Identification of old (vacuum tube) audio tech

Thread Starter

KingOfSpice

Joined Oct 16, 2021
2
Hi

Does anyone know what each of these are? They just looked very intriguing...:DThey had no documents with them nor any labels for identification and the person whom I got them from passed away before I could ask him what they were. The devices with no "back" images have only the casing and no ports at the back.

Thanks in advance!

PS I said they were audio tech but they probably are not and I could not edit the thread name...
 

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MaxHeadRoom

Joined Jul 18, 2013
25,211
Does anyone know what each of these are? They just looked very intriguing..
and the person whom I got them from passed away before I could ask him what they were.
Not sure of thier original function, but would appear that they have reached their end-of-life date also ! :oops:
 

crutschow

Joined Mar 14, 2008
29,791
Since those look mostly like home-made equipment it seems unlikely that you will be able to determine what they originally did.
 

KeithWalker

Joined Jul 10, 2017
2,354
They look like audio amplifiers and power supplies. You will probably be able to figure them out if you draw the circuit diagram for each one. I would not recommend that you apply mains power to any of them until you have thoroughly tested all the electrolytic capacitors and replaced any wire that has damaged insulation. You probably will not find any use for them but just getting them working would be a very interesting project.
Let us know if you need help identifying components or finding data on them.
 

Ian0

Joined Aug 7, 2020
5,131
1 looks like a variable power supply with a variac and a valve rectifier.
4 looks like an audio power amp with a pair of EL34s, which plugs into an external power supply. Probably with a small signal pentode inside that screening can as the input stage, then a double triode which gives another stage of amplification and a cathodyne phase splitter.
7 is probably another audio amplifier with a self-contained power supply.
The part numbers of the valves will give a better idea.
 

schmitt trigger

Joined Jul 12, 2010
497
I also agree that the identification of the tubes, would provide additional clues.

BTW, the circuit with the magic eye and large rheostat, baffles me.
 

sagor

Joined Mar 10, 2019
695
I also agree that the identification of the tubes, would provide additional clues.

BTW, the circuit with the magic eye and large rheostat, baffles me.
Agree about item #1. With two sets of jacks along the bottom, I would think it was some form of voltage/audio balance with the magic eye showing when things were "centered". Maybe?
 

AlbertHall

Joined Jun 4, 2014
12,023
I also agree that the identification of the tubes, would provide additional clues.

BTW, the circuit with the magic eye and large rheostat, baffles me.
I think it is a measurement bridge. Note the switch selecting a variety of resistors and, especially the black ones, look like precision values to me.
 

Reloadron

Joined Jan 15, 2015
6,585
The first two images appear to use a Magic Eye Tube as we called them. They were used in a variety of applications. I have an old Knight Kit LRC bridge which uses one and something else in the basement, I forget what. Images 3&4 look to be an audio amp. Remove the tube shields with a push down and twist and the tube part numbers should be visible. Remove the tube shields one at a time and note the numbers. Some of the remaining images look to be homebrew power supplies. Image 6 looks to be a transformer and choke with maybe rectifier tubes. Years ago it was popular to use an 8 pin octal base female for output and a connecting 8 pin male for connecting to. Again knowing the tube part numbers would go a long way. Those images bring back plenty of fond memories for me. :)

Ron
 
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