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.
Aswinth Raj
PermalinkSounds like you are upto an intresting design. I do not have much XP into audio but I am still curious to know how this turns up.
I had a similar problem with gain being manipulated the problem was with the input impedance of the op-amp being low. Also since you are splitting the same audio signal for both Echo and summing I think its the same problem here as well. Try removing the Echo and check if the gain is constant. If then you can solve this probelm by adding a buffer circuit before the summer.
Once you get this working you just have to duplicate the same for all five channel by providing five inputs to the summing amplifier.
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Joined August 16, 2016 1000Tuesday at 12:29 AM