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Williamson preamp identification help wanted

garncarz

garncarz

Member
I could use some help identifying an old tube premp that I recently purchased. See attached photo. It is marked “Williamson Model G???, L.A., 16 CALIF.” Google comes up with nothing of use. Any information about this unit/company would be greatly appreciated. A link to a schematic gets you a friend for life.

Thanks. John
 

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Cool find, never seen or heard of that one.
Can you post some pictures with the cover off ?, it looks interesting.
 
A pic of the bottom with the cover off if you can, I am just curious about what components
they used and hopefully someone will know more about it and maybe a schematic can be found.

I do like what you have and it may be a nice sounding pre, too bad about the model number
being smudged off and unreadable.
 
I have a memory of a friend buying a Williamson amp kit from Burstein Applebee in the late 60's. Of course my memory has a way of turning into fiction these days.
 
BrokenHill said:
A pic of the bottom with the cover off if you can, I am just curious about what components
they used and hopefully someone will know more about it and maybe a schematic can be found.

I do like what you have and it may be a nice sounding pre, too bad about the model number
being smudged off and unreadable.
Click to expand...

Here it is with the bottom off.

John
 
That’s a very nice preamp, I don’t know much about the circuit and how it sounds but it might have some
potential.

I had a similar situation with a preamp that I could not find any info or schematic on it at all, I posted some
pictures here at AK and nobody had any info about it.

You can see it here > http://www.audiokarma.org/forums/showthread.php?t=387066

I did rebuild it and replaced all the resistors and capacitors both electrolytic and film, I was able to read the
value of the all components and did the rebuild without a schematic.
The preamp did sound nice but it just did not have the imaging and soundstage that I was getting from a
rebuilt Eico HF-85 preamp that I have, although this thing was dead quiet.

The Stedman had a lot of those PEC circuits and without a schematic I just left them in the unit and that
might have been the downfall of this preamp.

Just a few weeks ago I rebuilt it again removing everything except the power supply and used the Eico
HF-85 three tube line stage circuit without the tone controls and now it sounds fantastic and it’s dead quiet.
The power supply in the stedman had used filtered 12.6 volts DC on the tube heaters and all I had to do is
change a few resisters to get the rest of the DC volts at the tubes right where I needed them, it has a very
nice input selector switch that I am rebuilding now.
It turned out to be a winner.

I did not see any of those PEC circuits in that Williamson preamp you have and it looks like it would be
very easy to work on, replacing the components could be done by just reading the values and making notes
of what went where and carefully finding replacements, having discrete componets like it has is at your
advantage and that makes a rebuild so much easier even without a schematic, although I hope you can find
one.

I would try it first and see how it sounds; a variac is very handy to slowly bring it up to normal voltage to
check things out.

You might have something there that could turn out real to be a real good thing, if you decide to rebuild
it I’m sure a lot of AK members can help one way or another.
 
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