Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Satellite^Guy on December 15, 2012, 11:41:42 pm
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Hi, all.
I'm looking into building a 1W amp, called the Heavywatter, and I'm trying to do it without breaking the bank.
The schematic is here: http://www.sonicdeli.com/ThunderTweakWeb/info/HEAVYwatter_v4.pdf (http://www.sonicdeli.com/ThunderTweakWeb/info/HEAVYwatter_v4.pdf)
I'm looking into inexpensive generic transformers, instead of the ones in the schematic. The reverb driver here: http://www.tubedepot.com/tr-dr-01.html (http://www.tubedepot.com/tr-dr-01.html) looks like it should work fine instead of the Fender reverb tranny the HW uses as output. My concern is with the power tranny. The Hammond 269JX seems kind of pricey, whereas the one here: http://www.tubedepot.com/tr-pw-13.html (http://www.tubedepot.com/tr-pw-13.html) pushes 200Vrms, instead of 250V of the Hammond. Also, the Hammond is 250-0-250, with a center tap, while the tubedepot one doesn't have the center tap.
Long story short, would the tubedepot power tranny work fine in this amp, or would I be underpowering it?
Also, which of the power stage tube choices listed in the schematic would be the best choice?
Thanks in advance!
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The TR-PW-13 PT is rated _3_mA. I figure the HW eats about 17mA. That just will not work.
It's also WAY shy on heater power. It can heat one small tube, NOT three.
> The reverb driver
That part is pretty common at that price. Look at the top of this forum page (or http://www.hoffmanamps.com/ (http://www.hoffmanamps.com/) ) and our host has the same thing. His price is a buck more but his shipping is FAST and not rounded-up $5 like the big shops do.
Good small not-TOO-small PTs are tough. Hoffman's "6G15 Reverb...power transformer" would work, and is also a common part. TD's price is lower than Hoffman's, even with shipping.
That schematic's PT detailing is VERY confusing. Also a change from 250-0-250 to single 250 winding needs a very different rectifier. Wall-power side of the PT offeres risks of shock and fire. Do you know what you are doing?
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Reverb driver is same as Fender, you can use this one . The cheapest Power Transformer won't work .