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kevin gilmore

High Rollers
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Everything posted by kevin gilmore

  1. new from the ground up symmetrical carbon in progress http://gilmore.chem.northwestern.edu/kgsshvcarbonv2.jpg 6 x 4.35 inches
  2. the 469 volts is a bit high, time to trim one resistor a bit
  3. there is already a pot trimmer. but some were out of range
  4. birgir's brain is on free-run after building 6 x carbons... pick the closest thing you can get to 440k and then recalculate the other resistor or pick numbers for 2 resistors that add to 880k it does not have to be super exact, the voltage will be slightly off, no big deal
  5. easier to test than unsolder. this applies to all the boards at all the desired current levels.
  6. got a batch of dn2540 and they have a 20% variance, so much easier to pick the resistor on a test circuit and stuff it in when you build the board.
  7. http://gilmore.chem.northwestern.edu/boards/kgsshvcarbonv2.zip this is the version 1 board above with the cascode current sources and 4 of the transistors replaced with pzta series parts. not tested, but I would have to be an idiot to mess this one up. (someone should check)
  8. the tested board is kgsshvcarbonv1.zip this is the original board with the original limited servo and the adjustment pot. joamat has tested the left and right versions of the boards. the Kerry servo an the joamat servo boards have not been tested. birgir thinks the extra servo is not necessary because the amp is extremely stable without all the extra parts.
  9. the original kgst boards are fine the ones with the cascode current source have the one heatsink ungrounded. how this happened, who knows. Its why i need a much bigger monitor.
  10. it fits just barely http://gilmore.chem.northwestern.edu/dynahibal17.jpg
  11. the oscillation was in the ltspice simulation. board run now, will know for sure once i build it. possibility of z-foil .15 spacing resistors, going to screw up the ground plane on the back will try later no 20 ohm z-foil resistors that i can find...
  12. so you have heard of book matched veniers... well... http://gilmore.chem.northwestern.edu/dynalobal16.jpg
  13. playing around with the board for sorenb, i found that the right heatsink is not grounded. really should be grounded, best place is the ground on the power connector this probably means the original board has the same issue will update boards now
  14. fireproof cardboard box always works. way way way back when, i built a 1kw xenon strobe in a cardboard box...
  15. the cree part is a to246, so no. besides which people want to run at 20ma or more, and at 450V power supplies that is 9 watts no onboard heatsink I know of is more than about 4 watts
  16. chevy spark is a very cheap car... http://www.chevrolet.com/2016-spark.html
  17. all the new cars I know of play music right from your ipad or iphone. or a host of other digital devices. wired or wireless. and the 2016's come with Pandora and iTunes direct from the onstar box.
  18. I would have gone with the resistors I used for the 20 ohm, but that should work fine. pretty quick assembly.
  19. for the truly insane among you (birgir really wanted this) (work in progress) http://gilmore.chem.northwestern.edu/ssdynalobalsmt.jpg
  20. well I do 10k, just because I don't want too many different versions in stock. but 50k or 100k works fine for this
  21. I do have 2 sets of the original boards with the mpsw parts if anyone is interested. also 2 sets of the unbal to bal boards, also with the mpsw parts.
  22. last set of boards is gone. power supply up next
  23. surface mount board finished and tested and bug free. http://gilmore.chem.northwestern.edu/dsc_0659.jpg there is one set of boards left if anyone is interested
  24. just imagine what that would cost if pete decided to sell it.
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