Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plexi50 on January 11, 2012, 01:36:46 pm
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I have an old amp that i think may be a Magnatone or Dickerson. Not sure. Todays Mystery Question*
What is this and who made it? Tubes are (1)5U4, (1) 12AY7, (2) 12AX7, (2) 6V6 ,
(http://i356.photobucket.com/albums/oo5/plexijtm45/FCM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/SGCM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/EQM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/InputsM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/SerialM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/UPM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/5U4PSM.jpg)
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Wow, that power transformer is rather large for that amp. What makes you think that is not
a custom amp, or an amp that someone slightly hacked to go in that cabinet? I would take the top
out and trace out the schematic... then you could tell what it is pretty readily.
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The umbilical between chasses also looks home-made.
The potted OT on the upper chassis, and the lack of control markings also makes me think this is some ham's homebrew, using much better techniques than most mass-production companies would bother with.
Take some good photos of the interior of those chasses!
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I agree with HBP. Also, I am digging the vintage no name Alnico speaker, but how is it connected
to the baffle? It sure looks like just grill cloth there. Strange indeed.
Yes, high res pictures inside the upper chassis at least.
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I thought the same thing! Like it was glued to the grill cloth. I don't see obvious mounting screws, and there's just cloth there anyway. Strange...
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The cab is Valco.
Jim
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Well does it work as is, and if so, how does it sound? I've never seen anything like it. Platefire
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I squeels like a pig. I opened it up and what was inside is a shame. Board broke etc,etc. It is not mine so i feel better. :l2:
It is suppose to be one of the rarest Supro amps ever made. I forgot the name already. The board is cracked at both ends of it. The grill cloth isnt cloth. It is a gold wire mesh. It looks original. The speaker is not the right speaker. I was suppose to have (2) small speakers in it. Other than what i have been told by the owner,I know NOTHING!
Stackpole Pot's and Capacitors dated 4-54
(http://i356.photobucket.com/albums/oo5/plexijtm45/ChassisM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/LSVCM.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/MB1.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/Socket.jpg)
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Ever hear of this guy, goes by the nick name of, Mr. Valco? I think he's in Ind. and was interviewed a few times in Tone Quest Report Mag. Seemed like a nice enough guy and sounded like he had a lot of experience with Valco amps. You know Valco made many amps under different names, one being Supro.
Here's his web site, maybe try and e-mail him the pics and see what he says? Like I said he seemed like a nice guy in the interviews.
http://www.valcoamp.com/ (http://www.valcoamp.com/)
Brad :icon_biggrin:
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There's a slightly odd mix of parts in that amp.
I can't think of the last time I saw a potted output transformer in a mass-production guitar amp from the 50's. All parts look like 50's.
The things that seems odd is the long carbon comp over near the choke and the (probably) 1st preamp stage. I've seen that resistor in early-50's Fenders; however, the other carbon comps are a more typical shorter-style. When I saw the long resistors in a Fender, they were all the same style.
The green resistors look like wirewound parts, and much more expensive than what a typical guitar amp would have. Then again, maybe the mish-mash is due to post-war surplus, and were cheap at the time.
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I think this is what the amp used to be. A Supro Golden Holiday. Here are the pics i found online at the Valco site. It's questionable that the chassis is a Golden Holiday. Not sure just yet. Looks like it was heavily altered
(http://i356.photobucket.com/albums/oo5/plexijtm45/CIMG2903Large.jpg)
(http://i356.photobucket.com/albums/oo5/plexijtm45/CIMG2900Large.jpg)
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That cabinet looks Valco for sure but the guts are not. I've been inside a few Valcos, heck I use one daily. Never seen a turret board in one, always tag strips. They were known to do some funky stuff, but nothing along the lines of letting can caps lay loose like that. Potted OT in a Valco, I thin NOT. No labeling... not from a company who made amps for themselves, Montgomery Wards, and Gretsch to name a few.
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I recognize the OT. I am thinking HeathKit, though maybe made by someone else. They were semi-common once. I recall swapping one into a Stromberg-Carlson radio.
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Well Plexi50, that's a pretty good mystery there. I would agree that it's a Golden Holiday cab, thats about all. Would be great to know "The rest of the story" but I would be surprised if it's obtainable. Never seen can caps laid out like that on a board, har! Looks like you got your work cut out for your to cast the squeels out. Keep us posted. Platefire
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Thanks for all the input guys. If i had known the caps were just laying on the board like that i would have never fired it up at all. Could of been deadly. The owner got it this way. It sure would be nice to figure out where the original chassis dissapeared to. Thats probably long ago and far away
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The cab is Valco.
Jim
I concur. That's a Valco serial number plate too.