After building a couple of microphone-parts.com 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...

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 buisiness 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.

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The frame of the mic with original circuit board removed

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Although it looks done, there's nothing inside the body yet. Ths is the kit bag in front of the donor body

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Early in the build - one of the two circuit boards in the kit

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Both boards done

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Boards wired in and attached to the frame

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Finished mic on the bench ready for calibration

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Calibrating the capsule polarization voltage (60.0 VDC)

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Finished mic with the two older siblings

Let's Compare and Contrast

I used an acoustic guitar as a sound source for this comparison. I put this mic against one of the 990s with the the Mic-Parts RK12 capsule and electronics and an early 90's 414BULS. In this sound sample, you hear the three mics play through the chord progression once solo'd out.  Then you hear the same three mics again one at a time in the full (very rough) mix. I dropped comments in where the different mics start.

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The three mics placed close together for the recording

The guitars have nothing on them. Zero EQ, Compression or anything else. They were recorded through the UA4-710d preamps set on "transistor" mode.

 

My impression (besides that I need new strings and to practice more)... 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.