Buchla 266r DIY Clone

...and how to do so...
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For the really obscure modular synth module fans ... A guy started making PCBs that had the Buchla functionality which he then modded to other format specs. Kind of a bitch to build but worth the effort ..

Fully populated boards after hours of scotch errr... I mean soldering ..

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In the system with blinky ... blinky is good .. it means my house didn't burn down when I clicked the on button. Always a good sign when you DIY.

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I got a question about what it does ... Yikes ... it does a lot of initially "normal" synth functions, but then has unique flavors on top...

Easy explanation (S&H, Noise, Voltage CV Outputs based on various distribution models, Slew Limiter/Integrator).

Longer explanation, Bottom up ..

Bottom Row is a S&H module with a pulse out mult on the left. It has a normal S&H CV input, but it has 3 outputs ... Normal and a Hi output and a Low output which gives you alternating CV output at half the Normal output rate.

Next row up is noise .. dirty triangle, white, pink .. multiple out each

ok, next section is where the rubber meets the road.

Left inputs/outputs = Fluctuating Random Voltage (FRV) .. takes CV input, such as the dirty triangle and based on an internal VCO clock pulse and an integrator slewing the output, gives you an LFO with randomly varying speed/amplitude. There are two slew modes FRV1/FRV2.

The Middle and Right sections give you varying lengths/voltages (i.e. duration/pitch) outputs based on various equations to determine the increment against the incoming pulse +/- a CV offset.

Top right is a integrator (slew) control for smoothing those voltage changes

EDIT: Oh, forgot to explain the flashy lights. They don't just beat in time to the pulse, the brightness is determined by the voltage .. dimmer = lower voltage, brighter = higher voltage.
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Yikes. A majority of that functionality would make a lot more sense powered by a single 8-pin processor and output to a 8-pin DAC. You'd then be left with a lot of multiplexors and s&h buffers but it would be a lot better.

Definitely an artifact of days before the "digital revolution". A lot like a discrete analog computer circuit.
Free plug-ins for Windows, MacOS and Linux. Xhip Synthesizer v8.0 and Xhip Effects Bundle v6.7.
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aciddose wrote: Definitely an artifact of days before the "digital revolution". A lot like a discrete analog computer circuit.
LOL, that's kind of the point ...
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aciddose wrote:Yikes. A majority of that functionality would make a lot more sense powered by a single 8-pin processor and output to a 8-pin DAC. You'd then be left with a lot of multiplexors and s&h buffers but it would be a lot better.
By the way, there are Arduino variations on this specifically for modular synths. But, so far they suck monkey nuts ... to use a technical term. The only thing that is one for one doable (where you don't run into the sample rate issues) is the random voltage distribution outputs. I'm over simplifying a bit. Obviously the CV portion of an analog synth is typically not diminished by the use of a DAC. But, it kind of hurts the asthetic :lol:
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You could easily generate audio-rate output at something like 150k although you'd need to throw out the idea of multiplexing to multiple outputs in that case.

For the strictly low-frequency random outputs it would work perfectly on a chip.

"Arduino" sucks so obvious things made with it tend to suck also :)

A competent designer wouldn't be using something like that as you'd be limited to its "general purpose" design, which goes directly against focusing the design toward meeting specific criteria.
Free plug-ins for Windows, MacOS and Linux. Xhip Synthesizer v8.0 and Xhip Effects Bundle v6.7.
The coder's credo: We believe our work is neither clever nor difficult; it is done because we thought it would be easy.
Work less; get more done.

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aciddose wrote:A competent designer wouldn't be using something like that as you'd be limited to its "general purpose" design, which goes directly against focusing the design toward meeting specific criteria.
Of course, but again .. the point of this is to do it the old school discrete way.
If you have to ask, you can't afford the answer

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cool! some link to buy PCBs ?

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lalo wrote:cool! some link to buy PCBs ?
the site is blocked where I'm at right now ...

it's synthcube.com and just look for 266r SOU
If you have to ask, you can't afford the answer

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