home entertainment 2007

TL-7.5, along with VTL’s Reference
Series power amplifiers and Halcro’s
own stunning Reference Series electronics,
were the first truly 21st-century
high-end products, establishing a
new standard with the transparency of
their sound.
In the five years since introducing
the TL-7.5, VTL has systematically
applied the model’s technologies to
other products. Mostly they’ve trickled
them down to update existing, lowercost
models, but VTL has also used the
TL-7.5’s basic design elements to
underpin new models—such as the single-chassis
TL-6.5 line stage and, more
recently, the Signature Phono Stage.
“With each application,” said VTL
principal Luke Manley, “we learn new
things, partially because the constraints
and goals are different, but partially
because new technologies and parts are
available. And after doing the Phono
Stage, we felt that there were enough
things to take advantage of that it merited
looking at the 7.5 again.”
The TL-7.5 Series II differs from the
original in four principal ways. First, it
costs $16,500, or $4000 more than the
original. 1 (A Series I TL-7.5 can be
upgraded to Series II status for $4500.)
The second is an accumulation of several
modifications to the power supply,
each minor in itself, but adding up to
and necessitating a substantial upgrading.
The third was the replacement of a
number of components. In some cases
these were simple swappings-in of
superior parts; in others, the replacement
also required changes in circuit
parameters and topography, or perhaps
added a bypass to an existing circuit
branch. As part of this scrubbing, VTL
ended up designing and had made a
number of proprietary passive components
when they were unable to find
off-the-shelf items that met their needs.
It’s the fourth element of the update
that VTL notes first, however: the
replacement of the TL-7.5’s 12AX7
tube with the Series II’s 12AU7, and
the redesigning of the surrounding circuit
to run the tube at a substantially
higher current than before. The resulting
lower plate impedance improves
the drive to the following MOSFET,
resulting in a wider frequency range.
Indeed, testing of my ‘7.5 confirmed
1 The TL-7.5 II costs $16,500; an upgrade from the original
TL-7.5 costs $4500. VTL Amplifiers Inc., 4774 Murrieta
Street, Suite 10, Chino, CA 91710. Tel: (909)
627-5944. Fax: (909) 627-6988. Web: www.vtl.com.
FOLLOW-UP
that where the original’s output began
to dip at about 20kHz, the Series II
was less than 0.5dB down out to
200kHz. The result, according to VTL,
is a faster, more open sound, particularly
at the frequency extremes. The
change has also resulted in the Series II
having slightly lower maximum gain:
20dB vs 26dB in balanced mode,
which tends to be a better match for
the high outputs of CD players.
If the original was perfect, is the
Series II more perfect? The best way
to set the stage for the TL-7.5 Series II
is to revisit Paul Bolin’s comments on
the original, from Vol.26 No.10: “It is
no easy thing to attempt to describe
the ‘sound’ of a component that had
less intrinsic sonic character than anything
else I have ever reviewed. The
TL-7.5 had such an infinitesimal sound
of its own, and did everything so
supremely well, that I found nothing to
rationally criticize. Sonically, it simply
did not exist in the signal chain.”
I agreed with Paul wholeheartedly.
My time with the Series I convinced
me that it combined the best attributes
of everything I’d heard up to that point.
The TL-7.5 had the transparency of the
best passive units, but without their
slight dulling of transients. It also had
the dynamics and speed of the best
active line stages I’d heard, while completely
removing from the sound all
traces of “electronic detritus,” to bor-
row a phrase from Michael Fremer.
My first response to the TL-7.5
Series II was exactly what VTL would
have predicted. I was impressed. The
II’s presentation was more dramatic,
and the presentation of even old
IN THE FIVE YEARS SINCE INTRODUCING THE
TL-7.5, VTL HAS SYSTEMATICALLY APPLIED THE
MODEL’S TECHNOLOGIES TO OTHER PRODUCTS.
favorites, such as Beverly Sills, with
Aldo Ceccato and the Royal Philharmonic,
in Verdi’s La Traviata (LP, Angel
SCLX-3780), had an energy that
immediately caught my attention—the
recording space itself seemed more
alive. On the wonderful Heifetz-Piatigorsky
Concerts (LP, RCA LDS-6159), I
felt more aware of the instruments’
textural and dynamic subtleties, and
the subtle nuances of those masters
The TL-7.5 keeps the audio circuits isolated from noise in a separate chassis.
were bolder and more tangible with
the Series II than I remembered hearing
through the original TL-7.5.
When I switched gears to a series of
classic rock albums, I was impressed
anew by the Series II. There was no
doubt that its dynamics and speed were
improved at the frequency extremes.
Bass guitars sounded both cleaner and
more powerful, and I was again aware of
increased detail. At the other end, everything
from the upper midrange/lower
treble on up was definitely more
dynamic, and the spaces between notes
and instruments were clearer and more
starkly defined.
Throughout my audition, which
Continued on p.127
www.Stereophile.com, May 2007 117