Marvel 35 amp?????

[John Billings]

Just got it yesterday. Anybody ever heard of this company? Actually looks to me like a Gibson product. Same covering, handle, etc., as my BR 1 amp.
One each of 6SL7GT, 6V6GT, 6Y6GT, and what appears to be a 5 1/2" speaker. All tubes are GE. Maybe it's a 6". Haven't taken it apart yet. 3 1/4" jacks, one of which is un-labeled.

[Blake Hawkins]

Don't know about the amp. However, I saw a Marvel
lap steel, many years ago. It had a lovely blue
sparkle finish.
Didn't have the money to buy it.
Never saw another.
That amp is in mint condition.
The tube lineup suggests 1940's.
Blake

[John Billings]

Blake, I was thinkin' very late Forties, or early Fifties, as the tubes are all glass bottles. My late Forties BR-1 also has glass tubes, by my '52 Fender Pro Amp does not.

[Blake Hawkins]

John,
There is a possible mistake in the tube line up.
The 6V6 GT and the 6Y6 G or GA are both beam power tubes.
They are similar and both have the same pin out.
So it is possible that the amp came originally
with either 2 each 6V6 or 2 each 6Y6 and somebody replaced one of them.
Since you do not show a rectifier tube (which would probably be a 5Y3GT) it may have a selenium rectifier which would indicate early '50's.
Blake

[John Billings]

Blake, the 6SL7 is the phase inverter, right? Just got out my old, and falling apart, RCA Tube Manual. And you're right. They're both beam power tubes. But then, why is there no preamp tube?

[Bobby Burns]

The Marvel guitars I've seen were pretty much Kays. I know there was a lot of crossbreeding, and inbreeding going on in Chicago in those days, and I've also been told that Lyon And Healy made some of the Gibson amps. So, I would not think it unreasonable to assume that this Marvel could have been made by the same folks who were making them for Gibson.

[Blake Hawkins]

John, The 6SL7 is a hi mu twin triode. It can be
used as a phase inverter and also as a preamplifier.
In an amp of that size, I'd expect to have a
6SL7 and one 6V6 with the third tube being a
rectifier.
The triodes of the 6SL7 would be wired as the preamplifier and the 6V6 would be the output driving
a 6" or larger speaker.
The third socket would most likely have a 5Y3GT rectifier however, there were 6 volt rectifier tubes such as the 6X4.

Best I can tell (I'm also using an RCA Receiving Tube Manual, of which I have several editions.)
The 6Y6 was intended for radio receivers but was
used in very early (1947 to 1949) television sets
as part of an RF power supply.
The big question: Does the amp work as you presently have it?

Of course, if you haven't tried it yet, please don't
plug it in until you know more about the circuitry.
The wrong tube in the third socket could blow something.

As I mentioned before, it is possible that the amp
uses two 6V6 tubes with the 6SL7 connected as
preamplifier (triode #1) and phase inverter (triode #2)
That would mean that there is a selenium rectifier
located under the chassis.
Blake

[John Billings]

Blake,
I'm not turning it on until it goes to my tech. But the owner said it worked, but had a hum. The "twins" being used as both preamp stage and phase inverter makes good sense. I'll pop it apart tomorrow for a look-see. It has a nice hefty PT, but no OT that I can see. I'll be surprised if the OT is within the chassis, as that would seem problematic. It's not a field coil speaker.

[John Billings]

The tubes seem to be all the same era. Identical lettering etc..

[Michael Lee Allen]

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[John Billings]

Thanks Michael Lee! I figured you would probably know something about the brand.
JB

[Michael Lee Allen]

DELETED

[John Billings]

No rush at all, MLA
Thanks
JB