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Discussion Starter #1 (Edited)
I was going thru some of my stuff and came across this old Hammond power transformer that I picked up a long time ago from heathkit CB and was wondering if it might be useful for an amp build ???

I m not as savy in this area and would really appreciate any information from experienced builders ...

Here are some pics of the transformer:

 

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I found mention of a fellow building a Williamson (audio) amp with KT66s. I can't find an old catalog online that might show the specs, maybe one of the other fellows has one?

Do you know how to use a voltage meter and follow safe high voltage practices? You could measure it out to find out.
 

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Discussion Starter #4
Others will be able to assist re: using it for an amp build.
I'm going to make a guess and say that I think it might have potential.

Will be following with interest.
Thanks for the info !!!

Got this from an old Heathkit communication set up!
 

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Here are some of the basic specs:

278X

800V C.T. @ 230ma.
5V C.T. @ 3A
6.3V C.T. @ 6A

#278X is listed on this link....
Hammond Mfg. - "Classic" Power Transformer - (263-282 Series)

Others will be able to assist re: using it for an amp build.
I'm going to make a guess and say that I think it might have potential.

Will be following with interest.
Greco, I don't think this is the same transformer. The part numbers don't match exactly and the VA rating between the two is quite different, unless you know something I don't know?
 

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Greco, I don't think this is the same transformer. The part numbers don't match exactly and the VA rating between the two is quite different, unless you know something I don't know?
I was in a hurry and hungry for my (being served) supper when I was posting.
You are correct, the VA on the 279x is closer at 186 VA.
Oh well, the linked Hammond page might at least be helpful...even if I'm not...LOL
 

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Discussion Starter #8
Based on the tube radio , the power supply should be this:

AC input voltage of 120 VAC 50-60 Hz.

It provides the following outputs:

Filament = Isolated 6 and 12 VAC, 5.5 Amp power supply.

High Voltage = +820 VDC, 250ma output generated by a full-wave voltage doubler.

Low Voltage = Internal jumper selectable, +350VDC or +275VDC, 100ma output generated by a half-wave voltage double.

Fixed Bias Voltage = -130VDC, 20ma generated by a half-wave rectifier.

Adjustable Bias Voltage = Adjustable, via Bias Control, up to -130VDC.


BUT ...........

Since the original power supply was lost, this one is a replacement home built from the previous owner.
 

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Discussion Starter #9

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400 Volts on secondary is too much for average guitar amp. It is doable, but too much hassle.
To help those of us that are trying to learn, could you (briefly ...not wishing to be a pain here) describe how it is doable and what makes it too much of a hassle (other than it would be easier to buy the proper one in the first place..LOL).

Thanks very much in advance for your time and effort.
 

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Rectified 650 to 700DC? Even with ultralinear or low screen voltage, you're entering the netherworld where EL34 is concerned. Especially new production. Even new 6550's will have a hard time with that. Old 6550/Genalex KT88's or some other old stock type power tubes probably will. Personally, I wouldn't want to waste tubes on that.
 

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I was looking at a YBA-3 which might be a close comparison, tho from pics, the Traynor PT appears to have a lot more iron.
I don't know the specs wrt power rating tho. (6CA7 power tubes). YBA3 Custom Special with 400-0-400 puts B+ to 540.
Yikes ... that's a monster. Certainly be careful with tube subs and component ratings, no monkeying around there.
Traynor stacked 450 vdc capacitors (in series) to get higher 900 vdc rating. Agree with other's re cost and complexity factor.
 
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