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SIT Power amplifier

Discussion in 'd.i.y.' started by russel, Apr 15, 2018.

  1. russel

    russel ./_dazed_and_confused

    I finally got round to finishing the Nelson Pass designed amplifier using SONY static induction transistors or power jfets. Rarer than very rare things , the 2SJ28, 2SK82 had a good reputation for sound quality, so had to be tried. Initial thoughts are it is very good, delivering a nice detailed punchy sound, maybe because it's got a low damping factor, about nine!, coz I am using it without feedback. In comparison with my previous best amplifier which is a home brew class A bipolar, the bipolar sounds a little more "hi-fi", i.e super accurate it will interesting to hear how the pass design sounds with extra feedback, supposed to sound more "neutral", so I guess it will narrow the difference between the two amplifiers.
     
  2. stevec67

    stevec67 pfm Member

    Interesting. Got a link to a schematic?
     
  3. russel

    russel ./_dazed_and_confused

  4. stevec67

    stevec67 pfm Member

    Hmm, there's quite a lot to that. I do like the way NP sets up his kits so that you solder on the resistors forst and then carry out a series of tests to ensure they are all in place correctly, before adding other things. That's smart. It's still quite a complex affair though, well done on sorting it. I'm still wrestling with a JLH, havent tested it yet. If it works the Pass L'Amp appeals, it's sufficiently way-out to be interesting in its own right, assuming it can be made with non-unobtainium parts.
     
  5. russel

    russel ./_dazed_and_confused

    The electronics side isn't a problem, where gloom and foreboding take hold is metalwork, as you are finding. I do manage to cut down on this by keeping circuit boards standard sizes, so I can reuse boxes and power supplies, though more difficult with the pass design as I had no control over board size, it does have a PSU which is interchangeable with my own class A design though.
     
  6. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Oh yes indeedy!!! Never have truer words been spoken!
     
  7. russel

    russel ./_dazed_and_confused

  8. iansr

    iansr pfm Member

    Whereabouts are you based Russel?
     
  9. russel

    russel ./_dazed_and_confused

    Southern Sweden, nearest airport is Copenhagen, so I guess not convenient to drop by for a listen.
     

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