[sdiy] Longish cables causing wierdish results

[Magnus Danielson]

From: Peter Grenader <peter at buzzclick-music.com>
Subject: [sdiy] Longish cables causing wierdish results
Date: Wed, 17 Sep 2003 15:05:22 -0700

> All,
> 
> No laughing (this means Magnus, too  :-) )

Is it that bad? I mean so you must specifically ask me not to make a big
laugth? May I sneak-jiggle a little up here in the back of the classroom?
Or is this a request for me to step up to the blackboard and wave the arms a
little and then draw a few almost comprehensible schematics cluttered with
incomprehensible formulas?

> I'm trying to test a Milton using a 20 foot cable from my synth to the unit
> for the drive clock.  Although the cable is shielded, as suspected, there
> are some problems and it's skipping stages all over the place, yet works
> hunky dory on a shorter (read: not quite so ridiculously long) rope.

Have you looked at the output with a scope? Look at the edges. If you have a
too sharp edge you might run into problems for that reason for instance...

Terrible ringing (might be much higher in frequency than you first may think)
might be a reason.

> I tried an inductor, I tried a cap to ground.  No improvement.  Any
> suggestions?  I need a clock to drive this thing and it has to be on the
> bench which is on the other side of a large room.  I tried setting up my
> scope, solder iron, et al by the synthesizer, but this wasn't working for me
> (what can I say, no room for the Pamela Anderson poster from my bench).

I can't see the wall behind my equipment, and I don't know if there is a
poster behind there or not...

Cheers,
Magnus