kevin gilmore

the angle brackets bolt to much bigger heatsinks, same way as T2 because the sicfets are bigger I am now using 1.5 x 1.0 inch aluminum angle bracket .125 thick

2 X 22 volts should be just fine, still need some heatsink on the pass transistors does not seem to be a standard value though

separate bias wires for each side, plus an antenna to detect arcing same as quad esl63's amplifier has much more voltage swing than hev90

1) 35V 581-TAP476M020CCS don't have a link for the 10uf 2) does not matter I used these 810-FK28C0G1H470J 3) I used these 505-MKS2-4.7/50/10 which are in stock and 50V, more than enough 4) I used these 505-MKS2.01/63/10

yes absolutely. If the outputs to the minus rail short out, then you are putting close to 900v on the diaphrams. Same as any other direct coupled electrostatic really we should have a protector for this. The 5.1k resistor is to prevent death to humans in case something bad happens. and as for the new sennheisier product, boy are some people over there delusional thinking its going to be only $15k.

10 ma for the driver is more than enough. needs to be 3 transformers, 2 of which have 4 windings of 380vac each the other is the kgsshv-carbon transformer

yep that is the idea over the weekend i replaced the 1.5k resistors with 2k original vishay resistors rated at .01% and 5 ppm voltages much more accurate. version 5 of the goldenreference board has a place for 1M pots that go in parallel with these resistors for those that just absolutely need to adjust to 6 places (actually those pots may influence overall thermal stability, cermet pots required)

1.25 volts 160 ma current draw on each rail at 20v

the circlotron is the only push pull fully direct coupled electrostatic amplifier that is buildable with current parts. Also at 25ma, rise and fall time are faster than any other electrostatic amplifier of any kind.

balanced in, balanced out, 7vrms out into 50 ohms 1khz goldenreference power supply at +20.0000, -20.0000 (hand trimmed resistors) thd is .011% which is actually the base line of this particular meter typically .003% on the quantasylum400 and less on the audio precision

a complete set of boards is 2 x output boards 2 x driver boards 4 x single hv900 power supply boards (or 2 duals which won't fit in a single box) 1 pair of fat power 450v supply boards (or the dual which also won't fit in the box)

the display is part number dd-52 and in the usa you can order at 800 833 9200

I just updated to what I think is the final board, I added a ground layer on the inside and flipped the relays on the top for uniform ground plane.

birgir got one from likely the same source, I bought one from a usa source. for sure they are all going to need new VF displays which are about $100 with shipping from Tektronix. The replacement of the display is not easy, many very fine traces, need the proper unsolder gun. that said, these are great for doing electrostatic measurements as they go higher in voltage than any other thing out there but have a low end limit of about .02%

#4 it is, new file posted v42 which is actually 4.2 but I'm lazy

the production board will be 2.0 inches wide, reduced from 2.05 inches wide so that the input/output jacks line up perfectly. i can also change the hole size to #4 if people want.

the holes are .125 inch, good for a #6 screw. I can certainly make the holes smaller for production boards. the 50 ohm resistors are the bigger ones, those attenuator resistors are the smaller ones. remember that the board is 2 x 3 inches, on my screen it shows up at about 2x other than the 3 caps, there are exactly the same number of components on the back of the board

typical high voltage zeners are +/-3% no matter what the specs are the el-cheapo meter works great for hand picking parts

posted for congo5 power supply board known working as expected from kerry's and my prototypes for the 400v version, input AC needs to be at least 310vac which would make 350vac necessary for the 450v version so with clearance i would pick 360 vac under load for the 400v version (500v caps sufficient) and 390 vac under load for the 450v version (550v or more caps sufficient)

hard to see if its really copper from that angle, but what probably happened is that the photo mask lifted at the edge and caused that.

on the old boards, you need 2 boards for balanced. the new board is balanced all on one board.

that is dual coil latching and would require the either the original board or more layers on the new board

clean install of windows 10 enterprise, there are already critical updates and the product is less than 24 hours old.

how many times are you going to continue to try to ask the same question in multiple different ways, expecting a different result. Its roughly the same number of square inches (and in fact cubic inches) no matter how you cut up the pie, split up to separate bias/lv etc. pick one. If its not compatible with the majority of the group buy, well tough. dual ground referenced 450v supply is 6 x 6.48, 39 square inches single fat ground referenced supply is 5.45 x 4.05, 22 square inches single skinny gound refenced supply is 3 x 6.48 inches, 19.5 square inches (exactly half of the dual supply) circlotoron 900v supply is 5.95 x 4.72 inches, 28 square inches i have done other boards for you with the power caps off board etc. And its still the same number of cubic inches. It has to be, its always the same exact number of the exact same parts. the 900v board MUST float. so offboarding the electrolytics to capacitor clamps is a very bad idea because caps float with the music. i do not understand why this is so hard. print out the board layouts, attach to cardboard and attempt to mount to your desired chassis. either it fits or it does not fit. yes the goldenreference lv supply is better than the pair of 3 terminal regulators. and it is also additional square inches.

none! its not instead of, its in addition too if you want to get it in the box, you will need a pair of fat 450v power supply boards AND you will need 4 of the 900v power supply boards putting 2 of the 450v power supply boards in series to get a 900v board is likely going to cause all sorts of problems.