Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: BigE on June 24, 2013, 12:08:39 pm
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On the bench is an old PV Deuce with the solid state rectifier. The plates are running @ 530v. What would be the first culprit and/or what could ya do to knock this down. It's got new 6l6's and has had a cap job. It's smoking 6l6 tubes, I'm assuming cause of the high plate voltage.
thanks in advance for the ideas/suggestions.
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Does it have a schematic?
However 530V *alone* won't kill 6L6GC. What's the current??
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schematic attached...
6l6's are running @ .045 ma...
the new 6l6's are JJ's. I've been having a LOT of trouble with new JJ's going bad. I guess it could be a coincidence that 2 of these new tubes went bad if he got a bad batch. But the owner says the amp runs REALLY hot temperature wise on-stage.
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6l6's are running @ .045 ma...
I think you meant 45mA? .045A = 45mA and .045mA is 45 thousands of an mA.
It's smoking 6l6 tubes
But the owner says the amp runs REALLY hot temperature wise on-stage.
And are you saying 45mA for each, single tube or for both added together? If 45mA for a single tube @ 530dcv, that's way too hot.
Brad :w2:
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I got a 1979 Peavey Deuce I had to rebuild. I do not recall the voltage near that high, but it is 120 watts and extremely loud (the mace is 6 6l6 tubes and 160 watts!).
The fix I had to do was to rebuild the rather primitive power section - I had to undo 35 years of poor repair jobs and mine still has the original transistors!
This amp is self-boasting (at least mine was) with no provision to 'dial it in'. A check of what the dissipation mine worked at for the tubed I had was around 60% of the 25 watt 6l6 rating. That was good enough for me.
These amps run hot and owners report spectacular deaths of these amps because of the voltage and heat they produce. I can't say I want mine to do that...
Mark of Dire straits used one for a year in the bands history, and these amps nail the Lenyrd Skynyrd sound and tone to the T: right down to the built in phaser effect.
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500 volts is the nominal: see if another set of tubes is better liked by the amp.
I have svetlannas in mine, and have a set of chino Rubey tubes that do just fine in this amp.
I'd check the power section: the only pain in the ass with these amps is the solid state preamp. The power supply and power tube section are Neolithic simple.
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This amp is self-boasting (at least mine was)
Now that's a term I haven't heard before. Is it an electronic term or a musical term? Or just braggin' rights? :wink:
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This amp is self-boasting (at least mine was)
Now that's a term I haven't heard before. Is it an electronic term or a musical term? Or just braggin' rights? :wink:
Lol no it's my iPad thinking for me again..I meant self biasing. It's like when my voice software on my smart phone sent "I am playing my eye bananas tonight" when I said "I am playing my Ibanez tonight"....
Gotta love technology...
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Smart phone technology is great. The funny part is I understood what you were saying. Just hat to tease though. :icon_biggrin:
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:l2:
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Played on my deuce tonight! I will be playing guitar on it on a side project for a couple months. Nice change of pace. I used the built in phaser - my favorite phaser tone. More of a phase 45 effect.
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I would have to say your problem is most likely those JJ's , I don't use them unless a customer insisted on them , I recommend Ruby's or if your brave you can try those mesa labeled tubes that are made in China they are made for higher plate voltages , also are measuring the plate voltage with the tube in the socket or out , if it's out that is the unloaded voltage and 540 is nominal.