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kevin gilmore

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Everything posted by kevin gilmore

  1. so here is what I think is going to happen. up to 1000 of these things in the field. as already reported elsewhere, plug anything into both the se and balanced output and the source resistors and possibly the fets fry. may be ok for the first 500 which have a lifetime transferable warranty, but once any of the second batch show up used and someone does the thing some damage and its not covered under warranty, or the warranty repair is Mikhail class, people are going to get mad. The pictures posted show that cavalli cannot do decent repairs to his own stuff. when this thing shows up on ebay as made in china kits for say $150, and are a better and more repairable product, the used price is going to fall thru the floor making even more people upset. having my own web server ( ) I know how many times the schematic has been looked at, and where the hits are coming from. More hits from china than I ever thought possible.
  2. mosfet current sources are depletion mode. made a very different way from enhancement mode mosfets.
  3. on srm717/727 only I think stax used this relay with a detect circuit that opened the relay if either of the + outputs exceeded + or -400V or the difference between the + and - power supply exceeded +/-30V. which is why that fucking idiot over there who thinks he was gods gift to modifying stax amplifiers had all sorts of trouble. on the T2 pretty sure it was a delay circuit only. will look later.
  4. absolutely we need to cryo all parts.
  5. actually it was the GG hard to keep track of who is building what.
  6. what is likely the final version posted including board file. actually performs better with bipolar outputs.
  7. you have to love open architecture
  8. The depleted uranium and the beryllium are enough thank you A tungsten knob would be nice. Almost as hard as the uranium
  9. great build not sure where to put this (because i'm lazy) but congo5 figured out what was wrong with his grounded grid dht amp. hint: 4.7M resistors replacing the 5.1k output resistors do all sorts of bad things to the sound. (unless you are a severe bass head) anyone know somebody that will make me a couple of metal knobs? I will supply the material. warning: toxic, and slightly radioactive
  10. so it helps to have it on the bench where you can monitor whats going on while you listen to it. unloaded balanced (which would be a 804 ohm load due to the feedback resistors), 40 volts peak to peak. and its a hard clip, but thats ok. Now add a 50 ohm balanced load and the output voltage dips to under 20 volts peak to peak balanced. Turn on the other amplifier and do the same, and with both running, 17 volts peak to peak. At which point everything, the output transistors, and everything else is getting pretty warm. A number of the surface mount transistors are running pretty close to their power limits. The why is probably obvious, the power supply is sagging. Down to less than +/-12V and the rails ride the music (or test signals) Plus you loose almost 7 volts due to the Vgs of the output fets. The liquid fire had a pretty crappy underpowered power supply too. Which is why even on hd800 you can hear compression in the music. And audeze... ouch. And he6 well don't even bother. The singlepower SquarewaveXL did a much better job of sounding better (till it burned up) A decent amplifier can actually be built in a box this size. But its not easy. And every single input/output connector just takes away from valuable board space Also makes you wonder how much better a liquid gold would sound with a real power supply. I should be able to take the goldreference power supply and get it to mount in the same holes. edit: i should mention that tests were done at 115 VAC. The switcher is likely to produce more power when run on 220V
  11. Singlepower had a 5 year warranty too. Now nothing currently made is anywhere near that bad, if cavalli is experiencing a return rate for repair of more than 2% he is in a world of hurt.
  12. as long as the voltage goes up on turnoff, no issue.
  13. much more better version now above. fets on the back side. just about 100% groundplane its about $15 per channel could use the caddok resistors for the .47 ohm, and double the price of the amplifier
  14. bigger version, most resistors .5 inch and laying down 3.85 x 3
  15. and it will sound a whole bunch better due to the power supply input fets no longer available as to92, so they are now sot23 may be the reason the liquid gold was canceled as that used to92 input transistors.
  16. here are 2 more, which I had known about a while. When you send something in to alex to repair, you probably don't get your unit back, just the outsides. and whats inside 2/15/16 <? and serial number 345 notice how much stuff has been replaced and how you expect a quiet power supply with only 1 pair of inductors (and very small ones at that), one on each power supply
  17. look at the size (power ratings) of the .47 ohm source output resistors.
  18. But but but so tiny... the resistors are currently .4 inch and the verticals are .2 inch this is the first of many boards. Due to stuff in the middle, .4 resistors are going to make the board much bigger. almost liquid gold bigger. Oops what do you want for 6 hours total. and its schiit magni uber updated board picture above board is 3.85 x 2.5 inches definitely the .47 ohms have to be made bigger, because the current surface mount ones are blowing up
  19. in progress
  20. so yesterday this showed up quoting alex... "In a nutshell, the Liquid Carbon is a fully-discrete, fully-balanced, transportable solid-state headphone amplifier that is capable of driving all but the most demanding of headphones - delivering satisfying levels and offering superb driver control for exceptional detail and linearity." lets run that thru fact check for a second. yep... "Liar Liar Pants on Fire" fully balanced? nope, not in the way that any truly differential amplifier would be. (like any of the super symmetry variants) and absolutely no common mode rejection. fully-discrete? nope not really, see the single ended to balanced converter in the schematic below http://gilmore.chem.northwestern.edu/lc.pdf so much fail in one package... can the stax mafia do better, you betcha. board in progress now, will run up to +/-24V and bolt to a heatsink. So say a liquid gold clone for about $300 in parts. people, why do you buy poorly built crap like this. Buy Schiit, or Audio-GD or many other high quality brands for a lot less money.
  21. well at least the chassis don't rust anymore.
  22. It does give you an indication of how grossly overpriced the cavalli gear is if you can get a 40% discount.
  23. there had better be a chassis to chassis connect between the two of those, otherwise you are in for a surprise!
  24. a complete wood set of male and female connectors. Going to sound SO much better... The people over there would eat it up. Say $1500 for a pair of connectors. Then upgrade to pure silver pins (doing the same to the tulip females is going to be a bear)
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