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  1. #1
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    Audio Mixing console

    I'm trying to design a 5 channel audio mixing console. I'm using TL072 OPAMP as my preamp and IC PT2399 for the echo. How can I connect a single PT2399 to provide echo for all 5 channels? I need to control echo of each channel seperately. Currently the output of my preamp is fed to a tone control circuit (modified baxandall). and then then output of tone control part is fed to an opamp. I took this output and split it using 2 resistors, one is fed to the PT2399 via a POT and other I have given as an input to a summing amplifier (5532 OPAMP). The circuit is working (tested with 2 channels), but the problem is that output gain is not perfect, and when I adjust the echo POT, the gain is changing. Also I want to connect a POT for PAN adjustment (L/R), for stereo output. Please help me and thanks in advance.

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  2. #2
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    Re: Audio Mixing console

    Review the description of usual mixer consoles. There are one or multiple effect/monitor sums with separate send level control for each input channel. You surely find schematic diagrams of mixer consoles on the net.



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  3. #3
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    Re: Audio Mixing console

    Quote Originally Posted by anandhuskumar View Post
    I want to connect a POT for PAN adjustment (L/R), for stereo output.
    A single pot can do this job.

    Click image for larger version. 

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    The resistors are unnecessary if some input resistance is in place to prevent high current through the pot to ground. Similarly for output resistance being present in the next stage.

    - - - Updated - - -

    (The pot was dialed back and forth as the simulation ran.)



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  4. #4
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    Re: Audio Mixing console

    Hi,

    Brad, I think your circuit shows a balance circuit for a stereo signal.

    A PAN circuit has only one input source and two (R, L) output channels.

    For sure one may connect both inputs ofyour curcuit. The drawback is, that the wiper resistance (and the noise during moving) comes into account. There are higher audio quality - maybe with dual pot - circuits.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.


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  5. #5
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    Re: Audio Mixing console

    The usual mixing console pan circuit is using a single pot, as suggested by KlausST both series resistors connected to the same mono channel output. I see (with A&H GS3) e.g. 4.7k series resistors, 10k pot, 22k summing resistors towards the L and R bus. The latter are missing in post #3. The bus nodes must be implemented as low impedance transimpedance amplifier inputs to avoid gain variation effects as reported in post #1.


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