kevin gilmore

there is no functional difference in the new boards, just for people without the mpsw parts probably lots more surface mount updates on everything else soon. the idea is 100% mouser available parts

because I'm being picked on elsewhere for using obsolete components... surface mount versions of the dynahi in the boards directory. smt pzta56 and pzta06 replace mpsw06 mpsw56 ssdynahibalsmt.zip ssdynahibalsmth.zip second one is on board heatsinks

other than the fact that i don't have any. two versions of the 6ra6 board http://gilmore.chem.northwestern.edu/kgst6ra6.jpg http://gilmore.chem.northwestern.edu/kgst6ra6cascode.jpg and cascode version of 6s4 http://gilmore.chem.northwestern.edu/kgst6s4cascode.jpg someone please check for errors

anyone find a 6ra6 or 9ra6 datasheet in english, or at least can tell if the pins are bottom view or top view?

I can do a version of the board for 9ra6 if you want but an adapter should be easy, the plate and the filament are the same pins the cathode and the grid each move down a one pin

yep in fact you can delete a number of the parts. 2 sets of RCRC and then a jumper on the C to ground.

that is definitely my layout. wish i could make boards at home, i could waste even more time and make the house smell of ferric cloride.

you are supposed to use 1kv diodes!

a variac will make testing easier

i will see if i can cram 5 watt resistors in that place. re: q27,q28 probably better to put 1 watt transistors in there, trouble is finding them. Those transistors are rated at 500mw, and they are running at 436mw new board will take 5 watt resistors, these http://www.mouser.com/ProductDetail/Ohmite/WHE1R0FET/?qs=sGAEpiMZZMtlubZbdhIBIFwx82bjKdTOEgG%252bjKeDnyQ%3d but seriously, that power supply should not be able to supply more than 1 amp, so the 1 watt resistors should have been sufficient. will turn q27 and q28 into pzta56,pzta06 new board http://gilmore.chem.northwestern.edu/cfp2c.jpg and new board file in the boards directory thanks to grindingthud for doing this, my time is more limited these days, and I knew this amp was going to be amazingly good, and fairly cheap by the way, on my prototype I had to take it to someone to measure it, because its below the range on my equipment. Ends up .003% thd at 20khz at 40v peak to peak everything else like thd at 1khz is basically unmeasurable with even equipment in the $25k range. And its flat to more than 1mhz, the result of being a current amplifier.

I agree with all of those numbers, especially the gain.

oops, those should be 5k. The board says 5K now. maybe we can increase those. what is the voltage on pin 6 of the opamp to ground.

updated schematic

a metcal soldering iron with the big tip. still its not going to be easy.

the 2 resistors go to C2 on the original schematic. top of R30, bottom of R15 the resistors join and connect to pin 6 of the opamp like this http://gilmore.chem.northwestern.edu/cfp2f.jpg

integrators do not work that way, but try it synthesis says that flipping + and - definitely does not work. the pair of resistors, but they need to be 5k not 50k

shit, looks like the feedback is upside down again. my simulation software continues to do that. I thought i had it fixed, evidently not. same thing happened to the original squarewave clone. i am changing to new simulation software, probably today. huge learning curve, not happy. will check when i get home, i don't think i have that file here. better idea... remove r19 from the board. solder in 2 x 50k resistors on the bottom of the board from the opamp output pin to the top and bottom of the bias generator. Same as this. http://gilmore.chem.northwestern.edu/multiamp.pdf let me know...

since grindingthud seems to be faster at building and testing my stuff than I am... http://gilmore.chem.northwestern.edu/th.jpg http://gilmore.chem.northwestern.edu/thps.jpg http://gilmore.chem.northwestern.edu/boards/th.zip http://gilmore.chem.northwestern.edu/boards/thps.zip the big high voltage cap is actually 470uf 160v and the little cap is actually 33uf 160v they are right on the boards, wrong on the pictures schematic http://gilmore.chem.northwestern.edu/th.pdf

its bipolar inputs, (one of my pure bipolar series) so there is input offset bias current. Input pot really should be 10k or 20k. very fast, very low noise, very low distortion.

thermal on pin 3 is definitely missing. will fix on the layout in a few minutes. pin 3 has to be connected to ground.

definitely ok on +/-20v

likely ,5 volt in which makes sense, gain of 5

actually everything i did was 3 oz copper, mainly for the filament traces. Also good for higher currents found in ssdynahi etc. and yes i own a metcal now, someone gave me one. hard to go back once you use one for a while. previously i was using a 40 year old weller.

rv3 is the common mode offset pot. with the 2 other pots in the center, and the servo's removed you adjust for minimum between both outputs and ground. then you adjust the other 2, then add the servos

about overkill... if you want 350v out, then the error amplifier really should get 400v from the zener string, which compensates for the hot/cold and then the unregulated input voltage should be 450v and that is right at the limit of a 450v cap. So while 2 caps in series is overkill you can always pick lower voltages and higher capacity, say 2 x 250v caps. Or 1 x 500v cap, and the 500v caps seem to go in and out of stock often. running things with less clearance on the voltages ends up raising the noise level. Still its much less than noise than the simple supply and the amplifier is definitely subject to power supply noise