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Resolved: bias adjustment on Almarro A318B

Discussion in 'Power Amps' started by sphinxvc, Apr 9, 2017.

  1. sphinxvc

    sphinxvc Gear Master (retired)

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    Edit: resolved, was a faulty tube

    OP: So, I just tried to adjust the bias on my A318B, and came up w. some troublesome readings. The bias is meant to be .18v. One side needed a small adjustment to come into compliance, but the other was at .27. From what I understand, this not only affects the sound, but the life of the tube. Using the trim, I was only able to bring it down to .23. What gives? The trim pot doesn't go down any further.

    FYI, the amp was on for about 3 hours before I took the readings.
     
    Last edited: Apr 15, 2017
    sphinxvc, Apr 9, 2017
    #1
  2. bozebuttons

    bozebuttons Friend

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    Try swapping tubes & see if the problem moves with the tubes.
     
    bozebuttons, Apr 11, 2017
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  3. sphinxvc

    sphinxvc Gear Master (retired)

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    Good idea. I'll try that. Thanks man.
     
    sphinxvc, Apr 11, 2017
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  4. sphinxvc

    sphinxvc Gear Master (retired)

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    Yea, you were right, just a faulty tube. Had another 6C33C that works just fine.
     
    sphinxvc, Apr 14, 2017
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  5. bozebuttons

    bozebuttons Friend

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    Good to hear.
     
    bozebuttons, Apr 14, 2017
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