UM 70 capsule with MV 692 preamp

Gefell UM70/MV692

The sound of this mic is what I was hoping to hear every time I bought a U87.

Just a nice natural sound with a clear, clean high end and enough proximity effect to give it body. These mics work great on acoustic guitar as well as male and female vocals. Gefell's M7 capsule -- the same capsule used in Neumann's no-longer-made but highly sought after U47 -- gives these mics its smooth natural sound. Unlike the modern UMT70S (which also employs an M7 capsule) the UM70 with MV 692 body (sometimes called the impedance converter or mic amp) includes a transformer which gives it that certain mojo the modern ones don't have.

Here's the catch -- there are so many variations of these mics that people get confused. First, you have the MV 691, which is essentially the same as an MV 692 except there's no low cut or -10db pad. Also, the originals came with Tuchel connections, although you can get them converted to XLR or just use a Tuchel to XLR cable to get around the connection problem. If you want to go back further, the MV 690, MV 691 and MV 692 models had no phantom power whatsoever and required a power supply to operate them. Phantom powered versions didn't come along until the MV 692 P48V version, although earlier versions could be converted.

There's more confusion. The MV 690, 691 and 692 models all came with their own set of idiosyncrasies. "The 690 has no built-in DC/DC converter so not all capsules will work or even fit," says TAB Funkenwerk's Oliver Archut, an expert on all things Neumann and Gefell.  "The 691 is the universal pre-amp that works for all capsules, but the quality spread due to East German/Russian components is quite large, and in my experience only two out of 10 will work quite fine. The 692 is an even bigger nightmare than the Elam, due to its 'people's own' duroplast. Once broken there are no replacements. But the bigger problem is the op amp based electronics."

Still more confusion. Two types of no-longer-made MV 692s exist, the older RFT model and the newer Microtech-Gefell version. The latter comes with factory installed XLR connectors and an updated Microtech-Gefell logo. They were later replaced with the non-modular UM70 (essentially the same mic without a removable capsule) and then the UM70S. According to Gefell spokesperson Michael Militzer, "The 'S' stands for 80V charging voltage."

Capsules can get confusing, too. The UM70 capsule can be adjusted to cardioid, omni and figure 8, but there's also an M71 which is a cardioid-only large diaphragm capsule and an M70 capsule which is a small diaphragm (or medium diaphragm for you purists)  nickel capsule. There are several no-longer-made capsules that can still be found on Ebay -- the M93 far field omni, M94 small cardioid, M69 near field omni and the M73 shotgun. And let's not forget, the modern versions have gone with the capsule names plus a T stands for transformerless so we now have the UMT70S and UMT71S.

There's also a tube version of the amp, the MV 582, but I don't want to get into that at all. Is that it? Nope. There's still one more confusing aspect to these mics.  The part that attaches to the capsule, the body or handle of the mic, is sometimes called the preamp -- not to be confused with the mic preamp you'll plug the mic into to amplify it and charge it with 48v phantom power. Other people call this handle the head amp and some others call it the impedance converter.

Finally, Archut emphatically adds, "You point out the confusion on the model and sub versions, but in my view the biggest confusion is the idea that it will sound like Neumann, which it does not!" Some people like to compare the UM70 to a U47 because they both employ M7 capsules, and that's definitely a mistake since a vintage U47 tube mic will sell for $7,000 or more.

There's one more downside to these mics: the only place to get the capsules properly serviced is in Germany. If you want your UM70 capsule reskinned, you'll have to either send it to Microtech-Gefell or Sigfried Thiersch -- and some will argue that only Gefell makes an authentic M7 capsule.*

However, to repair or convert the preamp can send it to either Gefell, Peter Drefahl or Andreas Grosser -- all who live in Germany -- or Marik (aka Mark Fouxman) in Salt Lake City, Utah at ribbonmic_at_comcast_dot_net.  The good news is that these mics can be be refurbished as good as new (or modified to sound better than new) and good working mics can be found on eBay or elsewhere for $1000 or less.

As I said at the onset, the UM70s I own sound better than both the modern and vintage versions of the U87s I used to own. Unfortunately, they don't impress singers in the studio the way a U87 does, probably because they look like little lollipops while the U87 looks like a real studio mic. Further, most people have seen a U87 on TV or in the movies -- whether they know it or not.

There's really only one thing a UM70 MV 692 combo has going for it -- sound. Nice, clean, natural sound.

* * *

(*It should be noted that some long-time uses of M7 capsules such as producer/engineer J.J. Blair and Neumann mic expert Klaus Heyne have noticed a decline in quality of the current M7 capsules coming from Gefell lately.)