SM57 impedance mod

Brett Siler · Post by **Brett Siler** » Wed Jun 29, 2011 3:51 pm

Has anyone done this mod? Basically you make this little thing that you plug you 57 into and it changes the impedance load being sent to your mixer and changes the frequency response of the 57 making it sound different. It's super cheap to make too. Just thought I'd ask if anyone has done this and what where your results?

http://www.recordingmag.com/resources/r ... l/330.html

kslight · Post by **kslight** » Wed Jun 29, 2011 6:06 pm

Even cheaper would be to remove/disconnect the transformer.

Brett Siler · Post by **Brett Siler** » Thu Jun 30, 2011 11:50 am

That is true, but I was just wondering if anyone on here tried this particular mod.

nobody, really · Post by **nobody, really** » Thu Jun 30, 2011 7:40 pm

nice, thanks for sharing that. something to try. makes me wonder what the impedance on my ramsa is, like maybe old live boards have more dynamic-friendly preamps?
so, what would removing/disconnecting the transformer on a 57 do?

Brett Siler · Post by **Brett Siler** » Thu Jun 30, 2011 8:10 pm

There was a mod featured in Tape Op issue #52 featuring a mod where you can take the transformer out of the 57 and it is suppose to extend the frequency range. I totally forgot about that, I think I got skipped that month's issue, but I remember people talking about it. Supposedly it makes it sound closer to an SM7 than a 57.

Brett Siler · Post by **Brett Siler** » Thu Jun 30, 2011 8:29 pm

http://messageboard.tapeop.com/viewtopic.php?t=32897

There are pretty simple instructions to do the transformer mod on the 2nd page. I think I might do it to one of mine tonight.

Am I hijacking my own thread?! Anyway impedance mod, back to it!

Jim Williams · Post by **Jim Williams** » Sat Jul 02, 2011 9:46 am

You lose 12 db of output if you remove the internal transformer. That makes them useless for vocals but great for kick drums. Low end will extend to 20 hz.

ubertar · Post by **ubertar** » Sat Jul 02, 2011 11:29 am

The DY-45G is a transformerless version of the sm57, no mod needed. Or better yet, there's the SM77, which A) is transformerless and B) has an aluminum voice coil (instead of copper) wound to be more powerful (more turns) but the same weight (aluminum is lighter than copper) to make up for the loss of gain from the lack of transformer.

Peterson Goodwyn · Post by **Peterson Goodwyn** » Sat Jul 02, 2011 11:59 am

Jim Williams wrote:You lose 12 db of output if you remove the internal transformer. That makes them useless for vocals but great for kick drums.

Actually, with a good pre they are extremely useful for vocals. My transformerless 57 into Hamptone HJFP2 (usually with gain cranked all the way) is one of my favorite vocal chains.

Brett Siler · Post by **Brett Siler** » Sat Jul 02, 2011 1:49 pm

Jim Williams wrote:You lose 12 db of output if you remove the internal transformer. That makes them useless for vocals but great for kick drums. Low end will extend to 20 hz.

Ohh sounds like it would be good for loud bass cabs too.

Brett Siler · Post by **Brett Siler** » Sat Jul 02, 2011 2:02 pm

Peterson Goodwyn wrote:
Jim Williams wrote:You lose 12 db of output if you remove the internal transformer. That makes them useless for vocals but great for kick drums.
Actually, with a good pre they are extremely useful for vocals. My transformerless 57 into Hamptone HJFP2 (usually with gain cranked all the way) is one of my favorite vocal chains.

I imagine screaming vocals would sound cool with it.

Jim Williams · Post by **Jim Williams** » Sun Jul 03, 2011 8:35 am

If you like that sort of thing. Better use a pop screen or you will be picking out pieces of the guy's last meal.

I don't know about the rest of you, but I hated getting yelled at when I was a kid.

I like it even less now that I'm older.

Brett Siler · Post by **Brett Siler** » Sun Jul 03, 2011 9:34 pm

What about screaming along with someone? It can be cathartic

I actually really like screaming vocals, when suited to the music, I understand people thinking it's obnoxious though.

Brett Siler · Post by **Brett Siler** » Sun Jul 03, 2011 9:38 pm

So I took out the transformer of a 57 last night. It is definitely has a lot more bass and seemingly less high midrange. Pretty cool. I painted it white so I knew which was the modded one and which ones aren't.

??????? · Post by **???????** » Mon Jul 04, 2011 7:35 am

Oliver Archut at AMI/TAB makes a nice transformer to replace the original, for another option.

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SM57 impedance mod

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