They're also tiny so they
> will easily fit in the back of a 1U unit even vertically. The biggest
> pain here might be making the rectangular hole and having it look any
> good. might be a case for custom die, maybe a small steel job that
> uses two bolts to screw together the two cutting parts through the
> sheet metal.
>
> "Pin and socket" connectors are the same kind of thing, just not
> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> useful alternative if more than 4 rails are necessary.
>
> D-sub connectors carry up to 3A... and are very cheap and can do panel
> mount of some sort. But I'll be damned if I use one of those cursed
> things for power.
>
> Automotive connectors seem inexpensive too, but I haven't really
> looked into them much other than a quick parametric search.
>
> I wonder what everyone thinks of this.
>
> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> <cheater00social at gmail.com> wrote:
>>
>> Don't you think this may have had something to do with you
>> distributing AC power, rather than DC with 0V potential?
>>
>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>
>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>
>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>
>>>
>>> This reminds me of a somewhat similar issue I had many years ago:
>>>
>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>
>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>
>>> /mr
>>>
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>


________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org
View archive at: https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://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  Thu Jul  9 16:06:40 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 16:06:40 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
Message-ID: <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>

In order to provide the bridging functionality it has to have at least 8 pins.

On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
>
> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>
> Ben
>
> > On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >
> > One way to have DC input, but retain the capability of using the
> > internal power supply, is to have a 4P2T switch for configuration.
> >
> > It seems that 4P2T switches are super expensive, especially if they're
> > supposed to withstand, say, 1A.
> >
> > So I started looking around. TLDR: classic pcie 8-pin power connectors
> > are probably the best, and also the cheapest.
> >
> > My first thought was to look at PCIE x1 slots. The cheapest advanced
> > connector on earth, for 0.4 Euro at unit price, you get a connector
> > that handles 1.1A per pin as per eg this document, page 6, 4.4
> >
> > https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >
> >> 4.4 CONTACT CURRENT RATING
> >> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >
> > The connector has 36 pins, so while I don't think it would handle 36A,
> > I'm sure it would handle something like 2A, especially if you share
> > pins. You can even leave pins empty to prevent shorts during
> > insertion.
> >
> > You could put the connector out the back, and either insert a plug-in
> > "card" (really just a small edge connector with wires soldered on)
> > that provides DC, or a pass-through "card" that shorts some pins
> > together to carry power from the internal power supply. And now
> > instead of $20-30 per unit, this costs $1 per unit. My main question
> > is how I would fix the connector, but maybe a simple screw hole in the
> > connector that mates with a threaded hole in the case could do the
> > trick.
> >
> > A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > rack unit, which is 45mm, so it doesn't take up much space either.
> >
> > The cheapest one that can be found at Mouser currently and can be
> > bought in low volumes is roughly 0.4 Euro.
> >
> > https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >
> > Qty.  Unit Price  Ext. Price
> > 1     ? 0,439     ? 0,44
> > 10    ? 0,372     ? 3,72
> > 25    ? 0,332     ? 8,30
> > 100   ? 0,316     ? 31,60
> >
> > By making the connector require a dummy plug to connect the internal
> > power supply into the circuit, it makes it impossible to connect both
> > DC power and mains AC, so that makes the design intrinsically safe
> > without using switches.
> >
> > Alternatively to a PCIE connector I could use some panel mount plug
> > with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > power from the internal power supply, and similarly use a shorting
> > plug to use the internal power supply.
> >
> > Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > Circular metric aren't better.
> > MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > so I can't find them by number of pins.
> >
> > PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > They're latching (no need for screws and stuff). There doesn't seem to
> > be a panel mount version, but one could mount a through-hole connector
> > to a pcb, and have the pcb have screw holes for mounting to the rear
> > panel. They handle high power - 150W meaning 3A per pin (half the pins
> > are return pins). Seems like a winner to me. They're also tiny so they
> > will easily fit in the back of a 1U unit even vertically. The biggest
> > pain here might be making the rectangular hole and having it look any
> > good. might be a case for custom die, maybe a small steel job that
> > uses two bolts to screw together the two cutting parts through the
> > sheet metal.
> >
> > "Pin and socket" connectors are the same kind of thing, just not
> > specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > useful alternative if more than 4 rails are necessary.
> >
> > D-sub connectors carry up to 3A... and are very cheap and can do panel
> > mount of some sort. But I'll be damned if I use one of those cursed
> > things for power.
> >
> > Automotive connectors seem inexpensive too, but I haven't really
> > looked into them much other than a quick parametric search.
> >
> > I wonder what everyone thinks of this.
> >
> > On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > <cheater00social at gmail.com> wrote:
> >>
> >> Don't you think this may have had something to do with you
> >> distributing AC power, rather than DC with 0V potential?
> >>
> >> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>
> >>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>
> >>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>
> >>>
> >>> This reminds me of a somewhat similar issue I had many years ago:
> >>>
> >>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>
> >>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>
> >>> /mr
> >>>
> >>> ________________________________________________________
> >>> This is the Synth-diy mailing list
> >>> Submit email to: Synth-diy at synth-diy.org
> >>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>> Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
>


From cheater00social at gmail.com  Thu Jul  9 16:08:04 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 16:08:04 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAPgGCkK+P2iMkTbE_Njpp6XBv9BnmfK3CkVrpApuQWmXAMqtPQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAPgGCkK+P2iMkTbE_Njpp6XBv9BnmfK3CkVrpApuQWmXAMqtPQ@mail.gmail.com>
Message-ID: <CAGn5V-_8J+yA-iYDfG_D4mph1iUBzmve+53TBjX_F1GhGy7-TQ@mail.gmail.com>

On Thu, Jul 9, 2026 at 2:10?PM S Ridley via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
>
> Molex Mini-Fit Jr?
>

Isn't that the same connector family the self-combusting 12V HPWR
connector comes from? I.e. smaller pins than the pcie 8-pin?

>
> On Thu, 9 Jul 2026 at 12:43, Ben Stuyts via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>>
>> Ben
>>
>> > On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>> >
>> > One way to have DC input, but retain the capability of using the
>> > internal power supply, is to have a 4P2T switch for configuration.
>> >
>> > It seems that 4P2T switches are super expensive, especially if they're
>> > supposed to withstand, say, 1A.
>> >
>> > So I started looking around. TLDR: classic pcie 8-pin power connectors
>> > are probably the best, and also the cheapest.
>> >
>> > My first thought was to look at PCIE x1 slots. The cheapest advanced
>> > connector on earth, for 0.4 Euro at unit price, you get a connector
>> > that handles 1.1A per pin as per eg this document, page 6, 4.4
>> >
>> > https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>> >
>> >> 4.4 CONTACT CURRENT RATING
>> >> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>> >
>> > The connector has 36 pins, so while I don't think it would handle 36A,
>> > I'm sure it would handle something like 2A, especially if you share
>> > pins. You can even leave pins empty to prevent shorts during
>> > insertion.
>> >
>> > You could put the connector out the back, and either insert a plug-in
>> > "card" (really just a small edge connector with wires soldered on)
>> > that provides DC, or a pass-through "card" that shorts some pins
>> > together to carry power from the internal power supply. And now
>> > instead of $20-30 per unit, this costs $1 per unit. My main question
>> > is how I would fix the connector, but maybe a simple screw hole in the
>> > connector that mates with a threaded hole in the case could do the
>> > trick.
>> >
>> > A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
>> > rack unit, which is 45mm, so it doesn't take up much space either.
>> >
>> > The cheapest one that can be found at Mouser currently and can be
>> > bought in low volumes is roughly 0.4 Euro.
>> >
>> > https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>> >
>> > Qty.  Unit Price  Ext. Price
>> > 1     ? 0,439     ? 0,44
>> > 10    ? 0,372     ? 3,72
>> > 25    ? 0,332     ? 8,30
>> > 100   ? 0,316     ? 31,60
>> >
>> > By making the connector require a dummy plug to connect the internal
>> > power supply into the circuit, it makes it impossible to connect both
>> > DC power and mains AC, so that makes the design intrinsically safe
>> > without using switches.
>> >
>> > Alternatively to a PCIE connector I could use some panel mount plug
>> > with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
>> > power from the internal power supply, and similarly use a shorting
>> > plug to use the internal power supply.
>> >
>> > Circular DIN connectors start at about 8 Euro per pair of socket and plug.
>> > Circular metric aren't better.
>> > MIL Spec connectors seem to be cheaper. But the mouser search sucks,
>> > so I can't find them by number of pins.
>> >
>> > PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
>> > They're latching (no need for screws and stuff). There doesn't seem to
>> > be a panel mount version, but one could mount a through-hole connector
>> > to a pcb, and have the pcb have screw holes for mounting to the rear
>> > panel. They handle high power - 150W meaning 3A per pin (half the pins
>> > are return pins). Seems like a winner to me. They're also tiny so they
>> > will easily fit in the back of a 1U unit even vertically. The biggest
>> > pain here might be making the rectangular hole and having it look any
>> > good. might be a case for custom die, maybe a small steel job that
>> > uses two bolts to screw together the two cutting parts through the
>> > sheet metal.
>> >
>> > "Pin and socket" connectors are the same kind of thing, just not
>> > specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
>> > useful alternative if more than 4 rails are necessary.
>> >
>> > D-sub connectors carry up to 3A... and are very cheap and can do panel
>> > mount of some sort. But I'll be damned if I use one of those cursed
>> > things for power.
>> >
>> > Automotive connectors seem inexpensive too, but I haven't really
>> > looked into them much other than a quick parametric search.
>> >
>> > I wonder what everyone thinks of this.
>> >
>> > On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
>> > <cheater00social at gmail.com> wrote:
>> >>
>> >> Don't you think this may have had something to do with you
>> >> distributing AC power, rather than DC with 0V potential?
>> >>
>> >> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>> >>>
>> >>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>> >>>>
>> >>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>> >>>
>> >>>
>> >>> This reminds me of a somewhat similar issue I had many years ago:
>> >>>
>> >>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>> >>>
>> >>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>> >>>
>> >>> /mr
>> >>>
>> >>> ________________________________________________________
>> >>> This is the Synth-diy mailing list
>> >>> Submit email to: Synth-diy at synth-diy.org
>> >>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> >>> Selling or trading? Use marketplace at synth-diy.org
>> >
>> > ________________________________________________________
>> > This is the Synth-diy mailing list
>> > Submit email to: Synth-diy at synth-diy.org
>> > View archive at: https://synth-diy.org/pipermail/synth-diy/
>> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>> >
>>
>>
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From ben at stuyts.nl  Thu Jul  9 17:56:56 2026
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu, 9 Jul 2026 17:56:56 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
Message-ID: <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>

You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.

Ben

> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> 
> In order to provide the bridging functionality it has to have at least 8 pins.
> 
> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
>> 
>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>> 
>> Ben
>> 
>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>> 
>>> One way to have DC input, but retain the capability of using the
>>> internal power supply, is to have a 4P2T switch for configuration.
>>> 
>>> It seems that 4P2T switches are super expensive, especially if they're
>>> supposed to withstand, say, 1A.
>>> 
>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
>>> are probably the best, and also the cheapest.
>>> 
>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
>>> connector on earth, for 0.4 Euro at unit price, you get a connector
>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
>>> 
>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>>> 
>>>> 4.4 CONTACT CURRENT RATING
>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>>> 
>>> The connector has 36 pins, so while I don't think it would handle 36A,
>>> I'm sure it would handle something like 2A, especially if you share
>>> pins. You can even leave pins empty to prevent shorts during
>>> insertion.
>>> 
>>> You could put the connector out the back, and either insert a plug-in
>>> "card" (really just a small edge connector with wires soldered on)
>>> that provides DC, or a pass-through "card" that shorts some pins
>>> together to carry power from the internal power supply. And now
>>> instead of $20-30 per unit, this costs $1 per unit. My main question
>>> is how I would fix the connector, but maybe a simple screw hole in the
>>> connector that mates with a threaded hole in the case could do the
>>> trick.
>>> 
>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
>>> rack unit, which is 45mm, so it doesn't take up much space either.
>>> 
>>> The cheapest one that can be found at Mouser currently and can be
>>> bought in low volumes is roughly 0.4 Euro.
>>> 
>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>>> 
>>> Qty.  Unit Price  Ext. Price
>>> 1     ? 0,439     ? 0,44
>>> 10    ? 0,372     ? 3,72
>>> 25    ? 0,332     ? 8,30
>>> 100   ? 0,316     ? 31,60
>>> 
>>> By making the connector require a dummy plug to connect the internal
>>> power supply into the circuit, it makes it impossible to connect both
>>> DC power and mains AC, so that makes the design intrinsically safe
>>> without using switches.
>>> 
>>> Alternatively to a PCIE connector I could use some panel mount plug
>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
>>> power from the internal power supply, and similarly use a shorting
>>> plug to use the internal power supply.
>>> 
>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
>>> Circular metric aren't better.
>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
>>> so I can't find them by number of pins.
>>> 
>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
>>> They're latching (no need for screws and stuff). There doesn't seem to
>>> be a panel mount version, but one could mount a through-hole connector
>>> to a pcb, and have the pcb have screw holes for mounting to the rear
>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
>>> are return pins). Seems like a winner to me. They're also tiny so they
>>> will easily fit in the back of a 1U unit even vertically. The biggest
>>> pain here might be making the rectangular hole and having it look any
>>> good. might be a case for custom die, maybe a small steel job that
>>> uses two bolts to screw together the two cutting parts through the
>>> sheet metal.
>>> 
>>> "Pin and socket" connectors are the same kind of thing, just not
>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
>>> useful alternative if more than 4 rails are necessary.
>>> 
>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
>>> mount of some sort. But I'll be damned if I use one of those cursed
>>> things for power.
>>> 
>>> Automotive connectors seem inexpensive too, but I haven't really
>>> looked into them much other than a quick parametric search.
>>> 
>>> I wonder what everyone thinks of this.
>>> 
>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
>>> <cheater00social at gmail.com> wrote:
>>>> 
>>>> Don't you think this may have had something to do with you
>>>> distributing AC power, rather than DC with 0V potential?
>>>> 
>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>>> 
>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>>> 
>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>>> 
>>>>> 
>>>>> This reminds me of a somewhat similar issue I had many years ago:
>>>>> 
>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>>> 
>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>>> 
>>>>> /mr
>>>>> 
>>>>> ________________________________________________________
>>>>> This is the Synth-diy mailing list
>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>> Selling or trading? Use marketplace at synth-diy.org
>>> 
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>>> 
>> 
> 



From cheater00social at gmail.com  Thu Jul  9 18:23:50 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Thu, 9 Jul 2026 18:23:50 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
Message-ID: <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>

Thanks. A few questions:

What if only some of the rails are connected, but not the one used for
steering the relay (a fault)?

Relays are kind of expensive, how much do you think that could end up costing?

If they don't get cycled a lot at all, wouldn't they end up getting stuck?

On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
>
> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
>
> Ben
>
> > On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> >
> > In order to provide the bridging functionality it has to have at least 8 pins.
> >
> > On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>
> >> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> >>
> >> Ben
> >>
> >>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >>>
> >>> One way to have DC input, but retain the capability of using the
> >>> internal power supply, is to have a 4P2T switch for configuration.
> >>>
> >>> It seems that 4P2T switches are super expensive, especially if they're
> >>> supposed to withstand, say, 1A.
> >>>
> >>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> >>> are probably the best, and also the cheapest.
> >>>
> >>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> >>> connector on earth, for 0.4 Euro at unit price, you get a connector
> >>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> >>>
> >>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >>>
> >>>> 4.4 CONTACT CURRENT RATING
> >>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >>>
> >>> The connector has 36 pins, so while I don't think it would handle 36A,
> >>> I'm sure it would handle something like 2A, especially if you share
> >>> pins. You can even leave pins empty to prevent shorts during
> >>> insertion.
> >>>
> >>> You could put the connector out the back, and either insert a plug-in
> >>> "card" (really just a small edge connector with wires soldered on)
> >>> that provides DC, or a pass-through "card" that shorts some pins
> >>> together to carry power from the internal power supply. And now
> >>> instead of $20-30 per unit, this costs $1 per unit. My main question
> >>> is how I would fix the connector, but maybe a simple screw hole in the
> >>> connector that mates with a threaded hole in the case could do the
> >>> trick.
> >>>
> >>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> >>> rack unit, which is 45mm, so it doesn't take up much space either.
> >>>
> >>> The cheapest one that can be found at Mouser currently and can be
> >>> bought in low volumes is roughly 0.4 Euro.
> >>>
> >>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >>>
> >>> Qty.  Unit Price  Ext. Price
> >>> 1     ? 0,439     ? 0,44
> >>> 10    ? 0,372     ? 3,72
> >>> 25    ? 0,332     ? 8,30
> >>> 100   ? 0,316     ? 31,60
> >>>
> >>> By making the connector require a dummy plug to connect the internal
> >>> power supply into the circuit, it makes it impossible to connect both
> >>> DC power and mains AC, so that makes the design intrinsically safe
> >>> without using switches.
> >>>
> >>> Alternatively to a PCIE connector I could use some panel mount plug
> >>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> >>> power from the internal power supply, and similarly use a shorting
> >>> plug to use the internal power supply.
> >>>
> >>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> >>> Circular metric aren't better.
> >>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> >>> so I can't find them by number of pins.
> >>>
> >>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> >>> They're latching (no need for screws and stuff). There doesn't seem to
> >>> be a panel mount version, but one could mount a through-hole connector
> >>> to a pcb, and have the pcb have screw holes for mounting to the rear
> >>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> >>> are return pins). Seems like a winner to me. They're also tiny so they
> >>> will easily fit in the back of a 1U unit even vertically. The biggest
> >>> pain here might be making the rectangular hole and having it look any
> >>> good. might be a case for custom die, maybe a small steel job that
> >>> uses two bolts to screw together the two cutting parts through the
> >>> sheet metal.
> >>>
> >>> "Pin and socket" connectors are the same kind of thing, just not
> >>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> >>> useful alternative if more than 4 rails are necessary.
> >>>
> >>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> >>> mount of some sort. But I'll be damned if I use one of those cursed
> >>> things for power.
> >>>
> >>> Automotive connectors seem inexpensive too, but I haven't really
> >>> looked into them much other than a quick parametric search.
> >>>
> >>> I wonder what everyone thinks of this.
> >>>
> >>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> >>> <cheater00social at gmail.com> wrote:
> >>>>
> >>>> Don't you think this may have had something to do with you
> >>>> distributing AC power, rather than DC with 0V potential?
> >>>>
> >>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>>>
> >>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>>>
> >>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>>>
> >>>>>
> >>>>> This reminds me of a somewhat similar issue I had many years ago:
> >>>>>
> >>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>>>
> >>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>>>
> >>>>> /mr
> >>>>>
> >>>>> ________________________________________________________
> >>>>> This is the Synth-diy mailing list
> >>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>
> >>> ________________________________________________________
> >>> This is the Synth-diy mailing list
> >>> Submit email to: Synth-diy at synth-diy.org
> >>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>> Selling or trading? Use marketplace at synth-diy.org
> >>>
> >>
> >
>


From gordonjcp at gjcp.net  Thu Jul  9 23:59:24 2026
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Thu, 9 Jul 2026 22:59:24 +0100
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
Message-ID: <20260709215924.GA19689@gjcp.net>

On Thu, Jul 09, 2026 at 01:40:46PM +0200, Ben Stuyts via Synth-diy wrote:
> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.

Oldschool DMX uses 5-pin but most new stuff has 3-pin.

Be careful with 4-pin, broadcast cameras and associated equipment use that for 12V power with ground on pin 1 (nearest the tab, wide-spaced side) and +12 on pin 4 (nearest the tab, narrow-spaced side).

3-pin is used in some comms equipment for 24V power with pin 1 being ground and pin 2 being +24.

-- 
Gordonjcp


From gordonjcp at gjcp.net  Fri Jul 10 00:00:02 2026
From: gordonjcp at gjcp.net (Gordonjcp)
Date: Thu, 9 Jul 2026 23:00:02 +0100
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
Message-ID: <20260709220002.GB19689@gjcp.net>

On Thu, Jul 09, 2026 at 06:23:50PM +0200, cheater cheater via Synth-diy wrote:
> Thanks. A few questions:
> 
> What if only some of the rails are connected, but not the one used for
> steering the relay (a fault)?
> 
> Relays are kind of expensive, how much do you think that could end up costing?
> 
> If they don't get cycled a lot at all, wouldn't they end up getting stuck?

Big mosfets would be better here.

-- 
Gordonjcp


From ben at stuyts.nl  Fri Jul 10 00:39:07 2026
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri, 10 Jul 2026 00:39:07 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
Message-ID: <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>

You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.

Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.

Ben

> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> 
> Thanks. A few questions:
> 
> What if only some of the rails are connected, but not the one used for
> steering the relay (a fault)?
> 
> Relays are kind of expensive, how much do you think that could end up costing?
> 
> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> 
> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
>> 
>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
>> 
>> Ben
>> 
>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
>>> 
>>> In order to provide the bridging functionality it has to have at least 8 pins.
>>> 
>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
>>>> 
>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>>>> 
>>>> Ben
>>>> 
>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>>>> 
>>>>> One way to have DC input, but retain the capability of using the
>>>>> internal power supply, is to have a 4P2T switch for configuration.
>>>>> 
>>>>> It seems that 4P2T switches are super expensive, especially if they're
>>>>> supposed to withstand, say, 1A.
>>>>> 
>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
>>>>> are probably the best, and also the cheapest.
>>>>> 
>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
>>>>> 
>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>>>>> 
>>>>>> 4.4 CONTACT CURRENT RATING
>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>>>>> 
>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
>>>>> I'm sure it would handle something like 2A, especially if you share
>>>>> pins. You can even leave pins empty to prevent shorts during
>>>>> insertion.
>>>>> 
>>>>> You could put the connector out the back, and either insert a plug-in
>>>>> "card" (really just a small edge connector with wires soldered on)
>>>>> that provides DC, or a pass-through "card" that shorts some pins
>>>>> together to carry power from the internal power supply. And now
>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
>>>>> is how I would fix the connector, but maybe a simple screw hole in the
>>>>> connector that mates with a threaded hole in the case could do the
>>>>> trick.
>>>>> 
>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
>>>>> 
>>>>> The cheapest one that can be found at Mouser currently and can be
>>>>> bought in low volumes is roughly 0.4 Euro.
>>>>> 
>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>>>>> 
>>>>> Qty.  Unit Price  Ext. Price
>>>>> 1     ? 0,439     ? 0,44
>>>>> 10    ? 0,372     ? 3,72
>>>>> 25    ? 0,332     ? 8,30
>>>>> 100   ? 0,316     ? 31,60
>>>>> 
>>>>> By making the connector require a dummy plug to connect the internal
>>>>> power supply into the circuit, it makes it impossible to connect both
>>>>> DC power and mains AC, so that makes the design intrinsically safe
>>>>> without using switches.
>>>>> 
>>>>> Alternatively to a PCIE connector I could use some panel mount plug
>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
>>>>> power from the internal power supply, and similarly use a shorting
>>>>> plug to use the internal power supply.
>>>>> 
>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
>>>>> Circular metric aren't better.
>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
>>>>> so I can't find them by number of pins.
>>>>> 
>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
>>>>> They're latching (no need for screws and stuff). There doesn't seem to
>>>>> be a panel mount version, but one could mount a through-hole connector
>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
>>>>> are return pins). Seems like a winner to me. They're also tiny so they
>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
>>>>> pain here might be making the rectangular hole and having it look any
>>>>> good. might be a case for custom die, maybe a small steel job that
>>>>> uses two bolts to screw together the two cutting parts through the
>>>>> sheet metal.
>>>>> 
>>>>> "Pin and socket" connectors are the same kind of thing, just not
>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
>>>>> useful alternative if more than 4 rails are necessary.
>>>>> 
>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
>>>>> mount of some sort. But I'll be damned if I use one of those cursed
>>>>> things for power.
>>>>> 
>>>>> Automotive connectors seem inexpensive too, but I haven't really
>>>>> looked into them much other than a quick parametric search.
>>>>> 
>>>>> I wonder what everyone thinks of this.
>>>>> 
>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
>>>>> <cheater00social at gmail.com> wrote:
>>>>>> 
>>>>>> Don't you think this may have had something to do with you
>>>>>> distributing AC power, rather than DC with 0V potential?
>>>>>> 
>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>>>>> 
>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>>>>> 
>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>>>>> 
>>>>>>> 
>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
>>>>>>> 
>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>>>>> 
>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>>>>> 
>>>>>>> /mr
>>>>>>> 
>>>>>>> ________________________________________________________
>>>>>>> This is the Synth-diy mailing list
>>>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>> 
>>>>> ________________________________________________________
>>>>> This is the Synth-diy mailing list
>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>> 
>>>> 
>>> 
>> 
> 



From crystals at sonic.net  Fri Jul 10 06:51:42 2026
From: crystals at sonic.net (crystal)
Date: Thu, 9 Jul 2026 22:51:42 -0600
Subject: [sdiy] 7815 / 7915, "vintage sound", and modern replacements
In-Reply-To: <CAGn5V-_HYonm5p8DB0QyWxDJN9B8+XbNnSVLjq2-gVHyPPB8yQ@mail.gmail.com>
References: <CAGn5V-_HYonm5p8DB0QyWxDJN9B8+XbNnSVLjq2-gVHyPPB8yQ@mail.gmail.com>
Message-ID: <07fe18f0-5a14-41ba-8d2c-271159591fd9@sonic.net>

I did this many years ago. My plan was to make everything able to run 
off solar power without inverters. My memory is a bit hazy, but, i 
completely bypasses most of the power supplies and just fed DC into the 
equipment. I made a central power supply that just had multiple voltage 
output. I used different sized?"molex" connectors and put different 
color zip ties and labeled everything clearly. I would not have wanted 
the average user to mess with the system. Admittedly is was a system 
suited to me but not everyone.

Back then i used LM317s with a lot of filtering both in the supply and 
in the equipment. I'd like to know the answer to better, more recent 
regulators.

c

On 7/9/2026 2:15 AM, cheater cheater via Synth-diy wrote:
> (this email seems to have been eaten by gmail... so I have to type it
> all out from memory)
>
>
>
> INTRO / BACKGROUND
>
> Hi all,
>
> I'm looking further into my project to modify rack devices to run on
> DC rather than AC. Looks like most of them use a 7815/7915 combo with
> a full-wave rectifier. Pretty much like the first circuit here:
>
> https://www.eleccircuit.com/power-supply-regulator-15v-15v-1a-by-ic-7815-7915/
>
>
>
> So the idea is to put a 4P2T switch (V, -V, phantom, 0V) or some
> jumpers, right after the rectifier but before the regulators, in order
> to either power the regulators from the internal power supply, or from
> the remote DC supply. I would feed DC in, and let the rack unit do its
> final volt or so regulation itself, to prevent sag and voltage rail
> based crosstalk from other rack devices (10-20 units) that live on the
> same DC distribution bus.
>
> It seems like most of those racks are below the 10W mark, meaning at
> 30V, we're talking about less than 0.5A being delivered by the
> regulators total.
>
>
>
> VOLTAGE REGULATOR QUESTIONS
>
> I've had a couple questions:
>
> 1. What is the best DC voltage to run to the 7815 / 7915 so they
> create the least dissipation, have the best regulation, and produce
> the least noise?
>
> 2. Are there any better modern replacement linear regulators for
> audio? (I'm assuming linear regulators are still what's recommended)
> Something with considerably better noise and regulation performance,
> no more than say $5 a pop, though that's not a fixed price. I'll be
> happy with something that's cents too if that's the go-to part. I
> don't need an exact pin for pin replacement, but being able to use
> something that doesn't require a massive amount of modification to the
> existing circuit would be nice. Although I might just bypass the
> existing internal power supplies completely, and build new ones, so
> feel free to suggest anything. Noise performance and ripple rejection
> are the most important thing here. I'm specifically not looking for
> any sort of "vintage sound".
>
>
> I would appreciate any info on the questions above. Thanks.
>
>
>
> P.S. "VINTAGE" SOUND
>
> I've also noticed something interesting when looking at 7815
> datasheets. Specifically the output impedance, which I found plotted
> in an older datasheet, on page 6 in the top left corner here:
>
> https://www.alldatasheet.com/datasheet-pdf/view/9046/NSC/7815.html
>
> The output impedance goes from 0.008 Ohm at 1 kHz to 0.03-0.04 Ohm at
> 20 kHz, even if bypassed with 1uF tantalum caps as the plot indicates.
>
> It's common to find that older synths sound darker and modern ones
> sound very bright (meaning older synths have lowered high frequency
> reproduction). I wonder if between this nature of the most popular
> linear regulators, and caps that were never good enough to bypass
> those frequencies when they were new (let alone after decades), that
> could explain some of that. Simply power supply sag in the higher
> registers, creating a compounding loss of gain. What do you guys
> think? I assume earlier voltage regulators were even worse than that
> plot.
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to:Synth-diy at synth-diy.org
> View archive at:https://synth-diy.org/pipermail/synth-diy/
> Check your settings at:https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Usemarketplace at synth-diy.org
>
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From elmacaco at hotmail.com  Fri Jul 10 17:58:17 2026
From: elmacaco at hotmail.com (el macaco)
Date: Fri, 10 Jul 2026 15:58:17 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
Message-ID: <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>

Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?

Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?

Or move the units away from where the mic can pick up the noise?

Not my area of expertise, just wondering if there may be a simpler solition.

Ed



Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
Sent: Thursday, 09 July 2026 17:39:07
To: cheater cheater <cheater00social at gmail.com>
Cc: synth-diy <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.

Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.

Ben

> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
>
> Thanks. A few questions:
>
> What if only some of the rails are connected, but not the one used for
> steering the relay (a fault)?
>
> Relays are kind of expensive, how much do you think that could end up costing?
>
> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
>
> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
>>
>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
>>
>> Ben
>>
>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
>>>
>>> In order to provide the bridging functionality it has to have at least 8 pins.
>>>
>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
>>>>
>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>>>>
>>>> Ben
>>>>
>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>>>>
>>>>> One way to have DC input, but retain the capability of using the
>>>>> internal power supply, is to have a 4P2T switch for configuration.
>>>>>
>>>>> It seems that 4P2T switches are super expensive, especially if they're
>>>>> supposed to withstand, say, 1A.
>>>>>
>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
>>>>> are probably the best, and also the cheapest.
>>>>>
>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
>>>>>
>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>>>>>
>>>>>> 4.4 CONTACT CURRENT RATING
>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>>>>>
>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
>>>>> I'm sure it would handle something like 2A, especially if you share
>>>>> pins. You can even leave pins empty to prevent shorts during
>>>>> insertion.
>>>>>
>>>>> You could put the connector out the back, and either insert a plug-in
>>>>> "card" (really just a small edge connector with wires soldered on)
>>>>> that provides DC, or a pass-through "card" that shorts some pins
>>>>> together to carry power from the internal power supply. And now
>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
>>>>> is how I would fix the connector, but maybe a simple screw hole in the
>>>>> connector that mates with a threaded hole in the case could do the
>>>>> trick.
>>>>>
>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
>>>>>
>>>>> The cheapest one that can be found at Mouser currently and can be
>>>>> bought in low volumes is roughly 0.4 Euro.
>>>>>
>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>>>>>
>>>>> Qty.  Unit Price  Ext. Price
>>>>> 1     ? 0,439     ? 0,44
>>>>> 10    ? 0,372     ? 3,72
>>>>> 25    ? 0,332     ? 8,30
>>>>> 100   ? 0,316     ? 31,60
>>>>>
>>>>> By making the connector require a dummy plug to connect the internal
>>>>> power supply into the circuit, it makes it impossible to connect both
>>>>> DC power and mains AC, so that makes the design intrinsically safe
>>>>> without using switches.
>>>>>
>>>>> Alternatively to a PCIE connector I could use some panel mount plug
>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
>>>>> power from the internal power supply, and similarly use a shorting
>>>>> plug to use the internal power supply.
>>>>>
>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
>>>>> Circular metric aren't better.
>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
>>>>> so I can't find them by number of pins.
>>>>>
>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
>>>>> They're latching (no need for screws and stuff). There doesn't seem to
>>>>> be a panel mount version, but one could mount a through-hole connector
>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
>>>>> are return pins). Seems like a winner to me. They're also tiny so they
>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
>>>>> pain here might be making the rectangular hole and having it look any
>>>>> good. might be a case for custom die, maybe a small steel job that
>>>>> uses two bolts to screw together the two cutting parts through the
>>>>> sheet metal.
>>>>>
>>>>> "Pin and socket" connectors are the same kind of thing, just not
>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
>>>>> useful alternative if more than 4 rails are necessary.
>>>>>
>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
>>>>> mount of some sort. But I'll be damned if I use one of those cursed
>>>>> things for power.
>>>>>
>>>>> Automotive connectors seem inexpensive too, but I haven't really
>>>>> looked into them much other than a quick parametric search.
>>>>>
>>>>> I wonder what everyone thinks of this.
>>>>>
>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
>>>>> <cheater00social at gmail.com> wrote:
>>>>>>
>>>>>> Don't you think this may have had something to do with you
>>>>>> distributing AC power, rather than DC with 0V potential?
>>>>>>
>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>>>>>
>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>>>>>
>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>>>>>
>>>>>>>
>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
>>>>>>>
>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>>>>>
>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>>>>>
>>>>>>> /mr
>>>>>>>
>>>>>>> ________________________________________________________
>>>>>>> This is the Synth-diy mailing list
>>>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>>
>>>>> ________________________________________________________
>>>>> This is the Synth-diy mailing list
>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>>
>>>>
>>>
>>
>


________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org
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From cheater00social at gmail.com  Fri Jul 10 18:03:00 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Fri, 10 Jul 2026 18:03:00 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>

there's one that's particularly noisy, but there are others that are a
little noisy too, and it adds up. plus the heat just makes the room
uncomfortable to be in. I've gone to great lengths to move all heat
and noise generating equipment out of my day room, including moving
the pcs to another place and connecting everything via fiber optics.
so having 80W less heating my head will be an improvement once more.

On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
>
> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
>
> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
>
> Or move the units away from where the mic can pick up the noise?
>
> Not my area of expertise, just wondering if there may be a simpler solition.
>
> Ed
>
>
>
> Get Outlook for iOS
> ________________________________
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> Sent: Thursday, 09 July 2026 17:39:07
> To: cheater cheater <cheater00social at gmail.com>
> Cc: synth-diy <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
>
> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
>
> Ben
>
> > On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> >
> > Thanks. A few questions:
> >
> > What if only some of the rails are connected, but not the one used for
> > steering the relay (a fault)?
> >
> > Relays are kind of expensive, how much do you think that could end up costing?
> >
> > If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> >
> > On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>
> >> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> >>
> >> Ben
> >>
> >>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> >>>
> >>> In order to provide the bridging functionality it has to have at least 8 pins.
> >>>
> >>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>>>
> >>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> >>>>
> >>>> Ben
> >>>>
> >>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >>>>>
> >>>>> One way to have DC input, but retain the capability of using the
> >>>>> internal power supply, is to have a 4P2T switch for configuration.
> >>>>>
> >>>>> It seems that 4P2T switches are super expensive, especially if they're
> >>>>> supposed to withstand, say, 1A.
> >>>>>
> >>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> >>>>> are probably the best, and also the cheapest.
> >>>>>
> >>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> >>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> >>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> >>>>>
> >>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >>>>>
> >>>>>> 4.4 CONTACT CURRENT RATING
> >>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >>>>>
> >>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> >>>>> I'm sure it would handle something like 2A, especially if you share
> >>>>> pins. You can even leave pins empty to prevent shorts during
> >>>>> insertion.
> >>>>>
> >>>>> You could put the connector out the back, and either insert a plug-in
> >>>>> "card" (really just a small edge connector with wires soldered on)
> >>>>> that provides DC, or a pass-through "card" that shorts some pins
> >>>>> together to carry power from the internal power supply. And now
> >>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> >>>>> is how I would fix the connector, but maybe a simple screw hole in the
> >>>>> connector that mates with a threaded hole in the case could do the
> >>>>> trick.
> >>>>>
> >>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> >>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> >>>>>
> >>>>> The cheapest one that can be found at Mouser currently and can be
> >>>>> bought in low volumes is roughly 0.4 Euro.
> >>>>>
> >>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >>>>>
> >>>>> Qty.  Unit Price  Ext. Price
> >>>>> 1     ? 0,439     ? 0,44
> >>>>> 10    ? 0,372     ? 3,72
> >>>>> 25    ? 0,332     ? 8,30
> >>>>> 100   ? 0,316     ? 31,60
> >>>>>
> >>>>> By making the connector require a dummy plug to connect the internal
> >>>>> power supply into the circuit, it makes it impossible to connect both
> >>>>> DC power and mains AC, so that makes the design intrinsically safe
> >>>>> without using switches.
> >>>>>
> >>>>> Alternatively to a PCIE connector I could use some panel mount plug
> >>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> >>>>> power from the internal power supply, and similarly use a shorting
> >>>>> plug to use the internal power supply.
> >>>>>
> >>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> >>>>> Circular metric aren't better.
> >>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> >>>>> so I can't find them by number of pins.
> >>>>>
> >>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> >>>>> They're latching (no need for screws and stuff). There doesn't seem to
> >>>>> be a panel mount version, but one could mount a through-hole connector
> >>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> >>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> >>>>> are return pins). Seems like a winner to me. They're also tiny so they
> >>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> >>>>> pain here might be making the rectangular hole and having it look any
> >>>>> good. might be a case for custom die, maybe a small steel job that
> >>>>> uses two bolts to screw together the two cutting parts through the
> >>>>> sheet metal.
> >>>>>
> >>>>> "Pin and socket" connectors are the same kind of thing, just not
> >>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> >>>>> useful alternative if more than 4 rails are necessary.
> >>>>>
> >>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> >>>>> mount of some sort. But I'll be damned if I use one of those cursed
> >>>>> things for power.
> >>>>>
> >>>>> Automotive connectors seem inexpensive too, but I haven't really
> >>>>> looked into them much other than a quick parametric search.
> >>>>>
> >>>>> I wonder what everyone thinks of this.
> >>>>>
> >>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> >>>>> <cheater00social at gmail.com> wrote:
> >>>>>>
> >>>>>> Don't you think this may have had something to do with you
> >>>>>> distributing AC power, rather than DC with 0V potential?
> >>>>>>
> >>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>>>>>
> >>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>>>>>
> >>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>>>>>
> >>>>>>>
> >>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> >>>>>>>
> >>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>>>>>
> >>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>>>>>
> >>>>>>> /mr
> >>>>>>>
> >>>>>>> ________________________________________________________
> >>>>>>> This is the Synth-diy mailing list
> >>>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>
> >>>>> ________________________________________________________
> >>>>> This is the Synth-diy mailing list
> >>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>
> >>>>
> >>>
> >>
> >
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From keysndrums at gmail.com  Fri Jul 10 21:23:27 2026
From: keysndrums at gmail.com (Paul McLean)
Date: Fri, 10 Jul 2026 13:23:27 -0600
Subject: [sdiy] GRP Genesi
In-Reply-To: <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
Message-ID: <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>

In my youth I would sneer at any preset synth (though I did enjoy fooling
around with the ProSoloist in the music store). Not for anyone serious
about synthesis and only for people who couldn't be bothered, or didn't
have the wearwithal to learn. (Funny how arrogant we can be in our youth).

The thing is, you can't discount how GREAT the ProSoloist/ProDGX sounds!
And you can't sneer at folks like Steve Walsh, Tony Banks, Denish DeYoung,
Michael Bodicker, Suzanne Cianni and the tons of other artists that used
the thing. Just can't replicate that "Fuzz Guitar 1" preset.

I found myself buying a ProDGX a few years ago and love it.

I've been amazed at just how much synthesis capability the ProSoloist/DGX
has; VCO (w/PWM), voltage-controlled low-pass filter,  4 high-pass filters,
10 band-pass filters, AR and ADSR envelopes, plus all the aftertouch
options. I asked SynthChaser about the possibility of patching one out, but
that guy is way too busy!

Pity ARP didn't develop it further.

Btw, I always read about how the ARP Explorer was a more patchable sort-of
ProSoloist. I played an Explorer for a while and I can assure they have
little in common beyond the shape of the case. Just sayin'...

- Paul McLean
Denver, CO

On Mon, Jul 6, 2026 at 9:42?PM Donald Tillman <don at till.com> wrote:

> On Jul 6, 2026, at 5:25?PM, Michael E Caloroso via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >
> >
> >
> > Other competitors - Moog, Roland, Yamaha, etc - had their preset synths
> but none lasted as long as the PS [...]
>
> Nobody else had the Tony Banks solo from Genesis' "Cinema Show".
>
>   -- Don
> --
> Donald Tillman, Palo Alto, California
> https://till.com
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mec.forumreader at gmail.com  Sat Jul 11 00:29:37 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Fri, 10 Jul 2026 18:29:37 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
 <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
Message-ID: <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>

The ProSoloist/DGX architecture is unique and none of ARP's other synths
had that architecture.  And the routing of filters and EGs changed between
presets.  So no, the Explorer is nothing like the PS.  Several of the
presets - not just the Fuzz Guitar - are inimitable on any other
non-modular synth.

You were not alone sneering at "preset synths"...  I was also arrogant
owning synths with a panel full of knobs and switches.  A friend offered to
sell his PS to me for a good price, and I thought "gee this sounds pretty
darn good".  The aftertouch is stellar.  When I assign AT to volume and
pitch, I can get a natural sounding vibrato.  None of my other gear with
aftertouch could duplicate that effect.  The new GRP module misses out on
the aftertouch.

I wasn't keen on the early Genesis/Tony Banks' connection when I bought my
PS, so my exploration of the PS was not biased by Genesis.  While the Fuzz
Guitar presets are good, many of the other presets sound organic.  The
flute preset is uncanny - I can hear a tone an octave above the
fundamental, but there's nothing in the circuit that generates the octave
tone!

A lot of inspiration came from the 2500 modular when laying out the
architecture in the design phase - voltage controlled filters, fixed
highpass/bandpass filters, PWM.  I've never seen any schematic for the
early Soloist to compare its architecture to the ProSoloist.  I know that
the Soloist had the 4027 (or 4017?) VCO module, probably the 4020 EG
modules, the fixed filters were encapsulated in modules, and a resistor
matrix to configure the presets.  Due to premature degradation, the
aftertouch element did not have a long life in the Soloist.  When it was
first shown at NAMM, Jeremy Hill was busy fixing Soloists that were
breaking.  I've seen one YT video of a restoration of a Soloist and they
were NOT service friendly!

After the poor reliability became known in the field, the decision was made
to design the ProSoloist.

Many owners dreamed about hacking a panel full of controls into a PS... not
worth the effort as you would be limited to VERY discrete settings of EG,
filter cutoff/resonance, etc.  Other than VCF cutoff, those sections are
not CV controlled - IE the ADSR elements were limited to 3-4 discrete
values per stage set by resistors that were shorted to ground via the OC
outputs of the ROMs.  There's no way to get continuous control of those
sections.

MC



On Fri, Jul 10, 2026 at 3:23?PM Paul McLean <keysndrums at gmail.com> wrote:

> In my youth I would sneer at any preset synth (though I did enjoy fooling
> around with the ProSoloist in the music store). Not for anyone serious
> about synthesis and only for people who couldn't be bothered, or didn't
> have the wearwithal to learn. (Funny how arrogant we can be in our youth).
>
> The thing is, you can't discount how GREAT the ProSoloist/ProDGX sounds!
> And you can't sneer at folks like Steve Walsh, Tony Banks, Denish DeYoung,
> Michael Bodicker, Suzanne Cianni and the tons of other artists that used
> the thing. Just can't replicate that "Fuzz Guitar 1" preset.
>
> I found myself buying a ProDGX a few years ago and love it.
>
> I've been amazed at just how much synthesis capability the ProSoloist/DGX
> has; VCO (w/PWM), voltage-controlled low-pass filter,  4 high-pass filters,
> 10 band-pass filters, AR and ADSR envelopes, plus all the aftertouch
> options. I asked SynthChaser about the possibility of patching one out, but
> that guy is way too busy!
>
> Pity ARP didn't develop it further.
>
> Btw, I always read about how the ARP Explorer was a more patchable sort-of
> ProSoloist. I played an Explorer for a while and I can assure they have
> little in common beyond the shape of the case. Just sayin'...
>
> - Paul McLean
> Denver, CO
>
> On Mon, Jul 6, 2026 at 9:42?PM Donald Tillman <don at till.com> wrote:
>
>> On Jul 6, 2026, at 5:25?PM, Michael E Caloroso via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>> >
>> >
>> >
>> > Other competitors - Moog, Roland, Yamaha, etc - had their preset synths
>> but none lasted as long as the PS [...]
>>
>> Nobody else had the Tony Banks solo from Genesis' "Cinema Show".
>>
>>   -- Don
>> --
>> Donald Tillman, Palo Alto, California
>> https://till.com
>>
>>
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>
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From tim.parkhurst at gmail.com  Sat Jul 11 02:45:47 2026
From: tim.parkhurst at gmail.com (Tim Parkhurst)
Date: Fri, 10 Jul 2026 17:45:47 -0700
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
 <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
 <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
Message-ID: <CACDGQT8USqGbUy2H4ifG=5jS+WG69m0T6EAi4k3YhnbxDdWz_Q@mail.gmail.com>

Cherry Audio has a Pro Soloist plug in with many of the extra ("under the
hood") control capabilities you speak of, in addition to a mod matrix,
split and layer functions, and several other niceties. I'm sure it requires
a good keyboard with aftertouch to really get the most out of it.
https://cherryaudio.com/products/pro-soloist


Tim (Amateur Soloist) Servo
---
"Imagination is more important than knowledge." - Albert Einstein





On Fri, Jul 10, 2026 at 3:36?PM Michael E Caloroso via Synth-diy <
synth-diy at synth-diy.org> wrote:

> The ProSoloist/DGX architecture is unique and none of ARP's other synths
> had that architecture.  And the routing of filters and EGs changed between
> presets.  So no, the Explorer is nothing like the PS.  Several of the
> presets - not just the Fuzz Guitar - are inimitable on any other
> non-modular synth.
>
> You were not alone sneering at "preset synths"...  I was also arrogant
> owning synths with a panel full of knobs and switches.  A friend offered to
> sell his PS to me for a good price, and I thought "gee this sounds pretty
> darn good".  The aftertouch is stellar.  When I assign AT to volume and
> pitch, I can get a natural sounding vibrato.  None of my other gear with
> aftertouch could duplicate that effect.  The new GRP module misses out on
> the aftertouch.
>
> I wasn't keen on the early Genesis/Tony Banks' connection when I bought my
> PS, so my exploration of the PS was not biased by Genesis.  While the Fuzz
> Guitar presets are good, many of the other presets sound organic.  The
> flute preset is uncanny - I can hear a tone an octave above the
> fundamental, but there's nothing in the circuit that generates the octave
> tone!
>
> A lot of inspiration came from the 2500 modular when laying out the
> architecture in the design phase - voltage controlled filters, fixed
> highpass/bandpass filters, PWM.  I've never seen any schematic for the
> early Soloist to compare its architecture to the ProSoloist.  I know that
> the Soloist had the 4027 (or 4017?) VCO module, probably the 4020 EG
> modules, the fixed filters were encapsulated in modules, and a resistor
> matrix to configure the presets.  Due to premature degradation, the
> aftertouch element did not have a long life in the Soloist.  When it was
> first shown at NAMM, Jeremy Hill was busy fixing Soloists that were
> breaking.  I've seen one YT video of a restoration of a Soloist and they
> were NOT service friendly!
>
> After the poor reliability became known in the field, the decision was
> made to design the ProSoloist.
>
> Many owners dreamed about hacking a panel full of controls into a PS...
> not worth the effort as you would be limited to VERY discrete settings of
> EG, filter cutoff/resonance, etc.  Other than VCF cutoff, those sections
> are not CV controlled - IE the ADSR elements were limited to 3-4 discrete
> values per stage set by resistors that were shorted to ground via the OC
> outputs of the ROMs.  There's no way to get continuous control of those
> sections.
>
> MC
>
>
>
> On Fri, Jul 10, 2026 at 3:23?PM Paul McLean <keysndrums at gmail.com> wrote:
>
>> In my youth I would sneer at any preset synth (though I did enjoy fooling
>> around with the ProSoloist in the music store). Not for anyone serious
>> about synthesis and only for people who couldn't be bothered, or didn't
>> have the wearwithal to learn. (Funny how arrogant we can be in our youth).
>>
>> The thing is, you can't discount how GREAT the ProSoloist/ProDGX sounds!
>> And you can't sneer at folks like Steve Walsh, Tony Banks, Denish DeYoung,
>> Michael Bodicker, Suzanne Cianni and the tons of other artists that used
>> the thing. Just can't replicate that "Fuzz Guitar 1" preset.
>>
>> I found myself buying a ProDGX a few years ago and love it.
>>
>> I've been amazed at just how much synthesis capability the ProSoloist/DGX
>> has; VCO (w/PWM), voltage-controlled low-pass filter,  4 high-pass filters,
>> 10 band-pass filters, AR and ADSR envelopes, plus all the aftertouch
>> options. I asked SynthChaser about the possibility of patching one out, but
>> that guy is way too busy!
>>
>> Pity ARP didn't develop it further.
>>
>> Btw, I always read about how the ARP Explorer was a more patchable
>> sort-of ProSoloist. I played an Explorer for a while and I can assure they
>> have little in common beyond the shape of the case. Just sayin'...
>>
>> - Paul McLean
>> Denver, CO
>>
>> On Mon, Jul 6, 2026 at 9:42?PM Donald Tillman <don at till.com> wrote:
>>
>>> On Jul 6, 2026, at 5:25?PM, Michael E Caloroso via Synth-diy <
>>> synth-diy at synth-diy.org> wrote:
>>> >
>>> >
>>> >
>>> > Other competitors - Moog, Roland, Yamaha, etc - had their preset
>>> synths but none lasted as long as the PS [...]
>>>
>>> Nobody else had the Tony Banks solo from Genesis' "Cinema Show".
>>>
>>>   -- Don
>>> --
>>> Donald Tillman, Palo Alto, California
>>> https://till.com
>>>
>>>
>>> ________________________________________________________
>>> This is the Synth-diy mailing list
>>> Submit email to: Synth-diy at synth-diy.org
>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>> Selling or trading? Use marketplace at synth-diy.org
>>>
>> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
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From mec.forumreader at gmail.com  Sat Jul 11 05:39:43 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Fri, 10 Jul 2026 23:39:43 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <CACDGQT8USqGbUy2H4ifG=5jS+WG69m0T6EAi4k3YhnbxDdWz_Q@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
 <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
 <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
 <CACDGQT8USqGbUy2H4ifG=5jS+WG69m0T6EAi4k3YhnbxDdWz_Q@mail.gmail.com>
Message-ID: <CAAv6=UDfF6R5VRQw=PNRLPJrK9BB41yFv2_LxPfX-pnGv5kb3g@mail.gmail.com>

I've tried plenty of software synths and plugins.  As an owner of several
vintage hardware synths, my assessment is that they do a better job looking
like the real thing than they sound.

That goes for most (not all) audio processor plugins too.

Guitar amp plugins and modelers are getting damn good though.  And I own
several vintage amps.

MC

On Fri, Jul 10, 2026 at 8:46?PM Tim Parkhurst <tim.parkhurst at gmail.com>
wrote:

> Cherry Audio has a Pro Soloist plug in with many of the extra ("under the
> hood") control capabilities you speak of, in addition to a mod matrix,
> split and layer functions, and several other niceties. I'm sure it requires
> a good keyboard with aftertouch to really get the most out of it.
> https://cherryaudio.com/products/pro-soloist
>
>
> Tim (Amateur Soloist) Servo
> ---
> "Imagination is more important than knowledge." - Albert Einstein
>
>
>
>
>
> On Fri, Jul 10, 2026 at 3:36?PM Michael E Caloroso via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
>> The ProSoloist/DGX architecture is unique and none of ARP's other synths
>> had that architecture.  And the routing of filters and EGs changed between
>> presets.  So no, the Explorer is nothing like the PS.  Several of the
>> presets - not just the Fuzz Guitar - are inimitable on any other
>> non-modular synth.
>>
>> You were not alone sneering at "preset synths"...  I was also arrogant
>> owning synths with a panel full of knobs and switches.  A friend offered to
>> sell his PS to me for a good price, and I thought "gee this sounds pretty
>> darn good".  The aftertouch is stellar.  When I assign AT to volume and
>> pitch, I can get a natural sounding vibrato.  None of my other gear with
>> aftertouch could duplicate that effect.  The new GRP module misses out on
>> the aftertouch.
>>
>> I wasn't keen on the early Genesis/Tony Banks' connection when I bought
>> my PS, so my exploration of the PS was not biased by Genesis.  While the
>> Fuzz Guitar presets are good, many of the other presets sound organic.  The
>> flute preset is uncanny - I can hear a tone an octave above the
>> fundamental, but there's nothing in the circuit that generates the octave
>> tone!
>>
>> A lot of inspiration came from the 2500 modular when laying out the
>> architecture in the design phase - voltage controlled filters, fixed
>> highpass/bandpass filters, PWM.  I've never seen any schematic for the
>> early Soloist to compare its architecture to the ProSoloist.  I know that
>> the Soloist had the 4027 (or 4017?) VCO module, probably the 4020 EG
>> modules, the fixed filters were encapsulated in modules, and a resistor
>> matrix to configure the presets.  Due to premature degradation, the
>> aftertouch element did not have a long life in the Soloist.  When it was
>> first shown at NAMM, Jeremy Hill was busy fixing Soloists that were
>> breaking.  I've seen one YT video of a restoration of a Soloist and they
>> were NOT service friendly!
>>
>> After the poor reliability became known in the field, the decision was
>> made to design the ProSoloist.
>>
>> Many owners dreamed about hacking a panel full of controls into a PS...
>> not worth the effort as you would be limited to VERY discrete settings of
>> EG, filter cutoff/resonance, etc.  Other than VCF cutoff, those sections
>> are not CV controlled - IE the ADSR elements were limited to 3-4 discrete
>> values per stage set by resistors that were shorted to ground via the OC
>> outputs of the ROMs.  There's no way to get continuous control of those
>> sections.
>>
>> MC
>>
>>
>>
>> On Fri, Jul 10, 2026 at 3:23?PM Paul McLean <keysndrums at gmail.com> wrote:
>>
>>> In my youth I would sneer at any preset synth (though I did enjoy
>>> fooling around with the ProSoloist in the music store). Not for anyone
>>> serious about synthesis and only for people who couldn't be bothered, or
>>> didn't have the wearwithal to learn. (Funny how arrogant we can be in our
>>> youth).
>>>
>>> The thing is, you can't discount how GREAT the ProSoloist/ProDGX sounds!
>>> And you can't sneer at folks like Steve Walsh, Tony Banks, Denish DeYoung,
>>> Michael Bodicker, Suzanne Cianni and the tons of other artists that used
>>> the thing. Just can't replicate that "Fuzz Guitar 1" preset.
>>>
>>> I found myself buying a ProDGX a few years ago and love it.
>>>
>>> I've been amazed at just how much synthesis capability the
>>> ProSoloist/DGX has; VCO (w/PWM), voltage-controlled low-pass filter,  4
>>> high-pass filters, 10 band-pass filters, AR and ADSR envelopes, plus all
>>> the aftertouch options. I asked SynthChaser about the possibility of
>>> patching one out, but that guy is way too busy!
>>>
>>> Pity ARP didn't develop it further.
>>>
>>> Btw, I always read about how the ARP Explorer was a more patchable
>>> sort-of ProSoloist. I played an Explorer for a while and I can assure they
>>> have little in common beyond the shape of the case. Just sayin'...
>>>
>>> - Paul McLean
>>> Denver, CO
>>>
>>> On Mon, Jul 6, 2026 at 9:42?PM Donald Tillman <don at till.com> wrote:
>>>
>>>> On Jul 6, 2026, at 5:25?PM, Michael E Caloroso via Synth-diy <
>>>> synth-diy at synth-diy.org> wrote:
>>>> >
>>>> >
>>>> >
>>>> > Other competitors - Moog, Roland, Yamaha, etc - had their preset
>>>> synths but none lasted as long as the PS [...]
>>>>
>>>> Nobody else had the Tony Banks solo from Genesis' "Cinema Show".
>>>>
>>>>   -- Don
>>>> --
>>>> Donald Tillman, Palo Alto, California
>>>> https://till.com
>>>>
>>>>
>>>> ________________________________________________________
>>>> This is the Synth-diy mailing list
>>>> Submit email to: Synth-diy at synth-diy.org
>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>> Check your settings at:
>>>> https://synth-diy.org/mailman/listinfo/synth-diy
>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>
>>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://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 Jul 11 10:51:51 2026
From: synthdiy at adambaby.com (Adam (synthDIY))
Date: Sat, 11 Jul 2026 18:51:51 +1000
Subject: [sdiy] GRP Genesi
In-Reply-To: <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
 <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
 <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
Message-ID: <1BBBC035-4184-4076-80A4-BA3CD7C7B68A@adambaby.com>



> On 11 Jul 2026, at 08:29, Michael E Caloroso via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Due to premature degradation, the aftertouch element did not have a long life in the Soloist. 


What was this element, exactly, do you recall?
I ask because the Hall sensor mechanism in my SH-2000, which gives a wonderful-feeling and musical aftertouch, is still working after 50 years....

A
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From mec.forumreader at gmail.com  Sat Jul 11 20:45:01 2026
From: mec.forumreader at gmail.com (Michael E Caloroso)
Date: Sat, 11 Jul 2026 14:45:01 -0400
Subject: [sdiy] GRP Genesi
In-Reply-To: <1BBBC035-4184-4076-80A4-BA3CD7C7B68A@adambaby.com>
References: <CAGHPcSBbwJvrOOqSTfwXODVFKDG19sZZx5Xj7a9Bwy9R1N_jFg@mail.gmail.com>
 <C19E2071-6FB4-421C-AC93-6655AEDAC5F3@adambaby.com>
 <CAGHPcSAZOX7HGnQ9W2tKsxYo83dq-WAuQT2nugP=B0bK_jLBHA@mail.gmail.com>
 <CAAv6=UCy=i+7gjK9g0r1wYb0Aq0kLgQfwBBqRkGfx530=A-z9Q@mail.gmail.com>
 <CAAv6=UBx7gjTYbJ0zNfqDV2OuUWQhizaQGknfkBzP8tdQhfLyg@mail.gmail.com>
 <CWLP265MB71328C23271EEC82E8C9A8E4DBF32@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <CAAv6=UBHa3YgE_EsWg00fdXkAB8Vc=D4BbV7636p+gXVPPoJ9Q@mail.gmail.com>
 <CACZGMxLj=HkVA=285xtNOQhOPqgauNNjq8HrRDyvWJMcY2dEGg@mail.gmail.com>
 <64ac45c1-87e6-4c80-a7e7-738db1ac50c8@go2.pl>
 <CWLP265MB7132035B0620077521D337ACDBF12@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM>
 <3AFB0585-C412-4851-9DF7-9BB40299791E@electricdruid.net>
 <CAAv6=UBPLv9gkqdEE28DjpU34w-J0-UN5DCm7iw5DmYYCCjxvg@mail.gmail.com>
 <C93682CE-2DDA-4FDF-A2A6-94528FD5A0A5@till.com>
 <CAPNAdpHvUuitoiwG=gM2q2S1Bh2XBAoOMi-=ifdG4LYMFm_cQw@mail.gmail.com>
 <CAAv6=UA1c2FRue5aFGSnrRM0Lvt3QxdtYM-nSA=ru3Dg2oK7aQ@mail.gmail.com>
 <1BBBC035-4184-4076-80A4-BA3CD7C7B68A@adambaby.com>
Message-ID: <CAAv6=UDQA2r0kT7AP4v3hmagd6ff7wAxWQ0RMgU0sDkq8J-sGw@mail.gmail.com>

> What was this element, exactly, do you recall?

>From a keyboardmag.com interview with Phil Dodds:

"The Soloist's troubles resulted from an all-analog design for both voicing
and changing preset, plus a primitive but patented method of responding to
aftertouch on the keyboard.  'Imagine a flat piece of metal about the size
of a piece of chewing gum, and another one above it' Dodds explains. 'We
took open-cell foam rubber that was impregnated with carbon and glued it to
one of the metal sticks.  There was a gap between the foam and the metal
stick above it, and there was a spring between them.  The whole keyboard
was such that when you pressed down extra hard it would bring these two
metal pieces together, compress the foam rubber, and become a variable
resistor.  The problem was that the foam rubber had a shelf life of about
eight months before it would dry out and quit working.  ...In the
ProSoloist, there was a bar running underneath all the keys with two
parallel strips of conductive material, a strip of carbon-based rubber
placed over that, and on top of that was a layer of piano felt.  When you
pressed the key hard, you'd be pressing into the piano felt, which would
cause the rubber to engage across the two conductors to create a variable
resistance [as the rubber was compressed between the metal strips].  It was
a vast improvement because the rubber had a lot longer shelf life.' "

It's worth noting that my ProSoloist is over 50 years old and
the aftertouch element still works.

On the Soloist, the element was placed between the synth base and the
bottom of the keyboard frame.  You could see the entire keyboard moving in
YT videos when pressure is applied for aftertouch.

On the ProSoloist, the element assembly was placed under the keys (the old
Pratt-Read assemblies which each key had a metal shell that the plastic
keyshell was fastened to), and fastened to a shelf on the metal assembly
that formed the combs for the key bumpers.

US patent 3,784,935 covers the ProSoloist aftertouch system, invented by Al
Pearlman and Dennis Colin.

MC

On Sat, Jul 11, 2026 at 4:52?AM Adam (synthDIY) <synthdiy at adambaby.com>
wrote:

>
>
> On 11 Jul 2026, at 08:29, Michael E Caloroso via Synth-diy <
> synth-diy at synth-diy.org> wrote:
>
> Due to premature degradation, the aftertouch element did not have a long
> life in the Soloist.
>
>
>
> What was this element, exactly, do you recall?
> I ask because the Hall sensor mechanism in my SH-2000, which gives a
> wonderful-feeling and musical aftertouch, is still working after 50
> years....
>
> A
>
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From listmail at misw.us  Sun Jul 12 17:47:11 2026
From: listmail at misw.us (listmail at misw.us)
Date: Sun, 12 Jul 2026 11:47:11 -0400 (EDT)
Subject: [sdiy] WTB: TR-808 PCBs
Message-ID: <87639058.200156.1783871231971@email.ionos.com>

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From cheater00social at gmail.com  Mon Jul 13 16:34:21 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Mon, 13 Jul 2026 16:34:21 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
Message-ID: <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>

So a person on another forum mentioned that converting the devices to
DC input could create ground loops.

As a reminder, I would be creating a "DC Bus" that carries +18, -18,
0V, and +48V, and I would wire it in a daisy-chain configuration going
from unit to unit. All of those units are in one rack on top of each
other.

Here's what they said:

> If you're intending to run them all off a single raw supply, that could
> introduce ground loops. The safest would be a bunch of small
> transformers, or one with multiple secondaries. Hammond 229 are
> small low profile transformers that could fit in a 1U cabinet.

So I've been thinking about this since they mentioned ground loops.
Here's what I think.

Currently all those rack devices already use a three-prong IEC C14
receptacle, with the earth wire connected to the chassis.

Instead of the chassis grounding point being connected via the C14
receptacle, and through a mains cable, to mains earth, it would now be
connected via my DC bus cable, which would have an earth conductor as
well.

So in terms of ground loops, not much changes.

However, given that we're talking about LOOPS, the area of the ground
loop would be important as well.

Currently each rack has a cable going to a power strip.

However, with my DC bus, I would be daisy chaining it, so the bus goes
to the bottom rack mount device, there's a plug there, then from that
plug there's a short cable going 1U above it, and so on.

That would create an extremely small area for the devices to create
ground loops.

I could (and maybe should) additionally put an earthed shield around
these wires, in order to shield them from EMI.

So in total, either nothing changes regarding ground loops, or it's
purely improved compared to the current situation.

I would be interested in everyone's thoughts on this matter.

Thanks.


On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
<cheater00social at gmail.com> wrote:
>
> there's one that's particularly noisy, but there are others that are a
> little noisy too, and it adds up. plus the heat just makes the room
> uncomfortable to be in. I've gone to great lengths to move all heat
> and noise generating equipment out of my day room, including moving
> the pcs to another place and connecting everything via fiber optics.
> so having 80W less heating my head will be an improvement once more.
>
> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> >
> > Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> >
> > Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> >
> > Or move the units away from where the mic can pick up the noise?
> >
> > Not my area of expertise, just wondering if there may be a simpler solition.
> >
> > Ed
> >
> >
> >
> > Get Outlook for iOS
> > ________________________________
> > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> > Sent: Thursday, 09 July 2026 17:39:07
> > To: cheater cheater <cheater00social at gmail.com>
> > Cc: synth-diy <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] Converting rack mount to DC input?
> >
> > You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> >
> > Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> >
> > Ben
> >
> > > On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> > >
> > > Thanks. A few questions:
> > >
> > > What if only some of the rails are connected, but not the one used for
> > > steering the relay (a fault)?
> > >
> > > Relays are kind of expensive, how much do you think that could end up costing?
> > >
> > > If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> > >
> > > On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>
> > >> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> > >>
> > >> Ben
> > >>
> > >>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> > >>>
> > >>> In order to provide the bridging functionality it has to have at least 8 pins.
> > >>>
> > >>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>>>
> > >>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> > >>>>
> > >>>> Ben
> > >>>>
> > >>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> > >>>>>
> > >>>>> One way to have DC input, but retain the capability of using the
> > >>>>> internal power supply, is to have a 4P2T switch for configuration.
> > >>>>>
> > >>>>> It seems that 4P2T switches are super expensive, especially if they're
> > >>>>> supposed to withstand, say, 1A.
> > >>>>>
> > >>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> > >>>>> are probably the best, and also the cheapest.
> > >>>>>
> > >>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> > >>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> > >>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> > >>>>>
> > >>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> > >>>>>
> > >>>>>> 4.4 CONTACT CURRENT RATING
> > >>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> > >>>>>
> > >>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> > >>>>> I'm sure it would handle something like 2A, especially if you share
> > >>>>> pins. You can even leave pins empty to prevent shorts during
> > >>>>> insertion.
> > >>>>>
> > >>>>> You could put the connector out the back, and either insert a plug-in
> > >>>>> "card" (really just a small edge connector with wires soldered on)
> > >>>>> that provides DC, or a pass-through "card" that shorts some pins
> > >>>>> together to carry power from the internal power supply. And now
> > >>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> > >>>>> is how I would fix the connector, but maybe a simple screw hole in the
> > >>>>> connector that mates with a threaded hole in the case could do the
> > >>>>> trick.
> > >>>>>
> > >>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > >>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> > >>>>>
> > >>>>> The cheapest one that can be found at Mouser currently and can be
> > >>>>> bought in low volumes is roughly 0.4 Euro.
> > >>>>>
> > >>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> > >>>>>
> > >>>>> Qty.  Unit Price  Ext. Price
> > >>>>> 1     ? 0,439     ? 0,44
> > >>>>> 10    ? 0,372     ? 3,72
> > >>>>> 25    ? 0,332     ? 8,30
> > >>>>> 100   ? 0,316     ? 31,60
> > >>>>>
> > >>>>> By making the connector require a dummy plug to connect the internal
> > >>>>> power supply into the circuit, it makes it impossible to connect both
> > >>>>> DC power and mains AC, so that makes the design intrinsically safe
> > >>>>> without using switches.
> > >>>>>
> > >>>>> Alternatively to a PCIE connector I could use some panel mount plug
> > >>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > >>>>> power from the internal power supply, and similarly use a shorting
> > >>>>> plug to use the internal power supply.
> > >>>>>
> > >>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > >>>>> Circular metric aren't better.
> > >>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > >>>>> so I can't find them by number of pins.
> > >>>>>
> > >>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > >>>>> They're latching (no need for screws and stuff). There doesn't seem to
> > >>>>> be a panel mount version, but one could mount a through-hole connector
> > >>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> > >>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> > >>>>> are return pins). Seems like a winner to me. They're also tiny so they
> > >>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> > >>>>> pain here might be making the rectangular hole and having it look any
> > >>>>> good. might be a case for custom die, maybe a small steel job that
> > >>>>> uses two bolts to screw together the two cutting parts through the
> > >>>>> sheet metal.
> > >>>>>
> > >>>>> "Pin and socket" connectors are the same kind of thing, just not
> > >>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > >>>>> useful alternative if more than 4 rails are necessary.
> > >>>>>
> > >>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> > >>>>> mount of some sort. But I'll be damned if I use one of those cursed
> > >>>>> things for power.
> > >>>>>
> > >>>>> Automotive connectors seem inexpensive too, but I haven't really
> > >>>>> looked into them much other than a quick parametric search.
> > >>>>>
> > >>>>> I wonder what everyone thinks of this.
> > >>>>>
> > >>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > >>>>> <cheater00social at gmail.com> wrote:
> > >>>>>>
> > >>>>>> Don't you think this may have had something to do with you
> > >>>>>> distributing AC power, rather than DC with 0V potential?
> > >>>>>>
> > >>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> > >>>>>>>
> > >>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> > >>>>>>>>
> > >>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> > >>>>>>>
> > >>>>>>>
> > >>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> > >>>>>>>
> > >>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> > >>>>>>>
> > >>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> > >>>>>>>
> > >>>>>>> /mr
> > >>>>>>>
> > >>>>>>> ________________________________________________________
> > >>>>>>> This is the Synth-diy mailing list
> > >>>>>>> Submit email to: Synth-diy at synth-diy.org
> > >>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > >>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > >>>>>>> Selling or trading? Use marketplace at synth-diy.org
> > >>>>>
> > >>>>> ________________________________________________________
> > >>>>> This is the Synth-diy mailing list
> > >>>>> Submit email to: Synth-diy at synth-diy.org
> > >>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > >>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > >>>>> Selling or trading? Use marketplace at synth-diy.org
> > >>>>>
> > >>>>
> > >>>
> > >>
> > >
> >
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Mon Jul 13 17:09:05 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Mon, 13 Jul 2026 17:09:05 +0200
Subject: [sdiy] Converting rack mount to DC input?
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Someone off-list made some comments, and here's what came out of it:

1. All my devices use balanced audio
2. The rack items actually tie together their grounds by using rack
screws and the rack rail
3. I don't know if the rack devices have isolated audio grounds, but
they're almost fully analogue, except for stuff like LED bar graphs
and on-off status LEDs for functions

On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
<cheater00social at gmail.com> wrote:
>
> So a person on another forum mentioned that converting the devices to
> DC input could create ground loops.
>
> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> 0V, and +48V, and I would wire it in a daisy-chain configuration going
> from unit to unit. All of those units are in one rack on top of each
> other.
>
> Here's what they said:
>
> > If you're intending to run them all off a single raw supply, that could
> > introduce ground loops. The safest would be a bunch of small
> > transformers, or one with multiple secondaries. Hammond 229 are
> > small low profile transformers that could fit in a 1U cabinet.
>
> So I've been thinking about this since they mentioned ground loops.
> Here's what I think.
>
> Currently all those rack devices already use a three-prong IEC C14
> receptacle, with the earth wire connected to the chassis.
>
> Instead of the chassis grounding point being connected via the C14
> receptacle, and through a mains cable, to mains earth, it would now be
> connected via my DC bus cable, which would have an earth conductor as
> well.
>
> So in terms of ground loops, not much changes.
>
> However, given that we're talking about LOOPS, the area of the ground
> loop would be important as well.
>
> Currently each rack has a cable going to a power strip.
>
> However, with my DC bus, I would be daisy chaining it, so the bus goes
> to the bottom rack mount device, there's a plug there, then from that
> plug there's a short cable going 1U above it, and so on.
>
> That would create an extremely small area for the devices to create
> ground loops.
>
> I could (and maybe should) additionally put an earthed shield around
> these wires, in order to shield them from EMI.
>
> So in total, either nothing changes regarding ground loops, or it's
> purely improved compared to the current situation.
>
> I would be interested in everyone's thoughts on this matter.
>
> Thanks.
>
>
> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> <cheater00social at gmail.com> wrote:
> >
> > there's one that's particularly noisy, but there are others that are a
> > little noisy too, and it adds up. plus the heat just makes the room
> > uncomfortable to be in. I've gone to great lengths to move all heat
> > and noise generating equipment out of my day room, including moving
> > the pcs to another place and connecting everything via fiber optics.
> > so having 80W less heating my head will be an improvement once more.
> >
> > On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> > >
> > > Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> > >
> > > Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> > >
> > > Or move the units away from where the mic can pick up the noise?
> > >
> > > Not my area of expertise, just wondering if there may be a simpler solition.
> > >
> > > Ed
> > >
> > >
> > >
> > > Get Outlook for iOS
> > > ________________________________
> > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> > > Sent: Thursday, 09 July 2026 17:39:07
> > > To: cheater cheater <cheater00social at gmail.com>
> > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > >
> > > You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> > >
> > > Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> > >
> > > Ben
> > >
> > > > On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> > > >
> > > > Thanks. A few questions:
> > > >
> > > > What if only some of the rails are connected, but not the one used for
> > > > steering the relay (a fault)?
> > > >
> > > > Relays are kind of expensive, how much do you think that could end up costing?
> > > >
> > > > If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> > > >
> > > > On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > > >>
> > > >> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> > > >>
> > > >> Ben
> > > >>
> > > >>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> > > >>>
> > > >>> In order to provide the bridging functionality it has to have at least 8 pins.
> > > >>>
> > > >>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > > >>>>
> > > >>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> > > >>>>
> > > >>>> Ben
> > > >>>>
> > > >>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> > > >>>>>
> > > >>>>> One way to have DC input, but retain the capability of using the
> > > >>>>> internal power supply, is to have a 4P2T switch for configuration.
> > > >>>>>
> > > >>>>> It seems that 4P2T switches are super expensive, especially if they're
> > > >>>>> supposed to withstand, say, 1A.
> > > >>>>>
> > > >>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> > > >>>>> are probably the best, and also the cheapest.
> > > >>>>>
> > > >>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> > > >>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> > > >>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> > > >>>>>
> > > >>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> > > >>>>>
> > > >>>>>> 4.4 CONTACT CURRENT RATING
> > > >>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> > > >>>>>
> > > >>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> > > >>>>> I'm sure it would handle something like 2A, especially if you share
> > > >>>>> pins. You can even leave pins empty to prevent shorts during
> > > >>>>> insertion.
> > > >>>>>
> > > >>>>> You could put the connector out the back, and either insert a plug-in
> > > >>>>> "card" (really just a small edge connector with wires soldered on)
> > > >>>>> that provides DC, or a pass-through "card" that shorts some pins
> > > >>>>> together to carry power from the internal power supply. And now
> > > >>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> > > >>>>> is how I would fix the connector, but maybe a simple screw hole in the
> > > >>>>> connector that mates with a threaded hole in the case could do the
> > > >>>>> trick.
> > > >>>>>
> > > >>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > > >>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> > > >>>>>
> > > >>>>> The cheapest one that can be found at Mouser currently and can be
> > > >>>>> bought in low volumes is roughly 0.4 Euro.
> > > >>>>>
> > > >>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> > > >>>>>
> > > >>>>> Qty.  Unit Price  Ext. Price
> > > >>>>> 1     ? 0,439     ? 0,44
> > > >>>>> 10    ? 0,372     ? 3,72
> > > >>>>> 25    ? 0,332     ? 8,30
> > > >>>>> 100   ? 0,316     ? 31,60
> > > >>>>>
> > > >>>>> By making the connector require a dummy plug to connect the internal
> > > >>>>> power supply into the circuit, it makes it impossible to connect both
> > > >>>>> DC power and mains AC, so that makes the design intrinsically safe
> > > >>>>> without using switches.
> > > >>>>>
> > > >>>>> Alternatively to a PCIE connector I could use some panel mount plug
> > > >>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > > >>>>> power from the internal power supply, and similarly use a shorting
> > > >>>>> plug to use the internal power supply.
> > > >>>>>
> > > >>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > > >>>>> Circular metric aren't better.
> > > >>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > > >>>>> so I can't find them by number of pins.
> > > >>>>>
> > > >>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > > >>>>> They're latching (no need for screws and stuff). There doesn't seem to
> > > >>>>> be a panel mount version, but one could mount a through-hole connector
> > > >>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> > > >>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> > > >>>>> are return pins). Seems like a winner to me. They're also tiny so they
> > > >>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> > > >>>>> pain here might be making the rectangular hole and having it look any
> > > >>>>> good. might be a case for custom die, maybe a small steel job that
> > > >>>>> uses two bolts to screw together the two cutting parts through the
> > > >>>>> sheet metal.
> > > >>>>>
> > > >>>>> "Pin and socket" connectors are the same kind of thing, just not
> > > >>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > > >>>>> useful alternative if more than 4 rails are necessary.
> > > >>>>>
> > > >>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> > > >>>>> mount of some sort. But I'll be damned if I use one of those cursed
> > > >>>>> things for power.
> > > >>>>>
> > > >>>>> Automotive connectors seem inexpensive too, but I haven't really
> > > >>>>> looked into them much other than a quick parametric search.
> > > >>>>>
> > > >>>>> I wonder what everyone thinks of this.
> > > >>>>>
> > > >>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > > >>>>> <cheater00social at gmail.com> wrote:
> > > >>>>>>
> > > >>>>>> Don't you think this may have had something to do with you
> > > >>>>>> distributing AC power, rather than DC with 0V potential?
> > > >>>>>>
> > > >>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> > > >>>>>>>
> > > >>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> > > >>>>>>>>
> > > >>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> > > >>>>>>>
> > > >>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> > > >>>>>>>
> > > >>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> > > >>>>>>>
> > > >>>>>>> /mr
> > > >>>>>>>
> > > >>>>>>> ________________________________________________________
> > > >>>>>>> This is the Synth-diy mailing list
> > > >>>>>>> Submit email to: Synth-diy at synth-diy.org
> > > >>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > >>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > >>>>>>> Selling or trading? Use marketplace at synth-diy.org
> > > >>>>>
> > > >>>>> ________________________________________________________
> > > >>>>> This is the Synth-diy mailing list
> > > >>>>> Submit email to: Synth-diy at synth-diy.org
> > > >>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > >>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > >>>>> Selling or trading? Use marketplace at synth-diy.org
> > > >>>>>
> > > >>>>
> > > >>>
> > > >>
> > > >
> > >
> > >
> > > ________________________________________________________
> > > This is the Synth-diy mailing list
> > > Submit email to: Synth-diy at synth-diy.org
> > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > Selling or trading? Use marketplace at synth-diy.org


From elmacaco at hotmail.com  Mon Jul 13 19:00:39 2026
From: elmacaco at hotmail.com (el macaco)
Date: Mon, 13 Jul 2026 17:00:39 +0000
Subject: [sdiy] WTB: TR-808 PCBs
In-Reply-To: <87639058.200156.1783871231971@email.ionos.com>
References: <87639058.200156.1783871231971@email.ionos.com>
Message-ID: <SJ2P222MB08540804C3F45C850503C8D1C4FA2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>

Do RE-808 boards from din-sync.com help?

Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Altitude via Synth-diy <synth-diy at synth-diy.org>
Sent: Sunday, 12 July 2026 10:47:11
To: Synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: [sdiy] WTB: TR-808 PCBs

Any condition, burned cracked in two, whatever
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From cheater00social at gmail.com  Mon Jul 13 21:24:02 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Mon, 13 Jul 2026 21:24:02 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
 <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>
 <CAGn5V-9aBX1N9aQK7pgPjiAgjcb1pSEo5LwhY4s=Hv8i0=fE3A@mail.gmail.com>
 <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
Message-ID: <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>

A little more to qualify my question, it's easier to find panel mount
hardware for those, can just use a keystone plug, and they take up
less space, so easier to fit on the back of a 1U device.

On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
<cheater00social at gmail.com> wrote:
>
> Another question - how is everyone feeling about rj-45 as a power
> plug? carrying up to 800 mA. I've seen threads where people say
> they've been putting 1A through those, per pin. Thanks.
>
> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
>
> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
>
>
> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
> <cheater00social at gmail.com> wrote:
> >
> > Someone off-list made some comments, and here's what came out of it:
> >
> > 1. All my devices use balanced audio
> > 2. The rack items actually tie together their grounds by using rack
> > screws and the rack rail
> > 3. I don't know if the rack devices have isolated audio grounds, but
> > they're almost fully analogue, except for stuff like LED bar graphs
> > and on-off status LEDs for functions
> >
> > On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
> > <cheater00social at gmail.com> wrote:
> > >
> > > So a person on another forum mentioned that converting the devices to
> > > DC input could create ground loops.
> > >
> > > As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> > > 0V, and +48V, and I would wire it in a daisy-chain configuration going
> > > from unit to unit. All of those units are in one rack on top of each
> > > other.
> > >
> > > Here's what they said:
> > >
> > > > If you're intending to run them all off a single raw supply, that could
> > > > introduce ground loops. The safest would be a bunch of small
> > > > transformers, or one with multiple secondaries. Hammond 229 are
> > > > small low profile transformers that could fit in a 1U cabinet.
> > >
> > > So I've been thinking about this since they mentioned ground loops.
> > > Here's what I think.
> > >
> > > Currently all those rack devices already use a three-prong IEC C14
> > > receptacle, with the earth wire connected to the chassis.
> > >
> > > Instead of the chassis grounding point being connected via the C14
> > > receptacle, and through a mains cable, to mains earth, it would now be
> > > connected via my DC bus cable, which would have an earth conductor as
> > > well.
> > >
> > > So in terms of ground loops, not much changes.
> > >
> > > However, given that we're talking about LOOPS, the area of the ground
> > > loop would be important as well.
> > >
> > > Currently each rack has a cable going to a power strip.
> > >
> > > However, with my DC bus, I would be daisy chaining it, so the bus goes
> > > to the bottom rack mount device, there's a plug there, then from that
> > > plug there's a short cable going 1U above it, and so on.
> > >
> > > That would create an extremely small area for the devices to create
> > > ground loops.
> > >
> > > I could (and maybe should) additionally put an earthed shield around
> > > these wires, in order to shield them from EMI.
> > >
> > > So in total, either nothing changes regarding ground loops, or it's
> > > purely improved compared to the current situation.
> > >
> > > I would be interested in everyone's thoughts on this matter.
> > >
> > > Thanks.
> > >
> > >
> > > On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> > > <cheater00social at gmail.com> wrote:
> > > >
> > > > there's one that's particularly noisy, but there are others that are a
> > > > little noisy too, and it adds up. plus the heat just makes the room
> > > > uncomfortable to be in. I've gone to great lengths to move all heat
> > > > and noise generating equipment out of my day room, including moving
> > > > the pcs to another place and connecting everything via fiber optics.
> > > > so having 80W less heating my head will be an improvement once more.
> > > >
> > > > On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> > > > >
> > > > > Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> > > > >
> > > > > Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> > > > >
> > > > > Or move the units away from where the mic can pick up the noise?
> > > > >
> > > > > Not my area of expertise, just wondering if there may be a simpler solition.
> > > > >
> > > > > Ed
> > > > >
> > > > >
> > > > >
> > > > > Get Outlook for iOS
> > > > > ________________________________
> > > > > From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> > > > > Sent: Thursday, 09 July 2026 17:39:07
> > > > > To: cheater cheater <cheater00social at gmail.com>
> > > > > Cc: synth-diy <synth-diy at synth-diy.org>
> > > > > Subject: Re: [sdiy] Converting rack mount to DC input?
> > > > >
> > > > > You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> > > > >
> > > > > Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> > > > >
> > > > > Ben
> > > > >
> > > > > > On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> > > > > >
> > > > > > Thanks. A few questions:
> > > > > >
> > > > > > What if only some of the rails are connected, but not the one used for
> > > > > > steering the relay (a fault)?
> > > > > >
> > > > > > Relays are kind of expensive, how much do you think that could end up costing?
> > > > > >
> > > > > > If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> > > > > >
> > > > > > On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > > > > >>
> > > > > >> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> > > > > >>
> > > > > >> Ben
> > > > > >>
> > > > > >>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> > > > > >>>
> > > > > >>> In order to provide the bridging functionality it has to have at least 8 pins.
> > > > > >>>
> > > > > >>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > > > > >>>>
> > > > > >>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> > > > > >>>>
> > > > > >>>> Ben
> > > > > >>>>
> > > > > >>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> > > > > >>>>>
> > > > > >>>>> One way to have DC input, but retain the capability of using the
> > > > > >>>>> internal power supply, is to have a 4P2T switch for configuration.
> > > > > >>>>>
> > > > > >>>>> It seems that 4P2T switches are super expensive, especially if they're
> > > > > >>>>> supposed to withstand, say, 1A.
> > > > > >>>>>
> > > > > >>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> > > > > >>>>> are probably the best, and also the cheapest.
> > > > > >>>>>
> > > > > >>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> > > > > >>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> > > > > >>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> > > > > >>>>>
> > > > > >>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> > > > > >>>>>
> > > > > >>>>>> 4.4 CONTACT CURRENT RATING
> > > > > >>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> > > > > >>>>>
> > > > > >>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> > > > > >>>>> I'm sure it would handle something like 2A, especially if you share
> > > > > >>>>> pins. You can even leave pins empty to prevent shorts during
> > > > > >>>>> insertion.
> > > > > >>>>>
> > > > > >>>>> You could put the connector out the back, and either insert a plug-in
> > > > > >>>>> "card" (really just a small edge connector with wires soldered on)
> > > > > >>>>> that provides DC, or a pass-through "card" that shorts some pins
> > > > > >>>>> together to carry power from the internal power supply. And now
> > > > > >>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> > > > > >>>>> is how I would fix the connector, but maybe a simple screw hole in the
> > > > > >>>>> connector that mates with a threaded hole in the case could do the
> > > > > >>>>> trick.
> > > > > >>>>>
> > > > > >>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > > > > >>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> > > > > >>>>>
> > > > > >>>>> The cheapest one that can be found at Mouser currently and can be
> > > > > >>>>> bought in low volumes is roughly 0.4 Euro.
> > > > > >>>>>
> > > > > >>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> > > > > >>>>>
> > > > > >>>>> Qty.  Unit Price  Ext. Price
> > > > > >>>>> 1     ? 0,439     ? 0,44
> > > > > >>>>> 10    ? 0,372     ? 3,72
> > > > > >>>>> 25    ? 0,332     ? 8,30
> > > > > >>>>> 100   ? 0,316     ? 31,60
> > > > > >>>>>
> > > > > >>>>> By making the connector require a dummy plug to connect the internal
> > > > > >>>>> power supply into the circuit, it makes it impossible to connect both
> > > > > >>>>> DC power and mains AC, so that makes the design intrinsically safe
> > > > > >>>>> without using switches.
> > > > > >>>>>
> > > > > >>>>> Alternatively to a PCIE connector I could use some panel mount plug
> > > > > >>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > > > > >>>>> power from the internal power supply, and similarly use a shorting
> > > > > >>>>> plug to use the internal power supply.
> > > > > >>>>>
> > > > > >>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > > > > >>>>> Circular metric aren't better.
> > > > > >>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > > > > >>>>> so I can't find them by number of pins.
> > > > > >>>>>
> > > > > >>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > > > > >>>>> They're latching (no need for screws and stuff). There doesn't seem to
> > > > > >>>>> be a panel mount version, but one could mount a through-hole connector
> > > > > >>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> > > > > >>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> > > > > >>>>> are return pins). Seems like a winner to me. They're also tiny so they
> > > > > >>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> > > > > >>>>> pain here might be making the rectangular hole and having it look any
> > > > > >>>>> good. might be a case for custom die, maybe a small steel job that
> > > > > >>>>> uses two bolts to screw together the two cutting parts through the
> > > > > >>>>> sheet metal.
> > > > > >>>>>
> > > > > >>>>> "Pin and socket" connectors are the same kind of thing, just not
> > > > > >>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > > > > >>>>> useful alternative if more than 4 rails are necessary.
> > > > > >>>>>
> > > > > >>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> > > > > >>>>> mount of some sort. But I'll be damned if I use one of those cursed
> > > > > >>>>> things for power.
> > > > > >>>>>
> > > > > >>>>> Automotive connectors seem inexpensive too, but I haven't really
> > > > > >>>>> looked into them much other than a quick parametric search.
> > > > > >>>>>
> > > > > >>>>> I wonder what everyone thinks of this.
> > > > > >>>>>
> > > > > >>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > > > > >>>>> <cheater00social at gmail.com> wrote:
> > > > > >>>>>>
> > > > > >>>>>> Don't you think this may have had something to do with you
> > > > > >>>>>> distributing AC power, rather than DC with 0V potential?
> > > > > >>>>>>
> > > > > >>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> > > > > >>>>>>>>
> > > > > >>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> > > > > >>>>>>>
> > > > > >>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> > > > > >>>>>>>
> > > > > >>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> > > > > >>>>>>>
> > > > > >>>>>>> /mr
> > > > > >>>>>>>
> > > > > >>>>>>> ________________________________________________________
> > > > > >>>>>>> This is the Synth-diy mailing list
> > > > > >>>>>>> Submit email to: Synth-diy at synth-diy.org
> > > > > >>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > >>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > > >>>>>>> Selling or trading? Use marketplace at synth-diy.org
> > > > > >>>>>
> > > > > >>>>> ________________________________________________________
> > > > > >>>>> This is the Synth-diy mailing list
> > > > > >>>>> Submit email to: Synth-diy at synth-diy.org
> > > > > >>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > >>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > > >>>>> Selling or trading? Use marketplace at synth-diy.org
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>
> > > > > >
> > > > >
> > > > >
> > > > > ________________________________________________________
> > > > > This is the Synth-diy mailing list
> > > > > Submit email to: Synth-diy at synth-diy.org
> > > > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > > > Selling or trading? Use marketplace at synth-diy.org


From list at mikebeauchamp.com  Mon Jul 13 21:55:57 2026
From: list at mikebeauchamp.com (Mike Beauchamp)
Date: Mon, 13 Jul 2026 15:55:57 -0400
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
Message-ID: <4dc49387-835a-439e-b191-361f633c2911@mikebeauchamp.com>

Hi Mattias,

If the 16 V AC is going into a standard rectified bipolar supply, one 
side of the AC line in each of those two units is being tied to ground.

In your case, I'd guess that each device ties a different side of the AC 
line to ground.

Here's the schematic for a really similar power supply:

https://musicfromouterspace.com/analogsynth_new/WALLWARTSUPPLY/wallwart_added_load_rs_schem.pdf


If you modify your Y cable to swap the AC lines on one of the outputs, 
it will probably work again.


Mike





On 2026-07-04 17:19, Mattias Rickardsson wrote:

> This reminds me of a somewhat similar issue I had many years ago:
> 
> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. 
> (Swedish-sold old Korgs had a big external power transformer to step 
> down from 220 V AC to 16 V AC, which is then what the instrument then 
> accepts via a plug with 2 flat prongs that doesn't seem roadworthy with 
> European electrical standards.)
> 
> So I made a short splitter Y cable on the 16 V AC side and attached both 
> instruments and turned them on. But then I connected an audio cable 
> between them (or audio cables from both units to the same mixer) and I 
> had a blown fuse! It was apparently not okay to connect those two 
> grounds together when running off the same AC supply.
> 
> /mr
> 
> 
> ________________________________________________________
> This is the Synth-diy mailing list
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From dh at atoav.com  Mon Jul 13 22:12:44 2026
From: dh at atoav.com (David Huss)
Date: Mon, 13 Jul 2026 22:12:44 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
 <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>
 <CAGn5V-9aBX1N9aQK7pgPjiAgjcb1pSEo5LwhY4s=Hv8i0=fE3A@mail.gmail.com>
 <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
 <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
Message-ID: <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>

Ethernet has a PoE (Power-over-Ethernet) standard and in its maximum 
PoE++ variant Type 4 switches can supply up to 100 Watts over one 
ethernet port.

HOWEVER: PoE similar to USB-C PD (Power Delivery) negotiates this power 
delivery with the device attached to it and also has some measures to 
detect faulty connections/cables. A self-baked solution may fail 
spectacularily (and consider what happens if someone plugs your power 
supply into an actual network port. Professional networking equipment 
can easily cost mor than most peoples cars are worth..

For this type of DC connection there are dedicated connectors and 
cables. The price ranges and features vary wildly, but a good and cheap 
solution that is tough enough for live-gig is the GX16 5-pin connector, 
you can get a pack of 5 plugs AND jacks (including a shitty 
screwdriver!) for 9 Euros on Amazon. The plug has a thread so it can be 
locked and it is not too hard to solder.

This type of plug has sometimes also be used in mixer power supplies 
that work with outboard power supplies with exactly the requirements you 
have, so it has been done before as well.

Cheers,
David



On 2026-07-13 21:24, cheater cheater via Synth-diy wrote:
> A little more to qualify my question, it's easier to find panel mount
> hardware for those, can just use a keystone plug, and they take up
> less space, so easier to fit on the back of a 1U device.
> 
> On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
> <cheater00social at gmail.com> wrote:
>>
>> Another question - how is everyone feeling about rj-45 as a power
>> plug? carrying up to 800 mA. I've seen threads where people say
>> they've been putting 1A through those, per pin. Thanks.
>>
>> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
>>
>> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
>>
>>
>> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
>> <cheater00social at gmail.com> wrote:
>>>
>>> Someone off-list made some comments, and here's what came out of it:
>>>
>>> 1. All my devices use balanced audio
>>> 2. The rack items actually tie together their grounds by using rack
>>> screws and the rack rail
>>> 3. I don't know if the rack devices have isolated audio grounds, but
>>> they're almost fully analogue, except for stuff like LED bar graphs
>>> and on-off status LEDs for functions
>>>
>>> On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
>>> <cheater00social at gmail.com> wrote:
>>>>
>>>> So a person on another forum mentioned that converting the devices to
>>>> DC input could create ground loops.
>>>>
>>>> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
>>>> 0V, and +48V, and I would wire it in a daisy-chain configuration going
>>>> from unit to unit. All of those units are in one rack on top of each
>>>> other.
>>>>
>>>> Here's what they said:
>>>>
>>>>> If you're intending to run them all off a single raw supply, that could
>>>>> introduce ground loops. The safest would be a bunch of small
>>>>> transformers, or one with multiple secondaries. Hammond 229 are
>>>>> small low profile transformers that could fit in a 1U cabinet.
>>>>
>>>> So I've been thinking about this since they mentioned ground loops.
>>>> Here's what I think.
>>>>
>>>> Currently all those rack devices already use a three-prong IEC C14
>>>> receptacle, with the earth wire connected to the chassis.
>>>>
>>>> Instead of the chassis grounding point being connected via the C14
>>>> receptacle, and through a mains cable, to mains earth, it would now be
>>>> connected via my DC bus cable, which would have an earth conductor as
>>>> well.
>>>>
>>>> So in terms of ground loops, not much changes.
>>>>
>>>> However, given that we're talking about LOOPS, the area of the ground
>>>> loop would be important as well.
>>>>
>>>> Currently each rack has a cable going to a power strip.
>>>>
>>>> However, with my DC bus, I would be daisy chaining it, so the bus goes
>>>> to the bottom rack mount device, there's a plug there, then from that
>>>> plug there's a short cable going 1U above it, and so on.
>>>>
>>>> That would create an extremely small area for the devices to create
>>>> ground loops.
>>>>
>>>> I could (and maybe should) additionally put an earthed shield around
>>>> these wires, in order to shield them from EMI.
>>>>
>>>> So in total, either nothing changes regarding ground loops, or it's
>>>> purely improved compared to the current situation.
>>>>
>>>> I would be interested in everyone's thoughts on this matter.
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
>>>> <cheater00social at gmail.com> wrote:
>>>>>
>>>>> there's one that's particularly noisy, but there are others that are a
>>>>> little noisy too, and it adds up. plus the heat just makes the room
>>>>> uncomfortable to be in. I've gone to great lengths to move all heat
>>>>> and noise generating equipment out of my day room, including moving
>>>>> the pcs to another place and connecting everything via fiber optics.
>>>>> so having 80W less heating my head will be an improvement once more.
>>>>>
>>>>> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
>>>>>>
>>>>>> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
>>>>>>
>>>>>> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
>>>>>>
>>>>>> Or move the units away from where the mic can pick up the noise?
>>>>>>
>>>>>> Not my area of expertise, just wondering if there may be a simpler solition.
>>>>>>
>>>>>> Ed
>>>>>>
>>>>>>
>>>>>>
>>>>>> Get Outlook for iOS
>>>>>> ________________________________
>>>>>> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
>>>>>> Sent: Thursday, 09 July 2026 17:39:07
>>>>>> To: cheater cheater <cheater00social at gmail.com>
>>>>>> Cc: synth-diy <synth-diy at synth-diy.org>
>>>>>> Subject: Re: [sdiy] Converting rack mount to DC input?
>>>>>>
>>>>>> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
>>>>>>
>>>>>> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
>>>>>>
>>>>>> Ben
>>>>>>
>>>>>>> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
>>>>>>>
>>>>>>> Thanks. A few questions:
>>>>>>>
>>>>>>> What if only some of the rails are connected, but not the one used for
>>>>>>> steering the relay (a fault)?
>>>>>>>
>>>>>>> Relays are kind of expensive, how much do you think that could end up costing?
>>>>>>>
>>>>>>> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
>>>>>>>
>>>>>>> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
>>>>>>>>
>>>>>>>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
>>>>>>>>
>>>>>>>> Ben
>>>>>>>>
>>>>>>>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
>>>>>>>>>
>>>>>>>>> In order to provide the bridging functionality it has to have at least 8 pins.
>>>>>>>>>
>>>>>>>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
>>>>>>>>>>
>>>>>>>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
>>>>>>>>>>
>>>>>>>>>> Ben
>>>>>>>>>>
>>>>>>>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>>>>>>>>>>
>>>>>>>>>>> One way to have DC input, but retain the capability of using the
>>>>>>>>>>> internal power supply, is to have a 4P2T switch for configuration.
>>>>>>>>>>>
>>>>>>>>>>> It seems that 4P2T switches are super expensive, especially if they're
>>>>>>>>>>> supposed to withstand, say, 1A.
>>>>>>>>>>>
>>>>>>>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
>>>>>>>>>>> are probably the best, and also the cheapest.
>>>>>>>>>>>
>>>>>>>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
>>>>>>>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
>>>>>>>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
>>>>>>>>>>>
>>>>>>>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
>>>>>>>>>>>
>>>>>>>>>>>> 4.4 CONTACT CURRENT RATING
>>>>>>>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
>>>>>>>>>>>
>>>>>>>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
>>>>>>>>>>> I'm sure it would handle something like 2A, especially if you share
>>>>>>>>>>> pins. You can even leave pins empty to prevent shorts during
>>>>>>>>>>> insertion.
>>>>>>>>>>>
>>>>>>>>>>> You could put the connector out the back, and either insert a plug-in
>>>>>>>>>>> "card" (really just a small edge connector with wires soldered on)
>>>>>>>>>>> that provides DC, or a pass-through "card" that shorts some pins
>>>>>>>>>>> together to carry power from the internal power supply. And now
>>>>>>>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
>>>>>>>>>>> is how I would fix the connector, but maybe a simple screw hole in the
>>>>>>>>>>> connector that mates with a threaded hole in the case could do the
>>>>>>>>>>> trick.
>>>>>>>>>>>
>>>>>>>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
>>>>>>>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
>>>>>>>>>>>
>>>>>>>>>>> The cheapest one that can be found at Mouser currently and can be
>>>>>>>>>>> bought in low volumes is roughly 0.4 Euro.
>>>>>>>>>>>
>>>>>>>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
>>>>>>>>>>>
>>>>>>>>>>> Qty.  Unit Price  Ext. Price
>>>>>>>>>>> 1     ? 0,439     ? 0,44
>>>>>>>>>>> 10    ? 0,372     ? 3,72
>>>>>>>>>>> 25    ? 0,332     ? 8,30
>>>>>>>>>>> 100   ? 0,316     ? 31,60
>>>>>>>>>>>
>>>>>>>>>>> By making the connector require a dummy plug to connect the internal
>>>>>>>>>>> power supply into the circuit, it makes it impossible to connect both
>>>>>>>>>>> DC power and mains AC, so that makes the design intrinsically safe
>>>>>>>>>>> without using switches.
>>>>>>>>>>>
>>>>>>>>>>> Alternatively to a PCIE connector I could use some panel mount plug
>>>>>>>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
>>>>>>>>>>> power from the internal power supply, and similarly use a shorting
>>>>>>>>>>> plug to use the internal power supply.
>>>>>>>>>>>
>>>>>>>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
>>>>>>>>>>> Circular metric aren't better.
>>>>>>>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
>>>>>>>>>>> so I can't find them by number of pins.
>>>>>>>>>>>
>>>>>>>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
>>>>>>>>>>> They're latching (no need for screws and stuff). There doesn't seem to
>>>>>>>>>>> be a panel mount version, but one could mount a through-hole connector
>>>>>>>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
>>>>>>>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
>>>>>>>>>>> are return pins). Seems like a winner to me. They're also tiny so they
>>>>>>>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
>>>>>>>>>>> pain here might be making the rectangular hole and having it look any
>>>>>>>>>>> good. might be a case for custom die, maybe a small steel job that
>>>>>>>>>>> uses two bolts to screw together the two cutting parts through the
>>>>>>>>>>> sheet metal.
>>>>>>>>>>>
>>>>>>>>>>> "Pin and socket" connectors are the same kind of thing, just not
>>>>>>>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
>>>>>>>>>>> useful alternative if more than 4 rails are necessary.
>>>>>>>>>>>
>>>>>>>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
>>>>>>>>>>> mount of some sort. But I'll be damned if I use one of those cursed
>>>>>>>>>>> things for power.
>>>>>>>>>>>
>>>>>>>>>>> Automotive connectors seem inexpensive too, but I haven't really
>>>>>>>>>>> looked into them much other than a quick parametric search.
>>>>>>>>>>>
>>>>>>>>>>> I wonder what everyone thinks of this.
>>>>>>>>>>>
>>>>>>>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
>>>>>>>>>>> <cheater00social at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> Don't you think this may have had something to do with you
>>>>>>>>>>>> distributing AC power, rather than DC with 0V potential?
>>>>>>>>>>>>
>>>>>>>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
>>>>>>>>>>>>>
>>>>>>>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
>>>>>>>>>>>>>
>>>>>>>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
>>>>>>>>>>>>>
>>>>>>>>>>>>> /mr
>>>>>>>>>>>>>
>>>>>>>>>>>>> ________________________________________________________
>>>>>>>>>>>>> This is the Synth-diy mailing list
>>>>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>>>>>>>>
>>>>>>>>>>> ________________________________________________________
>>>>>>>>>>> This is the Synth-diy mailing list
>>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> ________________________________________________________
>>>>>> This is the Synth-diy mailing list
>>>>>> Submit email to: Synth-diy at synth-diy.org
>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>>>>>> Selling or trading? Use marketplace at synth-diy.org
> 
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Tue Jul 14 14:03:20 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 14 Jul 2026 14:03:20 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
 <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>
 <CAGn5V-9aBX1N9aQK7pgPjiAgjcb1pSEo5LwhY4s=Hv8i0=fE3A@mail.gmail.com>
 <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
 <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
 <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>
Message-ID: <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>

Hmm, GX16 is interesting, thank you! Let me see if I can find one with
8 pins easily - that's the minimum that I need (see earlier emails
why: to either supply external DC (+17, -17, 0, 48) or loop back the
internal PSU (half the pins would carry the internal psu's voltages))

That's actually pretty cool because those are small and allow a
circular hole and are easily panel mounted. Thanks, great idea!

On Mon, Jul 13, 2026 at 10:19?PM David Huss via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Ethernet has a PoE (Power-over-Ethernet) standard and in its maximum
> PoE++ variant Type 4 switches can supply up to 100 Watts over one
> ethernet port.
>
> HOWEVER: PoE similar to USB-C PD (Power Delivery) negotiates this power
> delivery with the device attached to it and also has some measures to
> detect faulty connections/cables. A self-baked solution may fail
> spectacularily (and consider what happens if someone plugs your power
> supply into an actual network port. Professional networking equipment
> can easily cost mor than most peoples cars are worth..
>
> For this type of DC connection there are dedicated connectors and
> cables. The price ranges and features vary wildly, but a good and cheap
> solution that is tough enough for live-gig is the GX16 5-pin connector,
> you can get a pack of 5 plugs AND jacks (including a shitty
> screwdriver!) for 9 Euros on Amazon. The plug has a thread so it can be
> locked and it is not too hard to solder.
>
> This type of plug has sometimes also be used in mixer power supplies
> that work with outboard power supplies with exactly the requirements you
> have, so it has been done before as well.
>
> Cheers,
> David
>
>
>
> On 2026-07-13 21:24, cheater cheater via Synth-diy wrote:
> > A little more to qualify my question, it's easier to find panel mount
> > hardware for those, can just use a keystone plug, and they take up
> > less space, so easier to fit on the back of a 1U device.
> >
> > On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
> > <cheater00social at gmail.com> wrote:
> >>
> >> Another question - how is everyone feeling about rj-45 as a power
> >> plug? carrying up to 800 mA. I've seen threads where people say
> >> they've been putting 1A through those, per pin. Thanks.
> >>
> >> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
> >>
> >> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
> >>
> >>
> >> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
> >> <cheater00social at gmail.com> wrote:
> >>>
> >>> Someone off-list made some comments, and here's what came out of it:
> >>>
> >>> 1. All my devices use balanced audio
> >>> 2. The rack items actually tie together their grounds by using rack
> >>> screws and the rack rail
> >>> 3. I don't know if the rack devices have isolated audio grounds, but
> >>> they're almost fully analogue, except for stuff like LED bar graphs
> >>> and on-off status LEDs for functions
> >>>
> >>> On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
> >>> <cheater00social at gmail.com> wrote:
> >>>>
> >>>> So a person on another forum mentioned that converting the devices to
> >>>> DC input could create ground loops.
> >>>>
> >>>> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> >>>> 0V, and +48V, and I would wire it in a daisy-chain configuration going
> >>>> from unit to unit. All of those units are in one rack on top of each
> >>>> other.
> >>>>
> >>>> Here's what they said:
> >>>>
> >>>>> If you're intending to run them all off a single raw supply, that could
> >>>>> introduce ground loops. The safest would be a bunch of small
> >>>>> transformers, or one with multiple secondaries. Hammond 229 are
> >>>>> small low profile transformers that could fit in a 1U cabinet.
> >>>>
> >>>> So I've been thinking about this since they mentioned ground loops.
> >>>> Here's what I think.
> >>>>
> >>>> Currently all those rack devices already use a three-prong IEC C14
> >>>> receptacle, with the earth wire connected to the chassis.
> >>>>
> >>>> Instead of the chassis grounding point being connected via the C14
> >>>> receptacle, and through a mains cable, to mains earth, it would now be
> >>>> connected via my DC bus cable, which would have an earth conductor as
> >>>> well.
> >>>>
> >>>> So in terms of ground loops, not much changes.
> >>>>
> >>>> However, given that we're talking about LOOPS, the area of the ground
> >>>> loop would be important as well.
> >>>>
> >>>> Currently each rack has a cable going to a power strip.
> >>>>
> >>>> However, with my DC bus, I would be daisy chaining it, so the bus goes
> >>>> to the bottom rack mount device, there's a plug there, then from that
> >>>> plug there's a short cable going 1U above it, and so on.
> >>>>
> >>>> That would create an extremely small area for the devices to create
> >>>> ground loops.
> >>>>
> >>>> I could (and maybe should) additionally put an earthed shield around
> >>>> these wires, in order to shield them from EMI.
> >>>>
> >>>> So in total, either nothing changes regarding ground loops, or it's
> >>>> purely improved compared to the current situation.
> >>>>
> >>>> I would be interested in everyone's thoughts on this matter.
> >>>>
> >>>> Thanks.
> >>>>
> >>>>
> >>>> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> >>>> <cheater00social at gmail.com> wrote:
> >>>>>
> >>>>> there's one that's particularly noisy, but there are others that are a
> >>>>> little noisy too, and it adds up. plus the heat just makes the room
> >>>>> uncomfortable to be in. I've gone to great lengths to move all heat
> >>>>> and noise generating equipment out of my day room, including moving
> >>>>> the pcs to another place and connecting everything via fiber optics.
> >>>>> so having 80W less heating my head will be an improvement once more.
> >>>>>
> >>>>> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> >>>>>>
> >>>>>> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> >>>>>>
> >>>>>> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> >>>>>>
> >>>>>> Or move the units away from where the mic can pick up the noise?
> >>>>>>
> >>>>>> Not my area of expertise, just wondering if there may be a simpler solition.
> >>>>>>
> >>>>>> Ed
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> Get Outlook for iOS
> >>>>>> ________________________________
> >>>>>> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> >>>>>> Sent: Thursday, 09 July 2026 17:39:07
> >>>>>> To: cheater cheater <cheater00social at gmail.com>
> >>>>>> Cc: synth-diy <synth-diy at synth-diy.org>
> >>>>>> Subject: Re: [sdiy] Converting rack mount to DC input?
> >>>>>>
> >>>>>> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> >>>>>>
> >>>>>> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> >>>>>>
> >>>>>> Ben
> >>>>>>
> >>>>>>> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> >>>>>>>
> >>>>>>> Thanks. A few questions:
> >>>>>>>
> >>>>>>> What if only some of the rails are connected, but not the one used for
> >>>>>>> steering the relay (a fault)?
> >>>>>>>
> >>>>>>> Relays are kind of expensive, how much do you think that could end up costing?
> >>>>>>>
> >>>>>>> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> >>>>>>>
> >>>>>>> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>>>>>>>
> >>>>>>>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> >>>>>>>>
> >>>>>>>> Ben
> >>>>>>>>
> >>>>>>>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> >>>>>>>>>
> >>>>>>>>> In order to provide the bridging functionality it has to have at least 8 pins.
> >>>>>>>>>
> >>>>>>>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>>>>>>>>>
> >>>>>>>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> >>>>>>>>>>
> >>>>>>>>>> Ben
> >>>>>>>>>>
> >>>>>>>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >>>>>>>>>>>
> >>>>>>>>>>> One way to have DC input, but retain the capability of using the
> >>>>>>>>>>> internal power supply, is to have a 4P2T switch for configuration.
> >>>>>>>>>>>
> >>>>>>>>>>> It seems that 4P2T switches are super expensive, especially if they're
> >>>>>>>>>>> supposed to withstand, say, 1A.
> >>>>>>>>>>>
> >>>>>>>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> >>>>>>>>>>> are probably the best, and also the cheapest.
> >>>>>>>>>>>
> >>>>>>>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> >>>>>>>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> >>>>>>>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> >>>>>>>>>>>
> >>>>>>>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >>>>>>>>>>>
> >>>>>>>>>>>> 4.4 CONTACT CURRENT RATING
> >>>>>>>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >>>>>>>>>>>
> >>>>>>>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> >>>>>>>>>>> I'm sure it would handle something like 2A, especially if you share
> >>>>>>>>>>> pins. You can even leave pins empty to prevent shorts during
> >>>>>>>>>>> insertion.
> >>>>>>>>>>>
> >>>>>>>>>>> You could put the connector out the back, and either insert a plug-in
> >>>>>>>>>>> "card" (really just a small edge connector with wires soldered on)
> >>>>>>>>>>> that provides DC, or a pass-through "card" that shorts some pins
> >>>>>>>>>>> together to carry power from the internal power supply. And now
> >>>>>>>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> >>>>>>>>>>> is how I would fix the connector, but maybe a simple screw hole in the
> >>>>>>>>>>> connector that mates with a threaded hole in the case could do the
> >>>>>>>>>>> trick.
> >>>>>>>>>>>
> >>>>>>>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> >>>>>>>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> >>>>>>>>>>>
> >>>>>>>>>>> The cheapest one that can be found at Mouser currently and can be
> >>>>>>>>>>> bought in low volumes is roughly 0.4 Euro.
> >>>>>>>>>>>
> >>>>>>>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >>>>>>>>>>>
> >>>>>>>>>>> Qty.  Unit Price  Ext. Price
> >>>>>>>>>>> 1     ? 0,439     ? 0,44
> >>>>>>>>>>> 10    ? 0,372     ? 3,72
> >>>>>>>>>>> 25    ? 0,332     ? 8,30
> >>>>>>>>>>> 100   ? 0,316     ? 31,60
> >>>>>>>>>>>
> >>>>>>>>>>> By making the connector require a dummy plug to connect the internal
> >>>>>>>>>>> power supply into the circuit, it makes it impossible to connect both
> >>>>>>>>>>> DC power and mains AC, so that makes the design intrinsically safe
> >>>>>>>>>>> without using switches.
> >>>>>>>>>>>
> >>>>>>>>>>> Alternatively to a PCIE connector I could use some panel mount plug
> >>>>>>>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> >>>>>>>>>>> power from the internal power supply, and similarly use a shorting
> >>>>>>>>>>> plug to use the internal power supply.
> >>>>>>>>>>>
> >>>>>>>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> >>>>>>>>>>> Circular metric aren't better.
> >>>>>>>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> >>>>>>>>>>> so I can't find them by number of pins.
> >>>>>>>>>>>
> >>>>>>>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> >>>>>>>>>>> They're latching (no need for screws and stuff). There doesn't seem to
> >>>>>>>>>>> be a panel mount version, but one could mount a through-hole connector
> >>>>>>>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> >>>>>>>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> >>>>>>>>>>> are return pins). Seems like a winner to me. They're also tiny so they
> >>>>>>>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> >>>>>>>>>>> pain here might be making the rectangular hole and having it look any
> >>>>>>>>>>> good. might be a case for custom die, maybe a small steel job that
> >>>>>>>>>>> uses two bolts to screw together the two cutting parts through the
> >>>>>>>>>>> sheet metal.
> >>>>>>>>>>>
> >>>>>>>>>>> "Pin and socket" connectors are the same kind of thing, just not
> >>>>>>>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> >>>>>>>>>>> useful alternative if more than 4 rails are necessary.
> >>>>>>>>>>>
> >>>>>>>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> >>>>>>>>>>> mount of some sort. But I'll be damned if I use one of those cursed
> >>>>>>>>>>> things for power.
> >>>>>>>>>>>
> >>>>>>>>>>> Automotive connectors seem inexpensive too, but I haven't really
> >>>>>>>>>>> looked into them much other than a quick parametric search.
> >>>>>>>>>>>
> >>>>>>>>>>> I wonder what everyone thinks of this.
> >>>>>>>>>>>
> >>>>>>>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> >>>>>>>>>>> <cheater00social at gmail.com> wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>> Don't you think this may have had something to do with you
> >>>>>>>>>>>> distributing AC power, rather than DC with 0V potential?
> >>>>>>>>>>>>
> >>>>>>>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> /mr
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> ________________________________________________________
> >>>>>>>>>>>>> This is the Synth-diy mailing list
> >>>>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>>>>>>>
> >>>>>>>>>>> ________________________________________________________
> >>>>>>>>>>> This is the Synth-diy mailing list
> >>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>> ________________________________________________________
> >>>>>> This is the Synth-diy mailing list
> >>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>> Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Tue Jul 14 14:03:48 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 14 Jul 2026 14:03:48 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <4dc49387-835a-439e-b191-361f633c2911@mikebeauchamp.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <63165836-a201-4cc3-9a3c-5a2f2b2226f5@mnet-online.de>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <4dc49387-835a-439e-b191-361f633c2911@mikebeauchamp.com>
Message-ID: <CAGn5V-9POZkhJsO0q4PxhYemr59hNs8-XQ+Vb6XLm1M_v=EtbA@mail.gmail.com>

On Mon, Jul 13, 2026 at 10:02?PM Mike Beauchamp <list at mikebeauchamp.com> wrote:
>
> Hi Mattias,
>
> If the 16 V AC is going into a standard rectified bipolar supply, one
> side of the AC line in each of those two units is being tied to ground.
>
> In your case, I'd guess that each device ties a different side of the AC
> line to ground.
>
> Here's the schematic for a really similar power supply:
>
> https://musicfromouterspace.com/analogsynth_new/WALLWARTSUPPLY/wallwart_added_load_rs_schem.pdf
>
>
> If you modify your Y cable to swap the AC lines on one of the outputs,
> it will probably work again.
>
>
> Mike

Yep, that's exactly what I thought might have happened, too!


>
> On 2026-07-04 17:19, Mattias Rickardsson wrote:
>
> > This reminds me of a somewhat similar issue I had many years ago:
> >
> > I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck.
> > (Swedish-sold old Korgs had a big external power transformer to step
> > down from 220 V AC to 16 V AC, which is then what the instrument then
> > accepts via a plug with 2 flat prongs that doesn't seem roadworthy with
> > European electrical standards.)
> >
> > So I made a short splitter Y cable on the 16 V AC side and attached both
> > instruments and turned them on. But then I connected an audio cable
> > between them (or audio cables from both units to the same mixer) and I
> > had a blown fuse! It was apparently not okay to connect those two
> > grounds together when running off the same AC supply.
> >
> > /mr
> >
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org


From cheater00social at gmail.com  Tue Jul 14 14:07:38 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 14 Jul 2026 14:07:38 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
 <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>
 <CAGn5V-9aBX1N9aQK7pgPjiAgjcb1pSEo5LwhY4s=Hv8i0=fE3A@mail.gmail.com>
 <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
 <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
 <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>
 <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>
Message-ID: <CAGn5V-9d9OXiffShBmE0zhmr=Tfp7_jJYhOz_k5_wkevo-4o_w@mail.gmail.com>

Oh hell, yep, 8 pin is easily available - and, just like you said,
also very cheap on Amazon! at only 19mm across, that's a no-brainer!

On Tue, Jul 14, 2026 at 2:03?PM cheater cheater
<cheater00social at gmail.com> wrote:
>
> Hmm, GX16 is interesting, thank you! Let me see if I can find one with
> 8 pins easily - that's the minimum that I need (see earlier emails
> why: to either supply external DC (+17, -17, 0, 48) or loop back the
> internal PSU (half the pins would carry the internal psu's voltages))
>
> That's actually pretty cool because those are small and allow a
> circular hole and are easily panel mounted. Thanks, great idea!
>
> On Mon, Jul 13, 2026 at 10:19?PM David Huss via Synth-diy
> <synth-diy at synth-diy.org> wrote:
> >
> > Ethernet has a PoE (Power-over-Ethernet) standard and in its maximum
> > PoE++ variant Type 4 switches can supply up to 100 Watts over one
> > ethernet port.
> >
> > HOWEVER: PoE similar to USB-C PD (Power Delivery) negotiates this power
> > delivery with the device attached to it and also has some measures to
> > detect faulty connections/cables. A self-baked solution may fail
> > spectacularily (and consider what happens if someone plugs your power
> > supply into an actual network port. Professional networking equipment
> > can easily cost mor than most peoples cars are worth..
> >
> > For this type of DC connection there are dedicated connectors and
> > cables. The price ranges and features vary wildly, but a good and cheap
> > solution that is tough enough for live-gig is the GX16 5-pin connector,
> > you can get a pack of 5 plugs AND jacks (including a shitty
> > screwdriver!) for 9 Euros on Amazon. The plug has a thread so it can be
> > locked and it is not too hard to solder.
> >
> > This type of plug has sometimes also be used in mixer power supplies
> > that work with outboard power supplies with exactly the requirements you
> > have, so it has been done before as well.
> >
> > Cheers,
> > David
> >
> >
> >
> > On 2026-07-13 21:24, cheater cheater via Synth-diy wrote:
> > > A little more to qualify my question, it's easier to find panel mount
> > > hardware for those, can just use a keystone plug, and they take up
> > > less space, so easier to fit on the back of a 1U device.
> > >
> > > On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
> > > <cheater00social at gmail.com> wrote:
> > >>
> > >> Another question - how is everyone feeling about rj-45 as a power
> > >> plug? carrying up to 800 mA. I've seen threads where people say
> > >> they've been putting 1A through those, per pin. Thanks.
> > >>
> > >> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
> > >>
> > >> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
> > >>
> > >>
> > >> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
> > >> <cheater00social at gmail.com> wrote:
> > >>>
> > >>> Someone off-list made some comments, and here's what came out of it:
> > >>>
> > >>> 1. All my devices use balanced audio
> > >>> 2. The rack items actually tie together their grounds by using rack
> > >>> screws and the rack rail
> > >>> 3. I don't know if the rack devices have isolated audio grounds, but
> > >>> they're almost fully analogue, except for stuff like LED bar graphs
> > >>> and on-off status LEDs for functions
> > >>>
> > >>> On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
> > >>> <cheater00social at gmail.com> wrote:
> > >>>>
> > >>>> So a person on another forum mentioned that converting the devices to
> > >>>> DC input could create ground loops.
> > >>>>
> > >>>> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> > >>>> 0V, and +48V, and I would wire it in a daisy-chain configuration going
> > >>>> from unit to unit. All of those units are in one rack on top of each
> > >>>> other.
> > >>>>
> > >>>> Here's what they said:
> > >>>>
> > >>>>> If you're intending to run them all off a single raw supply, that could
> > >>>>> introduce ground loops. The safest would be a bunch of small
> > >>>>> transformers, or one with multiple secondaries. Hammond 229 are
> > >>>>> small low profile transformers that could fit in a 1U cabinet.
> > >>>>
> > >>>> So I've been thinking about this since they mentioned ground loops.
> > >>>> Here's what I think.
> > >>>>
> > >>>> Currently all those rack devices already use a three-prong IEC C14
> > >>>> receptacle, with the earth wire connected to the chassis.
> > >>>>
> > >>>> Instead of the chassis grounding point being connected via the C14
> > >>>> receptacle, and through a mains cable, to mains earth, it would now be
> > >>>> connected via my DC bus cable, which would have an earth conductor as
> > >>>> well.
> > >>>>
> > >>>> So in terms of ground loops, not much changes.
> > >>>>
> > >>>> However, given that we're talking about LOOPS, the area of the ground
> > >>>> loop would be important as well.
> > >>>>
> > >>>> Currently each rack has a cable going to a power strip.
> > >>>>
> > >>>> However, with my DC bus, I would be daisy chaining it, so the bus goes
> > >>>> to the bottom rack mount device, there's a plug there, then from that
> > >>>> plug there's a short cable going 1U above it, and so on.
> > >>>>
> > >>>> That would create an extremely small area for the devices to create
> > >>>> ground loops.
> > >>>>
> > >>>> I could (and maybe should) additionally put an earthed shield around
> > >>>> these wires, in order to shield them from EMI.
> > >>>>
> > >>>> So in total, either nothing changes regarding ground loops, or it's
> > >>>> purely improved compared to the current situation.
> > >>>>
> > >>>> I would be interested in everyone's thoughts on this matter.
> > >>>>
> > >>>> Thanks.
> > >>>>
> > >>>>
> > >>>> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> > >>>> <cheater00social at gmail.com> wrote:
> > >>>>>
> > >>>>> there's one that's particularly noisy, but there are others that are a
> > >>>>> little noisy too, and it adds up. plus the heat just makes the room
> > >>>>> uncomfortable to be in. I've gone to great lengths to move all heat
> > >>>>> and noise generating equipment out of my day room, including moving
> > >>>>> the pcs to another place and connecting everything via fiber optics.
> > >>>>> so having 80W less heating my head will be an improvement once more.
> > >>>>>
> > >>>>> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> > >>>>>>
> > >>>>>> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> > >>>>>>
> > >>>>>> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> > >>>>>>
> > >>>>>> Or move the units away from where the mic can pick up the noise?
> > >>>>>>
> > >>>>>> Not my area of expertise, just wondering if there may be a simpler solition.
> > >>>>>>
> > >>>>>> Ed
> > >>>>>>
> > >>>>>>
> > >>>>>>
> > >>>>>> Get Outlook for iOS
> > >>>>>> ________________________________
> > >>>>>> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> > >>>>>> Sent: Thursday, 09 July 2026 17:39:07
> > >>>>>> To: cheater cheater <cheater00social at gmail.com>
> > >>>>>> Cc: synth-diy <synth-diy at synth-diy.org>
> > >>>>>> Subject: Re: [sdiy] Converting rack mount to DC input?
> > >>>>>>
> > >>>>>> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> > >>>>>>
> > >>>>>> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> > >>>>>>
> > >>>>>> Ben
> > >>>>>>
> > >>>>>>> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> > >>>>>>>
> > >>>>>>> Thanks. A few questions:
> > >>>>>>>
> > >>>>>>> What if only some of the rails are connected, but not the one used for
> > >>>>>>> steering the relay (a fault)?
> > >>>>>>>
> > >>>>>>> Relays are kind of expensive, how much do you think that could end up costing?
> > >>>>>>>
> > >>>>>>> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> > >>>>>>>
> > >>>>>>> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>>>>>>>
> > >>>>>>>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> > >>>>>>>>
> > >>>>>>>> Ben
> > >>>>>>>>
> > >>>>>>>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> > >>>>>>>>>
> > >>>>>>>>> In order to provide the bridging functionality it has to have at least 8 pins.
> > >>>>>>>>>
> > >>>>>>>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>>>>>>>>>
> > >>>>>>>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> > >>>>>>>>>>
> > >>>>>>>>>> Ben
> > >>>>>>>>>>
> > >>>>>>>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> > >>>>>>>>>>>
> > >>>>>>>>>>> One way to have DC input, but retain the capability of using the
> > >>>>>>>>>>> internal power supply, is to have a 4P2T switch for configuration.
> > >>>>>>>>>>>
> > >>>>>>>>>>> It seems that 4P2T switches are super expensive, especially if they're
> > >>>>>>>>>>> supposed to withstand, say, 1A.
> > >>>>>>>>>>>
> > >>>>>>>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> > >>>>>>>>>>> are probably the best, and also the cheapest.
> > >>>>>>>>>>>
> > >>>>>>>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> > >>>>>>>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> > >>>>>>>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> > >>>>>>>>>>>
> > >>>>>>>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> > >>>>>>>>>>>
> > >>>>>>>>>>>> 4.4 CONTACT CURRENT RATING
> > >>>>>>>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> > >>>>>>>>>>>
> > >>>>>>>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> > >>>>>>>>>>> I'm sure it would handle something like 2A, especially if you share
> > >>>>>>>>>>> pins. You can even leave pins empty to prevent shorts during
> > >>>>>>>>>>> insertion.
> > >>>>>>>>>>>
> > >>>>>>>>>>> You could put the connector out the back, and either insert a plug-in
> > >>>>>>>>>>> "card" (really just a small edge connector with wires soldered on)
> > >>>>>>>>>>> that provides DC, or a pass-through "card" that shorts some pins
> > >>>>>>>>>>> together to carry power from the internal power supply. And now
> > >>>>>>>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> > >>>>>>>>>>> is how I would fix the connector, but maybe a simple screw hole in the
> > >>>>>>>>>>> connector that mates with a threaded hole in the case could do the
> > >>>>>>>>>>> trick.
> > >>>>>>>>>>>
> > >>>>>>>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > >>>>>>>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> > >>>>>>>>>>>
> > >>>>>>>>>>> The cheapest one that can be found at Mouser currently and can be
> > >>>>>>>>>>> bought in low volumes is roughly 0.4 Euro.
> > >>>>>>>>>>>
> > >>>>>>>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> > >>>>>>>>>>>
> > >>>>>>>>>>> Qty.  Unit Price  Ext. Price
> > >>>>>>>>>>> 1     ? 0,439     ? 0,44
> > >>>>>>>>>>> 10    ? 0,372     ? 3,72
> > >>>>>>>>>>> 25    ? 0,332     ? 8,30
> > >>>>>>>>>>> 100   ? 0,316     ? 31,60
> > >>>>>>>>>>>
> > >>>>>>>>>>> By making the connector require a dummy plug to connect the internal
> > >>>>>>>>>>> power supply into the circuit, it makes it impossible to connect both
> > >>>>>>>>>>> DC power and mains AC, so that makes the design intrinsically safe
> > >>>>>>>>>>> without using switches.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Alternatively to a PCIE connector I could use some panel mount plug
> > >>>>>>>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > >>>>>>>>>>> power from the internal power supply, and similarly use a shorting
> > >>>>>>>>>>> plug to use the internal power supply.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > >>>>>>>>>>> Circular metric aren't better.
> > >>>>>>>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > >>>>>>>>>>> so I can't find them by number of pins.
> > >>>>>>>>>>>
> > >>>>>>>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > >>>>>>>>>>> They're latching (no need for screws and stuff). There doesn't seem to
> > >>>>>>>>>>> be a panel mount version, but one could mount a through-hole connector
> > >>>>>>>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> > >>>>>>>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> > >>>>>>>>>>> are return pins). Seems like a winner to me. They're also tiny so they
> > >>>>>>>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> > >>>>>>>>>>> pain here might be making the rectangular hole and having it look any
> > >>>>>>>>>>> good. might be a case for custom die, maybe a small steel job that
> > >>>>>>>>>>> uses two bolts to screw together the two cutting parts through the
> > >>>>>>>>>>> sheet metal.
> > >>>>>>>>>>>
> > >>>>>>>>>>> "Pin and socket" connectors are the same kind of thing, just not
> > >>>>>>>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > >>>>>>>>>>> useful alternative if more than 4 rails are necessary.
> > >>>>>>>>>>>
> > >>>>>>>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> > >>>>>>>>>>> mount of some sort. But I'll be damned if I use one of those cursed
> > >>>>>>>>>>> things for power.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Automotive connectors seem inexpensive too, but I haven't really
> > >>>>>>>>>>> looked into them much other than a quick parametric search.
> > >>>>>>>>>>>
> > >>>>>>>>>>> I wonder what everyone thinks of this.
> > >>>>>>>>>>>
> > >>>>>>>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > >>>>>>>>>>> <cheater00social at gmail.com> wrote:
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> Don't you think this may have had something to do with you
> > >>>>>>>>>>>> distributing AC power, rather than DC with 0V potential?
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> /mr
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> ________________________________________________________
> > >>>>>>>>>>>>> This is the Synth-diy mailing list
> > >>>>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> > >>>>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > >>>>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > >>>>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> > >>>>>>>>>>>
> > >>>>>>>>>>> ________________________________________________________
> > >>>>>>>>>>> This is the Synth-diy mailing list
> > >>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> > >>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > >>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > >>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> > >>>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>
> > >>>>>>>
> > >>>>>>
> > >>>>>>
> > >>>>>> ________________________________________________________
> > >>>>>> This is the Synth-diy mailing list
> > >>>>>> Submit email to: Synth-diy at synth-diy.org
> > >>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> > >>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > >>>>>> Selling or trading? Use marketplace at synth-diy.org
> > >
> > > ________________________________________________________
> > > This is the Synth-diy mailing list
> > > Submit email to: Synth-diy at synth-diy.org
> > > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > > Selling or trading? Use marketplace at synth-diy.org
> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
> > View archive at: https://synth-diy.org/pipermail/synth-diy/
> > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org


From mbryant at futurehorizons.com  Tue Jul 14 14:22:16 2026
From: mbryant at futurehorizons.com (Mike Bryant)
Date: Tue, 14 Jul 2026 12:22:16 +0000
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
 <CAP92RBWx-2FkgpQROx+Jd-Zag5FtUnhL5zYu9Q3X6S5sDynq1g@mail.gmail.com>
 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
 <CAGn5V-_YQXp9kQW2L+uuB-zVFCa+OLjN4+SChNm0=Vr2z9ceaA@mail.gmail.com>
 <CAGn5V-9aBX1N9aQK7pgPjiAgjcb1pSEo5LwhY4s=Hv8i0=fE3A@mail.gmail.com>
 <CAGn5V--bAnfOnXoX2kHuTzTOx7P=2hN-6n9ZLb7cB1_Xqsf1gQ@mail.gmail.com>
 <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
 <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>
 <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>
Message-ID: <LO6P265MB7133729EC3F883FA95880B65DBF92@LO6P265MB7133.GBRP265.PROD.OUTLOOK.COM>

GX16 was the standard for lighting control voltages to the dimming racks before DMX appeared.  Very rugged and excellent choice.  Had the occasional wire break inside the connector due to bad roadie level handling, but very rare.

________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
Sent: 14 July 2026 13:03
To: David Huss <dh at atoav.com>
Cc: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Converting rack mount to DC input?

Hmm, GX16 is interesting, thank you! Let me see if I can find one with
8 pins easily - that's the minimum that I need (see earlier emails
why: to either supply external DC (+17, -17, 0, 48) or loop back the
internal PSU (half the pins would carry the internal psu's voltages))

That's actually pretty cool because those are small and allow a
circular hole and are easily panel mounted. Thanks, great idea!

On Mon, Jul 13, 2026 at 10:19?PM David Huss via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Ethernet has a PoE (Power-over-Ethernet) standard and in its maximum
> PoE++ variant Type 4 switches can supply up to 100 Watts over one
> ethernet port.
>
> HOWEVER: PoE similar to USB-C PD (Power Delivery) negotiates this power
> delivery with the device attached to it and also has some measures to
> detect faulty connections/cables. A self-baked solution may fail
> spectacularily (and consider what happens if someone plugs your power
> supply into an actual network port. Professional networking equipment
> can easily cost mor than most peoples cars are worth..
>
> For this type of DC connection there are dedicated connectors and
> cables. The price ranges and features vary wildly, but a good and cheap
> solution that is tough enough for live-gig is the GX16 5-pin connector,
> you can get a pack of 5 plugs AND jacks (including a shitty
> screwdriver!) for 9 Euros on Amazon. The plug has a thread so it can be
> locked and it is not too hard to solder.
>
> This type of plug has sometimes also be used in mixer power supplies
> that work with outboard power supplies with exactly the requirements you
> have, so it has been done before as well.
>
> Cheers,
> David
>
>
>
> On 2026-07-13 21:24, cheater cheater via Synth-diy wrote:
> > A little more to qualify my question, it's easier to find panel mount
> > hardware for those, can just use a keystone plug, and they take up
> > less space, so easier to fit on the back of a 1U device.
> >
> > On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
> > <cheater00social at gmail.com> wrote:
> >>
> >> Another question - how is everyone feeling about rj-45 as a power
> >> plug? carrying up to 800 mA. I've seen threads where people say
> >> they've been putting 1A through those, per pin. Thanks.
> >>
> >> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
> >>
> >> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
> >>
> >>
> >> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
> >> <cheater00social at gmail.com> wrote:
> >>>
> >>> Someone off-list made some comments, and here's what came out of it:
> >>>
> >>> 1. All my devices use balanced audio
> >>> 2. The rack items actually tie together their grounds by using rack
> >>> screws and the rack rail
> >>> 3. I don't know if the rack devices have isolated audio grounds, but
> >>> they're almost fully analogue, except for stuff like LED bar graphs
> >>> and on-off status LEDs for functions
> >>>
> >>> On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
> >>> <cheater00social at gmail.com> wrote:
> >>>>
> >>>> So a person on another forum mentioned that converting the devices to
> >>>> DC input could create ground loops.
> >>>>
> >>>> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> >>>> 0V, and +48V, and I would wire it in a daisy-chain configuration going
> >>>> from unit to unit. All of those units are in one rack on top of each
> >>>> other.
> >>>>
> >>>> Here's what they said:
> >>>>
> >>>>> If you're intending to run them all off a single raw supply, that could
> >>>>> introduce ground loops. The safest would be a bunch of small
> >>>>> transformers, or one with multiple secondaries. Hammond 229 are
> >>>>> small low profile transformers that could fit in a 1U cabinet.
> >>>>
> >>>> So I've been thinking about this since they mentioned ground loops.
> >>>> Here's what I think.
> >>>>
> >>>> Currently all those rack devices already use a three-prong IEC C14
> >>>> receptacle, with the earth wire connected to the chassis.
> >>>>
> >>>> Instead of the chassis grounding point being connected via the C14
> >>>> receptacle, and through a mains cable, to mains earth, it would now be
> >>>> connected via my DC bus cable, which would have an earth conductor as
> >>>> well.
> >>>>
> >>>> So in terms of ground loops, not much changes.
> >>>>
> >>>> However, given that we're talking about LOOPS, the area of the ground
> >>>> loop would be important as well.
> >>>>
> >>>> Currently each rack has a cable going to a power strip.
> >>>>
> >>>> However, with my DC bus, I would be daisy chaining it, so the bus goes
> >>>> to the bottom rack mount device, there's a plug there, then from that
> >>>> plug there's a short cable going 1U above it, and so on.
> >>>>
> >>>> That would create an extremely small area for the devices to create
> >>>> ground loops.
> >>>>
> >>>> I could (and maybe should) additionally put an earthed shield around
> >>>> these wires, in order to shield them from EMI.
> >>>>
> >>>> So in total, either nothing changes regarding ground loops, or it's
> >>>> purely improved compared to the current situation.
> >>>>
> >>>> I would be interested in everyone's thoughts on this matter.
> >>>>
> >>>> Thanks.
> >>>>
> >>>>
> >>>> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> >>>> <cheater00social at gmail.com> wrote:
> >>>>>
> >>>>> there's one that's particularly noisy, but there are others that are a
> >>>>> little noisy too, and it adds up. plus the heat just makes the room
> >>>>> uncomfortable to be in. I've gone to great lengths to move all heat
> >>>>> and noise generating equipment out of my day room, including moving
> >>>>> the pcs to another place and connecting everything via fiber optics.
> >>>>> so having 80W less heating my head will be an improvement once more.
> >>>>>
> >>>>> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> >>>>>>
> >>>>>> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> >>>>>>
> >>>>>> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> >>>>>>
> >>>>>> Or move the units away from where the mic can pick up the noise?
> >>>>>>
> >>>>>> Not my area of expertise, just wondering if there may be a simpler solition.
> >>>>>>
> >>>>>> Ed
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> Get Outlook for iOS
> >>>>>> ________________________________
> >>>>>> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> >>>>>> Sent: Thursday, 09 July 2026 17:39:07
> >>>>>> To: cheater cheater <cheater00social at gmail.com>
> >>>>>> Cc: synth-diy <synth-diy at synth-diy.org>
> >>>>>> Subject: Re: [sdiy] Converting rack mount to DC input?
> >>>>>>
> >>>>>> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> >>>>>>
> >>>>>> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> >>>>>>
> >>>>>> Ben
> >>>>>>
> >>>>>>> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> >>>>>>>
> >>>>>>> Thanks. A few questions:
> >>>>>>>
> >>>>>>> What if only some of the rails are connected, but not the one used for
> >>>>>>> steering the relay (a fault)?
> >>>>>>>
> >>>>>>> Relays are kind of expensive, how much do you think that could end up costing?
> >>>>>>>
> >>>>>>> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> >>>>>>>
> >>>>>>> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>>>>>>>
> >>>>>>>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> >>>>>>>>
> >>>>>>>> Ben
> >>>>>>>>
> >>>>>>>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> >>>>>>>>>
> >>>>>>>>> In order to provide the bridging functionality it has to have at least 8 pins.
> >>>>>>>>>
> >>>>>>>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> >>>>>>>>>>
> >>>>>>>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> >>>>>>>>>>
> >>>>>>>>>> Ben
> >>>>>>>>>>
> >>>>>>>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> >>>>>>>>>>>
> >>>>>>>>>>> One way to have DC input, but retain the capability of using the
> >>>>>>>>>>> internal power supply, is to have a 4P2T switch for configuration.
> >>>>>>>>>>>
> >>>>>>>>>>> It seems that 4P2T switches are super expensive, especially if they're
> >>>>>>>>>>> supposed to withstand, say, 1A.
> >>>>>>>>>>>
> >>>>>>>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> >>>>>>>>>>> are probably the best, and also the cheapest.
> >>>>>>>>>>>
> >>>>>>>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> >>>>>>>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> >>>>>>>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> >>>>>>>>>>>
> >>>>>>>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> >>>>>>>>>>>
> >>>>>>>>>>>> 4.4 CONTACT CURRENT RATING
> >>>>>>>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> >>>>>>>>>>>
> >>>>>>>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> >>>>>>>>>>> I'm sure it would handle something like 2A, especially if you share
> >>>>>>>>>>> pins. You can even leave pins empty to prevent shorts during
> >>>>>>>>>>> insertion.
> >>>>>>>>>>>
> >>>>>>>>>>> You could put the connector out the back, and either insert a plug-in
> >>>>>>>>>>> "card" (really just a small edge connector with wires soldered on)
> >>>>>>>>>>> that provides DC, or a pass-through "card" that shorts some pins
> >>>>>>>>>>> together to carry power from the internal power supply. And now
> >>>>>>>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> >>>>>>>>>>> is how I would fix the connector, but maybe a simple screw hole in the
> >>>>>>>>>>> connector that mates with a threaded hole in the case could do the
> >>>>>>>>>>> trick.
> >>>>>>>>>>>
> >>>>>>>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> >>>>>>>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> >>>>>>>>>>>
> >>>>>>>>>>> The cheapest one that can be found at Mouser currently and can be
> >>>>>>>>>>> bought in low volumes is roughly 0.4 Euro.
> >>>>>>>>>>>
> >>>>>>>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> >>>>>>>>>>>
> >>>>>>>>>>> Qty.  Unit Price  Ext. Price
> >>>>>>>>>>> 1     ? 0,439     ? 0,44
> >>>>>>>>>>> 10    ? 0,372     ? 3,72
> >>>>>>>>>>> 25    ? 0,332     ? 8,30
> >>>>>>>>>>> 100   ? 0,316     ? 31,60
> >>>>>>>>>>>
> >>>>>>>>>>> By making the connector require a dummy plug to connect the internal
> >>>>>>>>>>> power supply into the circuit, it makes it impossible to connect both
> >>>>>>>>>>> DC power and mains AC, so that makes the design intrinsically safe
> >>>>>>>>>>> without using switches.
> >>>>>>>>>>>
> >>>>>>>>>>> Alternatively to a PCIE connector I could use some panel mount plug
> >>>>>>>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> >>>>>>>>>>> power from the internal power supply, and similarly use a shorting
> >>>>>>>>>>> plug to use the internal power supply.
> >>>>>>>>>>>
> >>>>>>>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> >>>>>>>>>>> Circular metric aren't better.
> >>>>>>>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> >>>>>>>>>>> so I can't find them by number of pins.
> >>>>>>>>>>>
> >>>>>>>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> >>>>>>>>>>> They're latching (no need for screws and stuff). There doesn't seem to
> >>>>>>>>>>> be a panel mount version, but one could mount a through-hole connector
> >>>>>>>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> >>>>>>>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> >>>>>>>>>>> are return pins). Seems like a winner to me. They're also tiny so they
> >>>>>>>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> >>>>>>>>>>> pain here might be making the rectangular hole and having it look any
> >>>>>>>>>>> good. might be a case for custom die, maybe a small steel job that
> >>>>>>>>>>> uses two bolts to screw together the two cutting parts through the
> >>>>>>>>>>> sheet metal.
> >>>>>>>>>>>
> >>>>>>>>>>> "Pin and socket" connectors are the same kind of thing, just not
> >>>>>>>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> >>>>>>>>>>> useful alternative if more than 4 rails are necessary.
> >>>>>>>>>>>
> >>>>>>>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> >>>>>>>>>>> mount of some sort. But I'll be damned if I use one of those cursed
> >>>>>>>>>>> things for power.
> >>>>>>>>>>>
> >>>>>>>>>>> Automotive connectors seem inexpensive too, but I haven't really
> >>>>>>>>>>> looked into them much other than a quick parametric search.
> >>>>>>>>>>>
> >>>>>>>>>>> I wonder what everyone thinks of this.
> >>>>>>>>>>>
> >>>>>>>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> >>>>>>>>>>> <cheater00social at gmail.com> wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>> Don't you think this may have had something to do with you
> >>>>>>>>>>>> distributing AC power, rather than DC with 0V potential?
> >>>>>>>>>>>>
> >>>>>>>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> /mr
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> ________________________________________________________
> >>>>>>>>>>>>> This is the Synth-diy mailing list
> >>>>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>>>>>>>
> >>>>>>>>>>> ________________________________________________________
> >>>>>>>>>>> This is the Synth-diy mailing list
> >>>>>>>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>>>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>>>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> >>>>>>>>>>> Selling or trading? Use marketplace at synth-diy.org
> >>>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>> ________________________________________________________
> >>>>>> This is the Synth-diy mailing list
> >>>>>> Submit email to: Synth-diy at synth-diy.org
> >>>>>> View archive at: https://synth-diy.org/pipermail/synth-diy/
> >>>>>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
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> >
> > ________________________________________________________
> > This is the Synth-diy mailing list
> > Submit email to: Synth-diy at synth-diy.org
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> > Selling or trading? Use marketplace at synth-diy.org
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
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From cheater00social at gmail.com  Tue Jul 14 14:24:56 2026
From: cheater00social at gmail.com (cheater cheater)
Date: Tue, 14 Jul 2026 14:24:56 +0200
Subject: [sdiy] Converting rack mount to DC input?
In-Reply-To: <LO6P265MB7133729EC3F883FA95880B65DBF92@LO6P265MB7133.GBRP265.PROD.OUTLOOK.COM>
References: <CAGn5V-_OFFANadzX+JEFwrsr3XabJJ9pC_Y7BN89A3zFES0v0w@mail.gmail.com>
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 <CAGn5V-8PfSpdHULbMMRjnXXOxprnVqkcRWo+Uh=ijHDhsbynLQ@mail.gmail.com>
 <CAGn5V--YntuRi_c47Pf01T-qu54JevC8btpHpzxXw+X1D_4ytA@mail.gmail.com>
 <7D9F37DF-3CE0-4F4D-A235-23D54CFF71EE@stuyts.nl>
 <CAGn5V-8b_b7vacd_GhLDhmyo1LMERj+Tpcot1CagwbV+gjKRWQ@mail.gmail.com>
 <D6FDC011-8311-4444-B764-89089D4FF7F3@stuyts.nl>
 <CAGn5V--5zNoiPuQDDtAxVMBZxu0Fbwr8y-Y-ukHp9JhNnPtT8w@mail.gmail.com>
 <4FF68BCF-6326-4C5A-A90C-2C8107514CB2@stuyts.nl>
 <SJ2P222MB085443E5B264D86DDFE5791FC4FD2@SJ2P222MB0854.NAMP222.PROD.OUTLOOK.COM>
 <CAGn5V-8Qf3w78HENp9Bp=02OeD3w6Xeu+YxJeE-==qYESmOMeA@mail.gmail.com>
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 <CAGn5V-8Rs9v0YTAg2+pPm1gMDrrcVvW+pGiwp1D6bX+EqEgYTw@mail.gmail.com>
 <0fc06b89-c78a-4198-8755-7ef27ff92c93@atoav.com>
 <CAGn5V--DptQucQ1W4ST37FK-52EmPSB=Y_g4ZDZsp3FZ3Pz2JQ@mail.gmail.com>
 <LO6P265MB7133729EC3F883FA95880B65DBF92@LO6P265MB7133.GBRP265.PROD.OUTLOOK.COM>
Message-ID: <CAGn5V--ruHpt1nXRmjYukNO11g9Sz1Ku+S038CHDTBNDbeDdWw@mail.gmail.com>

oh yeah, no chance of that happening here, it's only for my own personal use.

On Tue, Jul 14, 2026 at 2:22?PM Mike Bryant <mbryant at futurehorizons.com> wrote:
>
> GX16 was the standard for lighting control voltages to the dimming racks before DMX appeared.  Very rugged and excellent choice.  Had the occasional wire break inside the connector due to bad roadie level handling, but very rare.
>
> ________________________________
> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of cheater cheater via Synth-diy <synth-diy at synth-diy.org>
> Sent: 14 July 2026 13:03
> To: David Huss <dh at atoav.com>
> Cc: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Converting rack mount to DC input?
>
> Hmm, GX16 is interesting, thank you! Let me see if I can find one with
> 8 pins easily - that's the minimum that I need (see earlier emails
> why: to either supply external DC (+17, -17, 0, 48) or loop back the
> internal PSU (half the pins would carry the internal psu's voltages))
>
> That's actually pretty cool because those are small and allow a
> circular hole and are easily panel mounted. Thanks, great idea!
>
> On Mon, Jul 13, 2026 at 10:19?PM David Huss via Synth-diy
> <synth-diy at synth-diy.org> wrote:
> >
> > Ethernet has a PoE (Power-over-Ethernet) standard and in its maximum
> > PoE++ variant Type 4 switches can supply up to 100 Watts over one
> > ethernet port.
> >
> > HOWEVER: PoE similar to USB-C PD (Power Delivery) negotiates this power
> > delivery with the device attached to it and also has some measures to
> > detect faulty connections/cables. A self-baked solution may fail
> > spectacularily (and consider what happens if someone plugs your power
> > supply into an actual network port. Professional networking equipment
> > can easily cost mor than most peoples cars are worth..
> >
> > For this type of DC connection there are dedicated connectors and
> > cables. The price ranges and features vary wildly, but a good and cheap
> > solution that is tough enough for live-gig is the GX16 5-pin connector,
> > you can get a pack of 5 plugs AND jacks (including a shitty
> > screwdriver!) for 9 Euros on Amazon. The plug has a thread so it can be
> > locked and it is not too hard to solder.
> >
> > This type of plug has sometimes also be used in mixer power supplies
> > that work with outboard power supplies with exactly the requirements you
> > have, so it has been done before as well.
> >
> > Cheers,
> > David
> >
> >
> >
> > On 2026-07-13 21:24, cheater cheater via Synth-diy wrote:
> > > A little more to qualify my question, it's easier to find panel mount
> > > hardware for those, can just use a keystone plug, and they take up
> > > less space, so easier to fit on the back of a 1U device.
> > >
> > > On Mon, Jul 13, 2026 at 9:13?PM cheater cheater
> > > <cheater00social at gmail.com> wrote:
> > >>
> > >> Another question - how is everyone feeling about rj-45 as a power
> > >> plug? carrying up to 800 mA. I've seen threads where people say
> > >> they've been putting 1A through those, per pin. Thanks.
> > >>
> > >> https://www.eevblog.com/forum/projects/rj12-rj45-rj50-max-current-per-pin/
> > >>
> > >> https://groups.google.com/g/sci.electronics.design/c/TPGrRTJjReA?pli=1
> > >>
> > >>
> > >> On Mon, Jul 13, 2026 at 5:09?PM cheater cheater
> > >> <cheater00social at gmail.com> wrote:
> > >>>
> > >>> Someone off-list made some comments, and here's what came out of it:
> > >>>
> > >>> 1. All my devices use balanced audio
> > >>> 2. The rack items actually tie together their grounds by using rack
> > >>> screws and the rack rail
> > >>> 3. I don't know if the rack devices have isolated audio grounds, but
> > >>> they're almost fully analogue, except for stuff like LED bar graphs
> > >>> and on-off status LEDs for functions
> > >>>
> > >>> On Mon, Jul 13, 2026 at 4:34?PM cheater cheater
> > >>> <cheater00social at gmail.com> wrote:
> > >>>>
> > >>>> So a person on another forum mentioned that converting the devices to
> > >>>> DC input could create ground loops.
> > >>>>
> > >>>> As a reminder, I would be creating a "DC Bus" that carries +18, -18,
> > >>>> 0V, and +48V, and I would wire it in a daisy-chain configuration going
> > >>>> from unit to unit. All of those units are in one rack on top of each
> > >>>> other.
> > >>>>
> > >>>> Here's what they said:
> > >>>>
> > >>>>> If you're intending to run them all off a single raw supply, that could
> > >>>>> introduce ground loops. The safest would be a bunch of small
> > >>>>> transformers, or one with multiple secondaries. Hammond 229 are
> > >>>>> small low profile transformers that could fit in a 1U cabinet.
> > >>>>
> > >>>> So I've been thinking about this since they mentioned ground loops.
> > >>>> Here's what I think.
> > >>>>
> > >>>> Currently all those rack devices already use a three-prong IEC C14
> > >>>> receptacle, with the earth wire connected to the chassis.
> > >>>>
> > >>>> Instead of the chassis grounding point being connected via the C14
> > >>>> receptacle, and through a mains cable, to mains earth, it would now be
> > >>>> connected via my DC bus cable, which would have an earth conductor as
> > >>>> well.
> > >>>>
> > >>>> So in terms of ground loops, not much changes.
> > >>>>
> > >>>> However, given that we're talking about LOOPS, the area of the ground
> > >>>> loop would be important as well.
> > >>>>
> > >>>> Currently each rack has a cable going to a power strip.
> > >>>>
> > >>>> However, with my DC bus, I would be daisy chaining it, so the bus goes
> > >>>> to the bottom rack mount device, there's a plug there, then from that
> > >>>> plug there's a short cable going 1U above it, and so on.
> > >>>>
> > >>>> That would create an extremely small area for the devices to create
> > >>>> ground loops.
> > >>>>
> > >>>> I could (and maybe should) additionally put an earthed shield around
> > >>>> these wires, in order to shield them from EMI.
> > >>>>
> > >>>> So in total, either nothing changes regarding ground loops, or it's
> > >>>> purely improved compared to the current situation.
> > >>>>
> > >>>> I would be interested in everyone's thoughts on this matter.
> > >>>>
> > >>>> Thanks.
> > >>>>
> > >>>>
> > >>>> On Fri, Jul 10, 2026 at 6:03?PM cheater cheater
> > >>>> <cheater00social at gmail.com> wrote:
> > >>>>>
> > >>>>> there's one that's particularly noisy, but there are others that are a
> > >>>>> little noisy too, and it adds up. plus the heat just makes the room
> > >>>>> uncomfortable to be in. I've gone to great lengths to move all heat
> > >>>>> and noise generating equipment out of my day room, including moving
> > >>>>> the pcs to another place and connecting everything via fiber optics.
> > >>>>> so having 80W less heating my head will be an improvement once more.
> > >>>>>
> > >>>>> On Fri, Jul 10, 2026 at 5:58?PM el macaco <elmacaco at hotmail.com> wrote:
> > >>>>>>
> > >>>>>> Is the noisey transformer just one unit?  Would a torroidial transformer have less physical noise?
> > >>>>>>
> > >>>>>> Or if it is vibration related maybe mounting it with rubber washers and making the electrical contact with wires?
> > >>>>>>
> > >>>>>> Or move the units away from where the mic can pick up the noise?
> > >>>>>>
> > >>>>>> Not my area of expertise, just wondering if there may be a simpler solition.
> > >>>>>>
> > >>>>>> Ed
> > >>>>>>
> > >>>>>>
> > >>>>>>
> > >>>>>> Get Outlook for iOS
> > >>>>>> ________________________________
> > >>>>>> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy at synth-diy.org>
> > >>>>>> Sent: Thursday, 09 July 2026 17:39:07
> > >>>>>> To: cheater cheater <cheater00social at gmail.com>
> > >>>>>> Cc: synth-diy <synth-diy at synth-diy.org>
> > >>>>>> Subject: Re: [sdiy] Converting rack mount to DC input?
> > >>>>>>
> > >>>>>> You could use both rails, i.e. connect the relay coil between the + and - supply. Not + and gnd. If you want anything more fancy you should build some sort of power-good circuit. But that applies to your homebrew connector solution too.
> > >>>>>>
> > >>>>>> Just look at any general purpose or small power relays from e.g. Panasonic, Omron, TE. They usually have an endurance of millions of cycles. A quick search on digikey shows lots of options, starting at a few euro?s.
> > >>>>>>
> > >>>>>> Ben
> > >>>>>>
> > >>>>>>> On 9 Jul 2026, at 18:23, cheater cheater <cheater00social at gmail.com> wrote:
> > >>>>>>>
> > >>>>>>> Thanks. A few questions:
> > >>>>>>>
> > >>>>>>> What if only some of the rails are connected, but not the one used for
> > >>>>>>> steering the relay (a fault)?
> > >>>>>>>
> > >>>>>>> Relays are kind of expensive, how much do you think that could end up costing?
> > >>>>>>>
> > >>>>>>> If they don't get cycled a lot at all, wouldn't they end up getting stuck?
> > >>>>>>>
> > >>>>>>> On Thu, Jul 9, 2026 at 5:57?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>>>>>>>
> > >>>>>>>> You could use an internal relay for the switch-over. If there is power on the DC connector -> switch over. Otherwise keep the AC rectifier connected.
> > >>>>>>>>
> > >>>>>>>> Ben
> > >>>>>>>>
> > >>>>>>>>> On 9 Jul 2026, at 16:06, cheater cheater <cheater00social at gmail.com> wrote:
> > >>>>>>>>>
> > >>>>>>>>> In order to provide the bridging functionality it has to have at least 8 pins.
> > >>>>>>>>>
> > >>>>>>>>> On Thu, Jul 9, 2026 at 1:41?PM Ben Stuyts <ben at stuyts.nl> wrote:
> > >>>>>>>>>>
> > >>>>>>>>>> Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.
> > >>>>>>>>>>
> > >>>>>>>>>> Ben
> > >>>>>>>>>>
> > >>>>>>>>>>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
> > >>>>>>>>>>>
> > >>>>>>>>>>> One way to have DC input, but retain the capability of using the
> > >>>>>>>>>>> internal power supply, is to have a 4P2T switch for configuration.
> > >>>>>>>>>>>
> > >>>>>>>>>>> It seems that 4P2T switches are super expensive, especially if they're
> > >>>>>>>>>>> supposed to withstand, say, 1A.
> > >>>>>>>>>>>
> > >>>>>>>>>>> So I started looking around. TLDR: classic pcie 8-pin power connectors
> > >>>>>>>>>>> are probably the best, and also the cheapest.
> > >>>>>>>>>>>
> > >>>>>>>>>>> My first thought was to look at PCIE x1 slots. The cheapest advanced
> > >>>>>>>>>>> connector on earth, for 0.4 Euro at unit price, you get a connector
> > >>>>>>>>>>> that handles 1.1A per pin as per eg this document, page 6, 4.4
> > >>>>>>>>>>>
> > >>>>>>>>>>> https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf
> > >>>>>>>>>>>
> > >>>>>>>>>>>> 4.4 CONTACT CURRENT RATING
> > >>>>>>>>>>>> 1.1 amp per contact minimum per EIA-364?70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25?C.
> > >>>>>>>>>>>
> > >>>>>>>>>>> The connector has 36 pins, so while I don't think it would handle 36A,
> > >>>>>>>>>>> I'm sure it would handle something like 2A, especially if you share
> > >>>>>>>>>>> pins. You can even leave pins empty to prevent shorts during
> > >>>>>>>>>>> insertion.
> > >>>>>>>>>>>
> > >>>>>>>>>>> You could put the connector out the back, and either insert a plug-in
> > >>>>>>>>>>> "card" (really just a small edge connector with wires soldered on)
> > >>>>>>>>>>> that provides DC, or a pass-through "card" that shorts some pins
> > >>>>>>>>>>> together to carry power from the internal power supply. And now
> > >>>>>>>>>>> instead of $20-30 per unit, this costs $1 per unit. My main question
> > >>>>>>>>>>> is how I would fix the connector, but maybe a simple screw hole in the
> > >>>>>>>>>>> connector that mates with a threaded hole in the case could do the
> > >>>>>>>>>>> trick.
> > >>>>>>>>>>>
> > >>>>>>>>>>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U
> > >>>>>>>>>>> rack unit, which is 45mm, so it doesn't take up much space either.
> > >>>>>>>>>>>
> > >>>>>>>>>>> The cheapest one that can be found at Mouser currently and can be
> > >>>>>>>>>>> bought in low volumes is roughly 0.4 Euro.
> > >>>>>>>>>>>
> > >>>>>>>>>>> https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D
> > >>>>>>>>>>>
> > >>>>>>>>>>> Qty.  Unit Price  Ext. Price
> > >>>>>>>>>>> 1     ? 0,439     ? 0,44
> > >>>>>>>>>>> 10    ? 0,372     ? 3,72
> > >>>>>>>>>>> 25    ? 0,332     ? 8,30
> > >>>>>>>>>>> 100   ? 0,316     ? 31,60
> > >>>>>>>>>>>
> > >>>>>>>>>>> By making the connector require a dummy plug to connect the internal
> > >>>>>>>>>>> power supply into the circuit, it makes it impossible to connect both
> > >>>>>>>>>>> DC power and mains AC, so that makes the design intrinsically safe
> > >>>>>>>>>>> without using switches.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Alternatively to a PCIE connector I could use some panel mount plug
> > >>>>>>>>>>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry
> > >>>>>>>>>>> power from the internal power supply, and similarly use a shorting
> > >>>>>>>>>>> plug to use the internal power supply.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.
> > >>>>>>>>>>> Circular metric aren't better.
> > >>>>>>>>>>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,
> > >>>>>>>>>>> so I can't find them by number of pins.
> > >>>>>>>>>>>
> > >>>>>>>>>>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.
> > >>>>>>>>>>> They're latching (no need for screws and stuff). There doesn't seem to
> > >>>>>>>>>>> be a panel mount version, but one could mount a through-hole connector
> > >>>>>>>>>>> to a pcb, and have the pcb have screw holes for mounting to the rear
> > >>>>>>>>>>> panel. They handle high power - 150W meaning 3A per pin (half the pins
> > >>>>>>>>>>> are return pins). Seems like a winner to me. They're also tiny so they
> > >>>>>>>>>>> will easily fit in the back of a 1U unit even vertically. The biggest
> > >>>>>>>>>>> pain here might be making the rectangular hole and having it look any
> > >>>>>>>>>>> good. might be a case for custom die, maybe a small steel job that
> > >>>>>>>>>>> uses two bolts to screw together the two cutting parts through the
> > >>>>>>>>>>> sheet metal.
> > >>>>>>>>>>>
> > >>>>>>>>>>> "Pin and socket" connectors are the same kind of thing, just not
> > >>>>>>>>>>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...
> > >>>>>>>>>>> useful alternative if more than 4 rails are necessary.
> > >>>>>>>>>>>
> > >>>>>>>>>>> D-sub connectors carry up to 3A... and are very cheap and can do panel
> > >>>>>>>>>>> mount of some sort. But I'll be damned if I use one of those cursed
> > >>>>>>>>>>> things for power.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Automotive connectors seem inexpensive too, but I haven't really
> > >>>>>>>>>>> looked into them much other than a quick parametric search.
> > >>>>>>>>>>>
> > >>>>>>>>>>> I wonder what everyone thinks of this.
> > >>>>>>>>>>>
> > >>>>>>>>>>> On Tue, Jul 7, 2026 at 6:39?AM cheater cheater
> > >>>>>>>>>>> <cheater00social at gmail.com> wrote:
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> Don't you think this may have had something to do with you
> > >>>>>>>>>>>> distributing AC power, rather than DC with 0V potential?
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> On Sat, Jul 4, 2026 at 11:33?PM Mattias Rickardsson <mr at analogue.org> wrote:
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> Den l?r 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy at synth-diy.org> skrev:
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> This reminds me of a somewhat similar issue I had many years ago:
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> /mr
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> ________________________________________________________
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> > >>>>>>>>>>>
> > >>>>>>>>>>> ________________________________________________________
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> > >>>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>
> > >>>>>>>
> > >>>>>>
> > >>>>>>
> > >>>>>> ________________________________________________________
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> > >
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> >
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>
> ________________________________________________________
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