Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on February 25, 2017, 06:31:14 am
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Today I got this small OT (hoping it will be for SE, but getting it anyway because cheap and new)
it is a Stelvio an old italian brand, 3000ohm primary / 4ohm secondary 2-2.5W (estimated power)
if it was for SE I had an use for it, but it is PP ...........
any idea of which can be the right tube for this OT ?
Thanks
Franco
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Maybe I'm wrong and this is not a push-pull transformer
I came to doubt whether it's an SE transformer with a primary side to feed the G2 (but not UL), I have to do some testing
Franco
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Back in the '60s it was very common for small, cheap single ended OTs to have a tap (not UL) for screens.
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Ciao Steve
One of the things that suggested me for a PP was the way the laminations are assembled, but looking better to the OT the doubt come to me
and I can say something further only after some test
I've also the doubt that this thing can be planned for a transistor unit output (???)
Franco
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A 3000Ω primary is not likely for a transistor. If I had this many doubts I'd probably put it in the trash. :icon_biggrin:
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:icon_biggrin: :icon_biggrin:
Is a bit of time that I look for a small SE OT with 3 - 3.5K primary, it seems is the good match for a 6AF11 project like the Squirrel Monkey
(http://solorb.com/elect/musiccirc/squirrelmonkey1/SquirrelMonkeyR1.jpg)
I've 2 or 3 tubes and a pair of sockets ...........
Sure if it was a PP would not know which tubes can be adopted, but let's wait until we see what it is
Franco
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If it's reflective would a 8ohm speaker make it 6k ? :think1: A fiddle tube amp. I was reading smaller OT's have better high frequency response , I was going to tweak one of these little amps here for electric violin.