[sdiy] (diy) MS 20 Ringmod

[Don Tillman]

   From: modlar at gmx.de
   Date: Tue, 21 Aug 2001 09:08:51 +0200 (MEST)

   > I don't understand; are you saying that the original four NAND gate
   > circuit is not an XOR?  It's a classic XOR implementation.

   Answered by Rene already !

Yes, two drawing errors in the schematic.  Except that the red dots
are covering them entirely, so there's no way I can tell that the
errors were originally there.  If I fill in what is most logically
under the red dots, there is no error.  So that confused me.

The photograph shows a perf board circuit mounted on top of a
production board, suggesting that you have built up a board to fix a
bug in the MS20.  But if the error is only in the MS20 schematic
drawing, there's no need to fix anything.  So that confused me even
more.

   >Why invert the output?  

   Why not ? Do you hear a difference between a normal or an inverted
   ringmod output ? You must be lucky, if !!!

One of the drawing errors in the original schematic was an inverted
output, so I thought it was a little strange that you were adding an
inversion stage.  Sure, the difference is audible when you mix the
ring modulated signal back in with other signals.

  -- Don

-- 
Don Tillman
Palo Alto, California, USA
don at till.com
http://www.till.com