I’m sure everyone out there has at least heard the number ‘57′ in respect to recording gear. It is a VERY widely used microphone and has been around for a long time. But this isn’t a history lesson. This is a modification lesson.

Today, I’m going to remove the transformer from this 57.

“Are you mad? It’s an SM57, it’s supposed to sound like an SM57!”

I know. I’m not modding this microphone to make it ‘better’. I’m modding it to make it different. I’m creating a different tone to use, a different brush with which to spread the paint across the canvas. I’m actually modifying two because I have an OCD complex when it comes to stereo pairs of things.

Removing the transformer has been claimed to make the modded SM57 susceptible to phantom power damage, so beware.

Please read all steps before attempting to do this yourself.

1. Unscrew XLR pin structure toward the ‘bottom’ of the mic using a tiny .4mm screwdriver.

This is what happens after you carefully pull it out:

2. Unscrew the hollow portion from the diaphragm portion of the microphone, at this joint:

This is what happens after you carefully do this:

3. Desolder the 4 points, 2 at the XLR connector end and 2 at the diaphragm end. The result will be 2 wires coming up one side of the hollow portion and 2 wires coming down the other side of the hollow portion:

You can clearly see the transformer suspended in some goo. Our goal is to remove that transformer.

3. Boil the hollow portion. Seriously. This will melt the goo and allow you to dislodge the transformer. Keep in mind I am modding 2, that’s why there are 2 hollow portions in the boiling water. DO NOT PUT THE DIAPHRAGM PORTION IN THE WATER, LEST YOU CARE TO END UP WITH A BROKEN SM57!

4. When enough of the goo has dissolved and the rest is soft, pick up the hollow portion while it is still hot, using tongs or some other device so as not to burn yourself on boiling-hot metal, and using pliers or a similar tool, grab that transformer and carefully slide it out. You do NOT want to fling molten goo on your skin, so be gentle. Once the transformer is freed, this is what it looks like. Remember, I removed 1 transformer from 2 different microphones. Now, let the hollow metal portion cool off.

5. Make new wires and solder! I used hot and cold leads from a short length of microphone cable – they were the perfect size. It is easiest to solder the XLR connector first, connecting the wires to the cups. You may have to add some solder for a secure connection. Then, feed the wires through the hollow portion of the microphone and screw the XLR connector back into place, from the first picture above. Now, solder the 2 wires to the 2 eyehole pins on the diaphragm portion of the microphone. One is clearly marked with a + and that pin should be connected to the hot pin of the XLR connector. The XLR connector is also labeled clearly.

Remember (for most modern applications):

Pin 1 = Ground/Earth

Pin 2 = Hot

Pin 3 = Cold

This is the result:

6. Cram the wire (gently) into the cavity and screw that mother back on. Clean up any excess goo that ended up on the chassis of the microphone and then JUBILEE! You’ve successfully modded an SM57! That is, IF it works. Here is what the final result should look like (duh):

Now test it! You should notice a few tonal changes (the reasons for doing the mod in the first place):

-The frequency response goes a little further in both the low and high frequencies

-That carefully sculpted midrange ‘presence boost’ should be smaller

-The overall frequency response should be a little flatter

Something to note as well:

-The output of the microphone will drop dramatically, about 10-12dB which means it probably won’t be suitable for quiet sources (not that the 57 is great for quiet sources anyway) and it will require more gain from the preamp it is used with, so noisy preamps probably won’t work out so well

Overall, the tonality changes are subtle, but if you are looking for a little spice in your SM57, this mod is great.

Let’s Record.

-Mitchell