64 Deluxe Reverb Voltage question

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Wailin, Sep 22, 2005.


  1. Wailin

    Wailin Member

    Messages:
    5
    Joined:
    Apr 17, 2004
    Location:
    Ontario, Canada
    Howdy all.
    I have a 64 Deluxe reverb that i love to death. It has Westinghouse 6v6's, and the plate voltage is 450 volts or so. From the research I have done, it should be 410 or so. I know that this is because of the rise in wall voltage over the years (120v vs 110). The tubes are holding up, but I would like to hear this amp at the voltages that the designer intended...and im worried that new tubes will die quickly in this amp. I have read about the reverse zener trick and it seems to get good and bad reviews...so what about a new voltage-corrected power transformer? Anyone have opinions on the best one? Or is the zener trick the best way?
    Love to hear your thoughts
     
  2. theelectic

    theelectic Guest

    Quite honestly, I wouldn't worry about it. #1, the amp was designed for 117V operation, even if that's supposed to be 290VAC (which gives 410VDC) with 122VAC it would give 302VAC (427VDC) - barely any difference.

    #2, I don't know where you got 410VDC from, but even the Fender schematic shows 420V after the standby AND it even says all voltages +/- 20%!!! So the 450V you're getting is perfectly in line with what the amp is supposed to be putting out (what the designers intended).

    #3 be more concerned about the plate dissipation, not just the plate voltage, i.e. if the amp is biased cold, say 15mA idle at 450V, that's not even 50% (6.8W) of the max (14W) dissipation! Up the idle current to around 70% of max (10W) and see if you like the tone! The plate voltage will go down as well.
     
  3. Wailin

    Wailin Member

    Messages:
    5
    Joined:
    Apr 17, 2004
    Location:
    Ontario, Canada
    When i said 410, I was talking on the plates, not after the standby switch. That is what it shows on the factory schematic.
     
  4. theelectic

    theelectic Guest

    It actually shows 415V, but still, +/-20% would be 332-498V. Anything in that range is "designer intended".
     
  5. markdurham

    markdurham Member

    Messages:
    19
    Joined:
    Sep 11, 2005
    Location:
    Texas
    You could use a 5V4 tube rectifier instead of the 5AR4. This will lower the voltages. It won't be quite as stiff as the 5AR4 but you may like the sound better. The 5V4 can deliver up to 175mA and will work fine in a 6V6 amp. Sounds fine to me in my 63' BFDR.
    markd
     

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