Please Help Indentify Transformers

I just got these from a friend & would like to know what they are & what they'd be good for? I'm gathering parts for the NYD one bottle &/or any mic pre project for that matter. I'm wondering if anyone knows about any of them or which would be best used where? I'm new to mic pre & these xformers.

I do know what the small triads are :wink:

link to that post: "Triad Input Transfomers"
http://www.groupdiy.com/index.php?topic=14290



MODEL- MI-69
PRIMARY IMP- 150/600
SECONDAR-IMP- 15k
USE*- LI, LO
PRI POWERLEVEL 600- +18
MAGNETICSHIELDING- ?10 dB
CASES- M

So I have the info for this one. Looking for opinions on quality or where to use.






This is the actual preamp circuit the Ampex came from & I thought it might help you guys help me. The transformer gives input impedence but not output.


RCA - I'd love to know the ratio's? I think it was out of a Solid State Pre.


ACDC, same-I'd love to know the ratio's? or if it's good for anything

I have two of those Ampex, they are 1+1:32 (50+50 / 50K).
Sowter have a replacement:
http://www.sowter.co.uk/acatalog/SOWTER_PRO_VINTAGE_TRANSFORMERS_5.html#a279
was used as the input transformer in the ampex 351 tape amplifier which can be modded to a tube mic pre.

[quote author="[silent:arts]"]I have two of those Ampex, they are 1+1:32 (50+50 / 50K).
Sowter have a replacement:
http://www.sowter.co.uk/acatalog/SOWTER_PRO_VINTAGE_TRANSFORMERS_5.html#a279
was used as the input transformer in the ampex 351 tape amplifier which can be modded to a tube mic pre.[/quote]

Thanks. how do you like them or should I say what can they be compared to?

I'm basically confussed on which ones would work for which pre or pre-amp tube or even at all?

Sorry to beat you guys up :green:

Edit: Damn... that link was perfect. That answers one.

[quote author="khstudio"]...how do you like them...[/quote]
oh, I like them, they look cool :green:
haven't build something with them (yet)

Link info from the Sowter Copy:

9735 Ampex 351 Input 200/50k ohms
Ratio 1+1:32. Input can be configured for 50 or 200 ohms. Max input level +12 dBu at 50 Hz. 100% Mumetal core and can. Colour coded leads.

Click to expand...

What does the 1+1:32 mean? I'm guessing it's pretty HOT :? or not?

Would it give more or less gain for the NYD One Bottle?

I'm not sure but wouldn't more up-front gain one the One Bottle be a good thing?

[quote author="[silent:arts]"][quote author="khstudio"]...how do you like them...[/quote]
oh, I like them, they look cool :green:
haven't build something with them (yet)[/quote]

Damn you :grin: I can see that.

[quote author="khstudio"]Link info from the Sowter Copy:

9735 Ampex 351 Input 200/50k ohms
Ratio 1+1:32. Input can be configured for 50 or 200 ohms. Max input level +12 dBu at 50 Hz. 100% Mumetal core and can. Colour coded leads.

Click to expand...

What does the 1+1:32 mean? I'm guessing it's pretty HOT :? or not?

Would it give more or less gain for the NYD One Bottle?

I'm not sure but wouldn't more up-front gain one the One Bottle be a good thing?[/quote]

The 1+1:32 means it's a very high turns-ratio transformer. This has both good and bad sides.

The good side: you'll boost the signal up high enough that the noise level of the tube will essentially be swamped by the stepped-up noise of the source. This makes for a preamp which adds very little noise to the microphone's inherent noise, good for ribbons. (DC resistance of the transformer windings will add some noise, though.)

Also good for ribbons is that the transformer was designed to operate into a tube grid with no shunt resistor. This means the impedance the microphone will see at the preamp input will be very high, which RCA ribbons and such really like.

The down side is that trannies with high turns ratios tend to have peaky frequency response at high frequencies, and that's hard to tame. Taming it usually involves load resistors and Zobel networks which then ruin that nice high input impedance the ribbon liked. Of course, you can leave them out and let the transformer be peaky in the hope that the ribbon's rolled off up there anyway...

The other down side is that the high turns ratio means very high gain for the overall preamp. This is nice for ribbons but hell for condensers, which will drive the circuit into overload very easily.

These are reasons why almost no one actually used the microphone inputs on the Ampex 351, even though they've become a fad lately as "phat toob preamps". They were essentially there for convenience and very occasional emergency use, and I suspect the marketing dept. had a hand in their inclusion.

Still, hook it up to a One Bottle and see what you get. Measure frequency response with a 150 ohm source and no grid shunt resistor.

Peace,
Paul

I have one of those RCA SXMG-09 units too. I believe it is a SS module similar to the Altec 1588 or something. Pulled the can off and its all "gooped" up in side. Can't see a thing. Haven't disected it further yet.

:shock: Oh no! I think I caught "CJ syndrome"! :green:

well, resistor take-aparts are pretty boring, so what else is there?
Funnest electronic component in the world to dissect.
Try it! You like!

Paul,
Thanks man, you post helped me a lot. I think for now I'll use the TRIAD's.

I looks like the sescoms are all I have for the output so we'll see.


ciminosound,
Are you saying it's for SS or is SS inside can?

[quote author="khstudio"]Are you saying it's for SS or is SS inside can?[/quote]

Both. Pulled it from a SS mixer amp. The only thing in it besides the octal sockets were what looked like a little summing board and a small power amp, all SS. I believe it's SS inside the can similar too the altec 1588 mic pre. Have too wait for further dissection to know for sure.