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  1. peterh

    Utracer help, doesn't work

    Seems like a ECC83 within spec. I do however think that the 2 plate curves are too similar and could indicate that the plate and "screen" are connected together OR that the specific ECC83 has very similar properties. Make another test with some other tubes and rise the plate from 200 to 350...
  2. peterh

    Dynaco PAS 3 X Cap and Resistor Update - More Troubleshooting Help Needed

    Even all new ecc83 varies a lot. But your values are not that much off. Is the plate resistors ok ?
  3. peterh

    Dynaco PAS 3 X Cap and Resistor Update - More Troubleshooting Help Needed

    It's not way off. Have you tried another ECC83 ?
  4. peterh

    Utracer help, doesn't work

    Both plate and "screen" current are plotted with different curves in the same diagram.Plate refers to first triode, "screeen" is the second triode plate.
  5. peterh

    Utracer help, doesn't work

    The "screen" is used to the second plate in a dual triode to recapitulate in ECC83 setup Both cathodes is connected together to the cathode connector of the utracer both grids are connected together and connected to the grid output of utracer plate on triode 1 is connected to "plate" of...
  6. peterh

    Utracer help, doesn't work

    Have you discussed with ronald ? Mail adress is at https://www.dos4ever.com/uTracer3/uTracer3_pag1.html ( contact)
  7. peterh

    Utracer help, doesn't work

    Now i see at #11. Ok.
  8. peterh

    Utracer help, doesn't work

    To mee it seems to be connected via your cross-coupling board. There is a screw connector plint on the uTracer board. What about connecting your tubesockets there and nothing else ?
  9. peterh

    Utracer help, doesn't work

    What i suggested was that the socket should be connected to the uTracer board and that nothing else should be connected to the uTracer test connector. Reason is that long cables will easily confuse and possibly disturb the measuring process.I have been there and seen this problem. Dit it pass...
  10. peterh

    Utracer help, doesn't work

    You have a connector at the end of the board. Whats the problem with connecting ONE tubesocket there ? Fault finding is in many cases an issue of reducing problem area. By using the uTracer with teh very minimal external cabling you will have a answer to the question : is the problem in the...
  11. peterh

    I need caps….

    Unless some are faulty, let it bee. Capacitors could start leaking if moisture creeps in, this is easily diagnosed. More then one amp has been damaged by "all out" work. What you could use is new tubes. Tubes has a limited life and won't be better as years go by.
  12. peterh

    Utracer help, doesn't work

    Just do it. One socket, one tube nothing else and see if it works.
  13. peterh

    Utracer help, doesn't work

    Can you repeat the test by using a single tube socket connected with short cables to the uTracer ? Your problem might be that the uTracer oscillates due to long cables and interference between the cables.
  14. peterh

    Erhard Audio PAS 3 Board Clones

    Ask the question on erhards forum : https://www.erhard-audio.com/EA-Forum/index.php
  15. peterh

    Dynaco st-70 coupling cap specs.

    0.1 uF couplings cap is correct **. I recommend 630Volt as during brief events more then 400Volt occurs ( startup before EL34 draws current but as bias comes quick there will be > 400 Volt across at least the "upper cap) This especially true if ss rectification is done. ** if the grid resistors...
  16. peterh

    Dynaco St70 Help

    I find these cable fasterners work well. They use a slightly oval hole that is present on Dynaco's gear
  17. peterh

    KT-88 Red plating question

    A tube that has become redplating hot might have been damaged. Damage might not be immediately but there is an enhanced risk of another redplating or flash-over. To be safe it should be replaced. And if it's a pushpull pair it should be replaced by a tube with similar properties as the other...
  18. peterh

    Opinions…on an issue with tube amp

    Changing capacitors won't increase power. Changing tubes could, but first a measurement and compensations of the original specifications.
  19. peterh

    KT-88 Red plating question

    There is a risk with dwindling supplies that tubes with various problems are sold as "perfect". Matching of tubes are also depending on high volumes. The alternative is to but from any of the non sanctioned brands, JJ comes to my mind ( eurotubes make good matching)
  20. peterh

    KT-88 Red plating question

    Both JJ 6550 and JJ KT-88 works fine in Dynaco MkIII , stable bias.
  21. peterh

    KT-88 Red plating question

    Get new tubes. Tubes has a limited lifetime. According to your estimate they already have 3000h on them.
  22. peterh

    Dynaco SCA-35 Tube Selection

    There is no shortage of EL84 quads ( and yes you will need a well matched quad to get best performance) It will cost $88 at eurotubes. eurotubes
  23. peterh

    Help Connecting Measurement Dots, Please

    Replace the EL84 ! Any tube that has flashed or redplated might been damaged and has a large probability to do so again. Take the easy and cheap way tubes are consumables. Transformers are much more expensive.
  24. peterh

    Dynaco SCA-35 Tube Selection

    It would be a dynaco with EFB !
  25. peterh

    Dynaco SCA-35 Tube Selection

    If the can cap is to be replaced then i should recommend EFB kit instead. This will replace all can caps with modern easily obtainable types. EFB has advantages such as lower dist and beeing gentler on the tubes.
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