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sunn concert bass voltages

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  • sunn concert bass voltages

    I'm not sure exactly which one this is to post a schematic, it is a silver face, has rca jacks for the distortion pedal, and a single rectifier, my question is are all of the single rectifier schematics the same? the schematic I've been looking at shows 34v -34v at the main caps and I'm seeing closer to 50v on both, and nothing at the output transistors, transistors were pulled and tested not bad via diode test.
    I think I know why nothing is getting to the ot's but need to figure the supply rails out first, I am very tired so I may have measured wrong or overlooked something.

  • #2
    this is the schematic I've been looking at

    Click image for larger version

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    • #3
      Scratch that, this one is the 6 wire transformer, 3 rectifier version with pre amp out/power amp in.
      I replied earlier but I guess it didn't post.
      I found r322 disconnected, someone had previously replaced it and a few capacitors by clipping the leads and soldering on the new parts to avoid removing the board.
      r322 had become disconnected also the +V from rectifier CR1 wasn't making it past the pin connector on the board.
      I fixed those 2 problems and now the amp is up and running.
      I need to go over some voltages next time I get back to it, everything seems to be working aside from dirty pots, and the transistors seem to be running pretty hot, moreso towards the right q3 q4 q5, after running it for a while into a 10ohm (8ohm) speaker.
      when I took the transistors out to test there were 3 different brands, so a new set might be in order if voltages check out.

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      • #4
        got everything working like it should, q4 was getting hot, it ended up being the solder connections on r322, the base emitter resistance on q5 was way off compared to the rest, now it's running cool and all of the voltages and resistance seems to be good.

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