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kevin gilmore

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kevin gilmore last won the day on April 26 2017

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About kevin gilmore

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    Staximus Maximus, Stax Mafia's Chief Cook and Bottle Washer

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  1. The ultimate DIY? A Stax SRM-T2!

    10 times the input capacitance, 20 times the output capacitance. Yes it will work as the gate follower, but in the gain stage the frequency response is definitely going to change
  2. Massdrop Cavalli Tube Hybrid

    flyback switcher on board. another stepdown flyback switcher for the filaments
  3. A hybrid electrostatic headphone amp design

    the 5.1k resistors are to protect the headphones.
  4. A hybrid electrostatic headphone amp design

    so all sorts of problems actually building this. 1) input transformer needs a center tap probably tied to about -420v 2) voltage swing on the ecc88 is such that you are going to loose 40v or more on negative swing 3) 6sn7 filaments would have to float and then you are still limited by the cathode to filament voltages to about 400V 4) 33R output resistor absolutely a bad idea 5) available 900V mosfets are high gate capacitance limiting frequency response 6) resistor plate loads for 6sn7 a bad idea 7) 900V npn output transistors no longer exist have to use obsolete parts, or currently best transistor is 800v no servo to control output stage dc
  5. Blue Hawaii BJT Build thread

    absolutely stunning, but I think the triumph would be a lot more fun, too bad i'm way past my prime to ride something like that. more than 20 years since the K100RT
  6. hum and heat are 2 issues the lyr3 seems to be getting a reputation for.
  7. yes the amp is balanced. whether there is a opamp unbal to bal converter like the liquid carbon or lcx, is unknown. But there is no reason why the front end cannot be a differential amplifier and then its balanced. of course that depends on your definition of balanced, its not the same kind of balanced as a super symmetry dynalo. its a unbalanced/balanced to balanced converter and then 4 x cfa output amplifiers. Same as liquid gold, liquid carbon, lcx. I see the confusion from my post, the single ended output is going to be limited to something like 18vpp (30 volts - VGS(x2)-2) whereas the cth would be about 26v This amp is definitely to compete with the lyr3. whether they knew that the lyr3 was coming or not. Both amps have serious limitations and issues. also that picture is the cavalli version the monoprice version will probably be different just like the differences in the original cth and the production version
  8. +/-15V power rails and mosfet output transistors. Single ended output with very limited voltage swings. Same super simple CFA output section as CTH,Liquid Carbon, Liquid Gold, Liquid crimson etc. Virtually no class A power. And this is $700?
  9. and now for something completely different part 3

    No reason for an extra buffer
  10. I am sure that the design is a version of his current source feeding a buffer output stage. Possibly ac coupled. With a fair bit of feedback.
  11. it may have been cute when schiit came out with its original batch of cheap shit. all sorts of compromises necessary to produce something for $149 But now we have schiit competing with massdrop competing with monoprice, producing seriously compromised product for prices approaching $700. All sorts of issues including virtually no class A output power, split rail power supplies, low component life due to some really high chassis temperatures, noisy external switching power supplies and flyback switchers internally. Throw away product for sure. When you can buy real products from real companies for $500 or less.
  12. and now for something completely different part 3

    the cfa input is a diamond buffer and is biased thru the base currents of the input pair.
  13. and now for something completely different part 3

    I think it may screw up the first stage bias currents, but you can certainly try it.
  14. Balanced to unbalanced board

    It's the complex impedance of the cables that can cause oscillations if driven from a zero impedance output. input impedance of the amp does not matter. this is why a buf634 can oscillate and it always has a gain less than 1