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Audio by Van Alstine Fet Valve EC PreamplifierThe $ensible Sound Manufacturer: Audio by Van
Alstine, 2665 Brittany Lane, Woodbury,
MN 55125; 651/330-9871 http://www.avahifi.com/
info@avahifi.com Several years ago I was able to spend some brief time auditioning the original Fet Valve preamplifier and power amplifier in my system. Those original units, built in Dynaco chassis, sounded impressive in the short time I had to spend with them — a matter of an hour or two as Frank Van Alstine stopped by my house on his way back to Minnesota from a road trip — but as the years went by, we never did get a Fet Valve unit in for full review. Recently, however, AVA updated the line with a handsome new preamplifier chassis (shared with the solid state Omega III EC preamplifier, which was reviewed a few issues back) and some modifications to the power amp circuitry. We have obtained both a preamplifier and an amplifier for review, and I can say that I am just as impressed by the units now that I have spent a good amount of time with them as I was in their brief visit way back when — more impressed, in fact, in light of their nice new wraps. The EC ("enhanced capability") chassis features a wealth of input and output capabilities. I'm not sure where to start, and hope I do not lose anybody on the way, but will attempt to work my way through the list of features. Perhaps it would be best to start with the front panel. Starting from the left, we first encounter a large knob that is used to select from among eight inputs, marked Tape 2, Tape 1, Tuner, CD, VCR, Spare 1, Spare 2, and Special. (Units equipped with the $180 optional phono section use this position for phono). Above this knob are two pushbuttons, the one on the left to switch between Tape Loop 1 and Tape Loop 2, the one on the right to choose between input and tape. Moving to the right, we encounter another large knob — this one for volume. Above it are two more pushbuttons, the left one an EPL (external processor loop — in my setup, this is where the Legacy Steradian processor gets wired in, while others might use it to switch in a surround sound processor for home theater applications) switch, and the one to the right a muting switch. Again attesting to the flexibility allowed by AVA, in my sample of the preamplifier I requested that the muting switch specified to produce only a moderate decrease in gain, so I could use it to reduce the gain when driving high efficiency speakers such as the Legacy Focus, but I could have instead requested a complete mute or some degree of muting in between. Moving to the right once again, we encounter a third large control knob, this one serving as the balance control. Above it are two more pushbuttons that allow full stereo/mono switching capability. Both buttons out gives regular stereo. Left button in gives left channel only to both outputs. Right button in gives right channel only to both channels. Both buttons in gives summed mono to both channels. The next step on our rightward journey brings us to a pair of smaller knobs, the bass and treble controls. Above this pair of knobs are two pushbuttons, the one on the left to switch in a high and low filter if so desired, and the one on the right to switch the tone controls in and out of the circuit. The last stop on our journey across the faceplate is the illuminated power switch, below which is found the headphone output, as the Fet Valve preamplifier includes a buffered headphone amp as standard equipment. As you might expect from all the controls available on the front panel, the rear panel is also quite full, with 14 pairs of gold-plated jacks for the various inputs and outputs, plus three switched and fused AC outlets. For those who do not need as much flexibility, the Fet Valve circuits are also available in two less elaborate versions. The Fet Valve SL ("straight line") has a six-position selector switch, two tape loops, balance control, a stereo/mono switch, headphone amp, but no tone controls, and sells for $899. I suspect that for many audiophiles, this would be the unit of choice. There is also a RB ("real basic" [I will resist the editorial urge to change that to "really basic"]) model for $789. It lives up to its name by supplying only two inputs, a tape monitor switch, and a volume control — but does include the headphone amp, and can be ordered with the optional phono section (which would leave you with only one line input). The Fet Valve circuitry common to all three units features a 12AX7A vacuum tube (one for each channel) working together with MOSFETs. It is my understanding that the vacuum tube does the voltage amplification while the MOSFETs handle the current gain. One MOSFET works in tandem with the tube to drive a power MOSFET output. Typical of AVA units, construction quality is robust but not ostentatious. The power supply is substantial, and the overall layout is neat and clean, inspiring a high level of confidence that the unit will work reliably for a long, long time (I used my previous AVA preamplifier, a Transcendence Series Two, for more than a decade of utterly reliable operation). For my listening sessions with the Fet Valve EC, I used the following equipment: Marantz CD-63 and Weltronics CD8 CD players; AVA Fet Valve 550hc and Sunfire power amplifiers; and Legacy Focus, Biro, technology L/2, and Platinum Audio Studio 1 loudspeakers. The Fet Valve EC preamplifier worked flawlessly in my system. The unit is designed to turn on and off without thumps, a design specification that can be quite useful when the power goes out unexpectedly. I tended to leave it on most of the time. I was concerned that a unit with tubes and MOSFETs might tend to have some background noise, but the unit seemed dead quiet, even with the highest gain setting and driving the highly efficient Focus speakers. Whereas the solid state Transcendence Series Two preamplifier always seemed to sound just a little bit on the warm side, the Fet Valve EC struck me as utterly neutral in terms of tonal balance. The Fet Valve EC also struck me as utterly unflappable particularly when used with its power amplifier counterpart, the Fet Valve 550hc, which is reviewed elsewhere in this issue, and I will have more comments along these lines in my review of the amplifier. From simple recordings of solo instruments through complex recordings of choral and orchestral forces, with thunderous climaxes and gut-rumbling bass, the Fet Valve EC seemed to produce every nuance of sound without ever calling attention to itself, and the switching flexibility proved quite handy in doing reviews of other pieces of equipment. For what more could I ask? For now, suffice it to say that the Fet Valve EC is the fines preamplifier ever to have graced my system. I could find nothing to criticize in terms of its sonic performance, and its flexibility and features are matched only by the AVA Omega III EC preamp, which features a solid-state circuit in the same chassis for $649. Frankly, for most people, the Omega III, a fine unit that received excellent reviews in these pages, is going to represent the much better value. Relying on sonic memory, however, I found that the Fet Valve amp/preamp combo offered slightly better smoothness and transparency, but I would not feel very confident about my ability to discern those differences in an ABX session. However, when all was said and done, and all my CDs (OK, not all of them — but a goodly number nonetheless) had been auditioned through the preamp, I was impressed sufficiently by the Fet Valve EC to make it my new reference preamplifier, finally retiring the venerable Transcendence Series Two, which had held pride of place and withstood all challengers for more than 10 years. Would I have been as happy with the Omega III? Maybe — but I shipped it back to AVA. (More precisely, I shipped it to Ken Duke, who eventually shipped it back to AVA). The Fet Valve EC is staying right here in Ostrander, along with its power amp companion. - KWN
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