[sdiy] Paia 4780 Sequencer bits

[Grant Richter]

> I have some PAIA 4780 sequencer bits.  One is complete except for 3 knobs,
> one is missing all knobs and is in pieces.
> 
> I bought this a couple years ago off another SDIYer.  Comes with all the
> PAIA4780 parts you see in the pix, plus photocopies of the manuals.  I just
> made a direction change from when I was building PAIA 47xx stuff and never
> found a use for this.
> 

One useful (to me anyway) mod is to add a switch to the reset line. The
design is based on a very clever LM3900 based shift register.
In the original design, when the first stage is loaded, the other stages are
cleared. If you add a switch to that reset line, you can have more than one
stage loaded. So you can have a sequence running, flip the switch, and the
extra stages at the end will transpose the original sequence in interesting
ways. Changing to a short loop, you can have 3, 4 or more stages all
transposing each other. Much more interesting than the "vanilla" original.

(I souped the 3900 shift register design up for the Neural Pulsers
http://www.musicsynthesizer.com/Neurons/Neurons1.html If you make the output
stage a pot with an overall summer, it becomes a sequencer where each stage
is modular)