The SM57 Transformerless Mod: You Know, The One Everyone Talks About But Nobody Posts Clips Of...

Sometimes you offer a friend or a client to do a project for them.  Then you put it off.  Then you forget about it (with the occasional "Yeah, I probably should get that done" reminder).  After about 5 of these, you have 40 hours of work to do and it all ironically ends up being due on the same weekend.  Such is life.

Rather than do the work.  I decided it was much better to procrastinate.  So I got out my soldering gun...

After patching up a few necessary things, I still had the itch to break stuff.  So I looked around the ol' man cave for something that I could tinker with and saw my pile of SM57's sitting in the corner.  I had read about this "transformerless" mod once or twice before, but I was never able to find any direct comparison videos/audio files.  So for fear of making a crappy mic sound worse, I never did it.  But procrastination was beckoning me and I couldn't refuse her sweet call.  It's a pretty rudimentary mod requiring little to no skill, so there's no need to assume I'm some sort of genius.

Basically, you disconnect the leads, boil the bottom to soften the glue (not the diaphragm!), pull out the transformer, reconnect the leads.  Done.  There are a bunch of videos/articles on how to do the mod, but for the sake of convenience, here's the one I watched:

Here's some photos of the mod taking place in my lab er... kitchen.

    

The transformer is covered in glue/plastic to hold it in place inside the microphone.
So when you yank it out, it looks like something birthed from an alien.

Once it was all put back together, I decided to test it out.  My chain was Tele w/ Lollar pickups > Vox AC15 > SM57's > 3124+.  I put the microphones right in front of the speaker cone pushed into the grill a little.  I call it my "Chris Walla" method.  (Though he didn't originate it by any means, he's known to do this frequently to get that speaker really in your face on records.)  I couldn't eliminate all the variables, but hey, what can you do?

**I'll tell you my opinions at the end, so you'll wanna listen to the samples first so your brain doesn't make predetermined assumptions.

I tried as best as I could to grab the exact same piece of air
with both mics.  The "T" is the mic with the mod.

Running into my API 3124+.  I matched levels as best as possible.  During the "Dirty" clips, I had to put the pad
on the standard SM57.  There's about a -10dB difference in the mic without the tranny.  **Ignore
what the blue tape says**

I used my EHX SuperEgo basically to send a fake "sine wave" into the amp so
I could match levels.  I didn't want one mic to sound better/worse because it was
louder or was clipping differently at the preamp.  I ran straight into the amp after
I got my levels.

Here are the results.  Pardon the shitty playing.  **FYI Soundcloud does compress, so if you're nitpicky you may want to download them instead of playing them through the player.

So what did you guys think?  Personally, I like both but for different applications.  To my ears, the mod rolled off some of the highs and there was slightly better bass response.  I think the modded 57 really improved the overdriven sounds, while the stock 57 won out for clean tones.  I will mention that I do like my clean tones a little jangly.  I did some reading and the mod is supposed to give the SM57 similar qualities to the SM7 (the two circuits are pretty much the same, or at least very similar).  I didn't have an SM7 on hand to compare it with, but it's something I'd like to do.

I must divulge and say that the SM57 definitely isn't my first choice for most things (especially guitar). But to most guitarists the words "guitar cab mic" is synonymous with "SM57".  I personally prefer the sound of a ribbon or a "better" dynamic over the 57 on amps.  However, it just has too many applications NOT to be used sometimes.  If you blend the brightness of a 57 with the darker ribbon mic, you can get a nice full bodied sound.  But it all depends on the guitar, amp, speaker, room, and personal taste.

Cheers!

-  Stonewall