Pearlman 250 Condenser Studio Microphone
By Barry Rudolph
The Pearlman 250 is a tube studio condenser microphone built as closely as possible to sound like the famous Telefunken ELa M 250E dual-pattern condenser microphone. The Pearlman 250 condenser microphone is hand built, one at a time by Dave Pearlman in the tradition of the Neumann and Austrian classics as they were original designed and constructed post-WWII. Same as Telefunken's ELa M 250E, the Pearlman 250 has both omnidirectional and cardioid polar patterns. The Telefunken ELa M 251E is a three-pattern version that adds figure-of-eight. First sold in 1959, the Telefunken M 250s (and 251s) used a hard-wired (soldered in place) Telefunken AC701k tube while a socketed 6072A tube was used in the export variant identified with a large "E" just below the pattern slide switch on the front of the microphone. 6072As were more readily available and easier to replace outside of Europe. Both microphones were manufactured by AKG and badged "Telefunken"; both used AKG's famed CK12 capsule also used in the C12 microphone. Made in Burbank, CA, the Pearlman 250 uses a hand selected NOS 6072A (my review microphone came with a hand-selected, Russian 6072A/12AY7) mounted in an inverted, shock-mounted ceramic socket. Like the exported Telefunken Ela M 250E/251E mics, this was done to replicate the shorter wire lengths-tube to the capsule-of the non-export mics. The Pearlman 250 uses a C12-type capsule made in Denmark by Tim Campbell. It is 33.3mm in diameter (same as the CK12), edge-terminated and with a 6-micron gold-evaporated diaphragm. It is mounted on a copy of the AKG's mount and insulated from mechanical vibration using rubber posts. The NOS carbon resistors, styrene capacitors are RoHS compliant and all hand soldered, point-to-point, on a small, custom fiberglass board. The output transformer is epoxied to the internal steel frame and is made by Cinemag. It is their direct replacement for AKG's C12 and Ela M 250E/251E mics. For reliability, longevity and consistent operation, a single Wima polypropylene output (DC blocking) capacitor replaces the electrolytic that was originally used. There are two mini toggle switches mounted to the internal steel frame: one for cardioid/omni switching that replaces the problematic pattern slide switches in the original Telefunkens; the other is an on/off switch for a gentle high frequency roll-off starting at 4kHz. The Pearlman 250 kit includes: attaché case, leatherette carrying pouch, standard shock mount basket, AC power cable, and a 20-foot multi-pin Mogami cable with Neutrik connectors, and Pearlman's US-made power supply.
Recording Acoustic Guitar
I started with cardioid pattern and tried 12-inches away and over the 12th fret of a Martin Custom D Classic Rosewood Acoustic Guitar (D-28). I found it easy to get a rich sound by staying well away from the sound hole. I liked this pattern/distance for single string picking and arpeggios--the 250 produced a thick, fat tone with good articulation without sounding artificially bright. I found its wide cardioid pickup pattern to work well for a natural musical balance. For full chords, I switched the 250 to omnidirectional, moved closer-about six-inches and shifted its location laterally towards the sound hole-about half way between the 12th and end of the fret board where the neck joins the body. The toggle cardioid/omnidirectional switch is an awesome feature for choosing between the two patterns quickly--when looking for the best pattern and sweetest spot. Because the mic distance was halved, I reset the RTZ pre-amp to only 20dB. In cardioid pattern, the 250's nominal output level is in the same range as modern condenser microphones but it has slightly less output level when switched to omnidirectional pattern. For loud strumming and without the cardioid proximity effect, the 250 produced a balanced sound with enough pick attack and thickness making it perfect for a guitar/vocal session.
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