RCA 901855-1 audio transformer info?

[12afael]

a friend gave me some audio transformers,

utc ha100x(for my next LA2a)
utc HA134( some vary mu???)
utc p12(for a 1176)
ampex 4580200-01 (maybe a mic pre)
two RCA 901855-1

I can´t find any info about the rca they look like input transformers. if someone have info about it and where can be used let me know.

12afael

 

[CJ]

hard to do much with tyhose private part numbers.
RCA used UTC by the thousands.
Ohm itout, and make a drawing.
What can?

 

[12afael]

here is a quick draw.

balanced to common mode , mic/line input???

 

[CJ]

Maybe not a UTC, I looked at all the lead diagrams and none match.

Looks like it might be something close to an Ouncer 10, line to 30,000 ohms, which would be about a 1:7.5 ratio, which you could check with a generator.

The 40 ohm windings are very most likely to be line level, so just find out what the turns ratio is and you can determine what that thing was supposed to drive. Or be driven by.

 

[rafafredd]

What´s the size of this?

If it´s small, just use it as a dual impedance mic to grid. Some will say the 82ohm winding one would not be cool for a mic. Well, I would include a switch so that you can try it with some mics. Some condensers will like a higher impedance load, as well as a lower ratio step-up.

If it´s large, use it as a plate to line... Might work for a V72 type of thing, if the HiZ winding is really on the order of 30k or so.

Simple!

 

[12afael]

Rafa the size is on the draw.

the ratio is 1:7,5 and 1:13,3 .(no too much precision on my old tube scope)
http://vacuumbrain.com/docs/Sub_Docs/utc.html
the case is the o-16 .
the specifications of the o-16 say low imp. to grid 250ct to 50000 max level +8dbm and 40ohm pri. resis. it is just on one leg or on the complete primary?

it seems to be the 0-16 I could be sure with the wire color code.

thanx to both for the help.

12afael

 

[emrr]

You might get a better clue if you study my other post from today:

http://www.groupdiy.com/index.php?topic=16210

These exist with UTC stamps, and without. That number is an RCA drawing #, and could have been made by many different companies over several years. The UTC # is N-6565 for their version, and would be marked with both. Bigger than a UTC O series case. Used on a lot of industrial, PA, and theater amplifiers.

The title of this thread has a typo; there's one less 8 in it, and one more digit than is ever found in the RCA drawing nomenclature.

 

[12afael]

The title of this thread has a typo; there's one less 8 in it, and one more digit than is ever found in the RCA drawing nomenclature.

Doug you are right, the number is 901855-1 and it have the same color code of your schematic and dcr is close too.

These exist with UTC stamps, and without. That number is an RCA drawing #, and could have been made by many different companies over several years. The UTC # is N-6565 for their version, and would be marked with both. Bigger than a UTC O series case. Used on a lot of industrial, PA, and theater amplifiers.

I can´t find info of the N-6565 on the 1970 utc catalog maybe it is posterior. the N is for militar standar transformer and inductors and there is not audio transformers on the N series of the 1970 catalog.

 

[emrr]

That UTC number was never in a catalog, like most UTC numbers. The N means nothing relative to any standard UTC nomenclature. These are from the late 1940's to mid 1950's.

The earlier versions with that part #, an RCA stamp, and no UTC ID or # have a different DCR, but are seen on the same amps, so I'd assume from that and others that RCA specified purpose, level, and impedance but left it to the contracted transformer companies to come up with their own winding ideas.

I'm still waiting for someone in their late 80's and in the know to comment on exactly who made the pre-1950 RCA iron, which doesn't really look like any of the regular companies at all. Maybe RCA really wound a lot of their own up to a point? There's this floated assumption that it's all UTC, but there's really no solid evidence to suggest that, and more to refute it from the looks of the product.

 

[12afael]

thanks for the info Doug :thumb:

here are some pictures of the transformer.
http://img150.imageshack.us/my.php?image=foto3cn3.jpg
http://img226.imageshack.us/my.php?image=foto2lz2.jpg

let me know if yours look like this.

 

[emrr]

yes, that's the earlier version.

 

[CJ]

What a delicious looking meal!
:thumb:
A diet rich in iron.

The Ouncer 16 was of course, the only wiring diagram missing from the terminal sheets.

I think the Ouncer 10 is same transformer, wired backwards, and with a tap brought out. The 2000 ohms is the giveaway.

I was told that all UTC terminal numbers either even or odd, are winding starts. I will have to go back over some dissections and see whats going on.