Output transformer primary / secondary (OT-424L)

[Bushbaby]

Hi All,
Happy New Year to you.

I must be a hoarder as I'm always picking up old small components that are cheap and I think might be useful (or maybe not!) especially if they have a 3 or 4 ohm windings as I wonder if they can be used with certain old small valve amps with 3 ohm speakers. 
I have just received an output(?) transformer but I can tell that much about its primary / secondary windings which are as follows:

side one:

• 3.2R (purple)
  
• CT (black)
  
• 0 (grey)
  
• NF (yellow)
  
• 0 (white)
  

Side 2

• 167R (Blue)
  
• 41R (Orange)
  
• 4R (Brown)
  
• 0 (Black)
  

It weights 1.4Kg 

Any help and guidance is very much appreciated.

Best Regards

[ppppenguin]

Are those markings or your resistance measurements? If they are your measurements then you've identified which way it will transform and roughly where windings are tapped but otherwise they don't tell you much. You need to check the ratios with an audio generator (frequency not critical, use 1kHz for preference) and AC voltmeter. Inject into the high resistance winding to avoid any nasty surprises. You can even do it with a volt or so of 50Hz.

If you're unlucky it might be a mains transformer. In this case it may work badly for audio output. The core will probably saturate with the DC and even if it doesn't saturate its frequency response may leave a lot to be desired.

[Bushbaby]

Hi Jeremy
Those are the indicated resistances on the transformer which made me think it was an audio transformer to start with.

Best regards

Rob

[ppppenguin]

Who is Jeremy?

[Bushbaby]

Sorry Jeffrey - my big mistake as I was trying to answer using my mobile.

Best Regards

[Murphyv310]

Sounds like an output transformer with a tapped hum bucking section.
Possibly out of or for a Pye Radio.

[Ed_Dinning]

Hi Rob, as was said, it may well be an output transformer were about 5% of the primary (down from HT) is taken off and used in a form of bridge circuit to reduce hum (Langford Smith has a good explanation)
This is the bit that often burns out and the set can still be used, albeit with a higher hum level or larger caps fitted.
It can still be used in a conventional amp and the tap ignored.

A picture and a sketch might help closer identification

Ed

[Bushbaby]

These are the pics I have of the transformer but dont have any other details.

Best Regards

       

[ppppenguin]

One thing we can be fairly certain of is that it's not British. Note 3,2 continental style, rather than 3.2.

If nobody recognises it, then it's time to measure winding resistances to establish the basic layout of the windings, then measure ratios.

[Murphyv310]

Hi.
Agree with Jeffery.
Not British and unlikely to be a valve compatible transformer. Perhaps some kind of matching transformer, perhaps for 100v line systems but again conjecture.