[sdiy] AC coupling caps on MS20 clone

[David G. Dixon]

> Well, I've just simulated it, and a blocking cap works just fine between
> the
> input resistors and virtual ground.  In fact, a smaller capacitor does the
> same job here than on the summer output.  I will rearrange my PCB layout
> accordingly.  Thanks for the tip, megaohm!

In fact, I added both options -- either between the input resistors and the
mixer summer's virtual ground, or directly on the mixer summer's output.  It
was very easy -- just four little traces out to the edge of the board.