Saturday, August 17, 2019

Putney Poor Man's Patcher

I was at the Vintage Synth Museum and got to screw around with a Classic VCS3 Putney.  No, not a clone, not a VST; this is the real thing. This is an incredible sounding synth and deserves its legendary status, but the best part I think is the peg board patcher.

You put in pins to choose from a matrix of patching options:



I'd love to be able to include a Putney style peg patcher in some of my DIY projects. But...I have not seen patch bays like this for sale, have read if you ever do find one they cost hundreds of dollars. So let's DIY. Can we do this budg?

Whipped this up with Eagle:




























Had ten of these made up at JLCPBC in China. $5 for all of them. If anyone is interested comment and I'll post the Eagle files and gerbers somewhere.

OK--need the pegs. But what,Scotty, what? Bought these on Ebay--chose them carefully based on the size of the vias in the wire pads found in the PCB, they were about $25 USD for a hundred:



Laid everything out:



Screwed it all together (still missing top nuts; added after I took this photo):


Let's test!



Does it work?

Yes!

With the peg through hole 1 x 1 from top board to bottom is continuous. Same for all other pins.

I now can see putting buffers and mixers around this matrix, but the basic idea--the ability to patch with one of the pins--is sound. Heck I could even build little plastic tops for the pegs and epoxy em on there?

But here's the rub, literally--Will it last? I can see the pegs wearing out the vias in the top board. Hard to say how many patches you'll get out of this system--I guess that's to be seen.

I've only patched each point about 10 times, some less. On the putney at the museum a few patch points were worn out--and that was the real deal--so I guess nothing lasts forever. I might need to find slightly smaller diameter pegs? That might spare the vias a bit longer? Or springy pegs somehow?

But anyway for now this simple matrix patcher works!

Applications: I may apply this to the noise! circuit from reverselandfill that I've been screwing with for months. That would be a good test and that circuit needs a large switching matrix.  Or maybe for an entire Lunchbox Lunetta setup. No idea really.

UPDATE 10-6-19 using 2.5mm spring banana plugs purchased from Amazon; it works!  I modded the top board w. 82mil drills, which seems to be the right size. I think the top board will last much longer, since the plugs are spring loaded; I patched and unpatched a whole bunch of times and couldn't see a lot of wear on the top board under my microscope.  Thanks to E-M member Phobos for suggesting this improvement.



And why not use a 2.5mm banana patch cord to mult matrix points?


OK that's it for this time, I'd say don't breathe the fumes but for this one NO SOLDERING. Ahoy.

2 comments:

  1. This is such a nifty idea. Would you mind sharing the Eagle/gerbers to help me get started on experimenting with it? Thanks for your great write up!

    ReplyDelete

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