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PB2 18th April 2009 02:40 AM

Was There a Heathkit W-1M or WM?
I know the Heathkit Williamson W-3M very well. It was the first amplifier that I worked on as a young kid. It was old at the time - caps were probably getting old. This Heathkit version used 5881's, UL, and an Acrosound output transformer.

I found the W-2 Schematic on the net which also uses 5881s, is UL, but has a Peerless output transformer.

I'm working on what I think is a Heathkit, but with 807s, triode connected, and a Peerless OT without UL taps. Here's a picture:

Was there a version like this from Heathkit, an earlier Williamson? Confirmation or any more info would be appreciated.

Pete B.

tomtt 18th April 2009 03:22 AM


PB2 19th April 2009 03:09 AM

Thanks, the Acrosound data is new to me, but saw the rest. I've not seen anything on a Heathkit with 807s.
I should probably write to one of the Heathkit historical sites.

Pete B.

DHT112A 19th April 2009 03:19 AM

Just a shot but maybe

PB2 19th April 2009 04:05 AM

Yes, I have that also. That seems to be the paper where 6L6 type tubes such as the 807 were tested in place of the original KT-66. The 6l6 types were not rated for the higher plate and screen voltage used in the Williamson. All the Heathkit Williamsons that I've mentioned use a 420-440V plate supply.

That paper does seem to be the basis for the one that I have triode connected rather than Ultra-Linear, and using 807s. I think this is a very early Heathkit implementation. That design seems to be one chassis, and uses more choke filtering. Other than that it is very close to this unit.

Pete B.

PB2 19th April 2009 05:18 AM

Here's a discussion:

And more AWV Radiotronics scans:

PB2 20th April 2009 07:24 PM

Heathkit WA-1 is listed here with a picture of the power supply alone:

Tom Bavis 20th April 2009 08:35 PM

Gary Kaufman said that there were two versions of the W1 - triode (earliest) and ultralinear - and said he had both schematics. You might give him an email: gkaufman(at)the-planet(dot)org.

PB2 21st April 2009 04:28 AM

Thanks, yes I saw that in his post on the linked forum above. I will email him and see if I can get more information about this particular unit.

The-Planet 21st April 2009 04:22 PM

Yup, that's the output section of the W1.

Hopefully you have the power supply section as well. Same shape chassis with a potted power transformer, choke and 5V4G.

Send me a private email and I can set you up with manual/schematic etc.

- Gary

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