5e3 no longer~

Discussion in 'Shock Brother's DIY Amps' started by dougstrum, Jul 17, 2019.

  1. dougstrum

    dougstrum Tele-Afflicted

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    Got my home built 5e3 working again. It needed work I had let it sit for abt a year.
    Played it at a festival 4th of July weekend.
    Really didn't like the lack of clarity on the bottom 2 strings; though I got several compliments on how good it sounded;)

    I decided to make some changes.
    Preamp already had 02 coupling caps and 10/25 bypass caps. The big change was going to fixed bias and el34's~383v plates drawing 34 ma. Pretty low voltage for el34's, and bias at abt 50%, but it sounds full and bottom 2 strings are tight. Tried a few different speakers and settled on an emi 1258.

    Can't wait to see how it behaves at a gig!
     
  2. Nickfl

    Nickfl Friend of Leo's

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    Adding negative feedback is a pretty worthwhile mod to consider if you are looking for other ways to tighten it up and make it a more versatile amp.
     
  3. David Barnett

    David Barnett Doctor of Teleocity

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    EL34s draw a lot more heater current than 6V6s, I hope your power transformer is up to the task. I've seen EL34 conversions in silverface Bassmans that melted down.
     
  4. dougstrum

    dougstrum Tele-Afflicted

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    I used to work with and old ham radio guy, when he retired he gave me boxes of tube amp stuff:D The PT in this amp is part of his old stash. It held up in a 6l6 amp for yrs.

    The other change was to go with SS rectifier, to bump up B+ voltage. So amp only has 2 12ax7 and 2 el34 so I'm pretty confident it will hold up; probably only about 3.5a heater draw.

    Also I tend to like amps w/out neg feedback.

    Guess I will find out this weekend:cool:
     
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