Old Shure Unidyne Model 545, pinout to XLR?

[guitar486]

Hey guys, I managed to get a hold of an old shure 545 from my work and am wondering if there is a simple way to get this baby into an xlr in or if I'll have to resolder it myself? It's got a 4 pin connection and I'm not sure which is which. Any help would be appreciated.

[guitar486]

I did some more digging and found this:

http://www.shure.com/stellent/groups...pro_545_ug.pdf

Also, this is a quote from another forum from a guy who has a 565:

"XLR: 1-neutral, 2-Pos, 3-neg
Amphenol: 1-neutral, 3-Pos, 4-neg

This scheme works for balanced, low imp.

The 2 on the Amphenol is for the high impedance. If you want to have it that way (with a jack, e.g.), then connect 1-neutral, 2-pos. It will be unbalanced."

So now that I'm done talking to myself....

[albee1952]

That's it in a nutshell. I believe the old mics with the 4 pin Amphenol were dual impedance. You might buy a ready-made cable off eBay but it will cost a lot more than making one yourself. If you have the proper 4 pin connector, that's the hardest part. If not, you could unscrew the guts and install them into a dead SM57 barrel. The capsules are the same(or so I have been told, they are SM57 capsules that didn't pass QC testing). Take that with a grain of salt. In any case, later 545 models were XLR only and I had a great sounding one back in the day(bought it DOA for $5, sent it to Shure with $45 and they sent it back with new guts......those were the days).

[guitar486]

Thanks. I've got the connector that came with it so I'm just going to make a small Amphenol-XLR Cable this weekend. The tricky part is going to be re-soldering the wires off the capsule to the case. (they were cut, I got this mic for free in the "old sh*t we'll never use and can't sell" bin at my day job)

[albee1952]

That could be fun. Were they cut or did they just break off from unscrewing the capsule? Worst case)assuming the capsule is still good) you can remove the transformer(glued in the bottom of the barrel) and wire the capsule leads direct to the hot and cold(shield goes to the case) and have a 50 ohm setup. It requires a tad more gain at the mic pre but will have faster transient response by bypassing the little transformer(which saturates fairly quick).

[guitar486]

I thought about removing the transformer...any benefits to this besdes transient response? Thanks for the input

[guitar486]

Bump

[albee1952]

No other benefits I am aware of. I learned that trick many years ago, thanks to a great live engineer named "Stormin" Norman Dunn. He had an RE-20 (minus the transformer) in an 18" bass drum and it was probably the best live bass drum I ever heard! Anyway, in conversation, he told me to try it on an SM57 I had in my band's bass drum(hey, we were on a budget) and sure enough, it made a noticeable improvement(so I did the same to the snare and tom mics as well). Alas, those mics are all long gone(and the whereabouts of Norman is up in the air as well).

[guitar486]

Right on. Any tips for getting the transformer free from the case with all that epoxy in there?

[albee1952]

I removed the XLR connector, shoved a big screwdriver(a piece of dowel would work as well) in the end and hit it with a hammer(The whole capsule section was not attached at the time). Hopefully you will have access to all that high-tech hardware.....yuk yuk. Yeah, its brutal.... Before you tackle this, you may as well wire the capsule to an xlr (pins 2&3)and test it before bothering with the rest of this. If the capsule is DOA, turn it into a prop.