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  • Warm Audio WA-251 Tube Condenser Microphone

    By Phil O'Keefe |


    Can you really get a '251 style mic for under $800? 





    In 1958, Telefunken GmbH (the German electronics giant, not the modern American-based Telefunken Elektroakustik) had a problem: Georg Neumann GmbH had decided to start handing their own product distribution, and would no longer provide Telefunken-branded U47s and U48s for them to sell, leaving Telefunken without a large diaphragm tube condenser mic in their product catalog. Telefunken turned to Vienna Austria's Akustiche und Kino-Gerate Gesellschaft mbH (better known as AKG), and asked them to provide them with one. AKG had been building their own C12 large diaphragm nine-pattern tube condenser microphone since 1953, but rather than re-branding that, a new microphone was developed that incorporated many elements of the C12, but also some from the U47, with a few new ideas tossed in for good measure. The new AKG-built microphone was marketed as the Telefunken ELA M 250 / 251. The 251 is a three (omni / fig.-8 / cardioid) pattern version while the 250, like the U47, has only cardioid and omni polar patterns. These are switched on the body (like a U47 / U48), not remotely as with the C12, and they have larger bodies than the C12, although not as large as the U47. Internally, the mic shares more in common with the C12; it has the same Haufe T14/1 output transformer, uses the same 6072 tube (in the "E" or export models; non-E models used the AC701k, as per German broadcast requirements at the time) and the famous (and highly complex) AKG CK12 dual backplate condenser capsule. However, the larger, flatter head grille on the 250 / 251 was given an extra layer of fine mesh screening internally that the C12 lacks; this, along with some internal wiring and construction differences contributes to the similar yet somewhat different sounds of the C12 and ELA M 251. 

    The Tele 250 and 251 are considered by many artists and engineers to be some of the finest sounding microphones ever made. Full and rich down low (especially when close-miking), with sweet midrange and a wonderfully smooth, detailed and extended high frequency range, they're simply amazing sounding mics. However, fewer than 2,000 of them were manufactured in the 1959-1963 production run, and today the vintage originals sell in the five figure price range… if you can find one for sale. The AKG C12 and the Telefunken ELA M 251 E have long been some of my favorite mics, and the CK12 is one of my favorite capsules. I'm one of the lucky few who has had the privilege of owning original 251's (actually, a pair of them) and also a Stephen Paul modified AKG C414 EB with an original CK12 capsule, along with a couple of very expensive and highly regarded 251 reproductions, so I know from extensive experience what the CK12 and a good 251 should sound like. Today, many companies make 251-style microphones; from nearly identical recreations to mics more loosely inspired by the originals. The model has also been popular with DIY builders, and mics based on its design can be purchased in kit form… but if you'd rather spend your time recording music than building the tools, you'll definitely want to check out the Warm Audio WA-251 microphone under review here…





    What You Need To Know

    • The Warm Audio WA-251 is a multi-pattern (omni / cardioid / Fig.-8 ) tube microphone that is based on the vintage 251. 


    • The WA-251 is an attractive looking microphone. The body is finished in a creamy yellow color. It isn't quite the same pale green-tinged shade as a vintage 251, but the finish is smooth and flawless and looks expensive, with the chromed bottom bell and grille assembly offering nice visual contrast.


    • The body is equipped with a round Warm Audio (WA) badge on the front side.




    • Warm Audio, the model name, and the CineMag logo are silkscreened on the back of the mic.   




    • The WA-251 measures 247 mm long and is 46 mm in diameter (9.72" x 1.81"), which makes it about 6 mm thinner than a vintage 251 (which is 52 mm in diameter) and a touch (3 mm) larger than a vintage C12's 43 mm diameter, making it look a bit more like a C12 than a 251.


    • The overall C12 vibe is further reinforced by the WA-251's head basket. While this uses a double layer mesh grille (like the vintage 251, and unlike the C12, which uses a single layer grille), its size and slightly dome-top shape is far more reminiscent of the C12 than it is of the 251.






    • Since the acoustic "space" the capsule resides in and the grille itself are two of the things that differentiate the two vintage AKG-built mics, I'm curious as to why Warm Audio decided on this particular body size and head basket style / shape for the WA-251, although I have to admit, the end result looks very classy, and the WA-251, while not being a direct copy of any other mic, does have its own vintage-flavored visual appeal.


    • Since a tube mic needs an external power supply, it's not surprising that the WA-251 comes with one included. It appears to be well-built. It has a very bright blue "jewel style" power on indicator lamp, the power on/off switch, a 115 V / 230 V mains power selector switch, and a IEC power receptacle on one side, while on the other end you'll find a 7-pin input jack (for the mic) and XLR output jack, along with a three-position pattern selector switch.


    • The pattern selector on the power supply is again, more reminiscent of the AKG C12, which uses a second external box that connects to the power supply for pattern selection, as opposed to the ELA M 250 and ELA M 251 which have their pattern selector switches mounted on the body of the mic. The WA-251 offers the same three options as the mic that inspired it, with omni, cardioid and figure-8 polar patterns.


    • The electronics of the WA-251 are based on the E or export version of the vintage 251. The capsule is an Australian-built model that Warm Audio calls the WA-12-B-60V. It's an all-brass, edge-terminated, dual-backplate design with 6 micron gold-sputtered diaphragms, and is similar to the vintage CK12.


    • While I wasn't able to disassemble the capsule (for obvious reasons) to check the depth of the resonant chambers or to see if the internal hole patterns are asymmetrical and match the original design, examining it from the exterior, it does bear a strong resemblance to the original CK12 capsules.




    • A JJ Slovak 6072a / 12AY7 is used for the tube. It is mounted in a ceramic tube socket with gold-plated contacts. It is oriented "correctly" for a 251 style mic, with the pins closer to the capsule, as opposed to the C12, which has the tube inverted, with the pins located further away from it. 




    • The rest of the parts are also of high-quality, with Solen French, Wima, and polystyrene coupling capacitors being utilized, along with 1% metal film resistors.




    • Instead of the Haufe T14/1 transformers of the originals, Warm Audio instead opted for a high-quality CineMag USA CM-13114 output transformer, which has a 12:1 ratio.




    • Warm Audio includes a five meter (16.4') Swiss-made Gotham GAC-7 cable with Zwee connectors to hook the mic up to the power supply. You'll still need your own XLR cable to connect the power supply to the audio interface / console / mic preamp, but the fact that Warm Audio includes a premium quality tube mic cable should not be discounted - it really does make an audible difference compared to cheaper cables.


    • One area where the WA-251 actually exceeds the performance of the original is noise - it's considerably quieter than the vintage microphones it was inspired by.


    • Warm Audio includes a nice set of accessories to complement the WA-251. In addition to the mic, cable and power supply, they also include a wood storage box for the mic itself, as well as a spider style shock mount. The shock mount holds the microphone much more securely than the one for the WA-47 - I was able to use the WA-251 in a "hanging" configuration on several occasions and never felt the mic was in any danger of falling out of the shock mount.






    • The Warm Audio WA-251 is covered by a one year limited warranty.




    • The difference in physical dimensions between the vintage 251 and WA-251 does have an impact on the sound, just as the differences contribute to the "similar yet different" sounds of the C12 and ELA M 251. Frankly, I am kind of surprised that Warm Audio didn't build the WA-251 inside of the Warm Audio WA-47Jr style body, which is much closer to the dimensions of the vintage 251, and even has a more similarly-sized and shaped head basket. It would have also allowed them to put the pattern selection switch on the body of the mic too, as with the originals. 


    • There is no pad or high pass filter on the mic or the power supply, but then again, a vintage 251 doesn't have those features either.


    • As I said about the WA-47, if you're looking for an exact clone of the classic vintage mic, this isn't it - but if you're looking for a mic that has some very similar sonic characteristics to the classic AKG tube mic designs, it's well worth auditioning one for yourself.


    • While no "camera style" case is included with the WA-251, the cardboard box it comes in does have internal foam that is cut out for the mic and accessories. The included foam could potentially be transferred into a user-supplied case; Harbor Freight offers some that sell for as low as $25 that might be easily modified into something suitable.




    Again, the question of your expectations is important; if you are expecting an exact reproduction of a ELA M 251 E for $799, you're probably going to be disappointed, but you'll also be missing the point - it's really amazing just how close you can actually get to those vintage mics for a heck of a lot less. Judged on its own merits and not comparing it to anything else, the WA-251 is a really nice mic - much nicer than the relatively affordable price tag might lead you to believe. It looks and sounds polished and expensive. You might be able to build something similar if you have the soldering chops and time, but you probably won't save much (if anything) by doing so, and with the WA-251 all of the work has been expertly done for you, and that work is warrantied. While it doesn't sound identical to any particular 251 (and considering the fact that the vintage originals have all aged for over 55 years now, and no two sound identical anyway), it does have an instantly familiar sound that bears a strong family resemblance to both the 251 and C12. While the internal circuitry is very similar, the WA-251 is not an exact replica of a vintage 251. The shape and size of the body, and specifically the head grille size and shape are different; the impression I get every time I look at it is "short body C12 replica" more than "251 replica", and sonically, it reminds me somewhat of a cross between those two vintage classics that leans more towards the 251. It definitely has a very vintage AKG-like sound to it. Strikingly so, considering the price tag. As such, it's a great choice for use on male and female vocalists, guitar amps, drum overheads, reed, brass and string instruments, piano… it's versatile enough to authoritatively handle practically any miking task where you'd normally employ a large diaphragm tube condenser.

    Warm Audio makes several other nice microphones, including the Warm Audio WA-47 that I reviewed previously, and a lot of people may be asking themselves which of the two tube mics they should get. Ideally you'd want both in a well-rounded mic cabinet, but if you can only afford one or the other the question becomes much more difficult. The price of the two is close enough that it shouldn't be a major factor, but the two microphones definitely sound different, with the WA-47 being a bit warmer, and with more forward low-mids, while the WA-251 is more open sounding, with a more present and detailed sounding high frequency range. If you're using them mainly for vocals, it will depend on which one sounds best with the individual vocalist. I would probably recommend the WA-251 for someone looking for a slightly more versatile mic - I think it works exceptionally well on a wider range of sound sources (not just vocals - it's a great instrument mic too), but when the WA-47's the right match, it can really shine too, so you really need to try them both for yourself to see what you like best. The WA-47 is great for warmth, "size" and impact while the WA-251 is brighter and more open sounding, and tends to sit just right in a mix more effortlessly, often needing little to no EQ. With both in your collection, you'll be ready to handle just about any vocalist, regardless of their individual vocal characteristics, and you'll be able to do a great job recording a wide range of instruments too, from guitar amps to acoustic guitars, to pianos and drums - while I didn't have two on hand for stereo, a single WA-251 sounded awesome as a mono overhead mic on my drum kit. The Warm Audio WA-251 is an impressive mic. Even with several other very nice mics in my collection, and as with the WA-47, I don't want to let this mic go - if Warm Audio will sell it to me, I'll be adding it to my collection. I suspect that upon hearing it, a lot of other people are going to do the same thing and purchase a WA-251 for themselves. It's definitely a keeper! -HC-


    Want to discuss the Warm Audio WA-251 or have questions or comments about this review? Then head over to this thread in the Studio Trenches forum right here on Harmony Central and join the discussion!




    Warm Audio WA-251 Tube Condenser Microphone ($799.00 "street")

    Warm Audio's product web page     


    You can purchase the Warm Audio WA-251 Tube Condenser Microphone from:


    Full Compass     

    Guitar Center     

    B&H Photo Video   

    Musician's Friend     


















    Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.  

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