Calling all tube heads, calling all tube heads

VR3 · June 22

I found these inside of an old sonograph on the side of the road.

What have I found??

maxward · June 22

Perhaps an Antiques Roadshow appraiser will declare your find to be a National Treasure!

pitdogg2 · June 22

Old crusty tubes. You didn't find gold, if good you may have $70 worth of tubes. MAY, remember that.

VR3 · June 22

Not really concerned about the money aspect, just curious what they are.

Figured I might be able to use some in my existing gear

I see some of the markings but some are hard to make out

VR3 · June 22

I'm thinking the mullard and get are el84s
The two smaller ones 12ax7?
And the larger one is a rectifier tube?

Toolfan66 · June 22

Well, One is a Mullard, One is a GE, One is a 12AX7, One is a Tung-Sol, and One is a RCA.. 🤣🤣🤣🤣

pitdogg2 · June 22

Two el84/6bq5 one Mullard, one GE
Two 12ax7 Tung-Sol
Looks like an RCA rectifier 5Y3 maybe

F1nut · June 22

Calling Brock

invalid · June 22

VR3 wrote: »

I'm thinking the mullard and get are el84s
The two smaller ones 12ax7?
And the larger one is a rectifier tube?

Probably a 5y3gt rectifier tube.

heiney9 · June 23

F1nut wrote: »

Calling Brock

LOL.

Hard to tell in the pic. I see an EL84 which today is used as a power tube, back then who knows
The GE is a 6BQ5 same as the EL84
12AX7 no writing, hard to tell. Maybe as Ivan said a Tungsol
The other Tungsol looks smaller compared to the signal tube next to it. Need more info, but a signal tube
The RCA is most likely a 6V6 because it's gray glass. Could be a rectifier as Ivan noted, but I think a 6V6 which today is a power tube used in many, many guitar amps from the 50's forward.

That thing is not in stereo, I won't guess how the tubes were used since today the same tubes might be used differently

But it appears you have (3) power tubes and (2) signal tubes.

Any idea the year of the phonograph? Is it real of a reproduction?

Is that all of the tubes? I don't see a rectifier tube. The EL84/6BQ5 can't be used as a rectifier and if the RCA is a 6V6 tube (pretty sure it is), it can't either.

H9

H9

heiney9 · June 23

Need to see the internal structure or the markings on the RCA to know if it's a 6V6 or rectifier like 5Y3. I can see markings obscured by dust. What does it say?

RCA did make 5Y3 rectifiers with gray glass (smoked glass). Since I don't see any other obvious choice it could be a 5Y3 rectifier. Not a 6V6

heiney9 · June 23

I can just make out a "5" in the stop sign on the RCA. It is indeed a 5Y3 rectifier.

H9

audioluvr · June 23

That phonograph was not powered hence the crank on the side. They were probably bad tubes that someone threw in there for S&G's

mhardy6647 · June 23

Actually, one could use pretty much any 'normal' vacuum tube (triode, tetrode, pentode, etc.) as a rectifier; just disconnect the grid or grids.

Electrons flow from cathode to plate; that whole negative charge thing.
Most repurposed multi-element tubes wouldn't be very useful for HV rectification in a DC power supply, but one could use 'em, e.g., as a detector for AM (or FM, for that matter).

mhardy6647 · June 23

audioluvr wrote: »

That phonograph was not powered hence the crank on the side. They were probably bad tubes that someone threw in there for S&G's

I think the crank's a ruse. Note also the speaker driver in the horn.

ahem. Also note the "modern"

multi-speed, automatic record changer.

tonyp063 · June 23

It's a Guild Grafanola. Built in the late '50's- early '60's & designed to look like an old Victorola player.

PP mono with a pair of 6BQ5s. One 12AX7 as the AF amp & phase splitter for the output pair.
5Y3 rectifier.

The radio section used a 6BE6 for the first stage converter & a 6BA6 as the IF amp. The other 12AX7 was the pre-amp & AF amp with the tone controls between it's sections.

I've got a schematic if you need it.

invalid · June 23

@tonyp063 you are quite right, the rectifier tube is a 5y3, there is no way that can be mistaken for a 6v6 as it has 4 pins, two larger pins and two smaller pins.