Re: 3 Channel Splitter

Posted by Padster39 on Mar 22, 2025; 2:50pm
URL: http://guitar-fx-layouts.238.s1.nabble.com/3-Channel-Splitter-tp51203p51208.html

Excellent work! I'm glad to hear that it's working without any issues or noise and that it fits in a 1590A. I'm glad I took the time to check it out.

I suspect the reason the send outputs wouldn't work at all without the mixer section is due a lack of reference at the outputs of each op-amp. With the mixer section in place, all three outputs eventually find a reference to ground through the channel pots, or else the final 10k resistor between Output and Ground. It sounds like you had neither of these in place initially.

I'm not completely sure why the 33k resistor between pin 13 and ground would fix this, it may simply be a different issue where the bias voltage was destabilised by the floating op-amp (at pins 12, 13, 14) and adding the 33k resistor stabilises the differential Voltage at that op-amp. Perhaps that fixed an issue with the bias Voltage connected at pin 12, but this is conjecture and it's difficult to say for sure without testing.

Anyway, enough of me waffling. Thank you for building it and letting me know it’s verified. All the best