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 trendal
J♠
 
Registered: 04/17/01
Posts: 20,814
Loc: Ontario, Canada 
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 Weird 60's stereo gear! What is this thing? *PICS NOW* 
#2017561 - 10/17/03 09:50 AM (19 years, 5 months ago) |
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So I got this nifty little peice of stereo equipment from my grandparents' house. I guess it was part of my mom's old stereo system, which was all tube 
I'll post some pics later today, but for now a description:
It's a rectangular box about 1/2' long. On the front it says "FM Stereophonic", has two LED's marked "Power" and "Stereo", and has a selector dial for "Off-MON-STEREO-FILTER IN".
On the back there is two sets of RCA terminals, Input and Output. The terminals themselves are labeled simply "A" and "B" in each set. Early Left/Right terminology? There are two small adjustor pots marked "Dimension Control" and "Indicator Adjust". There's also a single black cord coming out of the back that ends with an RCA plug.
Inside there are 4 tubes, one transformer and filter capacitor, and a few large and small things that look like variable resistors. One tube is a 6BL8, two are 6AQ8, and one is 6AU6.
I'll post the pics later...but until then: any ideas?
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Once, men turned their thinking over to machines in the hope that this would set them free.
But that only permitted other men with machines to enslave them.
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 Bruiser
Fuel Injected Suicide Machine
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 Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2017595 - 10/17/03 10:08 AM (19 years, 5 months ago) |
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Sounds like an amp of some sort. I'd like to see some pics.
Or it could be a dimensional gateway opener. 
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-I put the chrome to your dome
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trendal
J♠
Registered: 04/17/01
Posts: 20,814
Loc: Ontario, Canada
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Re: Weird 60's stereo gear! What is this thing? [Re: Bruiser]
#2017604 - 10/17/03 10:12 AM (19 years, 5 months ago) |
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Lol, this morning I traveled to Babylonia and back
No, I don't think it's an amplifier...though I could be wrong. My gut feeling is that it's something to do with FM Stereo demodulation...though I could be wrong
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Once, men turned their thinking over to machines in the hope that this would set them free.
But that only permitted other men with machines to enslave them.
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Bruiser
Fuel Injected Suicide Machine
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2017637 - 10/17/03 10:28 AM (19 years, 5 months ago) |
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Haha. Whatever it is, it sounds pretty cool. You don't see stuff like that everyday. Definately put up some pics when you get a chance.
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-I put the chrome to your dome
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Seuss
Error: divide byzero
Registered: 04/27/01
Posts: 23,480
Loc: Caribbean
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Re: Weird 60's stereo gear! What is this thing? [Re: Bruiser]
#2017680 - 10/17/03 10:51 AM (19 years, 5 months ago) |
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It is not an amplifier... at least not an output amplifier... possibly a preamp. There is not enough "stuff" inside to be an output (power) amplifier. Tube impedance is very large and you have to use a transformer to match the tube impedance to the speaker impedance. You need a transformer for each channel (left/right) and one for power. Since this device only has one transformer, it is most likely not a power amplifier. I don't know of any tube amps that used a single transformer for both power and impedance matching...
I believe the tubes listed are all pentodes (5 elements, 3 screens + cathode + anode). In most amplifiers, the screens are tied together into a triode configuration when pendotes are used. Again, you would have more tubes for amplification... you need two matched tubes for push-pull amplification for a single channel (left/right).
Are the "few large and small things that look like variable resistors" full of open air metal fins that line up like comb teeth? If so, these are variable capacitors and are usually used to tune an RF circuit.
My best guess so far is some kind of FM modulator or demodulator. The long black cable with the RCA plug could well be an antenna, which would indicate a demodulator. (A modulator would feed into a linear RF amplifier, which would use larger transmission tubes.)
As for the A/B, usually this is used to indicate different output sets... set A might be front speakers while set B might be back speakers. Donno if the same would apply to your device or not.
Finally, there are usually a lot of discrete components inside the base of any tube device. Mostly resistors and decoupling capacitors (used between amplification stages) and lots of wires.
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Just another spore in the wind.
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trendal
J♠
Registered: 04/17/01
Posts: 20,814
Loc: Ontario, Canada
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2017933 - 10/17/03 12:55 PM (19 years, 5 months ago) |
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Here's the pics:
the front:
the back:
inside top:
inside bottom:
Sorry for the blurriness of a couple
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Once, men turned their thinking over to machines in the hope that this would set them free.
But that only permitted other men with machines to enslave them.
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Bruiser
Fuel Injected Suicide Machine
Registered: 04/17/02
Posts: 15,255
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2018013 - 10/17/03 01:25 PM (19 years, 5 months ago) |
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Beats the Hell out of me That thing is older than 3/4 of the members here! 
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-I put the chrome to your dome
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Seuss
Error: divide byzero
Registered: 04/27/01
Posts: 23,480
Loc: Caribbean
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2018083 - 10/17/03 01:53 PM (19 years, 5 months ago) |
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Just another spore in the wind.
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chillywilly
Eat well - Diethome
Registered: 03/31/03
Posts: 104
Loc: 49 th State
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Re: Weird 60's stereo gear! What is this thing? [Re: Seuss]
#2018352 - 10/17/03 03:49 PM (19 years, 5 months ago) |
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I looks like a pre amp used to give a turntable or Microphone enough juice to let the regular amp do its job.
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Ripple
Ripple
Registered: 05/16/02
Posts: 21,014
Loc: the timbers of Fennario
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Re: Weird 60's stereo gear! What is this thing? [Re: chillywilly]
#2018593 - 10/17/03 05:52 PM (19 years, 5 months ago) |
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I agree.....I remember stuff with tubes in them and it predates even me.
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The bus came by and I got on that's when it all began!
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BluMonkee
keeper of thelittle people
Registered: 06/23/03
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Re: Weird 60's stereo gear! What is this thing? [Re: Ripple]
#2019159 - 10/17/03 09:20 PM (19 years, 5 months ago) |
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Would be cool to see some better pictures of the back, can ya'???
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"If I don't see ya' in the future, I'll see ya' in the pasture"
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LeaveMeAlone
Stranger
Registered: 04/19/02
Posts: 1,407
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Re: Weird 60's stereo gear! What is this thing? [Re: chillywilly]
#2019262 - 10/17/03 10:04 PM (19 years, 5 months ago) |
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Seuss gave a nice explenation and you're also right. It's a pre-amp.
trendal> Does it still work??
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Love.
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djfrog
omgws!!!1!
Registered: 10/22/00
Posts: 3,710
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2019339 - 10/17/03 10:45 PM (19 years, 5 months ago) |
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thats what they call a phat box
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trendal
J♠
Registered: 04/17/01
Posts: 20,814
Loc: Ontario, Canada
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Re: Weird 60's stereo gear! What is this thing? [Re: LeaveMeAlone]
#2019345 - 10/17/03 10:47 PM (19 years, 5 months ago) |
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Well I'm not sure how to hook it up...
All the tubes heat up and everything...but only silence comes from the speakers.
Any ideas?
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Once, men turned their thinking over to machines in the hope that this would set them free.
But that only permitted other men with machines to enslave them.
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Ripple
Ripple
Registered: 05/16/02
Posts: 21,014
Loc: the timbers of Fennario
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2020284 - 10/18/03 10:35 AM (19 years, 5 months ago) |
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Try shaking it!
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The bus came by and I got on that's when it all began!
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Thor
Anti-Theist OVERLORD
Registered: 08/12/98
Posts: 10,014
Loc: Iceland
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Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
#2021090 - 10/18/03 05:44 PM (19 years, 5 months ago) |
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Try to find some website with a message board that is about old stereo equipment, etc..
I'm sure there has to be some group out there that collectes and restores old stuff like that
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trendal
J♠
Registered: 04/17/01
Posts: 20,814
Loc: Ontario, Canada
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Re: Weird 60's stereo gear! What is this thing? *PICS NOW* [Re: trendal]
#2023559 - 10/19/03 07:21 PM (19 years, 5 months ago) |
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Looks like I was right
It's a FM Stereo demultiplexer. It's a type of add-on that you could get for a couple years in the early 60's when FM Stereo first came out in the US. It allowed equipment with stereo amplification to demultiplex stereo FM, as I guess there were a lot of systems still being built with stereo amps but no FM demultiplexer (hey, it's an add-on "feature"!).
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Once, men turned their thinking over to machines in the hope that this would set them free.
But that only permitted other men with machines to enslave them.
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OutkastSlug
Musician/Performer
Registered: 01/13/03
Posts: 228
Loc: B.C., Canada
Last seen: 18 years, 6 months
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Re: Weird 60's stereo gear! What is this thing? *PICS NOW* [Re: trendal]
#2026359 - 10/20/03 05:04 PM (19 years, 5 months ago) |
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I gotcha beat. I have an omnisonic imager. Weird old piece of stereo equipment. If anyonbe can tell me what the fuck an omnisonic imager is/does, that would be great. I use it all the time. I notice a weird kind of clarity and depth to the music that I don't get without it.
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