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kevin gilmore

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Everything posted by kevin gilmore

  1. kevin gilmore
    there have been updates in the boards to replace the 1 x 300k or 510k resistor with 2 x cmf60 resistors. although there is conflicting information from Vishay with 2 documents saying different specs for the cmf60. I think that in any case, the 2 x cmf60 has to work because the total power is 1 watt and the total maximum voltage is 550v someone have a different idea, I can certainly do that. the pdf I am going by is this http://www.mouser.com/ds/2/427/cmfind-239942.pdf the conflicting document is this http://www.vishay.com/docs/31027/CMFMIL.pdf
  2. kevin gilmore
    pcbnet actually has the large board runs made in china. only the rapid response stuff is made in Illinois quality is very good however, the T2 boards were made by them (my production)
  3. kevin gilmore
    the 1k resistor in series with the 2 x 11k resistors. change to 500 ohms and I never liked virtual ground anything. just a bad idea.
  4. kevin gilmore
    the problem with the e12 is the common summing. so even if you do 2 boards, and one hot output is +2v and the other hot output is -2v, the result is zero. if you think that can't happen with some of these whacky dacs, think again you really do need a pair of comparators on each of the 4 lines
  5. kevin gilmore
    you can change one resistor and the setpoint will be .25v or anything else you want. the e12 does not protect against dc offsets at the imput causing differential output voltage that can be significant but adds up to zero and then won't trip the relay
  6. kevin gilmore
    updated picture
  7. kevin gilmore
    http://www.mouser.com/ProductDetail/Phoenix-Contact/1902547/?qs=sGAEpiMZZMvZTcaMAxB2AKJ8wpDgQJg5WwkpmYrVFB4%3d
  8. kevin gilmore
    and then you have to change the driver power supply to +/-350
  9. kevin gilmore
    yeah, there is about 5 volts of offset, no biggie board posted there are 3 resistors in series for the feedback and its 890k total on the board. no, you definitely should not try to use this as a dual voltage supply because only one side is regulated. like this http://gilmore.chem.northwestern.edu/circlotronhvpowersinglenew.jpg
  10. kevin gilmore
    should you actually find music that will drive the amp at the speeds necessary, the output stage will drop out of class A and go into AB.
  11. kevin gilmore
    this is the new power supply schematic. i like it much better than the previous version. new board soon http://gilmore.chem.northwestern.edu/goldenreferencehv900new.pdf runs on much less voltage, so for the dht amp running at 50ma, less heat also less noise than the old version, and no pile of zeners
  12. kevin gilmore
    try not to do it hennyo style!
  13. kevin gilmore
    its low voltage, so standard silicone pad is just fine. takes up about 25th, so no room necessary
  14. kevin gilmore
    has to suck the heat from somewhere the heated heatsinks cause airflow
  15. kevin gilmore
    got something back from kemet that says their pdf is way out of date, and many of the sizes are 2 pin, but some are 4 pin. seems that mouser does not have the 4 pin in stock, but can order them, they would be a bit cheaper if we buy 100 or more. the layouts are updated just in case anyway.
  16. kevin gilmore
    kerry changed a few values from the original schematic, changing the labels on the boards now http://gilmore.chem.northwestern.edu/goldenreferencehvsic.pdf R1 to 4.7k (probably a good idea) D1 12V R6 to 50k (also probably a good idea) C7 down to 5pf (and yes it needs to be there) 3.9 ohms for R11 if you want to raise the current limit
  17. kevin gilmore
    holes, lots of holes top and bottom
  18. kevin gilmore
    kerry, you need a screen room, all copper you know you want one. do the entire apartment and wear an aluminum hat.
  19. kevin gilmore
    for signal input, unbalanced you put hot to amplifier input + you put ground to signal ground and input - for output you wire hot to amplifier out + and you wire ground to signal ground anything else, and bad things happen
  20. kevin gilmore
    calculate the power, and its pretty low. now sensitive iem's might be a different story, but you would be nuts to run those on this amp.
  21. kevin gilmore
    .5 volt sure seems reasonable to me. but all you have to do is change one resistor to make it anything you want.
  22. kevin gilmore
    if you are having power supply boards made make sure the board files have todays date on them or later. the new capacitor footprint should take care of any possible cap you can shove in there.
  23. kevin gilmore
    the following files have been updated with both footprints, please check for errors ...newleftfat ...newrightfat ...circlotronhvsingle there seem to be multiple errors in the kemet pdf for example size codes f and k do not exist http://gilmore.chem.northwestern.edu/circlotronhvpowersingle.jpg if you are planning on making any of the power supply boards make sure they have today's date or later on them. if not ask.
  24. kevin gilmore
    for the 550v caps there is conflicting information whether they are 2 lead or 4 lead, trying to find out real information, I think they are actually 4 lead. updating all layouts with both the 2 and 4 lead versions
  25. kevin gilmore
    its really no different than the kgsshv, its the same +/-450v output swing. and the 900v supplies are the same as the original supply, they just float. no big deal, nothing to see here, move along. made the single power supply a bit smaller. 5.95 x 4.35 inches by the way, the pdf of the kemet capacitors specifically says they can be mounted in any position.
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