Soft sync and medicine to cure it.

[Harry Bissell]

To see the reset pulse, You must use a 10X scope probe or the loading
will kill you. If you probe it, and the sync works but you see nothing, your
problem is scope speed or triggering. My ancient Telequpment scope can
just "barely" make out a sync pulse... but only in a dark room.

H^) harry

Rob wrote:

> Er, I *have* heard about this before to keep osc from locking. Actually, the
> guy was talking about oscillators within a piece of radio gear. Injecting
> noise on the PS line does work. Or, you could just overdrive the regulator a
> little bit and keep it just at its maximum so it is slightly out of
> regulation and noisy.
> Or, maybe have a very small (like 1pf) cap somewhere on one osc cv input and
> not on the other. I believe the Arp Oddysey is like that (as a matter of
> fact, I am fairly sure it has, I had to remove one of these caps to make osc
> 2 quit warbling).
>
> Or, you could just put a seperate regulator for each of the oscillators.
> That might do it.
>
> Lots of things you could try.. But, first off, I would say to put a very
> small filter cap on the CV input of one osc (but not the other) and see what
> happens. That *might* be enough.
>
> BTW, has anyone actually seen the pulse that syncs the oscillators on a
> scope? I have tried and tried, but it seems that merely the stray
> capacitance of the probe makes it stop!
>
> Rob
>
> ----- Original Message -----
> From: jhaible <jhaible at debitel.net>
> To: Magnus Danielson <cfmd at swipnet.se>
> Cc: diy <synth-diy at node12b53.a2000.nl>
> Sent: Monday, September 11, 2000 5:31 PM
> Subject: Re: Soft sync and medicine to cure it.
>
> > > This discussion also makes me think of the MiniMoog, too weak
> powersupply
> > and
> > > thus noisy powerlines which made it less prone to lock the oscillators
> to
> > > each other. When I was in Gothenburg and standing in line to get some
> > coffie I
> > > also came to think of the addition of noise into the oscillator CVs in
> > order
> > > to make them less eager to lock. Maybe that could also be of interest.
> > However,
> > > the noise level should not be too high.
> >
> > One should be able to introduce a controlled amount of psu noise at the
> > reference
> > pin of adjustable 3-pin voltage regulators (AC-coupling for the noise).
> Not
> > testet.
> >
> > JH.
> >
> >
> >
> >
> >
> >
> >
> >
> >