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Dirty-South Blues Harp forum: wail on! >
power tubes?
power tubes?
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jbone
549 posts
Jun 16, 2011
4:02 AM
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i'm wondering if a new set of power tubes would improve on the already-great tone in either or both of my amps. one is a relic, mid 60's silvertone 1482. features 2 power tubes. the other is a replica '59 bassman with the original circuit, hand wired and built as close as possible to original specs.
one school of thought says why change? another says, why not try something new and see if things can get even better? after all, a tube swap is not a big undertaking if one acts responsible around capacitors and always unplugs first!
any wise counsel out there? thanks in advance.
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Andrew
1338 posts
Jun 16, 2011
4:11 AM
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I've got a fabulous girlfriend, but I'm going to ditch her to see if I can get a better one!
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Andrew.
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Those who are tardy do not get fruit cup.
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5F6H
729 posts
Jun 16, 2011
5:41 AM
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The Sovtek 5881 WXT is a perfectly adequate tube for a 4x10 Fender, how the power tubes are biased will affect the tone, in a way that connot be countered by turning any of the knobs on the chassis. I tend to start out about 12-15mA per tube, if you want more crunch/fuzz go lower (say 7-8mA per tube), if you want a smoother, brighter sound try <35mA per tube. Lower currents reduce gain in the output stage & reduce feedback...but if you don't like the tone of lower currents you'll have to run on the hotter side (I'm assuming whoever wired your amp fitted a bias trim pot? If you can solder, I can tell you which resistor to change/add another in prallel - PM me if you need). The 5881WXT are NOT the same as the EH6L6 although they look identical apart from the lettering, I don't like the EH, or the SED 6L6 because they are a little blurry and note separation can fall apart under drive. I don't care much for the JJ6L6 in a 4x10. The TAD 6L6WGC is another current tube that can work well enough in a Bassman, if somewhat darker sounding than the others. NOS options are the Phillips 6L6WGB, seen by many as the ideal, value for money, NOS option in a tweed bassman, IF you can get some GE5881 these can sound great, tight & chimey, but you will have to pay. Original Tung Sols...price is probably restrictive.
The 1482 is cathode biased, sometimes called "self-biasing", voltages are fairly low so any brand that you like the sound of should be fine, JJ are bulletproof but tight sounding, the EH are a little softer/warmer.
in short, I'd experiment a little with bias settings in the bassman before subbing out the power tubes.
Last Edited by on Jun 16, 2011 5:41 AM
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