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kevin gilmore

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Everything posted by kevin gilmore

  1. So we actually can do it as the schematic is drawn and make darlingtons out of 2 different transistors So ksa1156 and ksc2752 for the output transistors, as the schematic is drawn they are 750mw each the driver transistors are 8mw each so definitely surface mount and the input transistors are 50mw each I think there might have been a better match for the ksa1156, someone go find it. also remember that Fairchild was bought by onsemi, so lets make sure the parts are going to be there for a while
  2. did not notice that. bad idea on the connectors
  3. check the link again, I added something
  4. actually 3 hands. (updated schematic with great respect to you know who) 1 hand for turkey baster (actually making casserole at the moment) short hand for mouse 1 hand holding 50 year old single malt we will definitely be building this one
  5. so sorenb really wanted this, so here it is http://gilmore.chem.northwestern.edu/cfaelectrostat.pdf the outputs are 300v darlington transistors just need to find a suitable npn match for the stn9360, and this can be done all surface mount tiny, fully complementary, fully dc coupled, decent input impedance (none of this 75 ohm nonsense) push pull output... edit: PBHV2160ZX looks great for the npn. so you can add one more set of outputs and run up to 500v power supplies balanced input only, and you need 4 of them
  6. I think you all will really like this one, a current feedback fully dc coupled fully complementary electrostatic push pull amplifier. what the msb could have been if they had decent engineers. just need to find a match for the stn9360 http://gilmore.chem.northwestern.edu/cfaelectrostat.pdf
  7. anyone that has ever listened to the koss esp950 will agree its clinical and cold. it tests pretty well, thanks to gobs of feedback. but lets look at the msb specs a bit Dynamic Range >140 dB Frequency Response 0Hz-20Khz, ±0.8dB XLR Input 75 Ohm Balanced 4Vrms Maximum Common Mode Rejection Ratio > 120dB CMRR @ 60Hz > 90dB CMRR @ 1kHz > 70dB CMRR @ 20kHz Crosstalk > 90dB Crosstalk @ 1kH > 65dB Crosstalk @ 20kHz now its obviously transformer input based, so 0 hz implying dc coupled. flat out lie. and its already down by almost 1db at 20khz meaning that its slew rate limited and likely this is into no load, once you add 120pf, its going to be worse. 75 ohm input definitely implies that transformer. that dynamic range number is at least 30db off. and where is the distortion specs. Likely the distortion specs are much worse because I don't see any opamps with piles of feedback. stupid massively overpriced crap.
  8. it would probably have to be all surface mount, so that is a fair bit of work
  9. unlikely. I would never use a transformer to drive a voltage stacker like they are doing, something like 900v inside that transformer and i'm sure its not designed for that.
  10. those transistors are all obsolete, would have to be re-designed with available parts
  11. looking at the picture blown up. 450V, 330uf and if you look, 10 transistors, all in series, banks of 5. and lots of resistors to balance them all. (sot223-4 transistors) sure looks to be a bipolar version of the koss esp950. so its a voltage stacker. transistors are likely matched pnp and npn, and are rated for 250 to 300v (5 transistors with 900v total power supply) there are no power output transistors attached to the heatsinks input transformers are used as the phase splitters IF (more like when) it blows up, its impossible to repair.
  12. the heatsinks and chassis bottom (and likely the top) are all sand castings. Pricy for sure. 450uf 300V power supply caps?
  13. electrolytic capacitor coupled inputs and outputs yep, definitely high end
  14. The thing from lockty7, yes I bought one, and had Marc write some custom scripts works very well up to 40 volts or something like that
  15. That is not a T2 clone. It is a massive piece of shit and similar to mikhail's disasters
  16. RIP Robert Vaughn Napoleon Solo
  17. surprisingly the GRLV power supply makes a bigger difference than I had thought.
  18. updated board file
  19. you won't be able to do a balance control that way, but you could 2 x SE and 2 x SE with different gains
  20. O2 has gain of 10db max electrostatic amps have gain in the range 54 to 60 db pick absolutely the most noise free input fet or bipolar you want, and you can't get to those noise numbers at 54db of gain even pumped liquid helium devices used in nmr cryoprobes (costing about $500k these days) have more noise than this. I have 2 of these and a lot of experience with the parts inside. the dscope as well as audio precision and every other digital computerized thd meter have maximum voltage input limits. So the question is whether they used an input attenuator to generate that, and in any case what the input impedance the amplifier really sees. Because even at 100k input impedance, the meter has a much lower impedance than the headphones would have at 1khz. Measuring this accurately is very hard. Generating bullshit numbers is easy. Every one of the ss amps i have built has a thd of less than .01% with an appropriate 10x attenuator running 95% voltage swing
  21. It should be clear by now that the cavalli audio liquid lightning version 2T has the lowest distortion of any amplifier on the planet.
  22. I never said it was not worthy. Besides at $1k, its at the lower end price wise and besides, its tubz never liked trying to make 2 power supplies out of one.
  23. in decreasing order of money (at least I think so, not so sure) all DHT direct coupled thing (no name yet) and a bit pricy (8 x emission labs output tubes) kgsshv carbon circlotron with emission labs tubes diy T2 with emission labs output tubes megatron with emission labs tubes kgbh with emission labs tubes diy T2 with 6ca7 output tubes kgsshv carbon circlotron solid state kgbh with 6ca7 tubes kgsshv carbon the rest do not matter (kgss,kgsshv,all triode,srx2) did I forget any?
  24. those are wire wound and are linear pots, not log. designed for chart recorders and other antiques. collins thing was 48 steps solid silver contacts and precision resistors. designed for radio station mixing boards, and millions of rotations.
  25. you just don't get it. you are 50 years too late, and i'm not selling mine. besides which they are absolutely huge.
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