The Taming of the Shure

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I just got a new issue of Recording Magazine. It has an article for another mod on the SM57 that supposedly brightens the top end, and allows the 57 to be used more like a condenser mic. The theory is that a lower load will allow you to "tame the shure". The author of the article tested it out in a recording class that he taught, which allowed him to get input from a variety of students with different tastes. According to the A-B tests they did, the class overwhelmingly thought this mod improved the sound of the 57. So there's the background, and here's the mod:

This mod does not require you to do anything to the mic. (phewwww) What you do is build what they call a "gizmo". It's easy to do, and all you need is a mic cable and a 698 ohms resistor. All you do is solder the resistor between pins 2 and 3 on the male XLR connector, and that in turn gives a total load of about 500 ohms that allows the dynamic moving coil to move more like a capacitor in a condenser mic, giving it a higher transient response, and in turn increased brightness on the top end.

I have not yet tried this mod. And I have a very limited knowledge of the way electronics work. Some of the concepts of this mod are above my understanding, so I copied what they talked about in the article for details sake. If I missed any details someone thinks are important just let me know and I'll peruse the article to see if I can find the answer. But all in all it is a simple mod, that in practice is very easy to do. You don't need to know the details to solder a resistor to an XLR connector.

The resistors can be found at www.mouser.com they are $1.10 for a package of ten, and the part number is 270-698.

Have fun, and let me know what you think. :)
 
The author(s) of the article, Paul Stamler (and Scott Dorsey) are regulars on the rec.audio.pro newsgroup. A new thread has just started there discussing this topic with them directly.
 
hmmmm i think i'm gonna give this one a go. but i have to say that i don't really see why i would want more brightness out of sm57 because i usually use sm57's if i want to tame something that is overly bright... (screaming vox, guitars turned up to 11, etc) But hey if you haven't tried it you'll never know what your missing.... I'll post my findings if i do get round to doing it.

greetings,

Thomas
 
SureShotStudio said:
hmmmm i think i'm gonna give this one a go. but i have to say that i don't really see why i would want more brightness out of sm57 because i usually use sm57's if i want to tame something that is overly bright... (screaming vox, guitars turned up to 11, etc) But hey if you haven't tried it you'll never know what your missing.... I'll post my findings if i do get round to doing it.

greetings,

Thomas
Click to expand...

Seeing that it's not an actual mod to the mic itself, the "device" could be useful for adding some versatility to the sm57 I would think. If someone could figure out a way to add switches for both this mod and the removed transformer mod, that would be slick and might make the sm57 alot more versatile.
 
actually i would like to know the details of how and where to solder it. mainly becuase i have very limited experience and knowledge of electronics. do you need to remove any of the wires(un-solder) from the XLR connector??? or do you just solder the resister across the pins while the wires are all still connected??? thanks a lot!!! this is very cool, and i hopt it works well!!!

thanks much for posting this mod!!!

Jacob
 
I read this article too and i thought it was supposed to get rid of some of the high end? I just skimmed through it though, i should probably go re read it.
 
Jacobi1211 said:
actually i would like to know the details of how and where to solder it. mainly becuase i have very limited experience and knowledge of electronics. do you need to remove any of the wires(un-solder) from the XLR connector??? or do you just solder the resister across the pins while the wires are all still connected??? thanks a lot!!! this is very cool, and i hopt it works well!!!

thanks much for posting this mod!!!

Jacob
Click to expand...
From what I read in the article, there is no need to de-solder the wires, just go ahead and solder the resistor across the pins inside the casing that houses the connections.
 
NegadivOne said:
I read this article too and i thought it was supposed to get rid of some of the high end? I just skimmed through it though, i should probably go re read it.
Click to expand...
From the tests they did in the article they used it on a crash cymbal. They said after the mod, the cymbal was much more clear, and brighter.
 
I can easily replicate the effects of this gizmo by using a pre that I have with a variable impedance on the input. Taking the impedance down to 600 ohms (versus 2000 + on the other end of the spectrum) does make a noticable differance to the sound of my 57's, and I was judging it on distorted guitar. Probably not the easiest place to tell a difference. I wouldn't say it brightens the top end. I would say it clears it up and smooths it out. Cuts down on the fizzy undefined top end you get when you aim it straight at a guitar cab. It's not a huge night and day difference, but then again you can easily hear it, so that may be huge to some people.
I would like to try this on some different sources and see what sort of results I get. I've never stuck a 57 on a crash cymbal.
 
They mentioned in the article that this could be done w/o the mod if you have variable impedance on your pre. Also, they just used the crash for the experiment so they had lots of top end. The also used it on an acoustic guitar, and it cleared up a lot of the fret noise, and picking.
 
If you want to clear up a 57, the best way to do it is to remove the transformer.
Then again, doing that does change the character of the mic quite a bit, and in my experience tends to make it not as usable as a live vocal mic, but it does sound better in many "studio" situations.

I wonder if these two mods can be combined. Probably not.
 
well, it would definitely be possible to make the transformer mod switchable... and then you could just change out cables for the resistor mod. or you could potentially make your cable switchable as well... but that would be some tiny intricate soldering and fitting things in a very small place. i would like to see what the cable mod will do with other mics!!!

Jacob
 
A lot of old Shures have variable impedance switches, those change the tone a good deal, and the output a little. Maybe if you don't like the 57, find an old 55 with the impedance switch.

Or if you want the modern mic but with a switch, get a 58S, rewire the switch with the resistor, and replace the ball with the Beta 57 basket.
 
I pulled out the tranny and put 665 ohms across 2 and three. Will check it out this weekend. I need to get metal film resistors probably, if I want to be a total tweakhead!
 
Sounds pretty good. The low end is definitely extended, and the highs have cleared up ever so slightly. Has anyone else done the transformerless and resistor mod? What do you think?
 
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