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Mirko

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Posts posted by Mirko

  1. 1 hour ago, Pars said:

    Per my previous question, the ZF resistor is the 1.9K resistor in the schematic and PCB? I assume so, but just wanted clarification,

    That's correct. R50/R51 on cfa3productionss.pdf

    1 hour ago, starcat said:

    Guys, where can I get some more information on the implementation of the SS/ZF switching board? Appreciated all the great work you are putting in. 

    There is none but you can do it like I did and use relays to short/open the positions.

  2. Another CFA is alive and well. Sorted out the issue with the bias when using the SS/ZF switch by doing the following (board rev 1.2):

    - Remove the 4 ZF jumpers near the 600pF

    - Increase R44/R49 to 50K

    - Increase R50/R51 to 4.2K

    - Remove C9/C10

    Set at 190mA, plays beautifly in both modes. A must-have as reference in the amp collection. Thanks to KG for developing this amazing circuit!

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    • Like 9
  3. 3 hours ago, MLA said:

    So, I would start with reflowing all solder joints and also double check that your R8 actually is 860R. Pic of the board would help trouble shooting.

    My bad the R8 is 820R and not 860R, as I did not have 750R at hand for the desired 15V. Checked the solder joints and everything seems fine.

  4. On 2016-01-20 at 3:00 PM, kevin gilmore said:

    the opamp blows up at +/-40V would have to check the other parts, but +/-30V should absolutely work

    speaking of power...

    unbalanced/balanced/cast to balanced input block for all sorts of things, but mainly the uberamp, just need to find a way to get it into the box will probably involve splitting off the driver section.  Uses GR power supply +/-30V for the front end and another GR power supply +/-40V to run the regulated output voltages to the output amp.  If i add zeners to the servo amp, can easily go to +/-50V  and as shown, its 100 watts of pure class A, and something north of 225 watts A/B

    front end NO feedback of any kind, .0025% thd at 20khz, 2nd harmonic.   3rd harmonic not measurable. output amps are current feedback.

    i think i have created a monster :lol:

    ubalbalcast.jpg

    uberamp2.jpg

    What size of capcitor would be suitable, 47000uF or more?

    ~1000VA transformer ok?

    Also where can I find the pdf or gerber for this?

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