Recording - May 2014 - 60

...where we bring you follow-up articles
with application hints and upgrade news
about gear already reviewed in Recording

&
Telefunken Elektroakustik
AR-51 and its New Capsule
A new heart and a new sound
for a well-loved condenser mic
by Paul Vnuk Jr.

Back in our November 2010 issue we took a look at a new microphone in Telefunken Elektroakustik's R-F-T series of microphones, the
AR-51. Since 2009, the USA-based Telefunken Elektroakustik has
been keeping the Telefunken legacy alive by offering USA handbuilt
spot-on recreations of classic Telefunken microphones, most notably
the ELA M 250 and 251 models.
Of course, when you see the words "recreation", "classic", and "handbuilt in the USA," the next word to follow
will usually be "expensive"! For this reason the company launched the R-F-T line, which takes its design principles and expertise and uses overseas parts and manufacturing to offer Telefunken models in the $1800 range
vs. the $5000-$7000 range of the USA-made products.
The R-F-T line makes use of a hybrid approach where
overseas parts are commingled with domestic parts and
assembled here in the USA.
Since its launch the R-F-T line has offered six different
models. The original AK-47 (U47ish) and M-16 (C12ish)
have been discontinued. The current line includes the
AK-47 MkII (reviewed October 2011), the CU-29
Copperhead (reviewed June 2011) which is a purely
modern Telefunken design, and the AR-51 which is
based on the ELA M 251E and the AKG C12. There is
also a stereo AR-51 called the AR-70.
The reason for this Reviewed & Revisited column is
that the AR-51 has recently undergone a capsule
change. The original model had a center-terminated TK67D capsule. The new upgraded capsule,
the TK51D, is a 34 mm dual-membrane,
edge-terminated capsule that Telefunken
feels is closer in sound and design to
the CK12-style capsules used in original ELA M microphones.
As of this review all AR-51 mics come
with this new capsule, and if you own
an older AR-51 you can send yours in and
get yours swapped for $199. But the question is, should you?
Questions and answers
After my original review I was so enamored of the
AR-51 that I purchased a pair; they are among my
favorite drum overhead mics ever. So in talking with the
guys at Telefunken, I had two questions: "Why did you
change it?", and more practically, "I already know I
love the sound of the original capsule... but will I like the
new one?"
The first question was answered by Telefunken Design
Engineer Ryan Loftus. His answer: "Since the AR-51 circuit is
designed after the C12/ELA M 251E, we wanted to introduce
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RECORDING May 2014

an edge-terminated style capsule in the AR-51 to
bring it closer to the sonic characteristics and construction of the CK12 used in those microphones."
He also took time to explain the benefits of the new
capsule. "The membrane of the TK51D has a larger
free-moving surface area than the center-terminated
TK67D. This inherently slows the transient response,
resulting in a smoother, open high end. This construction also provides an extended low-frequency
response that complements the amplifier perfectly."
Of course my last question still lingered: "Will I
like it?" Thankfully for myself and for our readers,
Telefunken shipped me out a TK51D-equipped AR51 so I could do some side-by-side comparisons of
the new mic with my original designs.
An AR-51 refresher
If you don't have the November 2010 issue handy,
let me quickly bring you back up to speed. The AR-51
is a tube microphone with 9 selectable polar patterns.
Internally it couples a NOS ECC81 twin triode
tube to an Austrian-designed amplifier circuit, a
USA-made PC board and a custom German
output transformer. It is housed in the
same C-12 steel body as the rest of the
R-F-T line, with a gray powder coat
finish and a smoky chrome covered
brass head basket.
It has an 86 dB signal-to-noise
ratio, 8 dBA equivalent noise, sensitivity of 13mV/Pa ±0.5 dB, 250 ohm
nominal impedance, 128 dB Max SPL,
and a 20 Hz to 20 kHz frequency
response.
Sound of the old
I found the original AR-51 exhibited a clear sound
with an airy width and depth. Its midrange exhibits
a lovely clarity and detail without being punchy or
forceful, and its low end is controlled yet smooth.
While I loved it on drums, it also became a prime
mic for bass cabinet and electric guitar cabinets.
However, I found the original mic rather source-specific
on most singers; I honestly never pulled it out much for
vocal duties.

Recording - May 2014

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