kevin gilmore

latest version with correct resistor values for Kerry's servo http://gilmore.chem.northwestern.edu/kgsshvcarbon.jpg parts set for 16ma at 450v

i will start. very simple power supply, roughly same as original BH supply at lower power, zener based. definitely drifts with temperature. resistor based output tube. See JimL posts on current sources. And the resistors look like 100K which is extremely inadequate, but match the power level of the tube.

no difference between the 2sc parts and the pzta or mpsw or mpsa parts 1486 does not need heatsinking. About 188mw

50 years is the golden anniversary 55 years is ?? in 5 more years, 60 years is?? and this is what happens when you edit an edit of an edit of an edit...

its getting pretty tight... http://gilmore.chem.northwestern.edu/kgsshvcarbon.jpg laying the rest of them horizontal is going to be a bit of trouble.

but but Mikhail said that a 6sn7 and a we421 were identical. and 6j6a and 5844... And he consistently shoved all of them into the same socket to prove it. (with adapters) and god only knows how many other tubes. and 3d21 In place of 6ca7...

the version of the carbon board i am working on has pzta42,pzta06,pzta56 and at the moment mpsa06 and mpsa56 all of these parts are current fairchild production i have been told that all these parts have at least 5 years more life left. i have also been offered this really nice bridge in SF recently painted... the stn9360 lay down because they need to dissipate a bit more heat the pzta parts stick up vertically, and are therefore real easy to solder in. i have also added the cascode to the carbon. should be 100% mouser parts except for the lsk170/lsk389 which are easily available. with 20ma per leg, should make the current crazies happy. and 32 watts of heat per channel getting kerry's servo in there is going to be fun

the new verskon uses the bc parts

yep grounded gate.

you want a transformer that has 360vac windings you change the 440k resistors to 390k

that schematic is close enough i'm redoing the kgsshv-carbon board for current parts, i added the cascade current source, is there anything else people might want?

coconut audio (patrick82) did stuff like this... be careful, its a slippery slope

when i do them, its a 3 step process per hole. which is why it comes out so nice. even though i'm using full up commercial NC mills, if i just drilled the holes single step, it would not be perfect. first you use a centering drill then you use a small drill bit then i machine each hole round with the mill bit now it really does not have to be this perfect, but its only a few minutes extra per bracket

what I do is float everything in the chassis. The chassis is connected to earth ground. everything else floats and the audio ground does not touch the chassis ground. this is easy with xlr connectors as the inputs only, and then rca to xlr adapters for single ended.

that is the company I buy from, but I go for the Teflon. its more expensive, but I have the right stripper and always liked Teflon.

raise the value of R1, say 1k will give you 3db more

you can give the amp a differential balanced input, and use the unbalanced output. why you would want to do this i don't know.

i wire 3 wires from each xlr jack to the pot for each channel, then the pot to the boards not a star ground, but works, and is completely silent the wires from the xlr jack are shielded triax

the cfa2 has gain, so it has feedback the cfa3 has no gain, so the phase splitter has the gain

sure you can do that, but you need a phase splitter, or have to run balanced input only if you want balanced output.

you should be able to use 15v regulators, the relay will get slightly hotter

if you are talking about the inputs, yes that is how its done. don't short the outputs to ground a stack of relays, or rotary switches is necessary to do the inputs right

speaking of krell klones http://www.ebay.com/itm/Assembled-Krell-KSA-05-Class-A-preamplifier-board-with-headphone-amp-CL-232-/191538328292?pt=LH_DefaultDomain_0&hash=item2c9892f2e4 and http://www.ebay.com/itm/YJ-Assembled-KSA-5-headphone-board-with-C1237-horn-delay-protection-circuit-/221740126195?pt=LH_DefaultDomain_0&hash=item33a0bdcff3

I'm sure I will add that. found a bunch of errors which hopefully I fixed. and I took out the surface mount transistors because they are only 200mw and there are a few places where its 270mw picture updated

preamp plus power amp please. I will send it back. actually more interested in the amp, because I know I'm extremely close on the preamp part. this really should be the end all dynamic amp, with 80 volts peak to peak output and up to 2.5 amps (more with a bigger heatsink) it should drive both hd800 and he6. you could actually put the volume control in the middle for even more reduced noise, although the noise is about 95db down.