buttachunk's cool little mixer

Quick comments:

JFETs are all over the place as regards drain current at a given gate-source voltage, even within a specific type number. When using discrete JFETs, you must either hand-select or design the circuit to be insensitive to these variations.

The biasing on the input source follower could be better.

The symbol for the JFET is wrong; it should be an N-channel JFET.

The panpot circuit won't work very well.

More detail (and suggestions for improvements) later if I have the free time...

Here's a quickie take on the idea. I just took it on faith that Borbely's source follower works as advertised and drew it verbatim, with +/-24V supplies. If it happens to work nearly as well on +/-18V, then that would certainly simplify PSU requirements. Anyway, the rest of the circuit is pretty conventional.

Schematic

you could use a jfet opamp like the forssell for the mix bus amps, so it would run on +-24 also...

Or Opamp Labs model 425... only $35 each new.

By the way, regarding the schematic I made... For a truly minimalist implementation, you could eliminate the JFET Q1 as well as C1, C2, R1 and R2. The input impedance of the panpot is high enough that you don't really need the buffer. Input impedance will range between 6K and 10K depending on control settings, and most gear can drive that without problems.

[quote author="buttachunk"]
i will post the bottom copper if anyone is interested.[/quote]

Yes, it would be nice!