pounds n Ouncers

[daArry]

Hey...

Got hold of some UTC iron - cpl 09's and a 015...looking thru the UTC cat (one of u loverly ppl posted a while back) I see the 09's are o/p trans with a pri of 15K and sec of 50, 200/250, 500/600 - could these fellas be used in place of A24's? The 015 is an 'interstage transformer'?? anything useful I can do with 1 of these?

Cheers!

D

 

[NewYorkDave]

The 09 is going to have a power handling rating somewhere in the milliwatt range, so the short answer is no, it can't sub for an A24.

 

[daArry]

o , so - useful for anything else? Or have I just 3 paperweights ere? :roll:

mebbe a headphone amp?

ta

 

[NewYorkDave]

Well, any application that falls within the impedance, frequency response and power-handling ratings of the transformer. There's a "right" application for any component.

 

[rafafredd]

just use it backwards as a mic preamp input :thumb:

Or as a mic output trafo.

 

[NewYorkDave]

Outputs and interstage usually don't have adequate shielding to be used for mic level.

 

[daArry]

y0 raf, nice - so here's the O-9 (reversed) placed in the hamptone jfp ckt:

that looking feasible?

mucho ta :thumb:

 

[rafafredd]

Man why is it mirroed? You should better mirro the trasformer drawing than the schem.

It confused me at first glance, but it looks ok at the second.

You could try the 150ohm winding for a 1:10 ratio instead at the mic input side. Just read the case.

Problem is the frequency response of the O9 lists as 200-10k in the UTC transformer catalogue. Checked the info and it is in fact a gapped transformer that can stand 4mA at the windings. Inductance should be low and maybe you will have frequency response problems with mics.

But you should try it and only then you will know if you are getting a satisfactory performance. Maybe it will sound funky, just what you want for a colored JFP mic preamp.

I think the O series should give you enought shielding for mic level use. I used O8s and O10s reversed (both O series output transformers, plate to line, but with no GAP, hence higher inductance, better FR) with no extra shielding and it sounds very good.

 

[daArry]

soz, dunno what logic i was workin on - ckt shud be more clear now. will try ur suggestions nehow. thanks.

 

[PRR]

The "Ouncers" are ultra-miniature units intended for voice-grade application in 1950s aircraft. Even a milliWatt at 50Hz will saturate them. Might be usable as mike transformers, if you don't mind some "flavor" and a drooping bass response.

 

[rafafredd]

There are some uncers, like the O8 and O10 that specs 30Hz-20KHz witha maximum level of +8dBm. I would say it´s plenty for any mic trafo. Some people even use those transformers as line inputs!!!

At least the UTC ouncers specs very good for audio.

ADM, UREI, LANGEVIN, etc, all used ouncers on high quality audio products.

Have a look at some specs for UTC ouncers:

http://img.photobucket.com/albums/v172/rafafreddy/016.jpg

PRR, do you still think we will have FR problems with mic levels with those UTC trafos?

I mean, they are not smaller than most high quality sowter, lundahl, haufe, cinemag, jensen, etc, mic trafos.

There is also the "sub-ouncer" series in UTC catalogue, and those are really small trafos. Most not suitable for proaudio even at mic levels. At least I wouldn´t use it.

But I recomend the ouncers for mic input, mic output and DI. :thumb:

The main problem with the O9 is the GAP and the O15 is a very high impedance trafo, so maybe you do not have the best models...

 

[daArry]

what about using em in a some sort of 'colour box' then? with a pot to vary the bite and another pot that mixes the signal either in or out...

I fancied a kinda saturator box like this anyway (was in fact the basis of my 1st post at the place proir to this)... the suggestion there was to use the amp section from the pultec clone...

cheers

 

[al_p]

[quote author="daArry"]what about using em in a some sort of 'colour box' then? with a pot to vary the bite and another pot that mixes the signal either in or out...[/quote]

thats what i was thinking. like a really agressive rock vocal mic preamp.

 

[nwsoundman]

I like the O-8 as a mic pre input trafo. I use them with the O-17 shield though. Sounds good to me.

NWSM

 

[NewYorkDave]

Americans caught affecting the European slang "trafo" will be fined. It's XFMR, buddy! :green:

 

[CJ]

UTC dosen't use shields on their input x-formers because of the hum bucking construction. So reversing is not a big deal.

 

[NewYorkDave]

I've got a bunch of old discrete Dynair line amps that use O-11s as bridging 50K:600 inputs. I've thought about using them as mic inputs (reversed) in tube circuits if i decide to part-out the line amps.

The 0-9 will probably give somewhat better LF response than the spec sheet says, in your application, since you won't be drawing direct current through it. The xfmr is designed to be no more than 1dB down at 200Hz WITH 4mA DC through its primary; without DC, the primary inductance will be higher and LF response should be better than the spec.

 

[nwsoundman]

[quote author="NewYorkDave"]Americans caught affecting the European slang "trafo" will be fined. It's XFMR, buddy! :green:[/quote]


I thought that was LAB slang. How did "trafo" come about?

NWSM

 

[NewYorkDave]

I WAS just kidding guys. I don't like the term "trafo"; but then again, I don't like European and British schematic conventions either (e.g., resistors as little boxes, continuous 0V lines running all over the page, etc.). But hey, you like what you're used to, right? I'd probably dislike Imperialist American zig-zag resistors if I'd grown up in Europe.

In verbal conversation, "tranny" seems to be most common in the States, although sadly it also happens to be slang for transvestite or transsexual :shock:... or, more innocuously, the transmission in a car.

 

[mcs]

[quote author="nwsoundman"]I thought that was LAB slang. How did "trafo" come about?[/quote]
It's "transformator" in Danish, but we often use the word trafo - just like the Germans...

Best regards,

Mikkel C. Simonsen