Choosing a World Class Microphone

PLEASE NOTE: This article has been archived. It first appeared on ProRec.com in August 2002, contributed by then Senior Editor Bill Park. We will not be making any updates to the article. Please visit the home page for our latest content. Thank you!

I’ve been upgrading my studio for a couple of years now. Each improvement and change has brought other weaknesses to light. Each improvement has been a double-edged sword, bringing both the joy of better audio and the curse of finding yet another area that could be addressed.

All along the way, various friends have remarked upon my lack of a world-class large diaphragm tube vocal microphone. I have an eclectic and interesting mic collection, and there is little to complain about. But when it comes to large diaphragm condensers, my choices are middling at best. I have a Neumann U-89. I have a pair of AKG 414s, one with the C-12 capsule, one with the newer capsule. These are my main choices. I have an Oktava 219 and a pair of Cascade M-20s, none of which I have ever used. It is easy to see that my options are not horrible, but not up to par with the rest of my system, and there is nary a tube to be found in the bunch.

I look at mics the same way that I look at guitars, amplifiers, and mic pres. This is the link in the signal chain where I try to pick my coloration. Correct choices in these areas lessens knob twiddling and effects chaining further down the line. Even the decision to use an uncolored mic and/or mic pre is a creative choice, with its own implications. My friends are correct… I am due for a large diaphragm tube microphone.

I look at the new offerings from the major manufacturers, and I look at the vintage market. The new offerings from major manufacturers hold some interest, but I’m drawn, probably like many other suckers, to the vintage market.

Buying Vintage

Now, there are really TWO “vintage” marketplaces. There is the ebay/internet/music store ‘vintage’ mic market, where anything with a little dust on it is ‘vintage’; and there are the people who understand The Real Deal. In the ebay/interent/music store market, anything that is labeled “Neumann” is valuable, and anything that purportedly has a C-12 capsule is valuable, and people pay outrageous amounts of cash in purchasing products that they do not understand. And there are more ways to scam the unwary buyer in used microphones than there are in used cars. As Tom Waits said, “There’s a sucker born every minute, and you just happened to be coming along at the right time…”

The actual vintage microphone market, as conducted by knowing professionals, is an interesting area. These people know the various scams that are perpetrated on clueless buyers. They know the various production runs of mic models, and which ones were good and which were dogs. They also know that, due to component aging and due to various methods of usage, care, and storage, most vintage mics do not sound alike within a given model. When one of these people sells a mic, there is a lot more to the description than “Crumpus 762!” and when one of them buys a mic, it is generally opened up and carefully examined for original parts, modifications, and any discrepancies.

Still, the ‘vintage’ sound is most desirable, and a vintage mic most appeals to me as the answer to fill my need for a World-Class Vocal Microphone. So what vintage mics are at the top of the heap in desirability?

Here’s my short list:

Neumann created the U47 in 1947. This is the granddaddy of all modern vocal microphones, and one of the designs that set the standard for how a large diaphragm microphone was supposed to perform. Among its other innovations, it was the first large diaphragm condenser to incorporate a pattern switch. The two patterns were cardioid and omni. Telefunken originally sold this microphone for export until 1963, when Neumann decided to join the export market. Although some people ascribe mystical qualities to a Telefunken-badge on a U47, there is no functional difference. There were model changes and updates throughout the production of the U47, but the nameplate is not an indicator.

The U47 first used the famous M7 capsule, which was also used in a number of other Neumann designs. Versatile and rugged when treated properly, these capsules provided a great sound and long life. But like any other diaphragm, the M7 is subject to aging and abuse. As the capsule ages it dries out and looses it’s flexibility. Tiny cracks begin to appear on the diaphragm membrane, and the microphone looses its response characteristics. Later versions of the microphone used the K-47 capsule.

The U47 amplifier section was designed around the Telefunken VF14, a steel tube originally built for the army and used in German field radios during World War II. In 1959 Telefunken ceased producing this tube. By this time, the only remaining customer for the VF14 was Neumann. Shortly afterwards, Neumann withdrew the U47 from production. By the 1970s, VF14 tubes were gone from the market. Thousands of Neumann U47s were produced, and with no replacement tubes available, countless modifications have been attempted to allow the microphone to operate with various other tubes or solid state replacement devices. None have proven to be satisfactory, and the buyer should beware.

The hardest to find of the popular rare vintage large diaphragm tube microphones would be the series that was built by AKG. These would be the C-12, Elam 250, and Elam 251.

The AKG C-12 was produced from 1953 to 1963. It had a remote controlled pattern selector box located between the microphone body and the power supply. Based upon the CK-12 capsule and the 6072 vacuum tube amplifier, this microphone had achieved cult status by the 1980s. The original C-12 was replaced by the C-12A, a microphone that used a Nuvistor amplifier circuit and looked a lot like the 414 of today. This is nowhere near as desirable a microphone, and it is entirely a different sort of product. In 1994 AKG attempted to re-issue the C12 as the C-12 VR, but it is not even close to the sound of the original.

A similar microphone based on the original AKG C-12 was produced for Telefunken as an export piece, designated the Elam 250. The major difference was the body construction, which was wider, with a heavier grille. A two pattern selector switch was placed on the microphone body.

A further modification came with the design for the Elam 251 and 251e, when a third pattern was added. A stock 251 can sell for upwards of $20,000. The “e” designates that the microphone was earmarked for export from Germany. These versions use the 6072 tube, also found in other designs. The non-export model used the AC701 vacuum tubes, which had become a standard tube in the German broadcast market.

The Neumann U67 was launched in 1960 as the planned successor to the U47. By the time the last U47 was made in 1965, the U67 had achieved this goal. A new capsule was developed for this design. The K-67 capsule allowed for a true figure of eight pattern. This enabled the U67 microphone to have three patterns instead of the previous two available on the U47. Also, a switch and compensation circuitry was incorporated to counter the proximity effect, as many singers were beginning to sing directly into their microphones. The amplifier circuit was built around the EF86 tube, at the time a more modern tube design than the war surplus VF14M or the 701. Following the long standing Neumann tradition of naming a microphone after the year that it was introduced, this microphone was originally released as the U60. But someone in marketing decided that U67 sounded closer to U47, and Neumann wanted to piggy-back on the success of the previous model. The official line was “to honor the origins…” or something like that. Many thousands were sold.

Buyer Beware

Okay, so I have a short list. I left off the M-49 and the C-24 and a few other options. But even with a list of four or five, there is just too much to know.

It is obvious to me that I cannot buy intelligently in the vintage market. It’s one thing to buy a couple of $700 or $800 Neumann or AKG small diaphragm condensers and have them brought back to factory spec. It is quite another to try to purchase an ELAM 251, Neumann U47, U67, or original AKG C-12. I simply do not have enough knowledge to play on this field at this level. After I research the pricing of desirable vintage mics from reputable dealers, I am also aware of the shortfall in my bank account that makes such a purchase an impossibility at this time. Probably at any time.

Another factor with top of the line highly desirable vintage microphones is that, due to their age, components are reaching failure points. A vintage microphone could need regular visits to the shop to replace old electronics. The total cost of ownership could rise well above what one might originally anticipate. The availability of replacement tubes is another question. Since some of these tubes haven’t been manufactured in decades, there are only so many to go around, and that number decreases daily. Consequently, an owner could find himself with a bill for $1,000 or more just to replace a tube, and eventually find that tube to be unobtainable at any cost. Solid state substitutes have proven unacceptable so far. And there is also the issue of diaphragms. Another hard to find, hard to replace part that just has to be seriously expensive. Even the appropriate cables and connectors are expensive and somewhat rare. Maybe I need to look at newer choices.

What is the next viable option? There are a handful of people out there manufacturing quality microphones to exacting specifications. I’m not talking about cosmetically similar Chinese knockoffs, mass produced off-shore; or parts made off-shore and assembled here and available at any music store for under $200. I mean real, hand crafted quality workmanship, with custom made diaphragms, individually tuned for perfect response. Some companies are even making functionally exact copies of famous vintage microphones.

Other Options

I am lucky to have one such company located in my area. In fact, Korby Audio Technologies is the company to which I send my mics for repairs, and my used microphone purchases to have them brought back up to factory spec. Tracy Korby is well known throughout the industry and has a stellar reputation. And he only lives a few miles from me. In addition to his repair work, Tracy has been making high quality microphones for many years, and has received accolades from many quarters. Eric Johnson, known for being seriously picky about details, particularly when it comes to his tone, uses a custom Korby Audio CM3 based upon an AKG C12. Lenny Kravitz owns two based upon the Elam 251, and several custom made Korby mics.

Chosing a new microphone with a vintage sound seems like a good plan. A new microphone is going to require much less maintenance than a vintage one; and the components, since they are new, are going to hold up a lot longer for me before they need to be replaced. Buying such a microphone locally has obvious advantages, too. It is even better that I know the manufacturer and have been a customer for a long time. I do not really consider buying from anyone else.

So what does Korby Audio have available today? Korby Audio Technologies has just released a microphone line with a unique twist in large diaphragm tube mic technology. It has removable capsule heads, and a number of microphone bodies with different electronics. I can buy one complete microphone now, and buy other bodies and capsules later to effectively expand my mic locker for several times less than what it would cost to own the vintage equivalents.

This new microphone is called “The Convertible” and, in their words, is: “An Interchangable Classic Microphone Capsule System Designed and Hand-Built by Korby Audio Technologies”. The new body style is a clean, powder-coated cylinder, color coded to designate model number and amplifier electronics. The capsule is housed in a sturdy bright nickel plate and mesh grille assembly. The capsule assembly simply pulls out, with no twisting required. The whole capsule assembly is mounted on a 4-pin socket. To replace a capsule assembly just line up the pins, and insert the capsule to the body with a gentle push. Done deal.

Korby Audio M10

The first available amplifier body in the series is the Model 10, which is an attractive gray/white color, containing electronics based around a 5703 vacuum tube. There are two additional microphone bodies under current development. One is a different tube style and one is a solid state model. More models are on the drawing board.

There are four capsule styles available at this writing. These are the 47, the 251, the 12, and the 67M, which correspond to the Neumann U47, the Elam 251, the AKG C-12, and a custom modified version of the Neumann U67. There are several more popular models in development. Korby Audio has always excelled in custom modifications, so virtually anything can be created for the customer who wants something special or unique.

The Model 10 microphone comes housed in a beautiful foam-lined wooden presentation case and is accompanied by a handsome and uniquely designed black shock mount, Korby Audio power supply, and cable. There is an optional flight case available, which holds all four capsules, the mic, shock mount, the power supply, and the cables.

I should explain about the 67 modifications. The original U67 is a microphone with an overly forward midrange. This has a lot of uses, and is great for fattening things up. But the downside of the original Neumann design is that the lows and highs were sacrificed. Korby Audio has been performing a modification to stock Neumann U67s, which extends the highs and lows, while preserving the mid characteristics. In my opinion, this yields a more useful, less dark sounding microphone. Korby Audio has made this modification a stock part of their 67M capsules. I now that it is a little confusing, but the other Korby capsules are all emulations of stock microphones. But the 67M is not a stock U67 emulation, but an emulation of the Neumann U67 after a Korby modification.

I call Korby Audio and ask which microphone capsule they would suggest for my voice. I sing in a kind of David Crosby-ish voice, and I asked their recommendation since I have no experience with mics like the Elam 251 or the AKG C-12. It is not that simple though. The Korbys insist that I need to hear the mics. I would just as soon take their recommendation, looking at it as the advice of an experienced professional. After all, that I what I expect my clients to do when I suggest something to them.

“What would you sell to David Crosby if he called you to buy a microphone today and wanted you to ship it out right now?” I press.

“Well,” Nadine Korby replies, “Since you live so close to us, you should really hear them. But I’d probably look at a 251 or our 67M capsules. Why don’t you come over and listen to them?”

I explain that since I don’t have any experience in this area of mics, that it would be a waste of our time. I don’t know what a real Elam 251 sounds like, so how could I judge their version of a 251, or any other microphone of that value? “Oh,” says Nadine. “We can fix that. What are you doing on Friday?”

Listening Test

And when Friday morning rolled around, Nadine showed up at the studio door with a vintage stock Elam 251, U47, U67, and a modified U67. These were not just any group of vintage microphones with unknown pedigrees. They happened to be the microphones used to record some very famous multi-platinum artists.

There is a certain synergy of events that has been telling me that this is the correct time to make this particular purchase, and here is a part of it. This particular group of rare microphones, all happening to be in the Korby Audio shop at the same time, all being completed at the same time and being available to be used for comparison is a good sign. The stars are in alignment. I got my black cat bone. My bread fell, buttered side up. The gypsy woman told me… well, you get the idea.

Although they have several AKG C-12 microphones in the shop, they did not happen to have one repaired and ready to show. Somehow I will suffer though this absence. In addition, Nadine bought the new Korby Audio Model 10 mic with the 251, 47, and 67M capsules. Not having a vintage AKG C-12 to show, she did not bring the Korby Audio C12 capsule.

It was an interesting morning. I was a little intimidated to be working with microphones of such quality and pedigree. Though we were using them with the owners’ permissions, I was reluctant to handle them. Since they were not mine, I preferred that Nadine do all the setup work. She knows more about it than I do, anyway.

I matched the gains between the Korby 251 and the original Elam 251, using my John Hardy mic pres. I pulled out my Santa Cruz, and played and sang. I did the same comparison between the Korby Audio versions and the Neumann 47 and the modified Neumann 67, and the stock Neumann 67 just for the fun of it. Eye opening. Which did I like best?

First let me say that the Korby mics do a fine job of duplicating the sounds of the original microphones. I do not think that anyone could identify which was which in a blind listening test. Not that many of us are going to get a chance to have such a World Class array of microphones at our disposal at any given time, anyway. The decision for me became a choice of which Korby microphone capsule I preferred for my voice and my guitar.

Damn, they all sound good, and in different ways. I can see a use for all of them, and I want them all. I have been very frugal this month, so I can buy the Model 10 and one extra capsule. I think that my capsule choices will be the 251 and the 67M. I know that the 251 will sound good with just about anything, while the 67M has a certain character that I found attractive. The 67M sounded outstanding with my Santa Cruz acoustic guitar, too.

I’ve made my decision and placed my order. With luck, I will get my brand new Korby Audio Technologies Model 10 by the time you read this. I’m going to do some side-by-side recording, and I’ll let you know how it comes out.

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