Saturday, 25 June 2016

Buchla format 212r - Dodecamodule

Some pics of a recent build. The 212r is a awesome sounding module.
(video to go up here soon). I would love to hear a vintage one.

These aren't building instructions, just some records for future reference should I decide to
build another..

It was quite a big build .... lost count of time after the first 20 hrs., but I reckon you could knock
one off in a weekend if you put your mind to it. (I'm not a professional technician).

This is PCB 1

PCB 2 ... reverb tank sits in the middle.
Its very much like the setup in a 208r version 1.




One cap exploded while I was testing various +15v to +24V voltage regulators.
I decided to just use my system's external +24v bus.

reverb tank fitted :-)

I've mixed the knobs up on purpose to remind me of the pot values. Davies are all 10k linear.
Serge style are 50k log.


I'm very impressed with the module. I esp like the output amplifier on the right.

I finally understand why there are a mix of 50k & 10k pots. Its a beautiful sound. We have voltage control over amplitude on the top, voltage control of location (left/right channels) in the middle, and CV of the reverb on the bottom.

More videos to be posted soon here.
...

Up till now I have been using a pulse from the buchla 281 to trigger the 212r. However a question in muffs from Robbot emcouraged me to test the dodecamodule again. It actually does not need an external clock (like the vintage 212). "The envelopes will self cycle using this trick - patch a cable from the red pulse output of the Triple Env Generator section of the 212 back to the red pulse input and then set the attack / decay time to the desired speed.

If that doesn't automatically start the env generator clocking, flipping the 'sustain' switch up/down and back will do". Thanks Robbot. :-)

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