Archive of the former Yahoo!Groups mailing list: MOTM
Subject: Re: [motm] some questions
From: jwbarlow@...
Date: 2003-08-09
1) Yes, you need mixers! Several of the modules have built-in mixers since they are so often used (like the signal and CV inputs to the VCFs). But you'll need some more for miscellaneous things.
2) If you have the Alan Strange book, I'm sure he mentions (somewhere) a technique called "non-linear" mixing which ∗is∗ mixing in multiples. When two (or more) audio siganls are connected together without the isolation provided by a mixer, you get all kinds of wierd modulation effects (IIRC they are the same as AM but have a different amplitude on the sum and difference tones). Get the Strange book!
JB
In a message dated 8/9/2003 10:15:34 AM Pacific Daylight Time, pugix@... writes:
Actually if the outputs go through 1K resistors (MOTM-300, MOTM-410,
MOTM-440, etc.) there is no harm in connecting these together by a multiple.
They will mix fine. In fact this is one of the design reasons for using 1K
resistors on the outputs, as noted in Electronotes. The signals mutually
attenuate each other, so that the combined peaks will not exceed the normal
output level (usually +5 to -5 V).
But not all modules have a 1K output resistor. In particular the MOTM-820
has low impedance outputs for driving longer cables. Something similar is
true of the Oakley Multimix. So these outputs may not mix well in a
multiple.
It is hard to damage an op amp by connecting its output to another output or
a ground. You don't have to worry that shorting an output to ground when
plugging patch cords will do any damage.