Tube Synth Power Supply

[seaweedfactory]

Hello All,
I've been looking over Eric Barbour's tube synth schematics on Ken Stone's Site. These are great articles and I'm very glad Eric and Ken have been kind enough to provide them.

http://cgs.synth.net/

On a number of these circuits, a negative high voltage power supply is required. However, Eric's power supply schematic only provides +140V.

Any idea how I can rig up a negative rail? In general, any advice on construction of these circuits and tube synths in general?

[Blue Hell]

Moved your message to the new CGS section (in the hope that the question will get better attention there )

[andrewF]

For the psu, I did it the way Paia does it for the Fatman and Tubehead pre-amp (although theirs is for 12V).
One output of the transformer is the power rail, the other to ground. Here's a very basic diagram, of course don't forgot all the caps, fuses and whatall.
Really it is worth trying to get your hands on a transformer that puts out 100-180V, a lot simpler. plenty on ebay.
It doesn't need to be big, tubes use very little 'high voltage' current .
The tube heaters are another story - expect 300mA per tube, so for say 10 tubes, you want a 6.3V 3A supply.(edit - crappy pre-coffee maths)
Keep in mind the caps will retain voltage for a long time after the PSU is turned off. originally mine still held 100V an hour after it was unplugged. You need to include bleeder resistors across the caps so they drain more quickly.
Keep one hand in your pocket.

Have a good look at Rene's neon VCO, very easy to build and sounds great...plus its V/Oct.

There are a lot of schematics in yahoo group - tubesynthdiy
that may or may not be useful

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[otherunicorn]

Basically What I did was to duplicate the positive section of the PSU, but with the diodes and capacitors reversed.

[seaweedfactory]

Otherunicorn, some thing like this? Or will I need another transformer?

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[otherunicorn]

[otherunicorn]

I finally found my dual PSU diagram.

use at own risk!

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[seaweedfactory]

Thanks a bunch, this is exactly what I was trying to find. The discharge switch is also a very nice feature.