Does anybody recognize this stereo?

[carlg]

Pair of el34s per side, no branding so maybe a kit? Belongs to a friend who'd like to get it going but it's missing a piece on the back panel that plugs into that tube socket. The wall supply passes through there and it's unclear to me exactly how the missing piece connected the various pins together. Anybody happen to have seen one before?

Here's a few pics:

http://imgur.com/BCOmzjU.jpg
http://imgur.com/FsjbmUp.jpg
http://imgur.com/W9UMrGM.jpg
http://imgur.com/49tVE9C.jpg

[The Dude]

I'm not saying it is, but it has the look of an old Bogen piece.

[TomCarlos]

This thing looks like it might have come out of an old 1950's or 1960's home stereophonic consoles, those big box things that had a receiver and turntable built into a single cabinet with a big speaker and maybe a tweeter or two? I think my cousin still has one, might be an RCA or Magnavox. If I recall, the main box has the electronics and one speaker. There might be an identical box that is speaker only? It's been a while.... my memory is a tad fuzzy.

[carlg]

Bogen huh, thanks for the suggestion. I'll try some searches and maybe I'll get a hit.

TomCarlos, yeah something like that crossed my mind too. I've only seen a tube socket used this way for a couple reasons before - As a switch, like the impedance selector on a hiwatt, or the other would be a connector to run power out to another piece of equipment that was originally used with this (maybe a preamp that was once paired with this?).

Everything is there inside for this to be a standalone piece though, so I should be able to make up a plug that will get it going. The socket has the two line supply wires on one side and two very likely looking leads on the other side that I assume are the wires they need to connect to (there's some kind of balancing pot connected to these with the wiper to ground), but there are a couple other pins on the mystery socket that aren't so easily identified. Two red wires are on separate pins, they run over to the power supply areas of each channel but I haven't worked out exactly how they're connected there yet. One last pin is connected to the ground bus.

[DrGonz78]

The wiring is very well done and very neat! I have never seen a fuse holder like that 2 amp one before and another thing that caught my eye is the 6CA7/EL34 tubes say made in Japan. Interesting find!

[carlg]

There are a number of components inside from japan as well. It is quite nicely made. It's almost perfectly mirrored left to right, everything in duplicate, with the ground buss running right down the middle. The two sides do share one huge power transformer, but then each side has it's own rectifiers and filter caps. There are some interesting wire wound resistors that appear to be adjustable by sliding a clamp to different positions along their length.

[52 Bill]

There are a number of components inside from japan as well. It is quite nicely made. It's almost perfectly mirrored left to right, everything in duplicate, with the ground buss running right down the middle. The two sides do share one huge power transformer, but then each side has it's own rectifiers and filter caps. There are some interesting wire wound resistors that appear to be adjustable by sliding a clamp to different positions along their length.

Unlikely a kit, but it does look like a homebuilt project. A lot of the parts look like they were made in Japan, the caps and the diodes especially. Adjustable resistors were fairly common in olden times. Sorta like trimpots of their day.

Where does the ac enter the chassis, through the tube socket that you are asking about?

Is the socket labeled 200 volts connected to the dc power supply? If it does, then it is probably meant to power a preamp for a home stereo.

[carlg]

I'm sorry the picture is so blurry. I need to go back over and take another. I think AC is meant to enter where it says 200 volts, although there's no cable on that connector at the moment. It's for a two wire cable. One side connects to the fuse and then to the mystery socket. The other side connects to what I'm guessing is the transformer primary then the other primary lead also runs over to mystery socket, but oddly they do not appear to connect there to complete the circuit. It seems like whatever plugged into mystery socket held the switch for turning the system on.

Looking at the picture again today I realize that the pair of striped leads going from mystery socket to the balance pot in the center of the amp appear to go on to feed the filaments of the preamp tubes. So I'm getting more sure that mystery socket is an umbilical for feeding a tube preamp because that makes a full set of the important points: It has the AC line pair, a filament supply pair, one connection to the ground bus, and the two mystery red wires that run over to the two power supplies... could be B+ for left and right channels in the preamp maybe?

Did any country use a 200v standard for wall outlets? Thanks for all your thoughts and help guys. I know I'm not providing much to go on with the blurry pictures.

[52 Bill]

Did any country use a 200v standard for wall outlets?

Not that I know of, but who knows. Japan uses 100 volt supplies, but I don't know if they have 200 volt service as well.

What is the history of this amp? Where did it come from and where does it reside now?

[carlg]

What is the history of this amp? Where did it come from and where does it reside now?

Unknown unfortunately. It currently resides on the west coast of Canada, in Vancouver. The friend I'm helping is a record seller who's always at the flea markets. This is one of his mysterious finds. It's possible the label is incorrect and it really needs 220 or 240? Once turning the thing on is sorted I'm thinking of pulling the tubes and powering it from a weak AC source. That should let me poke around with a meter to figure out whats what a little better and should give a clue about what voltage it really needs to produce a good heater voltage.