What is this? Siemens Core transformer

BenHoper

Member
2018-09-26 10:31 pm
I've got a valve circuit which may be from a tape machine, possible for sync? It has an EM84 indicator, and an ECL82 triode/pentode. The triode may be used as an oscillator, not sure.
So I'm focusing on the PSU. Unmarked feed wires come in and go out from the main machine via a multi-way connector. There is a transformer with multiple taps which seems to supply the DC HT to the valves. I've found two pairs which are connected, but haven't dared apply volts across just yet until I understand it bit more.
Have you seen this coil type of transformer and any clues on the wiring?
It's a Siemens core to the transformer. I've found lots of detail on the core, but not this application:
ftp://bitsavers.informatik.uni-stut...s/1983_Siemens_Ferrite_Cores_and_Hardware.pdf
There is not obviously a 6.3V output so I think this has come from the main machine. And there is no rectifier, which has stumped me.
I'm trying to repurpose the unit as a valve pre-amp so was hoping to use the existing PSU.
Any clues/tips appreciated.
 

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Beyond the obvious that it is a pot core, Page 107 of your download, the marking AL400 is the specific inductance of a gapped half. When mated with an ungapped half then the inductance of a winding on the result will be 400nH per root turn. So 400nH for 1 turn 40uH for 10 turns, 10^2*400nH and so on. N22 is the material type.

Not much help but I doubt that it is a power transformer or a supply transformer as such. Certainly not low frequency. This is more like an inductor but not a supply filter inductor. Values would be too low. Interstage coupling transformer?
 

Elvee

Member
2006-09-08 2:04 pm
A red button is a good clue for erase/record, but there has to be some way of latching it: you are not going to spend an hour or two keeping the finger on the button when you want to erase or record a program.
It probably latches when you push another button simultaneously, typically the play button.
 

BenHoper

Member
2018-09-26 10:31 pm
A red button is a good clue for erase/record, but there has to be some way of latching it: you are not going to spend an hour or two keeping the finger on the button when you want to erase or record a program.
It probably latches when you push another button simultaneously, typically the play button.

This unit looks like a bolt on side unit to something. See the pictures.
 

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as_audio

Member
2008-05-13 6:18 pm
The pictures belong in the first post, sorry.
This is a Siemens recording stage for 16 mm projector type "2000".
The unit is not suitable for conversion "as a valve pre-amp" and contains no power supply.
Some of the small resistors can be nicely used in a shot noise generator.
 

as_audio

Member
2008-05-13 6:18 pm
See also Ebay 264607876254 .
This is an ancillary plug adaptor for the amplifier (does not fit the amp in your Ebay ad).
There have been many different versions of the projector amps.
Some people throw the projector away and use the amp only.

Leave it as it is, it may be interesting for some collector in the UK, but certainly not on
the continent due to shipment cost. Estimated value is 20 Euro, but probably useless
now because you decided to pull the hf transformer.