Shure mic-input transformers... any good ?

Was wondering how older Shure microphone-input transformers are generally considered... those in their mixers, processors - so not those inside mics themselves.

I realize it depends on type etc, but what's the general idea...?

For instance:
- OK for voice, but otherwise lacking in bandwidth ?
- Re-use only recommended when you want to make an FX-box ? (like the level-loc for instance)
- Or actually decent ?

I'm thinking for instance on the one below, type 90D2150, from a Shure mic-processor-box which will be over 20 years old.







Will be a 1:10 stepup, '680 Ohm actual input impedance'
(to be used with source-impedances of 25 ... 600 Ohms).
Stated input clipping level over 40mV (-28dBV).
Height ~1.5", diameter ~0.8".


Thanks !

Peter

I think most people say these are not very good--if you are going thru the trouble of building a pre; use quality parts. I put one of those shure mic ins on a NYD 1 bottle and I did not think it sounded bad...maybe a little bandwidth limited and easy to overdrive, but its cheep color and isolation.
I've done no critical listening to what it does, but the step-up is serious.
Probably not 1st choice for accuracy, but for non-critical voice applications, quick and easy pre, or effects box. they are useful @ the going price.
http://i248.photobucket.com/albums/gg189/shabtek/DSCN2479.jpg
http://i248.photobucket.com/albums/gg189/shabtek/DSCN2471.jpg
http://i248.photobucket.com/albums/gg189/shabtek/DSCN2472.jpg

Thanks for the response. Yes, simple & cheap were the keywords, got a few of those boxes for little and I saw that it has plenty of potential gain inside, it's just that it's brought back to mic-level again.

I'm with you, if you start from scratch then use the best stuff.

For these though, with a few simple re-arrangements it can be changed to mic-level in, line-level out,
a.k.a. a mic-pre :wink: (and [VFWIW]an all discrete class-A TX-input featured one at that[/VFWIW]).

So then I started to wonder why those Shure-TXs don't get mentioned more often, as I assume there must be lots & lots of such TXs & variations on these around (this being the 90D2150).

The 1:10 is indeed a lot, maybe they simply needed that to keep the noise-contribution of the active processing part low... since this came from a mic-level-in, mic-level-out pre-processing unit (same for the older Shure level-loc IIRC).

That input-TX looks relatively big for its 40mV clipping level, it's at least te size of two of those Beyer-TXs, but that doesn't need to mean everything of course, it's hard to see how big the core actually is (and it won't be using the Beyer-trick to remain small I presume).

Since it's a simple mod I just try and then see in which department it needs to be stored: fun-pre for goofy sounds, or something else.

Bye,

Peter

Mine are from m67--I think they are the same though no part# is listed ; specs are very similar
the core is small, the can is (40mm)twice as tall as need be and 20mm in diameter...I cannibalized a shure mixer for the voo meter, started paring the pcb down to a 1ch mic pre, but 'tis on the shelf at the moment.
shures documentation was really good so its easy to see what each stage in the circuit does. I think they used shunt caps liberally in order to keep things as tame as possible

How does it test?

Try to provide a home for every transformer.

The worst thing a transformer can do is go through a nasty foreclosure.

If your transformer is handicapped by a high end roll off, don't put it in the Transformer Special Olympics, make a direct box for guitar out of it, you will love the harshness removing properties of the leakage.

How does it feel..
To be on your own...
With no direction home...
Like a Rolling Transformer...

What, don't quit the day job?

Doh!

[quote author="CJ"]

If your transformer is handicapped by a high end roll off, don't put it in the Transformer Special Olympics, make a direct box for guitar out of it, you will love the harshness removing properties of the leakage.
[/quote]

Da legacy hoff da uncle CJ's wisdom

Hey man, you should hear those Shiny Box ribbons, three distinct flavors.

Did he steal your Cobalt phase diagram?

You know, the one you sampled and mixed from melted Uranium west of Chernoybl?

OK, the World is so crazy right now, that we need a MP3 ala Marik, the latest hit you have in Europe of course.

But please, no C major.
That has to be the most boring key in the world.

I'm sorry, my childhood was a mess.
My parents made me sit though an hour of Lawrence Welk every Sunday, which is worse than the Chinese Water Torture.

[quote author="shabtek"]Mine are from m67--I think they are the same though no part# is listed ; specs are very similar
the core is small, the can is (40mm)twice as tall as need be and 20mm in diameter...[/quote]
They have at least alike clipping levels.

shures documentation was really good so its easy to see what each stage in the circuit does. I think they used shunt caps liberally in order to keep things as tame as possible

Click to expand...

Nice indeed they still provide the docs for all our old junk :wink:
but I didn't see much more either than RKC8, no typenumber like some other docs use...

Cheers,

Peter

[quote author="CJ"]How does it test?[/quote]
At first I'll sweep the total box when its in better health, a few caps need to be replaced.

Try to provide a home for every transformer.

Click to expand...

And then TXs might still be the lucky guys... TXs getting ripped from gear and even in a worst case scenario they see new use (after having lived in a box for years, then sent to a new home by means of The Black Market).

But the rest might get thrown in the bin right away... I mean, in these times of painted plastic made to look like metal, why not re-use more of those old boxes. Not all of them are cool, but some are and are sturdy & accessible and have the XLR-I/O ready to go. I don't bin them, I dig them.

Transformer Special Olympics, make a direct box for guitar out of it, you will love the harshness removing properties of the leakage.

Click to expand...

:thumb:

Bye,

Peter

Ah Man , when t.v. was b&w and we only got 3 channels
i had to watch Hee Haw cause my parents did , scared for life now
[ if only i'd known , i also hated the color brown in the 70's ]

Actually Buck & Roy were good , but the camp ! someone help me

Hmmm wonder if i can turn the world around with a new fuzzbox design
that uses a xfmr , good idea Cj