Thursday, September 24, 2009

NOS Toobz

These arrived from TubeDepot today. I think that we have an average age here of about 40... There is another couple of pencil tubes to do the Mean VCF, three 2D21's for a VCO and a Thermonic Noise source. To finish off a 6BN6 for a beam modulator... also a collection of ceramic tube bases for the PCB... should be fun!
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Wednesday, September 9, 2009


Bought this NOS valve, a 6ME8, to make a Sheet-Beam Modulator as per Ken Stones site where he hosts some of Eric Barbour schematics and articles. On closer inspection I can see that he inside of this one has become a bit munted... Not really sure how this is going to effect the sound but I suppose that we shall just have to give it a go...
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Monday, September 7, 2009

Mirrored VCO...

Further to Previous post -- here are the two PCB's (the one on the right has the copper on the top so the IC's are underneath!) The right hand board is configured as the squarewave output and the one on the left is the sawtooth -- this was the subject of the earlier postings.
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The Saga Continues!

Been a bit busy with the mundane part of life (you know family, work, that sort of stuff) so Forbin has been somewhat neglected but I have been trundling along with a few bits and pieces. This is our old favourite the Buchla 258 VCO clone... I have been doing a bit more work and have made a second PCB for the wave shaping section only. I have also taken some aspects of a Cat Girl design and worked it into the Waveshaping control along with some buffering and amplification of the output waveforms to boost them to +-5V so they are in line with the other VCO's in the Choir. This picture is to try and help out ericcoleridge with the FET placement. Good plan to write on the board the GDS of the pins just to make sure! It is a bit odd and confusing, you can see the squarewave board mirrored on the right (got the press and peel printed back to front yet again....) There has been some discussion about the pots used and I have used 100K's BUT my waveshape control input has an extra summer and buffer... I will draw up what I have done and try and get it up here soon. It does allow me better control of the wave shape as I was finding that most of my control was up at one end of the travel (more so with the squarewave than the sawtooth).
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