Lokes

Help please identifying some mic transformers

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Hi

I have a pair of small transformers that I'm going to cobble together to try in an MC step up device,

they meter 24 ohms primary and just over 2k secondaries

anyone able to identify the maker ?

Zilch on the outside but there is AF  Transformer Type 210 on the terminal end

diameter is roughly the same as a 50p piece

mic trans 3.jpg

mic trans 2.jpg

Mic tran 1.jpg

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Super Wammer
12 minutes ago, Lokes said:

Hi

I have a pair of small transformers that I'm going to cobble together to try in an MC step up device,

they meter 24 ohms primary and just over 2k secondaries

anyone able to identify the maker ?

Zilch on the outside but there is AF  Transformer Type 210 on the terminal end

diameter is roughly the same as a 50p piece

mic trans 3.jpg

mic trans 2.jpg

Mic tran 1.jpg

If these  are mic transformers, they'll probably have a 7:1 or 10:1 step up ratio, which will give you a 49:1 or 100:1 impedance step down. That'll make them suitable for MC cartridges except for low output ones that'll, need more like 15 or 20:1.  

If you like, I can measure them for you and see how good they are, but I'd expect them to be OK.

S

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Super Wammer
6 minutes ago, toprepairman said:

they look a bit Ferrograph to me

I think that's the right era, but the Ferrograph 6 series didn't have mic transformers, as their mic inputs went direct to a valve grid, and their line transformer had different part numbers. It might be earlier than the six series, but I don't think they had mic transformers either. My guess is that they came out of a mic mixer, possibly a PA amp, but no idea of the manufacturer. 

S

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Thanks Toprepairman and Serge

I think you may have cracked it, I googled Ferrograph and came up with this,

it's a pic of a Ferrograph 307 amplifier, maybe not the exact same transformer but

I'm well and truly on the right track,

Jules

ferro trans.JPG

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Super Wammer

Curiouser and curiouser! 

The F307 amplifier doesn't have any audio transformers in it, as far as I can see from the circuit diagram, and nor does the Series 7 tape machine, so I wonder what those transformers do, as the photo does indeed seem to be from a F307. 

S

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I had a quick squint at the cct diagram and you're right.

anyway, they're definitely manufactured by the company that made mine.

I have a couple of Partridge Transformers that were apparently removed from a Ferrograph tape machine, but these are

different, maybe cheaper units ?

I hope not

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