McIntosh MC60 Power Amp Power Supply Question

Discussion in 'McIntosh Audio' started by Hi-FiGuy, Jan 13, 2018 at 12:05 AM.

  1. Hi-FiGuy

    Hi-FiGuy Well-Known Member

    Messages:
    529
    Location:
    Southern California
    I have noticed that this amp has 80uF of capacitance right after the two 5U4 tubes. Wouldn't this amount of capacitance cause arcing of the rectifiers? Has anyone changed this when replacing the capacitors in this unit? Would it be better to reduce the input capacitance? I plan to replace the capacitors and could reduce this value to 60uF or lower.

    Thanks
     
  2. dewickt

    dewickt Will fix about Anything

    Messages:
    3,378
    Location:
    Knoxville, TN
    With 2 rectifiers in parallel and a perfect transformer you are safe to 80 uF, calculating in the transformer impedance the capacitance con go to well over 100 uF for 2 tubes. I have seen 680 uF used for the first filter with no apparent problems, though I would not recommend it. The number given in the RCA tube manual is the safe capacitance for worst case design.
     

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