[sdiy] Late EFM SBM Questions - VCA and unwanted TL074 oscillation

[vitreousflux]

Thanks for the tips

I wired up some shielded cable for the problematic modules - helps a bunch.

-----------

on the VCA issue (see below), the resistor change helped lower it, but they
still dont
go silent after cv has dropped.

The trimpots on my vca's don't seem to do anything at all.

I have temporarily resorted to routing the sbm thru an expand gate which
works real nice, but imo that's hardly a real solution..

Anything else I can try?

---------------

I wired all the mixers with shielded wire, the shield taps to ground. Nearly
all the crosstalk is gone, but now that the signal is clean, I can hear
another problem:

I am getting a strange oscillation from the mixer itself.  It seems I get
one sound out of each TL074 chip! I can adjust the mixer pots (even the
unused ones) and the pitch will change. Is this feedback oscillation?
(pardon my lack of opamp theory knowledge)

Is there an easy solution to this?

Thanks guys, this is getting very near completion!

Rob

----- Original Message -----
From: "tomg at efm" <efm3 at mediaone.net>
To: <EFM_Synth at yahoogroups.com>
Sent: Thursday, July 19, 2001 6:12 AM
Subject: Re: [efm] a few late SBM questions


> Tell ya what.....Try changing the (2) 150K resistors to 100K or 120K
>
> Tom
>
>
> >  > The VCA's work fine, but they don't drop to 'silence' once the
envelope has
> > > finished cycling.
> >
> > Offset trim ??
> >
> > Tom
>