kevin gilmore

That would work out to 2 watts per transistor, 8 watts, per channel. A bit too much, should be about 5 watts, about 1.25 watts per transistor. so about 125 mv.

its less than that, but I have that info at home. will look later. specific voltage across the emitter resistors.

The one board is clearly working, adjust the offset pot to get the outputs close to zero. On the other one, make sure the differential pot is set to the middle first and the offset pot set for the higher end of the resistance range.

so what we really want is avid part number 513202b02500g which is 2.0 inches high or 513302b02500g which is 2.5 inches high which is the to220 only version neither of which are stocked by digikey or mouser instock at Newark

I have the bigger heatsinks but one of the holes seems to limit The thermal efficiency. Will test... Would be nice if there was a taller heatsink with only one hole

this is the original krell heatsink mouser 532-513102B25

not so sure there are output caps. This may be very similar to the eddie current electra which has a center tapped inductor as the output device. also could be similar to the woo audio wes if they would pull their head out of their ass and use a center tapped inductor instead of a pair of inductors as the plate load. Clearly its push pull, same as the electra. How they control the output tube bias is another issue, as there are no didle knobs. If they actually load the secondary when in electrostatic mode, it may perform more linearly than the electra.

this should be as small as we can get it. please check for errors. http://gilmore.chem.northwestern.edu/dynahibal8d.jpg

sure as long as you use thermal isolation washers and in the one place isolate the two of them on the one bolt.

ha ha translation error. guinea pig.

i'm sure you could probably get it done in a day if you have all the parts and a pre-punched chassis. No high voltages to cause any grief.

That is about the right amount of time. You want the output filaments warm before the high voltage Kicks in. The timing cap is a lyric so the timing is not exact

http://gilmore.chem.northwestern.edu/ksa5ampfinal.zip but you should probably wait till we are finished testing.

so that's what a correctly assembled amb power supply looks like. I sure know what an incorrectly assembled one looks like.

i would love to do a version with NOS non polarized black gates, no chance of that now. not even for stupid amounts of money.

That's a riot. Bet they are on ebay soon.

well its not really similar in performance over temperature. So for the 500v supply the max really has to be a zener string of 480v which should result in an output voltage of 475v which should drift up to say 490v with temperature.

The mini psu is the same schematic. Just a smaller board. The all smd amp board is not ready yet.

finally for the first time I think in 3 years i'm back in the machine shop. http://gilmore.chem.northwestern.edu/knobblanks.jpg 2 x ebony 2 x rosewood 1 x cocobolo these will be inside knobs suitable for kgsshv http://gilmore.chem.northwestern.edu/knobinsert.jpg the aluminum piece is machined into and inserted upside down into the wood for a complete blind look, with an extremely tiny hole just barely big enough for the allen key. Also on the newest version of the mini power supply there is a labeling error. For the 450 volt version of the power supply the zener string needs to add to 500 volts. For the 500 volt version of the power supply the zener string needs to add to 550 volts.

lil-knight has the latest smaller power supply version which has double the space around all the holes and circuit lands to prevent arcing. You have always been able to partially populate the board, setting the zeners for the desired voltage and then putting a jumper in where the pass transistor is, driving the fets directly. leaving in the current protectors for the fets if desired. then its almost identical to a higher voltage version of the original BH power supply. Newest version has a terminal block for directly measuring the bias voltage before the high resistance resistors so you don't short it out and burn up circuit lands.

the 78xx and 79xx just need the regular thermasil or equivalent washers, they are low voltage. and nylon screws. the 10m90s current sources need the aluminum oxide washers and nylon or peek screws

NO, you have to use a thermal insulator on the 78xx and 79xx tabs are not ground

next up a singlepower squarewave and squarewave xl for the masses. with fixes. this is going to be a very sweet and uber cheap amp and as Jacob can testify, with the right power supply a really great sounding item for high impedance headphones. my version will have a servo, because the 1000uf blackgates are clearly no longer available, and take up way too much space. http://gilmore.chem.northwestern.edu/squarewaveproduction.pdf

well every metal is just a ball of solder at some temperature. that one would be 110 tons at a temperature of about 1500C

that's the minimum I want. depending on how many they really have.