Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tdvt on February 06, 2024, 10:16:45 pm
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A friend dropped off an unfinished Hoffman 2-6V6 30W project that he must have bought from Doug, probably late 90s...?
It came with a paper copy of the layout attached below (digital copy found here in the archives), but that was it. I am wondering if anyone has an actual schematic of the amp?
Thanks in advance.
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Err.. 30W from a pair of 6V6?
Guess I didn't know they could do that.
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Pics please.
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Err.. 30W from a pair of 6V6?
Guess I didn't know they could do that.
Me neither. Surely meant to be a quad of 6V6?
Or it may just be the name of the amp- ‘30W’ (which came between 30V and 30X).
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Err.. 30W from a pair of 6V6?
Guess I didn't know they could do that.
Me neither. Surely meant to be a quad of 6V6?
Or it may just be the name of the amp- ‘30W’ (which came between 30V and 30X).
The layout drawing (above) shows a single pair of 6V6. And on top of it, they're self-biased.
I feel safe thinking that this amp isn't good for more than about 15W.
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30 watt is just a name
I have a bunch of my old stuff on the library page herehttps://el34world.com/schematics.htm#Hoffman%20Amplifiers%20stuff
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30 watt is just a name
I have a bunch of my old stuff on the library page herehttps://el34world.com/schematics.htm#Hoffman%20Amplifiers%20stuff
I had looked at that archived stuff on the site, but I was hoping for an actual schematic to see what I am looking at. That layout was the only paperwork that was in the box. The tube compliment looks close to the Hoffman Plexi 6V6 but missing a volume.
The guy who it belonged to didn't remember too much about the circuit. Chassis looks to be recycled once already, presently sporting Princeton-ish sized transformers.
Probably not so far in to completely regroup, but I was interested in the intended design.
Anyway, pics as requested.
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Tangential distraction.
Found this faceplate under some stuff in the box this project came in.
Appears to have gone with the recycled chassis.
Never heard of them & Google comes up with nothing, unless the name isn't "Hilger", but that's what I am seeing.
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Looking at that image of that board.
That's not one of my boards.
Looks home made by someone.
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Looking at that image of that board.
That's not one of my boards.
Looks home made by someone.
Thanks for looking.
Maybe he just bought the individual parts from you.
The board appears to be following the layout of the 30W & there were some Hoffman Amps price-sheets/photo-copies with the layout drawing. He mentioned ordering stuff from you way back.
Was there ever a schematic for that 30W circuit? I could draw one but it would be nice not to if one already exists.
There were also some uninstalled transformers with it, made by "XFRMRS", but the other numbers on them don't Google. Were they one of your vendors?
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If you look at the layout, it looks like most vintage Marshall circuits.
It's a pretty common amp circuit
Use the Plexi 6v6 or Plexi 50 schematics in the library here
https://el34world.com/schematics.htm (https://el34world.com/schematics.htm)
One of my boards would have looked like this
https://el34world.com/Hoffman/images/Img_3451.png (https://el34world.com/Hoffman/images/Img_3451.png)
(https://el34world.com/Hoffman/images/Img_3451.png)
More pics here
https://el34world.com/Hoffman/Original30.htm (https://el34world.com/Hoffman/Original30.htm)
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This schematic should match that layout...
EDIT... Made minor changes to schematic.
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This schematic should match that layout...
Thank you, Steve!
Greatly appreciated!