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HP ET-1964 Variable AC Supply

Posted: Sat May 23, 2026 8:15 am
by Cubdriver
I saw a few of these over the years on the Bay of Evil, but never bought one. Decided the next one I saw I would go for; it arrived last week. It's nothing more than a metered variac in a Clement cabinet, but is a nice unit just the same. The Variac (a Superior Electric device) is rated for up to 9 A out, but the supply itself is fused at 6.25 A, giving a good healthy safety margin. The ammeter is shunted by default to 7.5 A full scale (still need to rig up a load to check it against a digital ammeter), and the button at the bottom of the front panel opens the shunt making the meter's native 1 A full scale rating what is read.

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More pics at https://pmanning.smugmug.com/Electronic ... -AC-Supply

-Pat

Re: HP ET-1964 Variable AC Supply

Posted: Sat May 23, 2026 9:50 am
by Zenith
It's a neater unit than my Lyons Regavolt, which works very well, but is just the variac in the usual round case with a huge dial/control on the top. I don't use it much, but sometimes there's no substitute. I must put it on a wooden base and add an enclosure for at least a voltmeter. The dial should give the output voltage, but it's nice to have confirmation.

Re: HP ET-1964 Variable AC Supply

Posted: Sat May 23, 2026 10:23 am
by synx508
That HP is very tidy and elegant. One of the rare opportunities to feel annoyed with British mains sockets, as you'd be lucky to fit just one on that front panel and even then you'd have to move the knob off-centre and use all sorts of bevel gears to get the driveshaft back to the middle of the variable autotransformer core.

Re: HP ET-1964 Variable AC Supply

Posted: Sat May 23, 2026 10:31 pm
by EC8010
Zenith wrote: Sat May 23, 2026 9:50 am It's a neater unit than my Lyons Regavolt...
Agreed. Mine's a 10A Berco Regavolt. It's jolly heavy.

Re: HP ET-1964 Variable AC Supply

Posted: Sun May 24, 2026 2:56 pm
by MED6753
That is a nice AC supply. Years ago I cobbled together this isolating supply from 2 salvaged transformers in series with a switchable output of approx 109V, 116V, and 123V. Limited to about 2 amps maximum.

Do not adjust your set, the pix is indeed a little out of focus. :lol:

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