The Korby Convertible is a tube microphone body with four hot-swappable capsules that claim to sound like Neumann U 67, Neumann U 47, Telefunken Elam 251 and AKG C 12 mics. The mic is hand made, and every capsule hand-tuned in the USA by Tracy Korby, who has been reparing and modifying vintage mics for over 20 years for people like Butch Vig and Mitch Easter. The Convertible is voiced from his experience with those mics. I first became interested in the Korby Convertible when I was looking to replace a fantastic sounding U 67 a friend had loaned me for almost a decade, but needed back. By the time the Korby review unit arrived, I had already found a U 67 that sounded as good as the loaner, and I couldn't afford to buy the Korby. Had the mic arrived sooner, I would have seriously considered buying it instead of the Neumann. Unfortunately, when the mic did arrive I was in the midst of tearing apart my studio and building a new control room, so testing mics was out of the question. I loaned the Korby to my friend and fellow studio owner, Kirt Shearer of Paradise Studios. Kirt owns a vintage Elam 251 and has recorded records for CAKE and Toni, Tone, Tony; so I thought he'd be a good person to give the mic a run through. According to Kirt:
"The Korby mic seemed to really capture the vibe of the mic it was emulating. The 251 capsule definitely had the flavor of the original, especially the top end. The first vocal I tracked with it was a male vocal that happened to be a great match for that capsule. My first impressions were, 'WOW! What a mic!' Giddy with power, I tried a female vocal on it during the same session. Not a great match. She sounded nasal and thin. Then, I switched to the C 12 capsule (without powering down). All the problems were solved. She sounded great on the C 12, he sounded great on the 251. We jumped back and forth all day between the two, which was very convenient. We were also doing sessions for the US Air Force Band, and their unusual rapid-fire back & forth mic switching made the Korby a perfect mic, although that doesn't happen every day. Although I didn't have a real U 47 for comparison, the Korby U 47 capsule seemed to have the midrange vibe of the original-not the top-end zing of the Korby 251 and C 12 capsules, but nice definition in the middle. However we seemed to get some distortion out of the C 12 capsule. It also didn't seem to have the SPL handling of the Korby 251 capsule and didn't deal as well with closer proximity. Overall, we noticed that the Korby 251 had a hotter output compared to the other capsules. I never even plugged in the U 67 capsule. I am evil."
When I finally finished my control room, Korby needed the mic back, but I talked them into letting me keep it for another few days. I had a session doing some demos for a guy on acoustic guitar and vocal, and he was nice enough to put up with me using him as a guinea pig. We A-B'd a couple of mics to the Korby. The first mic I threw up next to it, of course, was my U 67. To my surprise, I actually liked the Korby 67 better! The bottom and mids were very similar, but the Korby had a top end that the U 67 didn't; and on this singer, the Korby sounded better! It turns out that Mr. Korby based his U 67 capsule on a mod that he's been doing on 67's for people. This mod gives the 67 more bottom and top, and while I didn't hear the bottom compared to mine, the top end was much nicer. Bottom line, don't expect this to sound like a stock U 67.
Next, we compared the Korby U 47 to a Neumann CMV 563 with an M 7 capsule. Not really a fair comparison-but what the hell. In this case, the CMV won out, but not by a huge margin. The M 7 had slightly scooped mids and sounded better on this vocal. Next we put up the Korby 251 next to a Telefunken USA Ela-M 251 (reviewed in Tape Op #34). The results here were pretty amazing; the two mics were nearly identical; both sounded fantastic. I never touched the C 12, having nothing to compare it to.
Bottom line, the Korby Convertible sounds great and does a really good job of emulating the mics it claims to. It's not cheap, but it is cheaper by a long shot than some of the mics it emulates-and it's surely more reliable. Also, it's definitely more versatile. It doesn't have the cachet of the Neumann or Telefunken name, but not everybody cares about that, especially non-commercial recordists. In my opinion, it comes down to this: for four prized vintage sounding mics (even though you can only use one at a time), this is a bargain. On the other hand, you could buy one $2500 mic and a dozen Chinese mics for the same price. You've gotta make the call. Fortunately, if you decide to look into this mic, the folks at Vintage King will let you evaluate it with all four capsules for seven days before they clear out your bank account.
If you're seriously considering buying a Korby Convertible, there are some additional points to know. The mic body comes in a super-rugged case, and each capsule is packaged in a beautiful wooden case. I questioned the long-term durability of the wooden cases, but I was told they've never broken in actual use. Secondly, the shock mount is one of the best I've seen to date. Often you buy a pretty pricey mic, and the shock mount seems like an afterthought. The Korby mount is a rugged, engineered-from-the-ground-up, aircraft aluminum affair with heavy-duty rubber bands that should last years. Tighten up the oversized positioning screw and this mic is not moving.