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jose

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Everything posted by jose

  1. jose

    current feedback electrostatic amp

    Offset around +-150mVdc and balance at 100mV in both channels. The resistive value (121R + 1K trimmer in parallel) after regulation is 79.9 Ohm in all channels. My amp passed from 18mA to 20mA BIAS. This works and I'm quite plaised. I could leave it like that but I'm thinking about how to do this mod something more "elegant" and at the same time I with this kind of trimmers but I dont´want to separate the pcb to heatsink because is a pain.
  2. jose

    current feedback electrostatic amp

    Different 121r and 1k trimmer in parallel. Ok, it's no nice but we haven't space on the PCB.
  3. jose

    current feedback electrostatic amp

    Nice Michael !!!! I am going to try the same Mod but changing 100r for 120r and add a trimmer of 1K in parallel. In theory the result should be "similar" but who knows. Without magic smoke, not can be glory ... I suppose
  4. Thanks Michael!! Please, two sets for my if it´s possible.
  5. jose

    What are you listening to Part the Third

    The guy who sings the chorus is spectacular.
  6. jose

    DIY mini T2 Build Thread

    I guess you already had me in mind, right?
  7. jose

    current feedback electrostatic amp

    My amplifier was sounding about 5 hours continuously. I had no problem handling 18mA. Temperature with this heatsinks makes all measurements very stable. The body of the transistors was at about 40º after one hour and it remained in a range of about 40 ~ 45º all the time. I think it's right in choosing big heatsinks. As I mentioned, working with SE sources the amplifier goes perfectly, although with a balanced source the volume increases a little. I do not see anything wrong with modifying the BIAS. Maybe a trimpot could be added to future pcb´s ¿?. I will leave it at 18mA for the moment. What worries me a little is the offset. Although it´s stable (hardly varies ~ 0.7Vdc after being so long on) I don´t feel very comfortable with values of 14.5 / 9.22Vdc channel L and 13.76 / 11.88Vdc channel R maybe because I'm used to having levels close to 0Vdc.
  8. jose

    What are you listening to Part the Third

    Probably a minor work of Bruce but for me it has a very special meaning.
  9. jose

    current feedback electrostatic amp

    Thanks but my amps are very simple... besides this is a temporary wiring. It's all pretty chaotic. For the moment, I prefer to start with the values that Congo5 selected. Anyway, with these heatsinks, my amplifier stays moderately hot, so I rule out changing anything if it's not necessary.
  10. jose

    current feedback electrostatic amp

    I have not changed any value. I guess you mean R33 / 35 according to Dr. Gilmore's scheme ? Yes, 2K.
  11. jose

    current feedback electrostatic amp

    My CFA is already singing. Thanks to Kevin, Congo5 and Michael I´m using a SE source without problems (bridge "cold" channel to ground). My unicial assembly is a bit precarious but only because I wanted to check that everything works correctly. My "Mini BH PSU" to -407Vdc and + 404Vdc. Offset at the start with 14.5/9.22Vdc channel L and 13.76/11.88Vdc channel R. After one hour it is very similar on all channels. Balance 4Vdc and 2Vdc. I hope this is not worrisome. I am using "adequate" heatsinks 😈. Temperature transistors after one hour of use is barely 40º. I guess that's why the offset remains so stable.
  12. jose

    What are you listening to Part the Third

    It reminds me of some of Fripp and Eno's songs.
  13. jose

    What are you listening to Part the Third

    I think so too. ♥️
  14. jose

    Technical Assistance/Advice Thread

    Guys, yesterday I used my Shars Tap Holder with the CFA heatsink... incredible, in just 25 minutes I had finished screwing all the holes. All have been perfect !!!! Normally for this work I would need hours and surely some thread would be skewed. Great purchase and great discovery. Thank you!!!!!
  15. jose

    transconductance amp

    I have my doubts about that ... However, the interesting thing (for me) is to try it.
  16. jose

    DIY mini T2 Build Thread

    I have to look at this but maybe with + rail of the GRVH (Split pcb´s) maybe I can get + 220Vdc
  17. jose

    DIY mini T2 Build Thread

    I´m not sure but I think that it´s not possible. Used a specific PSU is a better idea.
  18. jose

    transconductance amp

    Maybe a GB?
  19. jose

    RIP someone or another

    Wow… descansa en Paz Luke
  20. jose

    transconductance amp

    Yes, it is what I had understood. Interesting. It looks like it's the size of a SquareWave. Pcb´s should not be very expensive.
  21. jose

    Now for something different...

    Maybe... I think it's a different species. My Square:
  22. jose

    transconductance amp

    I did not remember this amplifier ... I don´t think I have it in my collection.
  23. jose

    Happy Birthday Nate!

    Happy Birthday !!!!!
  24. jose

    Now for something different...

    The Squarewave does not sound bad but IMHO dynalo is superior: More balanced, more musical ...
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