Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mwelch55 on May 06, 2019, 02:49:05 pm
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I got a good price on a power transformer with specifications 300-0-300 270ma 5V 3A & 6V 9A. I was wondering if I could design a power amp with this trasformer so that 4 tungsol 5881 installed will give me around 40-50 watts?
I love the sound of the tungsol 5881 reissue. The problem with that tube is that you can't put two of them into a normal 50 watt amp because the voltage is too high. The tungsol 5881 is happier at a lower plate voltage. With secondary voltage at 300-0-300, I should be able to get around 400vdc. I love the way my previous amp sounds with 2 tungsol 5881s with a 6.6K OT and around 380-400 volts on the plate. In that amp I get around 20-25 watts. That arrangement is my favorite power amp.
I was hoping to do the same thing only around twice the power and I am hoping to get a similar tone as with 2 5881s. Does this seem like it will work as I expect it to?
Mike
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Wasn't the first 5F6a 40 Watts on two 5881, around 400V and 4k load?
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Wasn't the first 5F6a 40 Watts on two 5881, around 400V and 4k load?
schema states 432V. i don't imagine that 32V is going to make or break 5881, even the current production stuff.
--pete
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Comments. I like the idea of 4X 5881's to take advantage of the hi current handling of this PT's HT supply. Should yield about 35W. Personally I would drop about 100V with a combination of a bucking tranny + a large (inductive) power resistor.
A 5U4 rectifier should work; and help drop some B+.
The hi current heater supply calls out for creative use of small bottle tubes.