Raven Audio Tranformer - anyone familiar?

I found this at a flea market on Sunday. Made by Raven Radio, Inc. in Albany NY. I never heard of them, but for 1 dollar I couldn't pass it up. The connections are marked B-, A+, C and P.

A search turned up very little. Mostly about their super het radios, but no info about their transformers. Anyone know anything?

Jeff

That would be a 1920's radio transformer.  Guaranteed to be low bandwidth.  Investigate value to radio collectors, if any. 

Thanks, Doug.

http://www.clarisonus.com/Archives/Amp_Design/SH_trans_coupled.pdf

very nice article - thanks!

Jeff:

I collect vintage radios, including Raven from Albany NY. What would you like to know about your find? Will you keep it or is it for sale?

Thanks,

Terry

Well, that all depends (doesn't it always?).

I'd like to know the specs. Doug said it was likely to be low bandwith, is it? What's the freq response? What was it's intended purpose? What's it made of? Impedances?

Before I could make any decision on whether to keep it or sell it, I'd like have some info. Have any?

Jeff 

Jeff Goodman said:

Well, that all depends (doesn't it always?).

I'd like to know the specs. Doug said it was likely to be low bandwith, is it? What's the freq response? What was it's intended purpose? What's it made of? Impedances?

Before I could make any decision on whether to keep it or sell it, I'd like have some info. Have any?

Jeff   

Click to expand...

Raven was a radio manufacturer in the 1920's. They were AM only radios (535 kilohertz to 1,700 kilohertz). The transformer would have been part of the AF circuit design and in front of the AF tube stages and oscillator.

Terry

I'm guessing that example is late 1920s.

When tubes were EXPENSIVE and low-performance, best results were got with a "general purpose" (what we'd now call a fairly low-Mu) triode and a step-UP transformer to the next grid.

It was aMAZing to hear sounds from the air. Listening was either telephone earpieces or a telephone earpiece coupled to a horn. 300-3KC response would be generous. More important was GAIN. Your part is speced for a 1:5 ratio, a stunning step-up from the relatively high impedance of a tube plate.

I don't see what you want it for except as a paperweight. There's many other ways to get a narrow-band response for special studio effects. R-C filters. Digital filters. Transistor radio transformers: Mouser has most of them.

It is a lovely object, I'd offer $2 just to look at it a while.

Plate-to-grid transformers ARE very useful to radio restorers. I dunno how valuable they are today. It seems like everybody and his sister was winding transformers in the shed, also catalog suppliers. I know I have seen them offered inexpensively; also it is possible (not easy!) to rewind an original transformer which has failed.

Here you have Terry who actually knows this obscure radio maker and would surely give it a good home. I think the universe is giving you a hint. Get his contact, show it to all your firends, check around, and then do a deal with Terry.

Yep, agreed.  I never see the best-known units of this era sell for more than $10-$20, and I've never heard of this one.  Unless you have found evidence otherwise, it'd be a $5 ebay item, which might not sell. 

Well, now I have some info! Thanks to all.

As to whether I keep it or sell it, I haven't made my mind up yet. It is a very cool looking piece, but it seems to be worth very little, even to collectors. So, I'll probably hang on to it for a bit. If Radioterry needs it to finish a project, I would consider letting him have it. But if it's just for a collection, it might as well be in mine.

Thanks again to Doug, PRR and Radioterry.

Jeff