(Reprinted from Mix magazine, April 1998. Copyright 1998.
Courtesy of Intertec Publishing Corp., Emeryville, CA. All rights reserved)
by Arthur Bloom
D.W. FEARN VT-2 DUAL-CHANNEL VACUUM TUBE MICROPHONE PREAMP
In the '60s, Douglas Fearn worked as a broadcast engineer at WPEN in Philadelphia. Later, when he opened a recording studio, he built his first mixer from 1940s-era RCA tube microphone preamps salvaged from WPEN's junk pile. Decades later, Fearn rediscovered some tapes he recorded on his original tube mixer and was struck by their warmth and vitality. Compelled to recapture that sound, he developed the 1-channel VT-1 and 2-channel VT-2 all-tube, Class A mic preamps based on the vintage RCA design. Today he hand-builds the VT-1s and VT-2s that bear his name, and to buy one is to buy a piece of Douglas Fearn, a perfectionist with a tremendous knowledge of audio engineering and music.
Each preamp is tested, with the results inscribed in the manual. The spec sheet for the unit I received revealed numbers as good or better than those published on his promotional material. With two triodes and custom Jensen input and output transformers for each channel, the VT-2 supplies 53 dB of gain. Frequency response fluctuates less than 0.2 dB from 20 to 20k Hz with less than 0.2% THD and noise. With an EIN of -122 dBm, the VT-2 has a signal-to-noise ratio of 72 dB (unweighted).
However, specs fall short of describing the VT-2's real-world performance. Compared to ICs or transistor designs that can distort with sudden harshness, tubes -- particularly the single-ended triodes employed in the VT-2 -- distort more gradually and pleasantly, adding the even harmonics typical of acoustic instruments. In practice, the onset of distortion need not signal the end of headroom. Levels can be hotter, and the S/N ratio appears subjectively better than the printed spec. Furthermore, it is the VT-2's "virtual" headroom wherein lies its juice.
According to Fearn, the wide dynamic range and transients of microphones almost always overload preamps. Unlike less forgiving mic preamps, the VT-2 passes transients along with only minor and musical distortion. Indeed, I found the onset of distortion with the VT-2 more characteristic of a fine compressor than a distorting preamp, with subtle musical details slightly heightened rather than clipped.
Both the exterior and interior of the VT-2 are aesthetically beautiful and exceptionally solid. Its nostalgic, 1/4-inch-thick faceplate is painted with Imron to a deep and glossy burgundy, with a symetrical arrangement of VU meters, knobs and switches. Each channel includes an attenuator and switches for phase reverse, input level, 48V phantom power and meter on/off. A visual artist who recently visited my studio mooned over the VT-2 and noticed nothing else.
The input level knob has three settings: "0" connects the microphone signal directly to the input transformer; "-20" inserts a 20 dB pad ahead of the transformer, and "Lo-Z" inserts an impedance-matching network, optimizing the VT-2 for use with ultralow-impedance mics from companies such as Neumann, Schoeps, B&K and Earthworks. This came in handy when using the VT-2 with a transformerless 50-ohm Neumann TLM193.
The VU meters -- calibrated to the professional standard of "0" for +4 dBm -- can be turned off when the user wishes to purposely distort the signal. Though occasionally pinning the needles does not damage them, it is nice to have the option of protecting them from bands who wished they came from Seattle. Turning the meters off also invites the engineer to fly with eyes closed and ears open.
Inside, the VT-2s are custom-built and wired point-to-point. The unit's size allows tubes to be positioned vertically, for more stable, longer-life operation. A large toroidal power transformer (strong enough to power ten VT-2s) runs conservatively to further ensure tube longevity. The VT-2 uses new, "old-stock," military-grade 6072A tubes, made by General Electric and similar to 12AY7s. Fearn tests each tube and grades them for noise. A removable top panel allows access to the transformers, tubes and power supply, and an enormous blue, computer-grade, high-performance Mallory filter capacitor.
To asses the VT-2's performance, I solicited the opinions of other engineers. First I lent the demo unit to Jon Russel who owns Presence Studios in Westport, Conn. (featured on the cover of Mix's October '96 issue). Russel felt that, compared to his Tube Tech mic pre, the VT-2 had a more imposing personality. He thought it worked particularly well with vocals and power guitar, and it made his AKG 414s sound more full-bodied and luxurious. However, he was less enthusiastic about its use for recording percussive instruments, including piano. He was bothered by what sounded like "a subtle proximity effect" at times when he desired utter transparency.
Next, I lent it to producer/engineer Vic Steffens who owns the Horizon Music Group in West Haven, Conn. First, he used it with two Coles 4038 figure-8 ribbon mics in a Blumlein array to record a gospel choir and band. Steffens said it sounded "fabulous" and that it gave the mics a lot of "space." Compared to other tube preamps he has used, he was particularly impressed with the VT-2's low-mids, which were solid and well-defined, without "tubbiness."
Steffens also used the VT-2 with a matched stereo pair of AKG C12VR tube mics in spaced omni to record another gospel shoir. He characterized the combination of the C12s and the VT-2 as "stupid good!" He preferred using the VT-2 with the C12s over the Coles due to the C12s' superior articulation and brighter sound.
Whiles Steffens expressed concern about assimilating the VT-2's lush output into a large, multitracked mix, he felt if would be perfect for what he called "hi-fi, full-bandwidth, minimal miking" sessions.
Indeed, "hi-fi, full-bandwidth, minimal miking" describes Andy Smith's appraoch to recording Paul Simon's latest record, Songs From The Capeman, a recording for which Smith relied on a VT-2 for everything from vocals to piano, strings, flute, cello, trumpet and guitars. Although he recorded in The Hit Factory (aka "equipment heaven"), Smith kept the recording chain as short and pure as possible. Bypassing the console, he used the VT-2 with an AKG C24, Sony C800G, a Telefunken Elam 251, Neumann TLM50s and TLM170s, and B&K 4011s and 4007s.
Compared to the other high-end preamps he tried, Smith preferred the VT-2 for what he described as its "superior clarity, transparency and presence." He explained that the VT-2 allowed him to use virtually no EQ and minimal compression.
Indeed, the VT-2 blessed any vocal sent through it and minimized the need for EQ and compression down the road. I was also impressed with the ease with which it handled difficult-to-record acoustic instruments such as solo oboe and Celtic harp.
I recorded oboist Libby Van Cleve performing "Whistle Stop" by contemporary composer Scott Lindroth. The oboe itself is so full of harmonics that it was impossible to tell where the oboe ended and subtle distortion from the VT-2 began. On tape, the oboe sounded just a tad thicker and darker than live. I used an AKG 414 TLII placed at the bell and a Neumann TM193 placed over the top of the second joint -- run through the VT-2 and direct to DAT. Bypassing the console, you could touch the sound.
When recording Julia Cunningham playing Celtic harp, going direct from the VT-2 into a DA-P1 at line level -- using a TLM193 in front of the soundboard and a 414 TLII behind it -- percussive transients and bell-like sustains came alive. At the end of the session, Cunningham commented that she preferred the sound of the recording made with the VT-2 to what she hears when she is playing her harp live.
Although you might not want to use it in every situation, the VT-2 is by no means an effects box masquerading as a preamp. Rather, it is an exceptional implementation of vintage tube technology in a mic preamp. At $3,500, the VT-2 is also one of the more expensive microphone preamps in production. However, the price buys more than high-quality sound. It's rugged, built to last, and built to use. If recording is your bread and butter, the VT-2 is pure butter. The VT-1 is $2,000, and an optional 2-channel line pad is $80.