kevin gilmore

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.

you need 2 fat boards plus 4 of the hv boards for a circlotron

fat boards are needed for the circlotron. does not make sense to mount the power supplies vertical when you have to mount the boards horizontal in a 2U

i'm assuming that is for a balanced pair?

congo5 building and troubleshooting now. updated th.zip and thps.zip and th.jpg + and -15 flipped and -5 cap on amp board flipped all fixed. congo5 says its working now. one other thing, because of the tube, a warmup circuit or better, and output protector is required th2.zip has the output protector on the boards

yes an answering machine. that was almost 20 years ago. at the time i had 3 phone lines, now i have one, and its on a hardware blocker. But the merlin-20 is still hooked up to every single room in the house. Still works 30+ years later. i will bet the at&t does not build stuff with that quality anymore.

well they weren't anything like that much when I bought them, maybe $50 now this on the other hand... http://gilmore.chem.northwestern.edu/bigger2.jpg

i have a pair of mitutoyo absolute digimatic, not sure how much i paid, both are 4+ years old, no problems yet.

very nice

maybe the exploding caps on a couple of demo units coupled with hearing the switching noise every 20 seconds finally put him under. A solution in search of a problem that never existed. goldenreference power supply is infinitely more quiet, and about 10% of the board space. just can't put 10 supercaps in series without all sorts of special circuitry. and they say so in the pdf. sooner or later one of the caps is going to hit 2.6 volts, then ka boom. evidently the Vinnie rossi LIO website is still up and selling that pile of crap. $6155 for the full up version, ouch. and with respect to the darkstar, one rather famous person named the thing "Le Grande headache" but it could set a pair of he6 on fire...

I did not expect to buy a new mattress, but one of the air bladders was leaking, so went to mattress firm and ended up with the tempur-pedic, hardest one of the bunch. same day delivery, drag the oldest mattress away... the ones with the cooling gel were way too soft. the comfortaire was 12 years old. will see how long this one lasts. latest thing is 100% waterproof mattress toppers as an add on.

yes they are the gull wing parts, and the layout is exactly as specified in the pdf.

it does all fit, not by much http://gilmore.chem.northwestern.edu/attenuatorsmtv4.jpg 50 ohm resistors and smt caps added

the new board uses 1206 I might be able to lay 0805 on top of the 1206, not sure how great an idea that would be. other than the connectors, the entire board is surface mount only. I could even do the connectors as surface mount, also probably not a good idea. edit: I take that back, the capacitors are thru hole... but I could fix that too.