By Enti Bracamonte
Posted: May 15, 2022

 Transforming a 100-dollar
mic into a 400-dollar mic
on the cheap

Dynamic microphones are my favorite type of microphone. They are built to withstand a nuclear blast, and their internals are so simple, you really have to abuse them in order to cause them to fail.

That said, I recently had an SM58 mysteriously fail on me after little more than a year of very mild, infrequent use. I know, the SM58 is everyone’s favorite, the industry’s workhorse, how could that happen? I cannot tell you how that happened, I can only tell you that the mic was the last thing I though could fail, so my trouble shooting process was veeeeeery long and arduous, because I checked eeeeeverything else first.

I won’t go into the details of my trouble shooting process, firstly, because I’d be embarrassed to say, and, secondly, because it was very long and tedious. But the thing is I finally got to the point where I just had no other choice but to suspect the mic. I kept hearing this very low level 60-hertz-like hum in my recordings, and I could not figure out what was causing it (I use a hospital-grade isolation transformer, so I knew it was not a mains-related noise).

And before you have a chance to think it or say it, let me say first that I am aware that some microphones are very sensitive and their coils can act like antennas and pick up noise from external conductors or transformers. I unplugged everything and used a battery powered preamp with a headphone jack to make sure this was not the case.

Just when I started thinking I was going to have to dump my SM58 and get a new one, I happened to find this video on Youtube: 

Because I had nothing to loose, I decided to give it a try and, to my amazement and relief, it did work.

I did not boil the body of the mic, though, it seemed like a messy affair.

First I unscrewed the capsule from the body of the mic and, then, I unscrewed the XLR connector. Be careful when doing this, the screw does not come all the way out. I, then, carefully pulled the connector out, using a pair of long nose pliers, and, finally, desoldered the wires.

Next, I unscrewed the switch assembly and used my long nose pliers to pull out the hot-glue holding the transformer in place. If your mic does not have a switch, the process may be even easier.

If you can’t get a firm grip on a sizable chunk of glue and end up just pulling small pieces out, you may have to boil the body of the mic like in the video above.

Once all of the internals were out of the body of the mic and on the operating table, I simply returned the backplate of the switch assembly to the body of the mic (minus the slider) in order to cover the hole.

Then, because I was caught ill-prepared by the whole situation, I did not have the necessary length of wiring to fill the gap between the internal XLR pins and the capsule of the mic (now that the transformer and the switch had been removed), so I resorted to cutting as much wiring of the same gauge as I could possibly find around the transformer and soldered the pieces together. I did not use electrical tape to cover the splices; the voltages are so low inside a dynamic microphone that paper-based adhesive tape provided sufficient insulation in this case.

As gnarly as it was—and looks—putting all those segments of wire together, it worked like a charm. My SM58 sounds like a much more expensive microphone. I do have to drive the preamp hotter—all the way, actually—but the thing really works and is as silent as can be.

Now, I do not recommend doing this to a perfectly functioning microphone, especially because the SM58 is already very smooth sounding and there really wouldn’t be a good reason to do this, unless you are just curious and willing to sacrifice a perfectly good SM58. In my case, it really was a last-ditch effort, an act of desperation to try and salvage the mic—and it paid-off big time, luckily, but I would never had tried it without the need to.