MOTM

At the behest of Robert Rich, I built a triple reversing+bias module to 
his specifications.  Each stage provides -/+ 5V bias in the absence of a 
jacked input, and as each output is used, it is removed from being summed 
with the next stage.  All stages have a gain of -2 to +2.  Thus you have a 
3-to-1 mixer, or a gain stage with bias, etc.  Formulaically:

  2.500V
     |
  IN_A * (-2 to +2) = OUT_A
                          |
  2.500V                  |
     |                    |
  IN_B * (-2 to +2) + OUT_A = OUT_B
                                  |
  2.500V                  /------/
     |                    |
  IN_C * (-2 to +2) + OUT_B = OUT_C


  The dashed lines indicate the normalling jack switches for bias
reference and the section cascading.

  With thanks to Stooge Larry, I even have a nice panel for the 
prototypes:

http://www.oldcrows.net/~oldcrow/synth/crow/3xrevmix_ft.jpg
http://www.oldcrows.net/~oldcrow/synth/crow/3xrevmix_bk.jpg

  Looking around the web afterward, I noticed that Stooge Moe almost built 
the same thing.  This one is a bit different, though.  And is also quite 
different from an Oakley Multimix.

  I was pondering making a run of PC boards, and selling those along with 
three 250K type 149 pots for those interested.  (I got this stash of 149s 
from a former workplace and decided to do something with them, thus this 
1U module. ;)

Crow
/**/