Home | Community | Message Board
You are not signed in.
Sign In New Account
Forum Index Search Posts Trusted Vendors Highlights Galleries FAQ User List Chat Store Random Growery


This site includes paid links. Please support our sponsors.

Community > The Pub
Threaded Mode Threaded  Previous topic Previous  View all topics Index  Next topic Next 

Welcome to the Shroomery Message Board! You are experiencing a small sample of what the site has to offer. Please login or register to post messages and view our exclusive members-only content. You'll gain access to additional forums, file attachments, board customizations, encrypted private messages, and much more!

North Spore Shop: Cultivation Supplies

Jump to first unread post Pages: 1
Weird 60's stereo gear! What is this thing? *PICS NOW*
    #2017561 -

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  :smile:

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?

:smirk: 


--------------------
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.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2017595 -

Sounds like an amp of some sort. I'd like to see some pics.




Or it could be a dimensional gateway opener. :wink: 


--------------------
-I put the chrome to your dome

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: Bruiser]
    #2017604 -

Lol, this morning I traveled to Babylonia and back :wink:

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 :smirk:


--------------------
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.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2017637 -

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. :smile: 


--------------------
-I put the chrome to your dome

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: Bruiser]
    #2017680 -

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.


--------------------
Just another spore in the wind.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2017933 -

Here's the pics:

the front:


the back:


inside top:


inside bottom:


Sorry for the blurriness of a couple  :smirk: 


--------------------
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.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2018013 -

Beats the Hell out of me :wink: That thing is older than 3/4 of the members here! :tongue: 


--------------------
-I put the chrome to your dome

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2018083 -

I would post here:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&group=rec.audio.tubes and ask these folks. They will know.


--------------------
Just another spore in the wind.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: Seuss]
    #2018352 -

I looks like a pre amp used to give a turntable or Microphone enough juice to let the regular amp do its job.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: chillywilly]
    #2018593 -

I agree.....I remember stuff with tubes in them and it predates even me.


--------------------
The bus came by and I got on that's when it all began!


Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: Ripple]
    #2019159 -

Would be cool to see some better pictures of the back, can ya'???


--------------------
"If I don't see ya' in the future, I'll see ya' in the pasture"

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: chillywilly]
    #2019262 -

Seuss gave a nice explenation and you're also right. It's a pre-amp.

trendal> Does it still work??


--------------------
Love.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2019339 -

thats what they call a phat box

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: LeaveMeAlone]
    #2019345 -

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?


--------------------
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.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2020284 -

Try shaking it!


--------------------
The bus came by and I got on that's when it all began!


Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? [Re: trendal]
    #2021090 -

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 :smile:

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? *PICS NOW* [Re: trendal]
    #2023559 -

Looks like I was right  :smile:

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"!).


--------------------
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.

Extras: Filter Print Post Top
Re: Weird 60's stereo gear! What is this thing? *PICS NOW* [Re: trendal]
    #2026359 -

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.

Extras: Filter Print Post Top
Jump to top Pages: 1

North Spore Shop: Cultivation Supplies

Community > The Pub
Threaded Mode Threaded  Previous topic Previous  View all topics Index  Next topic Next 

Similar ThreadsPosterViewsRepliesLast post
* Check Out My Record Collection! (Pic & List of Albums...) RebelSteve33 2,703 9 05/20/03 07:16 PM
by RebelSteve33
* Ultimate 60's psychedelic compilation LearyfanS 2,650 11 01/22/03 11:48 AM
by sir tripsalot
* this is weird how does it work stefan 595 8 02/08/06 08:15 PM
by eligal
* Favorite pictures from the 60's
( 1 2 3 4 all )		 Ripple 5,871 68 04/21/03 09:34 AM
by Ripple
* an old pic Scratcher 1,619 9 02/24/03 01:40 AM
by In(di)go
* Bonnaroo Pics
( 1 2 3 4 5 6 7 all )		 baraka 11,085 121 06/17/04 02:52 PM
by Phishgrrl
* SHOW US PICS OF YOUR BEST SUNGLASSES POSE
( 1 2 3 4 all )		 ShroomFan 5,619 67 08/03/04 01:54 AM
by Zero7a1
* In 60 years, we are all doomed...
( 1 2 all )		 Purple Haze 3,906 29 08/29/03 03:26 AM
by PDU

Extra information
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Entire Staff
2,697 topic views. 6 members, 297 guests and 133 web crawlers are browsing this forum.
[ Show Images Only | Sort by Score | Print Topic ]
Search this thread:

Copyright 1997-2026 Mind Media. Some rights reserved.

Generated in 0.031 seconds spending 0.007 seconds on 16 queries.