The Mic Shop: MS47 Mark II Tube Mic

For many years, Bill Bradley (Tape Op #42) has built a reputation for expertly repairing microphones in the Nashville area. Over ten years ago, Bill branched into building his own mics, and the MS47 was born. Recently, Bill decided he could do better, and with James Brian, he's introduced the MS47 Mark II, an upgraded and "future proofed" version of this mic. I've been using one for the last few months and can report back that I am most impressed and happy with the MS47 Mark II. The mic is obviously based on the classic Neumann U 47 tube mic, and features cardioid and omnidirectional polar patterns like the original. Its tube circuitry is remotely powered, so it comes with a Mic Shop–built power supply and cable, and includes a typical shockmount and a sturdy Pelican carrying case.

For my first test, I put it in front of a drum kit, a few feet out pointing at the drummer. I was able to easily get a clean image of the drums. The kit remained as balanced as the drummer sounded in the room, and the low end of the kick was nice and solid and felt correct. The MS47 Mark II doesn't have a ridiculously hot output level, and it was nice not to hear any distortion/overloading coming from the mic itself — you wouldn't believe how many modern tube mics won't even work near a drum set without a pad. Like a classic U 47, the MS47 Mark II doesn't get super shrill in the top end, and the cymbals sounded clear and natural, much like I was hearing in the room. I noticed this same relaxed but natural high end on some fiddle tracks I tracked for Jolie Holland. Though I was on the ready to pull the mic and grab a ribbon mic if needed, I kept the MS47 Mark II up and got some great takes. On another session, for The Jackalope Saints, I had to track a song with a seven-person group chorus and six verses sung by six different vocalists. I decided to do it in a single pass, so I put the MS47 Mark II up, switched it to omnidirectional mode, placed all seven singers in a circle, and had each lead vocalist move up closer to the mic for their verse. The variety of voices was wide, and what's telling is that every single person, male and female, sounded very clear, up front, and present on this mic. I also noted that the group vocals were captured superbly. Despite the vocals being a little, er, "rangey," the mic didn't crap out with the high volume levels or loose pitch. Being in omni mode, it also picked up the room ambience really well, which worked great in the acoustic-based track.

Over the years, I've had a few go-to mics that I could put in front of a singer when I was in a rush and trust that they would perform well. This is already one of those mics for Jackpot! I was so impressed that I called Bill and James to find out how this mic was designed.

Bill, you're known as one of the premier vintage mic restoration people. What led to building a mic? Were all the parts just lying around?

Bill Bradley: As a matter of fact that's exactly what happened. James and I were in the parts room one day, and I saw this little box on the shelf, and I picked it up, and it was full of [Neumann] U 47 capsules. I went, "What do you do with 35 U 47 capsules?" It was the impetus to start building a mic.

Was it easy to find mic bodies?

BB: The bodies I buy new from a company in Europe.

I know that finding the original Telefunken VF 14 tubes is impossible.

BB: VF 14 tubes are basically gone. We tried EF 14s and had pretty poor luck with those. But there's a tube called a Siemens E 81 CC that has worked out brilliantly.

James Brian: The new circuit uses that, so this is the MS47 MARK II — the first version used the EF 14. We just couldn't get enough of them that were suitable noise quality. It got to the point where it was just impossible to even find one tube to make a mic anymore.

BB: It was really tough!

JB: So we decided to develop a new circuit that was just as good, and this actually measures better than the old EF 14 circuit. The point was to use parts that were not going to go extinct, instead of relying on these tubes that there is a finite amount of. We wanted to use parts to make a "future proof" U 47–inspired microphone.

BB: Those old metal tubes had been made in the ‘30s and ‘40s, and they are rough.

What do you do when you are repairing a vintage U 47 and it needs a new tube?

BB: If it needs a new tube, we try to talk the owner into going with something a little more civilized.

How do you source the capsules?

JB: The capsules are Siegfried Thiersch [Thiersch Elektroakustik] M7s. Originally, we had that glut of K 47s, but we made it through that.

BB: They're long gone!

JB: We do prefer the Siegfried Thiersch M7.

BB: And I can go out and actually buy them.

How many original Neumann U 47s were made?

BB: There were slightly over 5,000. Maybe 5,500.

That doesn't bode well for supplying everybody with one.

BB: Not exactly, no. We get U 47s in all the time for service, and they vary from almost pristine — like the day they were built — to, "Oh my god, what is this inside?"

JB: A lot of them have been changed over to various tubes, whether it's a nuvistor, an EF 14, or a UF 14. We have to deal with them as they are. If that needs to change, we'll change it to another configuration. It's pretty rare that the ones with VF 14s really have any issues. We do also have a rejuvenation rig for VF 14s, and we are able to bring most of them back.

BB: We can kind of wake them up.

This sounds like magic.

JB: It's definitely not magic.

B: When they were originally built and set up, they were done at a very relaxed voltage. Consequently, the tubes get kind of lazy. All they need is a good kick in the ass, and they come back to life.

Have you had clients do shootouts with other U 47–style mics?

BB: Oh sure. They like ours! I'm certainly glad for that. I haven't heard of a losing shootout. It's encouraging.

JB: A lot of our mics are in the hands of the top engineers and producers in Nashville.

BB: They get a lot of exposure, and they get used all the time.

Is there a noticeable difference between the original MS47 and the MARK II?

JB: There are some users where we have converted their EF 14 to the new MARK II version. Across the board, everyone prefers the MARK II version. It's a little more open, and it's got a little more solid bottom end. Lower distortion, and the output impedance is extremely low for this type of circuit. It also has lower noise and will be a lot more reliable than the EF 14s are.

BB: It's basically the same mic but quite a bit better.

JB: We've only got one capacitor involved in the entire signal path. We chose all the components by ear. We went through a mountain of output capacitors to pick the one part that was gonna work with everything else. We designed the circuit to work with the original, custom Haufe Bv 8 output transformer. I designed a bunch of circuits with different tubes, and everything measured great, but we ended up choosing this one based upon how it sounded.

Were you able to take it around to different studios?

JB: Once we had the start with firm measurements, and then took it from listening and got it to where we thought it sounded good, then we sent it out to trusted users, without trying to poison the well with our opinions — to people who know and love the original mic, who are U 47 people. It's definitely a type of person who really likes U 47s. Mike McCarthy [Tape Op #94] was a big help. He loves U 47s! He owns a MARK II now.

Have you built other mics based on older designs?

BB: We build an MS12, which is basically an [AKG] C 12, and it's great. I am a big-time fan of C 12s, and this definitely satisfies my need for a C 12. Everything in it is available; I can go out and buy every part.

There's a variety of prices for current U 47–style mics. How do you determine what to charge?

JB: We wanted ours to be priced competitively. Our mic has a lot more hands-on work in it. I build every one of them myself. I make the power supply and the cable. Each one of these microphones is labored over intensively. It does not leave until it is 100% perfect. There's no assembly line or army of college students soldering circuit boards. This is all point-to-point wiring inside, and I make them one at a time. I prefer to do it that way.

Do you do a burn-in time and leave them running for a few days?

JB: Oh yes. The burn-in time is ridiculous. Most mics will be on for weeks. I listen to music while I'm working, so they're sitting on a rack burning in, and being exposed to all sorts of sounds. Everything changes and settles in the tube as it burns in. The voltages will settle. One aspect of this circuit is that everything is adjustable, so for each tube, the bias is adjustable. Each tube will need a different adjustment. It's all tuned to that individual tube, burned in, and we make sure everything is rock-solid and double-checked before it gets put into the Pelican case and deemed to be ready to go out the door.