[sci.electronics] Audio Mixer

jantypas@hope.UUCP (John Antypas) (03/22/88)

A question for the net experts in this sort of thing?  We find
ourselves in need a mixer for audio recording.  Nothing fancy, but
nothing standard either.  We could go to a certain retail electronics
store and pay their "You can't go anywhere else" prices, but why?
Therefore, I (not an engineer) am writing to the experts for their
wisdom on this subject.

I may be wrong, but I figure that a 6 in/2 out (3 stereo/1 out) mixer
can't be that difficult (in theory) to build.  Is it?  What would we
need in terms of basic parts?  (Obviously we would need 6 pots, 14 .25" jacks),
What about the problem of signal degradation?  How do we overcome the problem
of squeezing six inputs into two?  

Now let's get fancy.  What would it take to add reverb?  Is this even
feasable? 

If anyone has any answers/schematics they'd like to provide, we'd be 
very grateful.

Many thanks.

John Antypas
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dje@datacube.UUCP (03/25/88)

I built a  sound mixer  11 years  ago.   Two phono  sources, two line
sources, a Mic., Cueing.  

It  used BiFet  op-amps (TL084),  audio taper  potentiometers, a tone
circuit borrowed from  the National  Audio Handbook,  two great phono
preamps  borrowed  from the  now defunct  Advent Reciever  (I made PC
boards for these), an op-amp mike preamp, a couple of radio shack LED
V-U meters, a box, power supply, and about 50-70 hours.  

As a new grad with time and  no money,  it was  fun.   But I wouldn't
repeat  the  process  today  seeing  some  of  the  low  cost  mixers
available.  

 				Dave Erickson
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