kevin gilmore

I actually did this because it was taking too much time to respond to every single person separately. Now I will just point to the file tree, and keep it updated.

hopefully i cleaned this up and its the current versions of everything see updated links on page 5

I have seen plastic covers for to220 transistors before. Where I have no clue

power supply board http://gilmore.chem.northwestern.edu/kgstpsu21.rar

this should handle the power angle bracket to big heatsink and 3 x fet per side http://gilmore.chem.northwestern.edu/kgsshvpsminiexternal.jpg

final kgst board http://gilmore.chem.northwestern.edu/kgst-miniv03.zip

birgir messed up the lsk389 footprint on the test boards. how, he does not know as this should have been a cut and paste. version .4 of the boards will be production. also the one cap was too close to the ic socket.

final pic before I put the fets in. works just fine. http://gilmore.chem.northwestern.edu/dsc_0591.jpg

300v pulls too much current for the kind of thing used in a srd. Besides which very low noise is rather important.

iwik is talking about the power supply, and technically the resistor was running very close to its voltage limits. So its now 2 resistors in series. Same value. Its on both of the 500v supplies

i really like Teflon http://gilmore.chem.northwestern.edu/staxmale2.jpg http://gilmore.chem.northwestern.edu/staxmale3.jpg http://gilmore.chem.northwestern.edu/staxmale4.jpg will knurl the end of the plug just for fun. setscrews are 0-80 the production versions will be white delrin i think. staxmafia personnel will get the Teflon versions.

a pair of 10m90s in parallel will definitely do it.

that stuff grips the pins very tight. no glue required. what the Teflon does, I do not know. also have to try delrin and nylon. I made the first one just to make sure I got the machine code right and in the right order. turns out I made the first one from kel-f. Not what I was intending on

you really want 100k. with 100k resistor, the servo gets it under 1mv in 30 seconds. otherwise its a few minutes. r7 and r8 can be up to .2 watt. if you short the output, about .5 watt and its a dual opamp in a single package you can get rid of both electrolytics, or the one electrolytic in the latest board by maching the fets and moving the left side of R21 to the junction of R1 and R2 and then shorting the bottom of R17 to ground. Then its fully dc coupled, but you have to go thru a bunch of fets to get the matching right.

following chinsettawong's idea ... http://gilmore.chem.northwestern.edu/staxmale.jpg will make more once I get some real Teflon. Plexiglass does not like to do this.

this is the final and correct schematic http://gilmore.chem.northwestern.edu/squarewaveproduction.pdf if you are careful and match the fets, you can get rid of the 1500uf caps. the original board had the servo inverted, hence the extra opamp to invert the output. latest stereo board http://gilmore.chem.northwestern.edu/sqwave9.jpg pair of boards installed in icariums SS1 http://gilmore.chem.northwestern.edu/sqwave10.jpg the corrected mono board is also available. R16 really should be 100k because the servo is too slow with 1M

so the real reason that 68k resistor was there is because otherwise the ccs transistor which is not heatsinked would get way too hot. And if the ccs transistor ever shorted the 68k resistor prevents the fets from blowing up. This is the problem when you try to make an amp with only the high voltage rails. same issue the one guy over did many years ago when he built a kgss with only high voltage power supplies.

Way simpler than what I was going to do. I was going to machine the pins from scratch. I will do it your way.

amazing job on those headphones. where did you get the male stax jacks?

http://gilmore.chem.northwestern.edu/dsc_0585.jpg http://gilmore.chem.northwestern.edu/dsc_0586.jpg on +/-15v power supplies maximum output is 16 volts peak to peak balanced into 50 ohms on +/-20v power supplies maximum output is 22 volts peak to peak balanced into 50 ohms

yep! Not quite that high unless you have big heatsinks

yep, due to solar/wind power stuff like this is rolling out the door. And way cheaper than the semisouth parts. Also way cheaper than the Fairchild parts which they don't seem to want to sell.

notice that those are TO247. Other than that, they are great parts as long as you bias them up heavy.

silicon carbide mosfet output version soon. all stock parts. too many projects in the air at the same time

same 10k input resistor, same 100pf cap. original was 10k x 4 pot.