I have designed this 4 stereo channel TRS switch.
You have 4 channel stereo input and 1 stereo channel out. You press a button and you switch which channel you want to send to the output. Once the input is selected by the flip-flop and the MAX359 it is amplified by a IC TEA2025B.
The power supply works like this: it is a virtual ground. It receives +15VDC from an external adapter and converts it to +7.5VDC / 0V / -7.5VDC, needed by the switch in order to keep the signal on the middle of the rail.
It is working almost wonderfully but I have two problems:
when I press the switch to select the input channel I hear a click/pop noise on the output. Like a transient.
I have hum noise all over the place. I am already with the whole thing assembled on a breadboard. I have no shielding anywhere. What should I shield when I have it on a PCB or what can I change to remove this noise.
What can I do, change or improve to fix both problems?
Thanks in advance.
NOTE: The diagram shows +5V and -5V. The voltages are in fact 7.5VDC and -7.5VDC.