• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Heathkit A7 ?

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Hi

I bought my self a Heathkit A7 amplifier but the mains transformer was busted.....

I have searched the net trying to fint a schematic but I cant seem to find it.

Is there someone out there who got a A7 or maybe a schematic???

It would be nice to repair it and use it to something
 
How could a solid lump like a mains power transformer get busted and the rest of the amplifier, like the comparatively flimsy chassis not be a total write off?????

You are speaking to a technical audience. You have to use descriptive technical terms to communicate unambiguously.

Do you mean that someone let the smoke out of the power transformer?
 
It's all too easy to let the smoke out of the transformers on the A7 - there's no line fuse... and a BUNCH of leaky caps.

Yes, I have one - it showed up after I sold my first one, KNOWING that I would never be able to make a pair... anyway there's a schematic on my web page for the A7-E, and I have a schematic for the C version (no phono preamp) and maybe one other verson too. Sooo, what tubes are innit?

A7E
 
Hi

Yes the tecnical term would be "fried"......

I have the A7E version so thats the right schematic.

Is this a good amplifier or a crappy type?

Is it worth to repair it and try to find another or is it best to salvage the outputtransformer and save it for future use?
 
Well it worked...

I replaced the transformer with one from my scrap pile and the amp played beautiful music...

the only problem I got now is that the transformer only gives out 375v instead of the 390v in the schematic. But I dont think it matters to much.

I was thinking about replacing all the caps but what about the eletrolytic in the powersuply? Its a special 4 in one cap with 40,30,10 uf 450v and 20 uF 25v.

The replacementcaps will not look as big as this one anyway

Now I just need another one...
 
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