Heiserman: H251 Tube Mic

Clones of classic vintage tube microphones have become a common occurrence in pro audio. As a result, I have had the opportunity to hear and compare many different reproductions of famous mic designs next to their predecessors, such as the Neumann U 47 and U 67, AKG C12, and Telefunken ELA M 251E. Unfortunately, a majority of copycats have left me unimpressed. Recently, however, Heiserman has been cracking the code on building clones that look and sound extraordinarily similar to well-known vintage mics. After successfully designing and building their H47 tube mic [Tape Op #145] (a remarkable-sounding replica of the prized Neuman U 47), Heiserman is now releasing the H251, their clone of the rare Telefunken ELA M 251E originally manufactured by AKG for Telefunken in the ‘50s.

My first impressions of the various H251 components were extremely positive. It comes in an industrial-grade Pelican-style case that comfortably and safely houses the mic with the included power supply and cable. Aside from the Heiserman badge, the H251 looks identical to its vintage counterpart. Heiserman has done a great job recreating the iconic look, from the grill down to the mount. The power supply is robustly built and noticeably heavy, which is generally a good sign in my experience. While it does not physically resemble the original power supply, it is well constructed with top-notch components. Heiserman has gone to great lengths to make this mic as true to the original as possible. The mic’s HK12 capsule (also available for purchase separately) is hand-assembled in the USA. Every dimension and all materials used are nearly identical to the original brass AKG CK12 capsule used in the vintage Telefunken version. The transformer is a historically accurate T14, and the tube is a modern TAD (Tube Amp Doctor) hand-selected 6072. The only difference between the internals of the H251 and the original is its binder-style connector to the power supply. Overall, the look and feel of all parts in the system is top quality with an exceptionally classy appearance.

To begin my testing, I recorded a simple song using the H251 on everything. But first, I let it warm up for about an hour, which is vital for a mic like this as often they do not reach optimum performance for at least 30 minutes. I did notice a little tube sputter coming off the output for about the first two minutes after powering on, but it went away, so I attributed that to the tube warming up. From the moment I started playing acoustic guitar in front of the H251 with headphones on, it was obvious that this mic had a beautiful sound. The top end is airy and clear, without any harshness, and the low end feels perfectly balanced. I did two passes of acoustic guitar, then moved on to record a vocal. On my voice, I again heard a lovely top end (without any noticeable sibilance) and a nice full-bodied bottom end that made it very inspiring to sing into this mic. The H251 has a gorgeous proximity effect that makes the voice feel sparkly, intimate, and “immediate.” Together, the guitars and vocals sounded smooth and balanced, with no EQ adjustment. I could hear a silky, airy top end without any harshness that I have long associated with vintage Telefunken 251s and AKG C12s. At this point, I wanted to see how it would respond to a louder, higher SPL source with a touch of distortion. I plugged my ‘40s Gibson lap steel into a low-watt guitar amp and cranked it up with the H251 about six inches away. To my surprise, the H251 had no problem handling the high SPLs and sounded excellent on the grungy vintage lap steel. All the tracks together had a lovely sheen and glue without any processing at all, which is exactly what I would hope for in a high quality tube mic.

Over the next ten days, I was mixing an album for an artist who had asked me to add some subtle production to their tracks. I set the H251 up in the control room and used it on various overdubs, mostly percussion tracks – such as tambourine and shaker – that tend to be difficult for brighter mics to handle. Like the original Telefunken mic, the H251 offers three polar patterns: cardioid, omni, and figure-eight. I experimented quite a bit using the omni and figure-eight polar patterns, sometimes at long distances, to get a feel for the mic's "reach." Great mics can reach out and capture a source from far away while still sounding immediate, and I wanted to see if the H251 exhibited these characteristics. To my delight, the Heiserman has fantastic reach in all polar patterns, and the omni setting is exceptional at bringing in some room sound without losing the immediacy of the source. Tambourines sounded wonderful from 10 to 15 feet away, and the H251 also captured the detail of a quiet saltshaker from several feet out, allowing it to sit perfectly in the track. Additionally, this mic has a low noise floor and never gave me any problems recording quiet sources. Overall, the H251 excels at recording percussion elements, and the selectable polar patterns are helpful for tailoring room sounds within the recording space.

I wanted to perform an A/B test with an original Telefunken ELA M 251E. For this, I traveled to Nashville, where Jeff Steiger of Classic Audio Products, Inc. fame had offered to let us use his “Dolly” mic, a beautiful vintage 251E formerly owned by Dolly Parton, that I could compare to the H251. Renowned producer Johnny K (John Karkazis) hosted this A/B test in his room at East Iris Studios, and singer Lera Lynn was our subject. With Johnny at the helm, we recorded Lera singing into both mics over an acoustic guitar bed and then set up a blind test in the control room for everyone. Both mics sounded wonderful on her voice and very similar. However, there were some slight differences – probably due to the age of the components as much as anything else. The H251 was slightly more open and clear sounding, while the “Dolly” 251 E was slightly more wooly and dark. The differences were subtle, and it was difficult for me to decide which one I liked better at that moment. The most important takeaway from this direct comparison was that Lera picked the H251 as her favorite in a blind test. That tells me that this mic can stand up proudly next to a “holy grail” vintage mic while sounding better to an artist, which is as essential as anything in the real world of making records. When I brought the tracks back to my studio’s familiar environment and did a blind A/B there, I also picked the H251 and ended up using that in a mix. Its clarity and immediacy brought out an intimacy in the vocal that felt the most musical to my ears.

Overall, my experience with the Heiserman H251 was resoundingly positive. After using it in my studio extensively and hearing it next to an original Telefunken ELA M 251E, I can say without hesitation that this is a world-class mic that stands tall next to the vintage classic it was designed to replicate.