Another Microphone (re)Build – MXL910

Editor’s Note: Since writing this article, I have been doing mic mods and builds with my own components instead of mic-parts kits. Mic-parts makes awesome stuff, but I am much more excited about my own discrete board designs and capsules. Please see my mic mod shop for more info and contact me if you have any questions. Now, please enjoy the article!

After building a couple of MXL990 kits last week, I did some shoot-outs between them and against other mics in my collection. I discovered that one of my existing mics had a problem. First, some background…

mxl 910 mod

Before I found out about mic-parts, I had a few microphones from a company called Michael Joly Engineering on Cape Cod, MA. MJE was in the business of doing mods on cheap mics and making them into really nice mics. MJE is no longer in the microphone business though. Like Mic-Parts, he had a “47” version of a capsule which had flat frequency response and could be a drop-in replacement for the cheap chinese mics with linear circuits (no high frequency compensation). He also did electronics upgrades. One of the MJE mics I had was a modified MXL910. It had the MJE “premium electronics” and his “K47” capsule. This mic always sounded great but it suffered from some intermittent noise and hum.

During the shoot-out, the MJE910 had a constant high frequency oscillation (like someone whistling). I took the mic to the bench and tried again to find out what was making it flaky, however all the solder connecitons looked fine and I didn’t see anything wrong visually. I sent an email to Matt at mic-parts and he suggested I swap in one of the 990 capsules that I had just removed from the previous donor mics as a test. That would eliminate either the electronics or the capsules as being the culprit. Great idea! I did just that, and the whistle was still there which clearly pointed to a problem on the circuit board. With that, I ordered the mic-parts kit that will fit this Mic – the MP-V57.

In just a couple hours, I had the mic re-furbished with new electronics and the existing MJE K47 Capsule. But not before painting the body cylinder the same funky green color I did the 990s with!

Below are some photos of the build.

mxl910 gutted and body painted
The frame of the mic with original circuit board removed
mxl 910
Although it looks done, there’s nothing inside the body yet. This is the kit bag in front of the donor body
Early in the build – one of the two circuit boards in the kit
Both boards done
mxl910 with mpv57 kit
Boards wired in and attached to the frame
modified mxl910 finished on bench
Finished mic on the bench ready for calibration
mp-v57 kit calibration
Calibrating the capsule polarization voltage (60.0 VDC)
Finished mic with the two older siblings

Let’s Compare and Contrast

My impression… The 414 and 990 are very similar. Silky top end and not really forward on the upper mids. The 910 with the K47 capsule has that neumann-ish upper midrange push. I am liking the 990 more than my 414. The 414 does more tricks (multi pattern, pad and filter), but the basic tone of that 990 is just a little nicer to me.

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