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
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
> >
>
>
>
>
> ------------------------------------
>
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