[sdiy] More on adding analog ins to digital

[J. Larry Hendry]

I found the same arrangement in an Evolution UC-16.  I plan to do the same
to get CV to MIDI and USB.
Larry Hendry

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Grant Richter
Sent: Friday, July 15, 2005 10:05 AM
To: Rainer Buchty
Cc: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] More on adding analog ins to digital


I opened up a Yamaha DJXIIB and traced out the front panel controls.

The pots are between 0 to 5 volts. They must run to a multiplexor and
be converted with an A/D.

I added a series of switched jacks to the +5 volt side of the pot so
that I could insert an external voltage to replace the 5 volts. This
seems to work fine and the pot can be used as an attenuator.

This spoof may work for other digital boxes that have faceplate pots,
but not for encoders.