Here is a multi channel audio mixer circuit based on 2N3819 n-channel JFET. It mixes as many as inputs into one channel. The design seen in the diagram is for only two channels (stereo into mono) but ...

If six channels is enough for you, you'll have to look long and hard to match the Gear4Music MIX02AU with its audio interface capability. Modest track count, plastic-feeling build, dreadful manual.

If you can live with the lack of digital I/O, this is an excellent mixer with lots of features musicians will love Best home studio mixers 2026: analogue and digital mixing desks for all budgets Best ...