Cgs synth

>Hello everyone,
>
>I've build a small system, only the bare minimum to make music, so far.
>
>I have the following modules built:
>Oakley Basic VCA
>Music From Outer Space Lowpass Filter
>Music From Outer Space Envelope Generator
>CGS VCO
>
>I hooked everything up today, but there's no noise coming out. This
>is how I've it patched:
>VCO -> Filter -> VCA
>and
>EG -> VCA
>
>I'm thinking there's a problem with the VCO. I've only wired three
>things: 1V/Oct input, tune knob, and square wave output. I tried
>hooking this straight into my keyboard amp, but did not get any sound.
>
>Also, I have no idea if the EG or Filter are working. Is there anyway
>to test them without a VCO?
>
>The VCA seems to be working. I connected my guitar to it, and the
>gain knob DID change the volume, so that's good.
>
>Where should I start troubleshooting?
>
>Also, when I was first starting up the system with the VCO in place, I
>was testing to see if it was getting the correct voltages from the
>power supply. It was, but, when I was probing it with my multimeter,
>I accidentally touched the bracket that the PCB is connected to. This
>created a small spark... Could I have shorted the circuit, making it
>unusable?
>
>Any help would be wonderful. This is very discouraging.
>
>Thanks,
>Cole
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>

--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
> 1) Use a different VCO output. The square wave likes the PWM input to be
> connected.
>
> 2) Sweep the tune knob, and if you still don't hear anything , try
adjusting
> the SPAN and ZERO trimmers. This VCO can quite happily work well
above the
> hearing range if these are wrong.
>
> Ken
>
>
> >Hello everyone,
> >
> >I've build a small system, only the bare minimum to make music, so far.
> >
> >I have the following modules built:
> >Oakley Basic VCA
> >Music From Outer Space Lowpass Filter
> >Music From Outer Space Envelope Generator
> >CGS VCO
> >
> >I hooked everything up today, but there's no noise coming out. This
> >is how I've it patched:
> >VCO -> Filter -> VCA
> >and
> >EG -> VCA
> >
> >I'm thinking there's a problem with the VCO. I've only wired three
> >things: 1V/Oct input, tune knob, and square wave output. I tried
> >hooking this straight into my keyboard amp, but did not get any sound.
> >
> >Also, I have no idea if the EG or Filter are working. Is there anyway
> >to test them without a VCO?
> >
> >The VCA seems to be working. I connected my guitar to it, and the
> >gain knob DID change the volume, so that's good.
> >
> >Where should I start troubleshooting?
> >
> >Also, when I was first starting up the system with the VCO in place, I
> >was testing to see if it was getting the correct voltages from the
> >power supply. It was, but, when I was probing it with my multimeter,
> >I accidentally touched the bracket that the PCB is connected to. This
> >created a small spark... Could I have shorted the circuit, making it
> >unusable?
> >
> >Any help would be wonderful. This is very discouraging.
> >
> >Thanks,
> >Cole
> >
> >
> >
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone sasami@...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>

--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
>
> >I connected the PWM to a front panel jack. Did you mean the SQ wave
> >doesn't work when there's nothing modulating the PWM input? Or that
> >it has to be connected to the front panel?
>
> It needs an input, usually from a pot, to work. If it doesn't have
one, the
> detection voltage the op-amp is seeing is outside the range of the
signal.
>
> Ken
>
> >
> >Cole
> >
> >--- In cgs_synth@yahoogroups.com, sasami@ wrote:
> >>
> >> 1) Use a different VCO output. The square wave likes the PWM
input to be
> >> connected.
> >>
> >> 2) Sweep the tune knob, and if you still don't hear anything , try
> >adjusting
> >> the SPAN and ZERO trimmers. This VCO can quite happily work well
> >above the
> >> hearing range if these are wrong.
> >>
> >> Ken
> >>
> >>
> >> >Hello everyone,
> >> >
> >> >I've build a small system, only the bare minimum to make music,
so far.
> >> >
> >> >I have the following modules built:
> >> >Oakley Basic VCA
> >> >Music From Outer Space Lowpass Filter
> >> >Music From Outer Space Envelope Generator
> >> >CGS VCO
> >> >
> >> >I hooked everything up today, but there's no noise coming out. This
> >> >is how I've it patched:
> >> >VCO -> Filter -> VCA
> >> >and
> >> >EG -> VCA
> >> >
> >> >I'm thinking there's a problem with the VCO. I've only wired three
> >> >things: 1V/Oct input, tune knob, and square wave output. I tried
> >> >hooking this straight into my keyboard amp, but did not get any
sound.
> >> >
> >> >Also, I have no idea if the EG or Filter are working. Is there
anyway
> >> >to test them without a VCO?
> >> >
> >> >The VCA seems to be working. I connected my guitar to it, and the
> >> >gain knob DID change the volume, so that's good.
> >> >
> >> >Where should I start troubleshooting?
> >> >
> >> >Also, when I was first starting up the system with the VCO in
place, I
> >> >was testing to see if it was getting the correct voltages from the
> >> >power supply. It was, but, when I was probing it with my
multimeter,
> >> >I accidentally touched the bracket that the PCB is connected to.
This
> >> >created a small spark... Could I have shorted the circuit,
making it
> >> >unusable?
> >> >
> >> >Any help would be wonderful. This is very discouraging.
> >> >
> >> >Thanks,
> >> >Cole
> >> >
> >> >
> >> >
> >> >
> >> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >> >
> >> >Yahoo! Groups Links
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
_______________________________________________________________________
> >> Ken Stone sasami@
> >> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> >> Australian Miniature Horses & Ponies
<http://www.blaze.net.au/~sasami/>
> >>
> >
> >
> >
> >
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone sasami@...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>

>> I connected the PWM to a front panel jack. Did you mean the SQ wave
>> doesn't work when there's nothing modulating the PWM input? Or that
>> it has to be connected to the front panel?
>>
>
> It needs an input, usually from a pot, to work. If it doesn't have one, the
> detection voltage the op-amp is seeing is outside the range of the signal.
>
> Ken
>
>
>> Cole
>>
>> --- In cgs_synth@yahoogroups.com, sasami@... wrote:
>>
>>> 1) Use a different VCO output. The square wave likes the PWM input to be
>>> connected.
>>>
>>> 2) Sweep the tune knob, and if you still don't hear anything , try
>>>
>> adjusting
>>
>>> the SPAN and ZERO trimmers. This VCO can quite happily work well
>>>
>> above the
>>
>>> hearing range if these are wrong.
>>>
>>> Ken
>>>
>>>
>

--- In cgs_synth@yahoogroups.com, Richard Brewster <pugix@...> wrote:
>
> Wait a minute. The PWM input does not need to be connected up. The
> 100K resistor to ground from the - input of the comparator sets the
> detection point to zero. And the AC-coupled sawtooth wave going to the
> + input of the comparator centers the waveform around ground. So
> without anything else connected you should get a nice square wave from
> the SQ output.
>
> -Richard Brewster
> http://www.pugix.com
>
> sasami@... wrote:
> >> I connected the PWM to a front panel jack. Did you mean the SQ wave
> >> doesn't work when there's nothing modulating the PWM input? Or that
> >> it has to be connected to the front panel?
> >>
> >
> > It needs an input, usually from a pot, to work. If it doesn't have
one, the
> > detection voltage the op-amp is seeing is outside the range of the
signal.
> >
> > Ken
> >
> >
> >> Cole
> >>
> >> --- In cgs_synth@yahoogroups.com, sasami@ wrote:
> >>
> >>> 1) Use a different VCO output. The square wave likes the PWM
input to be
> >>> connected.
> >>>
> >>> 2) Sweep the tune knob, and if you still don't hear anything , try
> >>>
> >> adjusting
> >>
> >>> the SPAN and ZERO trimmers. This VCO can quite happily work well
> >>>
> >> above the
> >>
> >>> hearing range if these are wrong.
> >>>
> >>> Ken
> >>>
> >>>
> >
>