Circuitbenders Forum
Circuitbenders Forum => Circuitbending discussion => Topic started by: SampleGrinder on March 01, 2015, 11:04:06 AM
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Hey you good people!
I bought a rack mixer called "FineLine" from MIDIman. Must be 90s or so featuring:
10 unbalanced mono line level inputs summing to one "left" output
10 unbalanced mono line level inputs summing to one "right" output
the individual channels habe no controls - no gain, no volume, no EQ - nothing.
All this unit basically does is summing these 20 inputs (there is a volume pot for the "left" & "right" master output sum)
(There are also some mic inputs and some sends, but this is not part of my topic)
I was curious about how this summing is done so I analyzed the circuit board.
What I found was so simple I could not believe it.
Each of these 10 inputs goes through a 4,7uF condensator, then through a resistor and then the inputs are just connected togehter to make the summing. after that all 10 summed signals go in to an op-amp.
I have made some pictures of the circuit if youŽd like to see.
My question is:
01: is it really THAT easy to do audio summing?
02: could I make my own summing mixer with as many inputs as I wish using this method?
03: What can be said about this procedure
- is is a good idea doing it in this way
- where are the problems / limitations in this method
- just basically your opinion on this & discussion
would be greatly appreciated!
Thanks - Si