Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TheKT88KilledJFK on November 22, 2017, 06:49:13 pm
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I looked through this site's store and didn't see any. Hammond has some (265U6) but they're as much as an actual 100w power transformer. Is this what people are using in high heater current setups?
I'm looking to power 5 12ax7s and 10 el84s from the same source.
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Hammond also has some affordable ones...
https://www.tubesandmore.com/products/transformer-hammond-filament-63-vct-10-enclosed
Are you building a shop heater? :icon_biggrin:
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Hammond also has some affordable ones...
https://www.tubesandmore.com/products/transformer-hammond-filament-63-vct-10-enclosed
Are you building a shop heater? :icon_biggrin:
Just building a 5 channel podwatt for a mini surround sound setup. I did the PCB design today. Thanks for the pointer! It will be like 60watts straight into heat though :(
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an SMPS makes good sense if it is just for the heaters, and the price is certainly nicer!
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If you're willing to use a 12.6v center-tapped transformer you can get one rated for 5+ amps even cheaper than a 6.3v rated for 10 amps: https://www.mouser.com/ProductDetail/Triad-Magnetics/F8-12/
This slightly complicates wiring but isn't too bad.
I have done this, and you should use the center-tap. I put 12.6v across a pair of EL84 in series, they didn't share voltage equally-- the resistance in the windings was different enough they were out-of-spec (usually a 6.3v tube shouldn't be lower than 5.9v or higher than 6.7v).
Tubes like 12AX7s which are meant to have the 2 sides heated in series should be balanced, so if it would be easier given your wiring scheme, you could just feed those tubes 12.6v.
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When looking at transformers solely wound for filament supply, you can get an indication of the current handling capacity from the power rating. Transformer power rating can either be in Watts, or Volts.Amps ('VA'). A filament transformer with a single 6.3VAC winding where the transformer rating is given as 63VA, will handle 10 amps (63/6.3=10) and so on.
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Sadly, some of my stuff is in storage a few states away. I have at least one 6.3vac @ 10A transformer in a potted can, which came from a tube-regulated power supply chassis. I don't know whether I'd ever find a use for it. But it will be quite a while before I get back to that storage unit to pull anything out.