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Everything posted by Mirko

  1. That's correct. R50/R51 on cfa3productionss.pdf There is none but you can do it like I did and use relays to short/open the positions.
  2. I built that one, Dukei is my handle on hf. 47uF cap is installed on the backside on the smd position.
  3. 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!
  4. Maybe my post was a little ambiguous. Right now have it at 200mA in ZF. I shut it down and "jump" the amp to SS. When I power it up I get something like ~300mA bias. My ultimate question is: should it act like this? Seems cumbersome adjusting bias up and down between the different modes.
  5. Running my CFA at 200mA bias in ZF mode, works perfectly but when I try to go over to SS mode it acts funny. Bias jumps up way high when only the SS jumpers are engaged, is this normal behaviour? Using the latest boards.
  6. @RudeWolf Nice build! What transistors are using instead of that340?
  7. @jamesmking is the heater from pin 7 on el34 connected correctly on your schematic? Seems that it's connected to the junction of r28/29 on the original schematic?
  8. What do we think of SBCP56-16T1G and SBCP53-16T1G as replacement for pzta06/pzta56?
  9. SJ109 (and sk389) are extinct for ages...Your best shot is to find linear systems parts, lsj689. But it is pricey
  10. @spritzer Did you listen to it, how does it sound?
  11. now that is what I call a mini, well done JoaMat!
  12. how big are the size of the boards? Looks like there are some space that can be further shaved off...
  13. Hi guys, quick question; what´s the current draw of the VAS transistors on the dynahi? Measuring the R17-R20 resistors gives me 4,6V (15mA). Is this the correct value?
  14. 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.
  15. Hi guys, just built the GRLV plus version but I have encountered some problems. It is configured R8=860R, R7=1500R which would give me roughly 15,4V. But here is the problem VAC is 16 and im getting 17.8V DC.. Red led D1 is not lit but D9 is. Checked the leds and transistors, everything seems to be working.
  16. 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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