UTC A-48 Hybrid Transformer

[CJ]

OK, here is the A-48.
Dissection has begun.
Hide the kiddies.

This is really two transformers in one.
They are completely independent.
That is so the hybrid phone circuit can be used.

Here is a hybrid circuit.
This 600 ohm 1:1 transformer is used to convert a 4 wire phone into a two wire.

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/hybrid_classical.gif

This is a cool little audio trans, two for the price of one.

 

[CJ]

OK, dissection is complete.

I took off some of the metal on the screw hole retainer thingies
so I could pop the plate without breakage:

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_2.jpg

This is the first A series UTC I have taken apart that had another can inside.
Wow. Look at all the pretty wires.
I wonder where they go.

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_c.jpg

A little black road tar holds the can in.
A little brown wax inside the shield can.

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_d.jpg

Here comes the whold enchillada:

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_e.jpg

Weird. One transformer on top of another.
So that's how they breed!

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_g.jpg

So mu can, fish paper, two xfmr's and the outer can.
Parts is parts.

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_h.jpg

Bobbin wound, 24-25 EE square stack of 80 Ni:

Tri-filar wound, 0.003 - 41 ga. wire, as many turns as you can get, probably about 5 or 600.

http://vacuumbrain.com/The_Lab/TA/UTC/A-48/a48_r.jpg

Notice the data jpg at the first post.
The starts are out of phase with eqach other.
This is the nature of the hybrid circuit.
So if you buy an A-48, and try to use it like a 600:600, you will be dis-appointed unless you know how to wire it.

There are two seperate transformers in that can, and they both are shown on the silkscreen wired out of phase.

Note that with two transformers in the same can, core space is cut in half, so this guy only has a 10 dbm rating.
Saturates pretty quickly, but nice B-H.

There ya go.
Every xfmr I open up is different, this one did not dis-appoint.

Thanks to Pmroz for the donation!
:thumb:

 

[pucho812]

awesome Cj. :thumb:

Another transformer gave it's life in the name of DIY :green:

 

[adrianh]

I got one.
Sad to see yours go to the hack saw.
I am using mine as a phone hybrid in the studio.
So when the wife of a musician calls.
I can patch them to the phone line without
the person in the tracking room doing a thing.
But remember while I am doing this no music is being
recorded and I am charging them $0.91 cents a minuite
so talk as long as you want!!!!!