Company UltraVerve Line Preamplifier
Review By Dick Olsher
here to e-mail reviewer.
My theory is that over the
years preamplifiers have been indirectly responsible for more audio grief
than any other hi fi component. It is literally a stealth sonic offender,
because so few audiophiles realize the mediocrity that lurks in their
front end. More money has been wasted, in my estimation, in futile
attempts to fix what is actually a front-end problem with downstream
tweaks. Imagine the expense showered on exotic interconnects and speaker
cables, when all that money could have gone toward a better sounding preamplifier. Many find comfort in owning a highly touted brand name or
an audio classic. Well, please take note of the following personal
observations, spanning a time frame of 35 years. With only a couple of
exceptions, solid-state preamplifiers, regardless of price or prestige
have failed to move me musically. Only a handful of tube designs have
passed my criteria of excellence in the areas of resolution, dynamics, and
transparency. And that grouping certainly does not include any vintage
tube gear. Avoid McIntosh, and incidentally, I find the Marantz 7 to be
more about hi fi than music.
Enter the deHavilland UltraVerve. It is,
with the caveats noted below, about as sonically pure and transparent, as
a line preamplifier can be. To understand its magic, one needs to reflect
on the four cornerstones of its design philosophy: simplicity, Octals,
power supply, and passive parts quality.
If you are looking for multiple gain
stages, high part count, circuit boards, or tone controls, look somewhere
else. The unit is fully hand-wired, in point-to-point fashion, and
minimalist as far as parts count. There is only one gain stage, followed
by a cathode follower stage. Hence, not only is the gain a modest 12dB,
which should be adequate for line inputs such as CD players and FM tuners,
but the unit also inverts polarity. The latter means that a positive going
input appears as a negative going output. This is not something to fear or
distrust and can easily be dealt with. All that is required as
compensation is an additional polarity reversal in the signal path. In my
system, I simply reverse the speaker leads at the power amplifier outputs.
At first glance it may appear that there is no balance control. However,
tucked along the rear top plate are two trimmer controls, which give
Left-Right balancing adjustment, by tweaking the output of one channel
relative to the other.
There are boys and there are men in tube
world. Designer Kara Chafee's dictum appears to be: do not send a boy
(e.g., 12AX7 miniature) to do a men's job. The eight-legged 6SN7GT is a
beefy medium mu dual triode tube that dates back to pre World War II days.
Its major production impetus, however, came in the 50s due to its use in
television vertical sweep circuits. The GTA and GTB types, are nothing
more than a GT on steroids - higher power dissipation versions of the
basic 6SN7GT tweaked for TV applications. Although there are several
military inventory designations (e.g., VT-231), these are essentially no
different than civilian production, though they typically do imply
A premium member of the family is the
industrial-grade 5692, the most sought after type being the RCA redbase
series. A nifty feature, much appreciated by a chronic tube roller, is the
ease with which octals can be substituted. Thanks to its keyed base,
octals may be rolled in without sight of the socket. The popularity of the
6SN7GT is well deserved thanks to its ability to portray a vivid palette
of harmonic colors and kick-butt dynamics, qualities that well suit Ms.
Chaffee's musical priorities.
power supply is well filtered and features tube rectification. The
directly-heated 5AW4 rectifier tube draw an impressive 3.7A and would
normally see duty in a power amplifier. But this is precisely the correct
strategy for authoritative preamplifier sound: treat the thing like a
power amplifier. Exceptional passive parts abound: Cardas Litz wiring,
mil-spec paper-in-oil capacitors, Roederstein resistors, and a beautiful
Goldpoint stepped attenuator that eliminates a few layers of soundstage
veiling relative to the industry standard conductive plastic
The 6SN7 is driven with kid gloves at about
one watt plate dissipation, so expect long tube life. Each triode section
is direct coupled to a 6AH4 triode cathode follower stage. A relative of
the 6BX7, 6BL7, and 6CK4, the 6AH4 is a TV vertical oscillator tube whose
current drive characteristics make it a natural for cathode follower duty.
There is only one blocking capacitor in the signal path.
The UltraVerve's single gain stage lives
and dies by the choice of 6SN7, since the preamplifier is adept at
revealing differences between the good, the bad, and the ugly.
Fortunately, the stock tube is a select vintage type. My unit was shipped
with a Sylvania "chrome top," an excellent vintage brand, though
due to limited supplies other brands may be substituted at the factory.
The "chrome dome" is fairly easy to locate, and features a warm,
detailed midrange. It comes close to equaling the magic of my favorite RCA
smoked-glass (grey RF shield sprayed on inside of envelope) VT-231, but
falls short in terms of dynamic nuances and vibrancy of timbral colors.
Note that the RCA VT-231 is a 6SN7-GT type, which is my opinion is the
premier type worth hunting for, as it denotes the original version of the
tube, and most likely a production date prior to the TV era. Beware, there
are 6SN7 types to avoid at both ends of the price spectrum. The affordable
new production Russian types are definitely in the ugly category, while
the much hyped RCA 5692 redbase was a definite disappointment - at least
in this context - with a rather bland harmonic disposition. What follows
is based on extensive auditions using the RCA VT-231.
The thing does not sound at all like a
vintage tube preamplifier. Adjectives such as mellow, romantic, soft,
overly liquid, or bright do not apply. There is no euphonic veil under
which to hide sins of commission. Forget about sugar-coating front-end
problems or mitigating loudspeaker brightness. It sounds fast and detailed
without etching or exaggerating treble transients. Low-level detail
retrieval is entirely a function of the front end and program material.
This line stage shines in the context of a superior high-end system. Given
full scope of expression, it is capable of an open, detailed, airy, and
Please do not misunderstand the above
characterization of the UltraVerve (UV) and its lack of obvious tube
colorations to imply that it is devoid of tube virtues. Unlike
silicon-based amplification, the really good tube stuff is capable of
kindling reproduced music's verve. True to its name, the UV speaks
directly to the heart and soul with energy and vitality. Timbral colors
were painted vividly using a rich harmonic spectrum. Midrange textures
ebbed and flowed with commendable neutrality, though to be perfectly
honest, my preference is toward a slightly more romantic voicing. Female
voice was superbly portrayed. Dynamic nuances were propelled forward with
dramatic flair and subtle vocal inflections were caressed with consummate
fidelity. The transition from soft to loud was especially noteworthy,
zipping through a gear shift without hesitation or constriction. It stands
to reason that the circuit's simplicity, tube rectification, and of
course, that fabulous 6SN7 big-tone are in great measure responsible for
this level of directness and musicality.
The UV had no trouble at all driving long
interconnect runs. This is a consequence of its well-designed cathode
follower output stage, which can be thought of as a low-impedance stage
capable of adequate current drive. Surprising perhaps for a tube line
stage, was the UV's convincing reproduction of bass lines. Bass impact and
pitch definition were quite convincing. Bass extension scored high on the
Richter scale. And best of all, the upper bass range was full-bodied, with
a seamless transition to the lower midrange.
The soundstage was portrayed with excellent
width and depth. Far from being tethered to the loudspeakers, massed
voices were arrayed linearly across a 3-D soundstage. Closely mic'ed
voices were fleshed out with almost spooky focus and palpability. The
sensation of being able to reach out and touch someone was never any
About 20 years ago the great J. Gordon Holt
pronounced the sound of the Berning TF-10 preamplifier so exemplary as to
make further advances in the art unnecessary. That judgment has proved to
be premature, so wisely I will not go that far. But having lived with some
of the elite high-end pre-amplification from the likes of Jadis, Sonic
Frontiers, and Air Tight, the deHavilland UltraVerve is currently my first
choice in line amplification. At a retail price of $2,495 it upsets the
ultra high-end applecart; the point being that simple, minimalist,
well-engineered designs can rise to the top while being quite affordable.
Low on parts count, but high on tube magic, the UltraVerve scores big in
Bandwidth: 20Hz to 80kHz
Maximum Output: 30 Volts Push-Pull
Voltage Gain: approximately 12dB
Signal Triodes: 6SN7 GT, GTA, GTB, WGT
Rectifier Tube: 5AW4 rectifier tube
Signal To Noise Ration: 85dB
Inputs: four stereo
Outputs: two stereo
Input Impedance: 50 kOhm
Output Circuit: Cathode follower; minimum
10 kOhm load recommended
Dimensions: 18 x 11 x 6 (WxDxH in inches)
Weight: 15 lbs (shipping)
Power Requirement: 115 VAC/60Hz, 40 Watt
Warranty: Two-year parts; one-year labor;
90-day on tubes. Warranty is not transferable.
deHavilland Electric Amplifier Co.
2401 NE 148th Court
Vancouver WA 98684
Voice: (360) 891-6570