Re: [AH] Cwejman S1 help and tips?

From Peter Grenader
Sent Tue, Nov 1st 2005, 18:58

This may or not not work.  A lot of mixers use what's called decoupling caps
which are there to kill stray voltage on the line and return the input's
'resting state' to ground.  They are there to correct voltage offsets
Problem is, the cap doesn't know the difference between stray DC and DC
you're feeding through as a control signal. AC waveforms - no problem.  DC
(either a constant voltage level, or one that doesn't pass through zero or
does so at a very slow rate) - this may not work.  It won't blow anything up
if you try it, the decoupler will just do it's job and stop these signals
from passing into the internal summer.

Not all mixers are fitted with these caps.  Blacet's mixer/processor is one.
Doepfer's 'EXP' A-138 is another.  My model 18 won't have them, either.

But in all cases of mixing signals from different synths, grounding and
voltage range is an issue.  Both systems will need to have the have ground
reference or the VC coming form the outside world  won't do jack to the
other instruments.  Also you must kep an eye for overdriving.  A serge and
Modcan is expecting a 6 volts signal.  A Buchla, Wiard, Blacet can put out
10 or above. It's usually not a problem, but I have seen cases in certain
Modcan modules where a zener in a CV input blows if fed a 10 volt signal.

- P

hope this helps,

- P wrote:

>> another thought was can I mix CV signals outside the synth
> with a 'normal' mixer?
> **Uhh, you may want to be very careful with scenario.  If you try this, take
> your channel trims WAAAAAY down before you go feeding a raw voltage into a
> conventional mixer intended for audio.  There may be potential audio level
> (and grounding?) issues.  This is actually how people used to derive 'click
> tracks' from sequencer boxes - take the trigger output into a mixer channel,
> record the sixteenth note 'thud' and then feed that into a trigger input on
> something else.**
> Pat