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Subject: Re: Mixer again

From: "Paul Schreiber" <synth1@...
Date: 1999-11-28

>
> Well, I hate to open this can of worms (mixer) again, BUT, it always
> generates some interesting and informative discussion. Has anyone else
> checked out the Blacet site lately? I thought his mixer was certainly
> thought provoking. Seems that each input has gain both directions
> apparently with 180 degree phase reversal in one direction of the knob.
> So, looks like the mixer kind of doubles as a inverting attenuator / maybe
> with gain.


Corect, but being the clever folks we are would rather "build-in" this
feature
into each module. :)

>
> Anyway, I can see the advantage and handiness of having the inverter
> (separate). However, I wonder how / why one might choose to invert the
> phase of one of the signals being input to a mixer. The only thing that
> comes to mind is the cancellation that could be achieved between the
common
> parts of two signals. Some of you guys enlighten me please.

99% it's for CVs, not audio. LFOs, for example. Inverted audio has no
meaning unless you
are trying to cancel out something (like a phaser! :) )

>
> And what is the scoop with the "bias" control? When I think of bias, I
> think of setting the mid point of the range where the signal rides on the
> input of an amplifier. Back in my old tube days, the correct bias would
> assure that you were operating on the linear portion (or not, if that was
> your choice) of the tube's characteristic (input voltage to output
> current). Seems like, on solid state, biasing off a center desirable
point
> would just result in ugly distortion. What am I missing here?


It's a DC offset, again for CVs.

Paul S.