kevin gilmore

alcohol AND diy, especially electrostatic power amps. at the same time. usually entertaining, and possibly deadly.

overkill? ME? NO, never. the resistors i picked are actually 1.5 inches long, the layout is 1.8 inches. So you can use the concrete resistors. i don't like the sound of protection circuits. So this amp is capable of about 30 amps into .1 ohm. Its just so much simpler this way.

you are buying the 10m90 from mouser right?

susy is low impedance input, so you can't use a 50k pot. 10k pot max!

the attenuator resistors are not actually 10k, they depend on attenuation per switch and total impedance.

partial schematic suitable for checking http://gilmore.chem.northwestern.edu/attenuatorv2.pdf board pictures http://gilmore.chem.northwestern.edu/attenuatorsmtv42flipground7.pdf

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I think it's closer to a 6U as a stereo balanced the board is 4.35 inches high and 11.55 wide the transistors take up a bit of extra space past the board so say 10 inches X 15 inch heatsinks

if people really want, I can probably flip the tubes to the other side to make stuff like this easier.

if you want a fully balanced amp, then you need 2 amp boards per channel plus one input board plus 2 goldenreference boards one set for 40v and the other set for 30v plus a very large transformer, a pair of 25 amp diode bridges and some really honking large power caps and mass quantities of heatsinks. if you ever saw the original levinson monoblock class A amps, those were 18 watts (really about 30) This is 100. you can also build the unbalanced version which is still pretty silly and less parts. And still stable into 1 ohm.

if you don't already have the boards, there are new shorter versions of the boards that make doing the c2m1000 much easier

the opamp blows up at +/-40V would have to check the other parts, but +/-30V should absolutely work speaking of power... unbalanced/balanced/cast to balanced input block for all sorts of things, but mainly the uberamp, just need to find a way to get it into the box will probably involve splitting off the driver section. Uses GR power supply +/-30V for the front end and another GR power supply +/-40V to run the regulated output voltages to the output amp. If i add zeners to the servo amp, can easily go to +/-50V and as shown, its 100 watts of pure class A, and something north of 225 watts A/B front end NO feedback of any kind, .0025% thd at 20khz, 2nd harmonic. 3rd harmonic not measurable. output amps are current feedback. i think i have created a monster

It does about 1.5 amps there will be a higher voltage one soon that does 6 amps

not a liquid.

pure ethylene glycol. I use it by the gallon to cool the xray cameras. slightly toxic.

the tidbits i post over there are an attempt to get people to turn their fucking brains on. It rarely if ever works. Like the bit about which of my children (amp designs) i like more. They clearly don't fucking get it. and isn't it chang 3.0?

great build job

go ahead and try other compatible tubes. whats the worst that can happen, fried tubes or blown parts. i have tried kt88, 6550 and 6l6, all end up the same way with G3 toasted.

yes you can do this, you need adjustable cathode tail resistors. basically the same as srm007t2 board is going to get a bunch bigger

because that is how jiml gets away with half the amount of parts. for the srx circuit it works because a low impedance ground is not necessary. i myself would not do this, i would do the usual 2 supplies tied together. It only took me about 1 hour to do that layout, so no biggie.

the all dht version is $18k or so in parts. you want the best thing there is, the ggdht (which i just posted) is as close as you are going to get for <$10k here is the thing, the gain of this amp, and there are only 2 other ways to do the filament, both have problems with the high gain. 1) hum pot between the 2 filament wires, the center of the pot is the cathode. This limits the voltage gain of the output stage a bit. 2) high frequency center tapped transformer, 40khz minimum (seriously, everything else sucks) and then there is still hum, but you can't hear it. this is the problem with using DHT's in a dc coupled electrostatic design. Also why 300B's are absolutely the wrong thing for the job. http://www.emissionlabs.com/Articles/APP-NOTES/AN6-Center-tap/center-tapped-index.htm

all those parts can be mounted on the other side. latest version of the board has silkscreens both sides for the pots

20B-v4 really is the only candidate that i know of that does both 800v and has a center tapped filament. Even if you run DC for the heaters, and then you need 4 of those boards.

nope, that is a different board. with the fets replaced with bipolar. practically they are almost identical.

here is something for you people to play with. emission labs 20b-x4 tube in the kgsshv-carbon-tube is a direct plugin. just cut the filament lines tying the 2 tubes together, there are already 2 connectors, one for each tube. 4 tubes about $2100. solves the center tap filament issue.