Buchla 208 Random PCB

[vtl5c3]

Based on this schematic by Scott Stites:

http://electro-music.com/forum/phpbb-files/buchla208_randv_532.png

It's a cool little random voltage generator. It uses the CD4015 as its core, has only one pulse input and four pseudo random CV outputs. The board layout has been confirmed. I've built one of these units and think that it's lots of fun. It does a lot for the tiny amount of panel space that it takes up.

I appear to be out of file space on electro music, so I'm posting these external links until I find a better home for them:

First the PCB, then PCB with parts placement.

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[ericcoleridge]

Super Cool! Thanks VTL5C3!

[Blue Hell]

[vtl5c3]

Woot!

And now to give you an earful of what this module can do. Two samples of the RND 208 playing 4 VCOs, just a steady pulse clock driving it. First track without FM, the second with. I'm just fading channels in and out manually to experiment with different mixes of the 4 VCOs being randomly played. I can't get over how complex the random melodies get with no pots to set anything.

http://web.pdx.edu/~rfahl/Audio/208rnd_4vcos.mp3

http://web.pdx.edu/~rfahl/Audio/208rnd_4vcos_w_FM.mp3

[Luka]

i have a bit of space left on my dual wogglebug panel so i could of these might be the ticket. good stuff, thanks for sharing

can you link the real schematic instead of the thumbnail pls vtl
i cant seem to get anything out of it except pixels

[Quad]

Full size:

http://electro-music.com/forum/phpbb-files/buchla208_randv_532.png

[Funky40]

Thanks VTL

i will make a euroversion with printmounted jacks.
It is mostly drawn allready based on VTLs artwork

[/mr]

Few components, no critical layout.
Almost easier to build on veroboard?

[andrewF]

I like the MP3s
inspires me to build one of these.

seems a pity to waste three sections of the 4016, would it be worth/work connecting the spare 4016 switches to three of the CV outputs and getting 3 psuedo random gate sources?

[Photon]

Funny, I was just last week looking over the schematic for this and drawing up a parts list so I could breadboard it. awesome work, vtl5c3.

Maybe this could coexist behind a panel with the sample and hold from the Buchla 266 Source of Uncertainty. If I remember correctly that uses just 2 sections of a 4016.

p

[vtl5c3]

Why would anyone want to clone the Buchla 266?

I'm cleaning up my board layouts (also press & peel) for the 266 and will post them as I finish. It's a great module... actually 5 modules behind one panel.

[Photon]

[ringer]

Please, elaborate some more, thanks.

R

[Scott Stites]

I think what Andrew is getting at is one could feed a switch input with +V (or whatever level you like your gates), then run the control switch from one of the shift register outputs to each of the switch controls. This would produce a gate every time each of the connected register outputs went high.

This is pretty cool, VTL5C3 - I love those samples. I always thought this would make a great addition to a home-built SOU. Jeff Pontius and I got into the SOU functions - Jeff actually built one in MOTM format. I, on the other hand, got distracted....

The design we worked on replaced the MM noise chip, which is close to unobtanium, with a white noise to comparator circuit. It actually worked out pretty well. The MM noise chip was cyclical; this setup wouldn't be. Peter Grenader was of the opinion that the cyclical nature of the noise IC gave the 266 SOU it's own noise flavor. I'm not a fan of cyclical digital noise, but I've never played with a real 266, so, couldn't tell ya.

The fluctuating random voltage function of the 266 SOU is the schnitz.

Cheers,
Scott

[ericcoleridge]

I was looking at the Music Easel panel layout, and can't really tell, so i wanted to ask here, are all 4 Random ouputs sent to their own banana jacks on the Music Easel? I do see 4 grey banana jacks along the bottom row of jacks on the front panel, but they aren't labeled. Just curious.

[cbm]

[vtl5c3]

I recently tried an experiment with the 4 outputs, feeding them into separate inputs on a CGS matrix mixer. I set the mixer into bipolar mode and fed four of its outputs into a dedicated VCO. All of a sudden, I was able to sculpt the pseudorandom sequences going into each voice. In a weird kind of way, it reminded me of Klee.

[cbm]

[Luka]

is the fluctuating random voltage the basis of the wogglebug?

[cbm]

[vtl5c3]

I think so. Either that, or the Buchla 265 SOU, which is very similar to the Fluctuating Random Voltage section in the 266.

[ericcoleridge]

[funkyfarm]

Waouhhh ! Easel flavour !

Did I say "AMAZING !" yet ?

[funkyfarm]

http://electro-music.com/forum/viewtopic.php?highlight=218&t=19064


Coupled with your 218 vc-portamento, you can emulate the clock rate/slew time correlation, as on the 266, if using the same signal (1V/oct, velocity...) for controlling both parameters (S&H pulse input and Portamento cv input), aren't you ?

[ericcoleridge]