The 247v Sequential Voltage Source

I have been working on a new Sequential Voltage Source. It is only a single module space and packs a big punch. It does most of the things a MARF or ARF does, but without any menus. It can act as an 8 stage sequencer with two rows, voltage control of the clock/slide rate, switchable slides/pulses, pulse outs on each channel and the ability to loop from any stage to any stage.  It can act as a multi-stage envelope, up to all 8 stages with any stage as a sustain stage or any stage pausing unless a key is held. It can act as ADSR, AHDSR, HADSR, AD, AR, AHD, LFO saw, pulse, square, triangle, something more complex, LFO that only runs when a key is held, LFO that only runs when a key is lifted.

I wanted a small sequencer with every function on the panel. I wanted to do TB-303/MC-202 type sequences with slides selectable per stage, where the pulse output holds the whole stage on a slide stage but only pulses 25% of the stepped stages. I desperately scrambled to complete two for my performance during the NAMM show. I made panels from PCBs because they take less time to manufacture. I only got one finished and then it didn't work when I got there! Anyway, it's working now. It's pretty fun.

Quantizer/Analog Shift Register take II

In 1972 as a resident at CalArts, Fukushi Kawakami made four modules as additions to the school's rather extensive Buchla 200 system. The modules are a Control Voltage Switching Matrix, two Control Voltage Integrators and what I believe is the world's first Analog Shift Register. 

http://barryschrader.com/the_fortune_modules/

Since then, the world has fallen into disarray, computers have taken over, analog modulars have gone in and out of favor several times and those four Fortune Modules have ended up in Grant Richter's hands. Somewhere in the middle of all that, Serge made an analog shift register and wrote about it (under the nom de plume Arpad Benares) in Synapse. Even before the Fortune Modules, Buchla had made a rather amazing Control Voltage Integrator called the 155, but that's another post.

Anyway....

Analog Shift Registers are a bank of Sample and Holds. In fact, using only the first output, it is a Sample and Hold. When a pulse is applied, the CV on the input is stored on output one. Whatever was on output one is moved to output two, and so on. 

In 1997 I made 2 copies of a module that was a dual four stage analog shift register as well as an 8 channel voltage quantizer. One of these is still in daily use over at OSI music and the other is rotting on a shelf in my shop. When this photo went around the forums and blogs some people suggested that rearranging the panel to allow the analog shift register outputs to be quantized via shorting bars would be a good idea. Point taken.

 

I had a couple of ideas of my own that could make it a better module. Sadly, it got back-burnered and never saw the light of day until now. The new version has rotary switches to select the scale to quantize to. The ASR outputs can be plugged into the quantizer with  shorting bar. There is no longer a "slave" switch to chain the two ASR's together, but a cable and shorting bar can now do that too. Some new ideas have come up as well, like using the quantizer to look-up the voltages from the "random" voltage sequences from the 266. It's obviously not as glamorous as an oscillator or filter, but it will come in useful to some people.

Unearthing Greatness

In the last trade I did, I ended up with 2 modules that seem to be very early examples. The first is a 292B labeled "Prototype" on tha back of the panel. It's written in pencil, funny enough. This one worked well and matches the 292B I already had here.


The front panel was dirty, I had to take all the parts off to clean it up.




The other, a beat up old 207, has "Model" on an orange sticker, stuck to the back of the panel. I believe this means that Don built this up for the assemblers to use a reference while they were hammering them out. This thing had a few broken sliders, so I decided to replace all of them, since I was ordering a set for the 207 I was building from scratch. Synth Restore in the UK has re-manufactured sliders for ARP synths, and these were CTS too, so they work for Buchla stuff. To my horror, the inside of this thing was filthy! Balls of hair at the top and bottom of each slider and crumbs were everywhere.


I took out the sliders and blew out the crap to get started.


The sliders went in really nice and even though the shafts are shorter than Buchla used, they look great. Now, I just have to finish his buddy...