Cgs synth

I've replaced the 4051s and the 4024. The 4051s were MPF4051 and I
replaced them with CD4051.
The vco pitch goes sub audible. low low lowwww.
-pete

On Dec 3, 2008, at 2:00 AM, andrewlistmayer wrote:

> I'm not too sure if the 3140 would be causing your problem, but I
> wouldn't expect so. If you are getting 3 clean square waves from the
> 4024, but they are not clocking the filter, I'd check the 4051's.
> About the bleeding problem, maybe try removing the 4051's and 4024 and
> see if it persists? just to try to get a better idea of where it's
> coming from.
>
> Just curious, how low does the pitch of the VCO go then fully CCW? I
> have much the same problem on mine, where it goes up to the high audio
> range then cuts out, however it DOES clock the filter and doesn't
> bleed through. The minimum pitch I can get is fairly high, too.
>
> --- In cgs_synth@yahoogroups.com, casperelectronics <pete@...> wrote:
> >
> > Hey,
> > thanks for the response! I discovered a huge problem. Somehow one of
> > the traces on the board was cut and there was no ground
> connection to
> > the 4051s or the 4024. Connecting fixed a few issues but had no
> > noticeable effect on the VCO leak through problem.
> > I checked the outs of the 4024 and I'm getting 3 clean square waves.
> > One strange issue is that the VCO cuts off, just stops running at a
> > high frequency ALMOST out of the audible range.
> > When you turn it up to a certain point it cuts very noisy then just
> > cuts off.
> > Plus As I mentioned a bunch of times, I'm still getting strong bleed
> > through.
> > I've replaced every chip except the CA3140. I don't have a
> > replacement for that. Could that be responsible for my cutoff
> problem?
> > -pete
> >
> > On Dec 1, 2008, at 4:07 AM, andrewlistmayer wrote:
> >
> > > Mine isn`t working properly either, but based on what you said I`m
> > > 99.9999% sure your isn`t either. The VCO is supposed to clock the
> > > filter, so the frequency of the filter changes with it. When the
> > > filter receives no clock from the VCO, it seems to lock to a fixed
> > > frequency which is below the audible range. Mine did this before I
> > > fixed the VCO. The reason you get a filter sweep in the last
> 20% of
> > > the bandwidth knob is because you are simply increasing the
> band large
> > > enough to let some audio through, while the center point still
> sits in
> > > the sub audio range, so it`s acting like a normal lowpass
> filter. At
> > > least that`s how I interpreted it when my VCO wasn`t working.
> > >
> > > Now, the VCO leaking through into the audio without clocking the
> > > filter, that`s a new one to me. I`m no expert at this, so all I
> can
> > > say is that it`s clear your filter and VCO are working, so your
> > > problem mostly likely lies in the circuitry that is supposed to
> make
> > > them work together. The filter is clocked by 3 outputs of the
> 4024, so
> > > I`d check around there. Good luck.
> > >
> > > --- In cgs_synth@yahoogroups.com, casperelectronics <pete@> wrote:
> > > >
> > > > Hello everyone.
> > > > Sorry to continue the Bi-N-Tic questions. I know there have
> been a
> > > > lot and I've read them all and I still have a few more.
> > > > I think I got the whole thing working right but I'm not sure,
> it's a
> > > > weird module (as I'm sure you'll all agree)
> > > > The way it is working now it is really two modules, a filter
> and a
> > > > VCO, but I don't see (or hear) much connection between the two.
> > > >
> > > > If I turn the coarse and fine tune knobs all the way down,
> there is
> > > > no oscillator.
> > > > Then if I feed a signal in the IN jack i can get some really
> nice
> > > > filter cut sweeps using the BANDWIDTH knob and resonance
> using the
> > > > DAMPER knob. The whole filter sweep is in the last 20% of
> turn of
> > > > the bandwidth knob.
> > > > As I turn UP the coarse tune, a square osc, mixes into the
> signal.
> > > > It doesn't effect the filter, it just mixes into the audio path.
> > > > When I turn it up almost beyond the audio range, the osc
> suddenly
> > > > cuts off.
> > > > Anyway.. maybe this is just how it works? I'd like to talk to
> > > > someone who has built one or two of these so that I know if I
> should
> > > > work on it some more.
> > > > I really wish there was some kind of CV for filter cut. Am I
> missing
> > > > something?
> > > > Thanks!!!!
> > > > -pete
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > On Nov 28, 2008, at 9:54 PM, casperelectronics wrote:
> > > >
> > > > > Hey Scott,
> > > > > I want to add the wave outputs on my bintic filter but I can't
> > > find
> > > > > the info.
> > > > > Do you sell daughter boards/ host schematics for that on your
> > > site??
> > > > > Thanks!
> > > > > -pete
> > > > >
> > > > >
> > > >
> > > >
> > > >
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> > > >
> > >
> > >
> > >
> >
> >
> >
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