Cgs synth

>Hello,
>I've tried sending the triangle out of the VCO to a few different wave
>shapers. The sine shaper built onto the vco board, the wave
>multiplier, and now the blacet miniwave. On all of them I get a
>substantial glitch where the wave crosses the 0v point. It shows up
>as a spike on the scope, and an audiable buzz. The vco page mentions
>that the built on sine shaper will most likely have a glitch. I just
>figured that the wave mult. might as well. The MW shouldn't have the
>same glitch. Its late, and I haven't gone through the archives to see
>if this could be a problem w/ the MW, but I figured I'd post the
>problem here to see if anyone had any ideas. The glitch looks/sounds
>the same and is the the same spot w/ all wave shapers. Could the VCO
>be causing it?
>
>Thanks,
>Scott
>
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>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
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>

>I took some fuzzy photos of my scope, so you can see the glitch Im
>getting. I posted them in a new folder in the file section (vco
>wavesahape glitch). They are very fuzzy photos, but I think you can
>see them enough to get the idea. W/ the wave mult, it doesn't matter
>what shap Im making the wave, its alwas got a spike in it.
>I hooked up the miniwave to my old paia vco, and I get no glitch. I
>then hooked up the wave mult to my paia vco and I get only a tiny
>tiny glitch, but you can't hear it. Only thing is, I dont really use
>the paia anymore.. it doesn't tune up very well at all.
>I didn't take a photo of this, because its very subtle, but the saw
>wave out of the CGS vco has a little bit of a rounded top, but the
>bottom of the wave is sharp.
>I didn't leave out any caps or anything when I built the CGS VCO.
>Elby accidentally sent a bunch of 10n caps rather than 100n for the
>decoupling caps. Could that make a difference? Otherwise, if you can
>think of somewhere for me to add caps or change them or anything, I'd
>really appreciate it.
>
>Thanks,
>Scott
>
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>

--- In cgs_synth@yahoogroups.com, Richard Brewster <pugix@...> wrote:
>
> I'm a little confused, Scott. You said, "I've tried sending the
> triangle out of the VCO to a few different wave shapers." The VCO
has no
> triangle out. Are you talking about the ATSO output, which is one of
the
> sine outs? Or are you talking about the SAW out? Can you upload a
photo
> of the output of the VCO you are using?
>
> The Miniwave wants a 10V zero-centered sawtooth wave on the input.
From
> that you can dial up a sine wave out, among many other waveforms. The
> MW needs to be matched with the driving sawtooth to minimize its own
> glitch in the sine wave. It has trimmers for that. If you tune it to
> one VCO it may still have a glitch with another. Maybe you tuned
the MW
> to your PAIA VCO.
>
> -Richard Brewster
>
> http://www.pugix.com
>
>
> c10h14no2i wrote:
>
> >I took some fuzzy photos of my scope, so you can see the glitch Im
> >getting. I posted them in a new folder in the file section (vco
> >wavesahape glitch). They are very fuzzy photos, but I think you can
> >see them enough to get the idea. W/ the wave mult, it doesn't matter
> >what shap Im making the wave, its alwas got a spike in it.
> >I hooked up the miniwave to my old paia vco, and I get no glitch. I
> >then hooked up the wave mult to my paia vco and I get only a tiny
> >tiny glitch, but you can't hear it. Only thing is, I dont really use
> >the paia anymore.. it doesn't tune up very well at all.
> >I didn't take a photo of this, because its very subtle, but the saw
> >wave out of the CGS vco has a little bit of a rounded top, but the
> >bottom of the wave is sharp.
> >I didn't leave out any caps or anything when I built the CGS VCO.
> >Elby accidentally sent a bunch of 10n caps rather than 100n for the
> >decoupling caps. Could that make a difference? Otherwise, if you can
> >think of somewhere for me to add caps or change them or anything, I'd
> >really appreciate it.
> >
> >Thanks,
> >Scott
> >
> >
> >
> >
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>

>Hi,
>Sorry, I meant the saw out.. not triangle. (sorry.. I know I should
>get my terms straight w/ this stuff.. it was late!)
>
>I did tune the miniwave to the CGS VCO and it had the glitch. It made
>the sine wave shape, but it has a big ole spike in it.
>
>Then I put the paia VCO in it. I did have to re-adjust the MW for the
>paia VCO, and then it put out a perfect sine wave.
>
>Same w/ the wave mult. There is always a spike in it. I uploaded
>some files to the file section so you can see what I mean. I put the
>paia VCO into the wave mult. and it does not have the spike. It has a
>very small spike, but you can't hear it.
>
>Im dieing for some help here. Please let me know if you have any
>ideas as to what is causing this.. On the scope it looks like the
>wave goes up then down then where it resets it jumps up and down
>really really fast again before it starts the next wave.
>
>If you have the MW, then maybe you will understand this next bit..
>The last step for the calibration is to input 10v w/ the MW on
>quantizer mode. The output should be 5 volts. My output was 4v..
>John Blacet helped me work out the problem, and he said its because I
>had the MW's input span tweaked way way too far. He said the only
>reason he could think of that I would have to have the trimmer
>adjusted so far is if there was a problem w/ the VCO I was feeding it
>w/. I moved the input span trimmer back to a more reasonable
>position, and the quantizer works perfectly. However, the sine wave
>no longer looks right.. Its like a squished sine wave w/ a straight
>line on the end...
>
>another thing I have noticed is that w/ the paia vco, the saw wave is
> like a square that has been cut diagnally.. the height and lenght
>are equil. The cgs saw out is much longer. the length is about 1.5x
>the height. (this could be because my scope is super old and doesn't
>do much, and I dont know how to use it properly.. dono.. but there is
>a difference between the two)
>
>I first built the VCO to the CGS specs, and had a bunch of clipping on
>the wave.. I then re did the biasing resistors to what the ASM 1 docs
>say, and the clipping is gone. Should I remove the cap that connects
>to the saw output now, or does that make no difference?
>
>thanks
>Scott
>
>
>--- In cgs_synth@yahoogroups.com, Richard Brewster <pugix@...> wrote:
>>
>> I'm a little confused, Scott. You said, "I've tried sending the
>> triangle out of the VCO to a few different wave shapers." The VCO
>has no
>> triangle out. Are you talking about the ATSO output, which is one of
>the
>> sine outs? Or are you talking about the SAW out? Can you upload a
>photo
>> of the output of the VCO you are using?
>>
>> The Miniwave wants a 10V zero-centered sawtooth wave on the input.
>From
>> that you can dial up a sine wave out, among many other waveforms. The
>> MW needs to be matched with the driving sawtooth to minimize its own
>> glitch in the sine wave. It has trimmers for that. If you tune it to
>> one VCO it may still have a glitch with another. Maybe you tuned
>the MW
>> to your PAIA VCO.
>>
>> -Richard Brewster
>>
>> http://www.pugix.com
>>
>>
>> c10h14no2i wrote:
>>
>> >I took some fuzzy photos of my scope, so you can see the glitch Im
>> >getting. I posted them in a new folder in the file section (vco
>> >wavesahape glitch). They are very fuzzy photos, but I think you can
>> >see them enough to get the idea. W/ the wave mult, it doesn't matter
>> >what shap Im making the wave, its alwas got a spike in it.
>> >I hooked up the miniwave to my old paia vco, and I get no glitch. I
>> >then hooked up the wave mult to my paia vco and I get only a tiny
>> >tiny glitch, but you can't hear it. Only thing is, I dont really use
>> >the paia anymore.. it doesn't tune up very well at all.
>> >I didn't take a photo of this, because its very subtle, but the saw
>> >wave out of the CGS vco has a little bit of a rounded top, but the
>> >bottom of the wave is sharp.
>> >I didn't leave out any caps or anything when I built the CGS VCO.
>> >Elby accidentally sent a bunch of 10n caps rather than 100n for the
>> >decoupling caps. Could that make a difference? Otherwise, if you can
>> >think of somewhere for me to add caps or change them or anything, I'd
>> >really appreciate it.
>> >
>> >Thanks,
>> >Scott
>> >
>> >
>> >
>> >
>> >
>> >The CGS Modular Synth home page: http://www.cgs.synth.net/
>> >
>> >Yahoo! Groups Links
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>>
>
>
>
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
>
>
>