MIDI to analog

Paul Perry pfperry at melbpc.org.au
Thu Nov 27 13:58:58 CET 1997

At 07:23 AM 27/11/97 GMT, Andreas Plass wrote:

>I am thinking of building a MIDI controlled switching matrix.
......perhaps Batz has an opinion on this ;)

A few years ago
>I had started to experiment with the 74HCT22106, which is an 8x8 matrix. The
>result was not very convincing and I stopped the project then. This IC needs
>a +5V power supply and therefore it only allows  0 ... +5V  switching.

.....are you wanting to switch audio only or go down to DC? If the supply is
+2.5 and -2.5 I suppose you could get a more useful range.....I suspect the
today is to work with lower and lower rail voltages, much to our inconvenience

 The on
>resistance is about 100 Ohm. So there must be some buffering amps around it,

A lot depends on the amount of distortion you can tolerate... for audio the
matter is not so bad (assuming you are running old analog synths thru it)
but if you are looking at control voltages running oscillators things might
get sticky. Horowitz and Hill (The Art of Electronics) have useful things to
say on fet switching.

good luck.... I once bought sa Master Matrix system to automatically route
CVs and it turned out to be capacitor coupled.....embarassing mistake...

paul perry melbourne australia

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