[sdiy] Sound Lab Mini Questions

[Ray Wilson]

Hi Rude

This is the kind of thing I'm talking about. Has anyone used this?

http://polly.phys.msu.su/~zeld/oscill.html

Ray


----- Original Message ----- 
From: "Rude 66" <r.lekx at chello.nl>
To: "Ray Wilson" <raywilson at comcast.net>; "john mahoney"
<jmahoney at gate.net>; "Synth-Diy" <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, June 20, 2004 10:10 AM
Subject: Re: [sdiy] Sound Lab Mini Questions


>
> hi ray,
>
> thanks for the tips. unfortunately, i don't have a scope here, just a
> multimeter..;-) i can have access to one some time this week.
>
> in the mean time, i do have a computer. is there any software (free,
trial,
> demo, etc) that could help here?
>
> thanks!
>
>
> ruud
>
>
> ----- Original Message -----
> From: "Ray Wilson" <raywilson at comcast.net>
> To: "Rude 66" <r.lekx at chello.nl>; "john mahoney" <jmahoney at gate.net>;
> "Synth-Diy" <synth-diy at dropmix.xs4all.nl>
> Sent: Sunday, June 20, 2004 5:38 PM
> Subject: Re: [sdiy] Sound Lab Mini Questions
>
>
> > Hi Rude
> >
> > > osc 2 is still problematic. by itself, it isn't there. i've patched
mine
> > > out, and if i give it a cv from osc 1, it sounds but very weakly. it
> > sounds
> > > like a weak copy of osc 1, but by also giving it an lfo in (long live
> > banana
> > > plugs)  i could determine that the sound was indeed osc 2 as osc1 was
> not
> > > affected by the lfo.
> >
> > If you look at the output of IC6-D (pin 14 of IC6) you should see the
raw
> > sawtooth wave
> > output of Oscillator 2. You should see a very narrow positive going
pulse
> > wave (a few uSecs) at the same
> > frequency at pin 8 of IC6-C. If the sawtooth is there the pulse is
> > definitely there. If neither of them are
> > there then check all the components associated with Osc 2 for correct
> values
> > and good soldering. If you used
> > a sub for the MPF102 make sure the leads are oriented correctly.
> >
> > Next look at the output of IC2-A pin 1. You should see a rectangle wave
> > whose width will depend on the setting
> > of of R85. The width should vary quite a bit as you adjust R85 and in
> > conjunction with the LFO switch turned on
> > may fade in and out as the bias at pin 2 of IC2-A becomes higher (or
> lower)
> > than the amplitude of the signal at ZZ.
> > By adjusting the level of the LFO and the setting of R85 you should be
> able
> > to get good PWM without the pulse
> > wave going away. With S15 off you should be able to get from 10% to 90%
> > pulse width variation using R85.
> > If this is not what you are seeing then look over the panel wiring to
make
> > sure that R85 is connected on both sides to
> > +9V and GND through the correct value resistors.
> >
> > Look at the bottom of the Sound Lab page for more trouble shooting info
on
> > the PWM and noise circuits.
> >
> > >
> > > it's only giving sound though when the frequency knob is sort of in
the
> > > middle. when turned either way, it fades out almost like the pulse
width
> > has
> > > gone too far. i can't get pwm to work either, but that's a later
> > worry..;-)
> >
> > The pulse width should not vary so much as you adjust the frequency that
> it
> > disappears unless it is
> > adjusted to a very narrow pulse.
> >
> > >
> > > i'm missing noise (also not a main concern) and the trigger knob
doesn't
> > > work. vc in works, the gate input works, but i can only hear it when
the
> > > vca's initial gain is open pretty far. it's there, but it seems to
weak.
> >
> > See the bottom of the Sound Lab page.
> >
> > >
> > > any ideas on this before i start diving into the rat's nest? ;-)
> > >
> > > but even with one vco, filter, lfo and eg it's already one hell of a
fun
> > > box!
> > >
> > > r./
> > >
> >
> > I hope this helps
> >
> > Ray
> >
> >
>