cross-point switches (was : PolyModular)

[jbv]

Edward Leckie :

>      OK, I have another idea. How about using cross-point switches and OTAs
>      to route signals? But that loses the beauty of a modular, the manual
>      routing of patch cables. So how about using some sort of simple
>      digital I/O to communicate connection between modules. Each output
>      could transmit a let's say a 5V pulse sequentially, and each input
>      could sense the pulse and configure the n (= number of voices)
>      cross-point switches accordingly. That way, you can use single
>      conductor patch cables and VC modules for a poly synth. Pots could be
>      used to control VCAs of signals entering or leaving the cross-point
>      switch matrix. To generate the serial data one simple uC and some
>      decoder ICs. The beauty of this as well, is that a patch setup can be
>      stored!! To interface to the outside world, an external CV inputs to
>      crosspoint switches should be included.
>
>      Ed.
>

Yep, that sounds like a good idea, at least on paper...
Telling the truth, I explored that possibility a year ago or so, and I found that
AD manufactures
a nice 200 MHz 16x16 buffered crosspoint switch (AD8116). That device can also be
arranged in
more complex matrix (48 x 48 crosspoint array, using nine AD8116, for instance).
So the idea was to run every in/out signal (audio & CV) trough such a matrix, and
to store / recall
patches through MIDI sysex.

The only drawback is that the AD8116 comes only in 128 pins TQFP package !!!
Has any DIYer already tried to solder a 128 pin TQFP IC ? Or even tried to design a
PCB for it ?
I guess that tons of prozac should be necessary...


jbv