Yahoo Groups archive

Cgs synth

Index last updated: 2026-04-28 23:16 UTC

Thread

cgs75 hot voltage outputs

cgs75 hot voltage outputs

2011-09-13 by scozbort

Hi!

Can't believe I only just found this place...

I'm having an issue with my VCS build and hoping someone has come across it before.

When I use the trigger in and slow fall times the module outputs very hot voltages - I think it would go to 15v if I let it.

But in cycle mode it outputs normal voltages.

I suspect a wiring fault but I can't see any mistakes, unless of course I have misunderstood how to wire it up - which is likely!

Hoping its an easy fix and thanks in advance
- Kevin

Re: cgs75 hot voltage outputs

2011-09-22 by scozbort

OK here is some more info.

Most people seem to have difficulty with the transistor pin-outs not matching the circuit. I don't think this is the problem here. The module functions perfectly (except for hot output), and the transistors were supplied in an Elby kit. I have emailed Laurie to see if the transistors he supplied are correct (can't seem to find a datasheet for them).

Also the calibration trimmer does offset the hot output voltage, but no where near enough. I was wondering if a 20 turn trimmer here would allow me to drop the voltage of the output right down whilst still maintaining the correct triangular waveshape?

Like I said it only outputs high voltages when its being triggered.

It's completely useful as it is, I just have to attenuate the output. Not comfortable send 15v signals around the modular. Or do I not need to worry about this at all? I know it distorts my VCAs pretty quick.

Any help much appreciated!
- Kevin
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@...> wrote:
>
> Hi!
>
> Can't believe I only just found this place...
>
> I'm having an issue with my VCS build and hoping someone has come across it before.
>
> When I use the trigger in and slow fall times the module outputs very hot voltages - I think it would go to 15v if I let it.
>
> But in cycle mode it outputs normal voltages.
>
> I suspect a wiring fault but I can't see any mistakes, unless of course I have misunderstood how to wire it up - which is likely!
>
> Hoping its an easy fix and thanks in advance
> - Kevin
>

Re: cgs75 hot voltage outputs

2011-09-22 by Elby Designs

The END OUT output should be clamped to 5V because there is a zener diode in
that line. If that is the output you are having problems with then the zener
is either faulty, not fitted, or the wrong value.
The OUT output doesn't have any such protection and it is feasible for the
output to approach power rail levels as it is driven directly from the
output of an opamp. I will need to study the front end more to determine if
there is any internal clamping but it might be worth asking Ken what are the
normal output levels to be expected. Maybe this output needs a simple
resistor divider.
The transistors are standard and should fit the pcb as is.

The only other problem I can see is that Ken has 4 x 220K listed in his BOM
and then says in the text that they should be 22K. I have supplied 220K

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com

-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
Of scozbort
Sent: Friday, 23 September 2011 6:43 AM
To: cgs_synth@yahoogroups.com
Subject: [cgs_synth] Re: cgs75 hot voltage outputs

OK here is some more info.

Most people seem to have difficulty with the transistor pin-outs not
matching the circuit. I don't think this is the problem here. The module
functions perfectly (except for hot output), and the transistors were
supplied in an Elby kit. I have emailed Laurie to see if the transistors he
supplied are correct (can't seem to find a datasheet for them).

Also the calibration trimmer does offset the hot output voltage, but no
where near enough. I was wondering if a 20 turn trimmer here would allow me
to drop the voltage of the output right down whilst still maintaining the
correct triangular waveshape?

Like I said it only outputs high voltages when its being triggered.

It's completely useful as it is, I just have to attenuate the output. Not
comfortable send 15v signals around the modular. Or do I not need to worry
about this at all? I know it distorts my VCAs pretty quick.

Any help much appreciated!
- Kevin
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@...> wrote:
>
> Hi!
>
> Can't believe I only just found this place...
>
> I'm having an issue with my VCS build and hoping someone has come across
it before.
>
> When I use the trigger in and slow fall times the module outputs very hot
voltages - I think it would go to 15v if I let it.
>
> But in cycle mode it outputs normal voltages.
>
> I suspect a wiring fault but I can't see any mistakes, unless of course I
have misunderstood how to wire it up - which is likely!
>
> Hoping its an easy fix and thanks in advance
> - Kevin
>




------------------------------------

The CGS Modular Synth home page: http://www.cgs.synth.net/
Yahoo! Groups Links

Re: cgs75 hot voltage outputs

2011-09-22 by scozbort

Cheers Laurie, I appreciate you input!

Its the main OUT that gets hot. And I'm using a REV1.0 PCB so the 220k resistors should be correct. I thought about sticking a resistor on the output but that would affect the cycle out as well, which does not need attenuation.

Its sounding more like its functioning perfectly. Am I being over-cautious worrying about throwing (potentially) 15V slopes around the system?

- Kevin
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "Elby Designs" <elby_designs@...> wrote:
>
> The END OUT output should be clamped to 5V because there is a zener diode in
> that line. If that is the output you are having problems with then the zener
> is either faulty, not fitted, or the wrong value.
> The OUT output doesn't have any such protection and it is feasible for the
> output to approach power rail levels as it is driven directly from the
> output of an opamp. I will need to study the front end more to determine if
> there is any internal clamping but it might be worth asking Ken what are the
> normal output levels to be expected. Maybe this output needs a simple
> resistor divider.
> The transistors are standard and should fit the pcb as is.
>
> The only other problem I can see is that Ken has 4 x 220K listed in his BOM
> and then says in the text that they should be 22K. I have supplied 220K
>
> Best Regards
> Laurie Biddulph
> Mobile: 0400 257 645
> Web: www.elby-designs.com
>
> -----Original Message-----
> From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
> Of scozbort
> Sent: Friday, 23 September 2011 6:43 AM
> To: cgs_synth@yahoogroups.com
> Subject: [cgs_synth] Re: cgs75 hot voltage outputs
>
> OK here is some more info.
>
> Most people seem to have difficulty with the transistor pin-outs not
> matching the circuit. I don't think this is the problem here. The module
> functions perfectly (except for hot output), and the transistors were
> supplied in an Elby kit. I have emailed Laurie to see if the transistors he
> supplied are correct (can't seem to find a datasheet for them).
>
> Also the calibration trimmer does offset the hot output voltage, but no
> where near enough. I was wondering if a 20 turn trimmer here would allow me
> to drop the voltage of the output right down whilst still maintaining the
> correct triangular waveshape?
>
> Like I said it only outputs high voltages when its being triggered.
>
> It's completely useful as it is, I just have to attenuate the output. Not
> comfortable send 15v signals around the modular. Or do I not need to worry
> about this at all? I know it distorts my VCAs pretty quick.
>
> Any help much appreciated!
> - Kevin
>
> --- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@> wrote:
> >
> > Hi!
> >
> > Can't believe I only just found this place...
> >
> > I'm having an issue with my VCS build and hoping someone has come across
> it before.
> >
> > When I use the trigger in and slow fall times the module outputs very hot
> voltages - I think it would go to 15v if I let it.
> >
> > But in cycle mode it outputs normal voltages.
> >
> > I suspect a wiring fault but I can't see any mistakes, unless of course I
> have misunderstood how to wire it up - which is likely!
> >
> > Hoping its an easy fix and thanks in advance
> > - Kevin
> >
>
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>

Re: cgs75 hot voltage outputs

2011-09-22 by Richard Brewster

It is not functioning right if the output swings to +15V when cycling.
Ken's notes:

Adjustments on the VCS board are set to obtain a 0 to +5 volt level when
the unit is cycling, producing a 100Hz triangle wave. An oscilloscope is
required for this adjustment. In an oscilloscope is not available,
adjust for the least distorted sounding waveshape.

I guess that he means the single trimpot by "adjustments on the VCS
board". I built two of these and did not have any problems.

Richard Brewster
http://pugix.com
Show quoted textHide quoted text
On 9/22/11 6:29 PM, scozbort wrote:
> Cheers Laurie, I appreciate you input!
>
> Its the main OUT that gets hot. And I'm using a REV1.0 PCB so the 220k resistors should be correct. I thought about sticking a resistor on the output but that would affect the cycle out as well, which does not need attenuation.
>
> Its sounding more like its functioning perfectly. Am I being over-cautious worrying about throwing (potentially) 15V slopes around the system?
>
> - Kevin
>
>
> --- In cgs_synth@yahoogroups.com, "Elby Designs"<elby_designs@...> wrote:
>> The END OUT output should be clamped to 5V because there is a zener diode in
>> that line. If that is the output you are having problems with then the zener
>> is either faulty, not fitted, or the wrong value.
>> The OUT output doesn't have any such protection and it is feasible for the
>> output to approach power rail levels as it is driven directly from the
>> output of an opamp. I will need to study the front end more to determine if
>> there is any internal clamping but it might be worth asking Ken what are the
>> normal output levels to be expected. Maybe this output needs a simple
>> resistor divider.
>> The transistors are standard and should fit the pcb as is.
>>
>> The only other problem I can see is that Ken has 4 x 220K listed in his BOM
>> and then says in the text that they should be 22K. I have supplied 220K
>>
>> Best Regards
>> Laurie Biddulph
>> Mobile: 0400 257 645
>> Web: www.elby-designs.com
>>
>> -----Original Message-----
>> From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
>> Of scozbort
>> Sent: Friday, 23 September 2011 6:43 AM
>> To: cgs_synth@yahoogroups.com
>> Subject: [cgs_synth] Re: cgs75 hot voltage outputs
>>
>> OK here is some more info.
>>
>> Most people seem to have difficulty with the transistor pin-outs not
>> matching the circuit. I don't think this is the problem here. The module
>> functions perfectly (except for hot output), and the transistors were
>> supplied in an Elby kit. I have emailed Laurie to see if the transistors he
>> supplied are correct (can't seem to find a datasheet for them).
>>
>> Also the calibration trimmer does offset the hot output voltage, but no
>> where near enough. I was wondering if a 20 turn trimmer here would allow me
>> to drop the voltage of the output right down whilst still maintaining the
>> correct triangular waveshape?
>>
>> Like I said it only outputs high voltages when its being triggered.
>>
>> It's completely useful as it is, I just have to attenuate the output. Not
>> comfortable send 15v signals around the modular. Or do I not need to worry
>> about this at all? I know it distorts my VCAs pretty quick.
>>
>> Any help much appreciated!
>> - Kevin
>>
>> --- In cgs_synth@yahoogroups.com, "scozbort"<kevin.babbage@> wrote:
>>> Hi!
>>>
>>> Can't believe I only just found this place...
>>>
>>> I'm having an issue with my VCS build and hoping someone has come across
>> it before.
>>> When I use the trigger in and slow fall times the module outputs very hot
>> voltages - I think it would go to 15v if I let it.
>>> But in cycle mode it outputs normal voltages.
>>>
>>> I suspect a wiring fault but I can't see any mistakes, unless of course I
>> have misunderstood how to wire it up - which is likely!
>>> Hoping its an easy fix and thanks in advance
>>> - Kevin
>>>
>>
>>
>>
>> ------------------------------------
>>
>> The CGS Modular Synth home page: http://www.cgs.synth.net/
>> Yahoo! Groups Links
>>
>



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

Re: cgs75 hot voltage outputs

2011-09-22 by scozbort

That's the thing! When cycling it does produce around 5v. But when triggered externally it can get right up to 15v. But only with long fall times. Its like each successive trigger adds to the voltage when using long fall times.
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, Richard Brewster <pugix@...> wrote:
>
> It is not functioning right if the output swings to +15V when cycling.
> Ken's notes:
>
> Adjustments on the VCS board are set to obtain a 0 to +5 volt level when
> the unit is cycling, producing a 100Hz triangle wave. An oscilloscope is
> required for this adjustment. In an oscilloscope is not available,
> adjust for the least distorted sounding waveshape.
>
> I guess that he means the single trimpot by "adjustments on the VCS
> board". I built two of these and did not have any problems.
>
> Richard Brewster
> http://pugix.com
>
> On 9/22/11 6:29 PM, scozbort wrote:
> > Cheers Laurie, I appreciate you input!
> >
> > Its the main OUT that gets hot. And I'm using a REV1.0 PCB so the 220k resistors should be correct. I thought about sticking a resistor on the output but that would affect the cycle out as well, which does not need attenuation.
> >
> > Its sounding more like its functioning perfectly. Am I being over-cautious worrying about throwing (potentially) 15V slopes around the system?
> >
> > - Kevin
> >
> >
> > --- In cgs_synth@yahoogroups.com, "Elby Designs"<elby_designs@> wrote:
> >> The END OUT output should be clamped to 5V because there is a zener diode in
> >> that line. If that is the output you are having problems with then the zener
> >> is either faulty, not fitted, or the wrong value.
> >> The OUT output doesn't have any such protection and it is feasible for the
> >> output to approach power rail levels as it is driven directly from the
> >> output of an opamp. I will need to study the front end more to determine if
> >> there is any internal clamping but it might be worth asking Ken what are the
> >> normal output levels to be expected. Maybe this output needs a simple
> >> resistor divider.
> >> The transistors are standard and should fit the pcb as is.
> >>
> >> The only other problem I can see is that Ken has 4 x 220K listed in his BOM
> >> and then says in the text that they should be 22K. I have supplied 220K
> >>
> >> Best Regards
> >> Laurie Biddulph
> >> Mobile: 0400 257 645
> >> Web: www.elby-designs.com
> >>
> >> -----Original Message-----
> >> From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
> >> Of scozbort
> >> Sent: Friday, 23 September 2011 6:43 AM
> >> To: cgs_synth@yahoogroups.com
> >> Subject: [cgs_synth] Re: cgs75 hot voltage outputs
> >>
> >> OK here is some more info.
> >>
> >> Most people seem to have difficulty with the transistor pin-outs not
> >> matching the circuit. I don't think this is the problem here. The module
> >> functions perfectly (except for hot output), and the transistors were
> >> supplied in an Elby kit. I have emailed Laurie to see if the transistors he
> >> supplied are correct (can't seem to find a datasheet for them).
> >>
> >> Also the calibration trimmer does offset the hot output voltage, but no
> >> where near enough. I was wondering if a 20 turn trimmer here would allow me
> >> to drop the voltage of the output right down whilst still maintaining the
> >> correct triangular waveshape?
> >>
> >> Like I said it only outputs high voltages when its being triggered.
> >>
> >> It's completely useful as it is, I just have to attenuate the output. Not
> >> comfortable send 15v signals around the modular. Or do I not need to worry
> >> about this at all? I know it distorts my VCAs pretty quick.
> >>
> >> Any help much appreciated!
> >> - Kevin
> >>
> >> --- In cgs_synth@yahoogroups.com, "scozbort"<kevin.babbage@> wrote:
> >>> Hi!
> >>>
> >>> Can't believe I only just found this place...
> >>>
> >>> I'm having an issue with my VCS build and hoping someone has come across
> >> it before.
> >>> When I use the trigger in and slow fall times the module outputs very hot
> >> voltages - I think it would go to 15v if I let it.
> >>> But in cycle mode it outputs normal voltages.
> >>>
> >>> I suspect a wiring fault but I can't see any mistakes, unless of course I
> >> have misunderstood how to wire it up - which is likely!
> >>> Hoping its an easy fix and thanks in advance
> >>> - Kevin
> >>>
> >>
> >>
> >>
> >> ------------------------------------
> >>
> >> The CGS Modular Synth home page: http://www.cgs.synth.net/
> >> Yahoo! Groups Links
> >>
> >
>
>
>
> [Non-text portions of this message have been removed]
>

Re: cgs75 hot voltage outputs

2011-09-23 by sasami@hotkey.net.au

A 20 turn trimmer will not increase your range of adjustment.
Most modulars would be unphased by seeing 15 volts at an input. Remember
that this voltage is current limited by both input and output resistors. For
example, the Serge is stated as being able to handle 25V at its inputs
without issue. It won't worry any of my designs either.
I would avoid plugging a hot voltage into an Analog Solutions module though!
I don't know the cause of this. It may in fact be operating correctly for
what you are doing to it. At the moment I am not in a position to test this
out myself.
Ken
Show quoted textHide quoted text
>OK here is some more info.
>
>Most people seem to have difficulty with the transistor pin-outs not
matching the circuit. I don't think this is the problem here. The module
functions perfectly (except for hot output), and the transistors were
supplied in an Elby kit. I have emailed Laurie to see if the transistors he
supplied are correct (can't seem to find a datasheet for them).
>
>Also the calibration trimmer does offset the hot output voltage, but no
where near enough. I was wondering if a 20 turn trimmer here would allow me
to drop the voltage of the output right down whilst still maintaining the
correct triangular waveshape?
>
>Like I said it only outputs high voltages when its being triggered.
>
>It's completely useful as it is, I just have to attenuate the output. Not
comfortable send 15v signals around the modular. Or do I not need to worry
about this at all? I know it distorts my VCAs pretty quick.
>
>Any help much appreciated!
> - Kevin
>
>--- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@...> wrote:
>>
>> Hi!
>>
>> Can't believe I only just found this place...
>>
>> I'm having an issue with my VCS build and hoping someone has come across
it before.
>>
>> When I use the trigger in and slow fall times the module outputs very hot
voltages - I think it would go to 15v if I let it.
>>
>> But in cycle mode it outputs normal voltages.
>>
>> I suspect a wiring fault but I can't see any mistakes, unless of course I
have misunderstood how to wire it up - which is likely!
>>
>> Hoping its an easy fix and thanks in advance
>> - Kevin
>>
>
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: cgs75 hot voltage outputs

2011-09-23 by sasami@hotkey.net.au

>>
>> The only other problem I can see is that Ken has 4 x 220K listed in his BOM
>> and then says in the text that they should be 22K. I have supplied 220K

The BOM and overlay are correct. There was a SINGLE 220k that needed to be
changed to 22k, and only on the red version of the PCB.
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: cgs75 hot voltage outputs

2011-09-23 by scozbort

Thanks for the info Ken. I've been using it fine with an attenuator on the output. I'm have mostly Frac and DIY modules, with 1 Euro and 1 or 2 DIY running on 12V, so I will just watch it with those ones. I will keep an ear out for anyone else experiencing the same thing, but I suspect there is nothing wrong with it. Thanks for making such a great device available!

- Kevin
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
> A 20 turn trimmer will not increase your range of adjustment.
> Most modulars would be unphased by seeing 15 volts at an input. Remember
> that this voltage is current limited by both input and output resistors. For
> example, the Serge is stated as being able to handle 25V at its inputs
> without issue. It won't worry any of my designs either.
> I would avoid plugging a hot voltage into an Analog Solutions module though!
> I don't know the cause of this. It may in fact be operating correctly for
> what you are doing to it. At the moment I am not in a position to test this
> out myself.
> Ken
>
> >OK here is some more info.
> >
> >Most people seem to have difficulty with the transistor pin-outs not
> matching the circuit. I don't think this is the problem here. The module
> functions perfectly (except for hot output), and the transistors were
> supplied in an Elby kit. I have emailed Laurie to see if the transistors he
> supplied are correct (can't seem to find a datasheet for them).
> >
> >Also the calibration trimmer does offset the hot output voltage, but no
> where near enough. I was wondering if a 20 turn trimmer here would allow me
> to drop the voltage of the output right down whilst still maintaining the
> correct triangular waveshape?
> >
> >Like I said it only outputs high voltages when its being triggered.
> >
> >It's completely useful as it is, I just have to attenuate the output. Not
> comfortable send 15v signals around the modular. Or do I not need to worry
> about this at all? I know it distorts my VCAs pretty quick.
> >
> >Any help much appreciated!
> > - Kevin
> >
> >--- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@> wrote:
> >>
> >> Hi!
> >>
> >> Can't believe I only just found this place...
> >>
> >> I'm having an issue with my VCS build and hoping someone has come across
> it before.
> >>
> >> When I use the trigger in and slow fall times the module outputs very hot
> voltages - I think it would go to 15v if I let it.
> >>
> >> But in cycle mode it outputs normal voltages.
> >>
> >> I suspect a wiring fault but I can't see any mistakes, unless of course I
> have misunderstood how to wire it up - which is likely!
> >>
> >> Hoping its an easy fix and thanks in advance
> >> - Kevin
> >>
> >
> >
> >
> >
> >------------------------------------
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >Yahoo! Groups Links
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone sasami@... otherunicorn@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.