Mystery ot

[Ang3lus]

Ive received this OT from a hifi guy, claimed its a 50w UL OT

Problem is i cant figure out the connections...

No wires going out at all, cant tell the pri from sec so i can measure with some 3vac trans i have...

Any ideas?

[xtian]

Haw. Made myself laugh. I don't even know what's going on in that photo. It's feeding itself! It's an ouroboros OT!

[Phil_S]

LOL, that's the worst mess. I'm not sure you can rely on anything you were told. It might or might not be an output transformer.

I think I'd do this. Now that you have a good picture of how it was wired, feel free to remove all or most of the wires. Then, I think I'd meter for connectivity between terminals.

The primary should have a high ohms reading. I suppose it could be anything from 50Ω to 500Ω If there are UL taps, you'll see continuity and high ohms readings on those, too. I'm not really sure how many ohms. I'd guess anything above 10Ω probably belongs to the primary.

The primary will contrast to the secondary, where you are likely to see 1Ω or less or in that vicinity. The point is, you'll know the primary from the secondary PDQ, if it is, indeed, and OT.

So, it is likely to take a while. Clip onto terminal 1 and then see what each of the other 21 terminals tell you. Then clip onto #2 and see what the remaining 20 terminals tell you, etc., until you are down to #21 and #22. Once you have it all written down, you might actually know something.

I am thinking the existing wiring has some hints, about what, I don't know. My best guess is there are multiple windings meant to be wire in series or parallel.

I'm curious enough to ask you to post a chart of what you find, if you are able to do that.

[martin manning]

I'm wondering if the jumper wires aren't connecting different sections of the windings for interleaving. The heavy gauge wires are the secondary and maybe you can tell if some of the lugs have had leads soldered to them, but beyond that I have no idea.

[Stevem]

I would send that thing back in a hurry if the seller can not tell you what the terminals are and provide a wiring diagram!!!

It looks home grown from a Marshall PT or OT core!

[trobbins]

Perhaps do simple resistance tests, and apply a test voltage to the highest resistance winding to work out turns ratios - same as would need to do for any unknown OT. Hi Fi OT would likely have .multiple secondaries - eg as per a WWFB for a Williamson amp, and a PP windings would have similar resistances. Measure inductance at 5VAC of primary windings - to confirm PP use rather than SE.

[Ang3lus]

turns out it belonged to one of Israel's most famous Transformers winders, this is an example of some of his last works, in his own words (so i was told) he said "this is the best i've wound in 35 years of being in business)

it's a hi-fi trasnformer used to provide the lowest noise possible for audio use.

I have a friend of a friend who might help me with it, meanwhile, looking closer at it, I see 4 white wires coming from the left side and 2 whites from the right side along with a thick cable in the lower part.

here are some pics

on an educated guess, I would guess the 4 wires are the primaries ?

[Ang3lus]

white wires on 2,5
big wire is on pin 10

[Phil_S]

After seeing the later picture and your comment about the winder, I think Martin is on to something. I want to withdraw my suggestion to remove the black wires. See if you can just work with it as-is. if you keep at it, I think you will be able to figure it out.

[Stevem]

Here's a question, are you building a hi fi, Bass or keyboard amp?

I have heard some great Hi fi types used for guitar builds who's top end made for harsh treble when the amp was clipping!
Unless your building a Bass or keyboard amp you want OT roll off to take place well before 15 kHz, no less 20 kHz!

[tubeswell]

What Martin said was also my first thought.

Only way to determine the Pr:Sec VAC ratio is to measure yourself some VAC.

[Ang3lus]

I want to use it for a guitar amp if it's this good, super heavy though, 100w heavy, not 50w heavy.

guess only way is to try after i measure the ratio