Mystery transformers

[andrew_whitham]

Hey all

Can anyone help me with an odd transformer question? I just got some very small transformers. In theory these are 6.8 ohm to 3k6 SE output transformers. BUT the DC resistance of the 3K6 side is a whopping 1k9

Any idea what gives? I suppose they could just be real high loss types but if they arent output types what might they be?

Cheers

Andy

[Shoog]

Could they be preamp loads. Seems that a high DCR on the primary would help in power supply isolation, also voltage drop wouldn't be significant at low currents,

Shoog

[Miles Prower]

Originally posted by andrew_whitham
Can anyone help me with an odd transformer question? I just got some very small transformers. In theory these are 6.8 ohm to 3k6 SE output transformers. BUT the DC resistance of the 3K6 side is a whopping 1k9

Any idea what gives? I suppose they could just be real high loss types but if they arent output types what might they be?

From the description, that seems to be an ultra-cheap OPT from an AM BCB radio that was originally tacked onto the frame of the speaker. Probably for a 50L6 final.

These radios were designed to be cheap, cheap, cheap, and that thing'll sound:

[andrew_whitham]

picture might help I guess...?

Could these perhaps be power transformers under a different guise?

I'm also pretty sure that they won't make a serious OPT but they were (well) made for something

Cheers

Andy

[diesel_tech]

thats a reactor for an old tv i think..

Jeremy

[andrew_whitham]

A WHAT? Actually I don't think they are old at all they lack that characteristic smell...

on other thing that crosses my mind this morning. How can you see / check they are gapped? Could these are parafeed types? they're tiny arent they?

Andy

[Shoog]

Whatever they are they are top quality build. C-cores are the best.
I have a pair of similar looking power transformers from an old reel to reel.

Shoog

[Dave Cigna]

Andy, in the photo I can see two markings: 0 and 3K6. Are there markings on the other side?

Also, what's that blue thing along the base? Wire? Connecting the two windings? Are they really autoformers?

Could they be TV flyback transformers? I'm no expert on those; just a wild guess... Maybe pulse transformers of some kind.

They do look nice though. I like looking at quality stuff.

-- Dave

[EC8010]

No, it's not a line output transformer - they need ferrite cores, not steel laminations. It might be an output transformer for a ring main amplifier. Broadcast centres used to have ring mains of various feeds going round offices etc. The amplifiers tended to have single digit output resistances to drive all that cable and the many loads that could be connected. Additionally, a low output resistance meant that if you padded it out at each distribution point with a pair of largish resistors, if some twit plugged tone back up the hole, it would be significantly attenuated by the amplifier, leaving the feed (just about) usable until you could disembowel the aforesaid twit.

[rdf]

Far East a possibility? I thought that construction looked very familiar. From my experience rational design isn't always a criteria. From Ebay seller tubeamparts: