I don't know if there are "audio summing amps", but with a classic opamp, resistors and potentiometers, you can add analog voltage level signals (also known as AUX or RCA with 3.5mm), while scaling them independently.
https://www.electronics-tutorials.ws/opamp/opamp_4.html
https://www.electronics-tutorials.ws/opamp/opamp_4.html
Statistics: Posted by robertojguerra — Thu Jan 22, 2026 6:07 pm