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5e3 power tranfo

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  • 5e3 power tranfo

    I picked up a power transformer - 235 V AC input (in Europe) puts out
    HT 380 V
    valve 5.2 V
    lamps 6.5 V
    With my limited experience I believe these voltages should work for a deluxe.
    This transformer is a bit larger than the usual one for 5e3.
    If I use it, I'll have to drill new holes and make the cut-out in the chassis larger.
    Is there anything else, other than voltages, I should be looking for as for whether it's compatible for the 5e3?
    Thanks, Paul

  • #2
    Well, The 380V is unloaded. Is that 380-0-380, or 190-0-190, or 380 with no CT? Your actual Vp will depend on these things and the rectifier configuration you plan to use. And it would help to know the current rating on those secondaries to better answer your Q. .
    Last edited by Chuck H; 10-30-2011, 05:10 PM.
    "Take two placebos, works twice as well." Enzo

    "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

    "If you're not interested in opinions and the experience of others, why even start a thread?
    You can't just expect consent." Helmholtz

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    • #3
      I believe it's 380-0-380.
      States 2 x 380 V, and the terminals are labeled PL - PM - PL. I'm guessing PM means "Prise Masse" which translates to ground tap. (I'm American in France more than 20 years but am not sure.) Maybe a Frenchman can confirm. I can ask tomorrow.
      I was planning the normal 5Y3G rectifier.
      For the current ratings I don't have any other information. Is there a way to measure the current with a DMM?
      The transformer is old, paper core, and bigger than the standard transformer for a 5E3, which makes me think the current handling will be large enough.

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      • #4
        Originally posted by pbiagi View Post
        The transformer is old, paper core, and bigger than the standard transformer for a 5E3, which makes me think the current handling will be large enough.
        Probably. But not certainly. The filament secondaries are what I'm wondering about. Your 5V tap is marked valves and your 6V tap is marked, uh, lamps? Maybe some term for preamp tubes I'm not familiar with but this has me wondering if you'll have enough 6V for all the tube filaments. I don't know of any test that will tell the current ability of a transformer.

        380-0-380 will put your Vp around 430 to 440Vp. That's pretty high for 6V6's and certainly high for a 5e3. If that transformer is larger than average for a pair of small bottles perhaps it's meant fr a pair of big bottles that are more likely to handle the plate voltage. But, you can always use a zener to drop some volts too. Provided your filament secondaries are up to the job it can be made to work.
        "Take two placebos, works twice as well." Enzo

        "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

        "If you're not interested in opinions and the experience of others, why even start a thread?
        You can't just expect consent." Helmholtz

        Comment


        • #5
          Actually the 6.5V is labeled as 'CH L', (so I wrote lamps), but the taps are noted 'CH FIL' (filament).
          Given the high B+ voltage, zeners.., the chassis cutting.. I'm convinced this transformer is more trouble than it's worth for a 5E3.
          Thanks for going through this. I may revisit using it for a bigger amp sometime.
          Problem here is since a transformer weighs a bit, shipping gets pricey.

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