Was There a Heathkit W-1M or WM?

[PB2]

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:
http://baselaudiolabs.googlepages.com/Williamson3.JPG

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

Pete B.

 

[tomtt]

http://www.heathkit-museum.com/hvmhifi.shtml

http://en.wikipedia.org/wiki/Heathkit


http://www.hifilit.com/hifilit/Acrosound/acrosound.htm


10/?

 

[PB2]

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]

Just a shot but maybe

http://www.retrovox.com.au/A515.pdf

 

[PB2]

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.

Thanks,
Pete B.

 

[PB2]

Here's a discussion:
http://www.antiqueradios.com/forums/viewtopic.php?p=859725&sid=a09c73eafbf1507f48a62aa9e043db2c

And more AWV Radiotronics scans:
http://greygum.net/radiotronics/

 

[PB2]

Heathkit WA-1 is listed here with a picture of the power supply alone:
http://www.nostalgickitscentral.com/heath/products/heathkit_audio.html

 

[Tom Bavis]

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]

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]

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

 

[gallon]

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:
http://baselaudiolabs.googlepages.com/Williamson3.JPG

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

Pete B.

The Heathkit WA-A1 was reviewed in Audio Engineering of May 1952. It is a PP 807 in triode mode. The Peerless is a custom job. This design is essentially the same as the famous 'Musicians Friend' published in the 1949 Audio Engineering, designed by Sarser, a professional musician. Send a PM and I can send scans for you. You are lucky to have that!

 

[PB2]

Thank you to both Garys for sending those articles.

Pete B.

 

[PB2]

This article discusses the substitution of 807s as outputs and testing of them with elevated screen voltages: http://greygum.net/files/radiotronics/PP807-A515.pdf

Interesting ...

Pete B.

 

[PB2]

Previous link is dead, here it is again:
http://www.mif.pg.gda.pl/homepages/jasiu/eka/wil/williamson-807.pdf

This might also be of interest with regard to the Williamson design:
"Improving the Williamson by Talbot M. Wright":
http://stiftsbogtrykkeriet.dk/~mcs/Williamson/index.html