Micparts is a DIY microphone mod/build company started by Matthew McGlynn, of the wonderful microphone resource website recordinghacks.com and Roswell Pro Audio. Matt started Micparts a few years ago to offer upgrades for "donor mics" (generally less expensive Chinese mics, like the MXL 990) that were good platforms for modification to the electronics, capsule, or both. More recently the company has been offering complete mic kits (both solid-state and tube) that include the body, capsule, and circuit.
One of their latest kits is the 12-251, a reinterpretation of the original Telefunken ELA M 251 with the elongated AKG C12 body style made of heavy brass. This body is available in a black powder coated finish with the Micparts logo, or a bead-blasted silver finish without a logo. It's a classy look that's a little closer to the original AKG C12 cylinder. A note about the AKG C12/Telefunken ELA M 251 history: AKG introduced their C12 in 1953 and built them for about 10 years. Telefunken commissioned the ELA M 251, which was manufactured by AKG and based on the C12. The AKG C12 and the Telefunken ELA M 251 share the same capsule, but there's a variation in the circuit of the Telefunken that rolled off the top end a few dB, and the mics had different body/head baskets as well. As of publishing this review, Micparts has introduced a new kit called the V-251, which retains the single-stage circuit design of the original Telefunken ELA M 251. The capsule of the 12-251 is Micparts' own RK-12, which they also sell separately as an upgrade for "donor mics." This is a dual-diaphragm capsule that is rigorously tested and subject to strict quality control by Micparts.
The full 12-251 kit comes with a flight case and all necessary components to build the mic: An Electro-Harmonix 6072 tube, a 7-pin cable, an IEC power cord, and a pre-built, Chinese made power supply. For $169, you can add their VPS1 premium power supply kit, which includes Neutrik connectors and larger heat sinks for better long-term reliability, better noise filtering, and higher quality components throughout.
When I ordered my kit, I opted for the 12-251 in the silver finish (a $20 upcharge over the black finish) and added the VPS1 power supply kit. I've built a number of preamp and compressor kits over the years (Classic Audio Products, Inc. [Tape Op #77 & #95] and Hairball Audio [#84, #93, #110, & #126] mostly) and I'm generally comfortable with a soldering iron and digital multimeter, but this was my first foray into the land of mic building. There are two small PCBs for the mic, and the main components on them are pretty straightforward. The trickier part of the build is the wiring for the tube socket, the 7-pin output, and then from the socket to the boards, as well as from the capsule to the boards. If you're a first-time builder, this may not be the best kit to start with. The VPS1 power supply build was similar to the mic build in that the PCB population was mostly a straightforward affair, but the trickier part of the build was the wiring from the pattern selector switch to the jacks to the board. Nothing was insurmountable though - when I was done, everything metered proper continuity and voltage as expected (always a nervous moment in a build)!
Testing your build is always a bit nerve-wracking, as you hope for the best but always expect the worst, so I was overjoyed when the first thing I heard when I spoke into the mic with headphones on was my voice sounding big, resonant, and clear. It reminded me of what I like about my Soundelux E47 [#37] - a really pricey mic with a richness of tone that's just lush and "expensive" sounding. A good torture test for a mic is to see how it behaves when placed smack in front of a drum kit. The 12-251 doesn't have a particularly pronounced proximity effect, so back a meter or so from the drum kit gives a rather neutral, unexaggerated picture of the whole set. If you want a pushed or blown-out, extended low end, there are obviously better mic choices, but the 12-251 certainly holds its own as a hyper-detailed and smooth mic.
To hear how the 12-251 fared next to my Soundelux E47, I placed their capsules as close to each other as I could while running both through Vintech X73 [#47] preamps to my Apogee Symphony Mk II [#118] converters. Talking into the mics (set to cardioid at their power supplies) straight on axis from 8-inches away, the Soundelux E47 had the chestiness I'm so used to from that mic along with an airy, but decidedly non-hyped, high end. The 12-251 sounded equally classy but is very much its own microphone - the extreme low end was a bit less exaggerated, but no less present, and the top was like silk with a little more of the "air" frequencies than in the Soundelux E47, without even a touch of harshness. On my speaking voice, which is a reedy baritone (who actually likes their own voice?), I preferred the 12-251 over the Soundelux for its more balanced reproduction.
To really give the Micparts build a proper workout, I invited Lacey Brown laceybrown.com to my studio, along with her beautiful voice and acoustic guitar. I placed the 12-251, my Soundelux E47, and my Neumann U 89 capsules as close to each other as I could and recorded Lacey playing her guitar and then doing the same singing over the guitar arrangement. For these tests I used Seventh Circle Audio's T15 [#84] mic pres, which are transformerless and ruler flat from below 20 Hz to up around 40 kHz - so they provided a perfect testing platform to compare the pure sounds of the mics. I intentionally didn't label the tracks with any identifying clues and sent the Pro Tools session to a couple of other engineer friends to get their take on the three mics (I obviously knew which tracks were which mic). The consensus was unanimous that the 12-251 was the vastly superior mic on the acoustic guitar tracks - it provided the perfect balance of string attack/airiness and body from the guitar. I would be happy to have that acoustic guitar sound forever more.
Vocals were more interesting, and I think that's as much down to how we as people react to the sound of the human voice as it points to anything technical. Two of us preferred the 12-251 and the Soundelux E47 equally on voice, while the other preferred the Soundelux E47 and the Neumann U 89. Lacey has some pronounced sibilance in her vocal delivery that was slightly more apparent on the 12-251 than with the other mics, but I would gladly trade a little more sibilance in the source if it's balanced by the glorious presence and dimension that the 12-251 offers. She truly sounded like she was right in front of me rather than playing back on my monitors!
For my final round of tests, I compared the stock 7-pin cable the microphone ships with, to Micparts' premium cable made with Neutrik XLR7 connecters and Gotham GAC7 cable. I'm not usually a fan of cable tests - perhaps I'm too tin eared to hear enough of a difference? However, in this instance when using the 12-251 in front of a Fender ‘68 Deluxe Reverb (on loan from my friend Bill Rieflin), the sound from the XLR7 when compared to the stock cable was tighter and sounded more like what I was hearing from the amp in the room. The stock cable made the transients a little splashier for lack of a better description. Is it worth the extra $94 for the premium cable? I think so!
Enough of me waxing on about this mic. I think it's bloody brilliant and I imagine that Micparts will have difficulty keeping these in stock due to the orders. I honestly feel that if you're handy with a soldering iron and want a high-quality tube mic that easily stacks up to the classics, this is the way to go. Get one!