Roger Sanders has been a big name in
American hi-end audio since 1974. Several
years ago he founded InnerSound, a famous
maker of electrostatic loudspeakers that
received great press reviews in the US and
throughout the world.
He ended his participation in InnerSound in
July 2004 and has now started his own
company based Colorado, were he designs and
sells a new line of amps (derived from his
Innersound products) under the SANDERS SOUND
SYSTEMS label. These amps are specifically
designed to drive difficult loads like
electrostatic loudspeakers, which he
obviously knows very well. He therefore
calls the amp the "Electrostatic Amplifier"
(commonly called the "ESL amp"), although it
will drive any type of speaker with ease.
I had read some literature on-line about his
products and I was quite curious as I own a
pair of Quad 988s. I am convinced that
sometimes we can find better solutions to
the setup we already have, which in my case
is a pair of OTL tube amps especially built
for QUAD.
With a little luck and intuition I decided
to contact Roger Sanders and I had one of
his ESL amps sent to me for a trial. I
choose the smallest one of his line, a
"little" stereo amp rated at 360 watt per
channel. He offers power amps that go to
more than a kilowatt at 8 ohms in the mono
version.
Roger also produces line-stage and phono
preamplifiers and electrostatic speakers.
Also available are quite inexpensive
interconnect cables and speaker cables that
are specifically designed for electrostatic
speakers.
Roger is an engineer and has scientific
approach to hifi, (Okay, he doesn't believe
in cable influence from a physical point of
view and in all my theories on fuses, but he
is very nice and down-to-earth and I was
very sorry I couldn't visit him during my
trip to the U.S. last summer). I had several
long e-mail exchanges on the philosophy
behind his products and I will try to
summarize them here for my readers.
His first theory is that no matter how good
a tube amp is, it is not the best feed for
an ESL (ElectroStatic Loudspeaker). This is
because if it is played loudly, it will go
into clipping, which produces high
distortion levels, loss of detail, and
compression of the music's dynamic range.
Tube amplifiers also have relatively high
output impedance. Since you cannot drive a
low impedance load with a high impedance
source, most tube amps will cause a loss of
high frequencies when used with ESLs.
This is because an ESL's impedance is
inversely proportional to frequency, which
means that an ESL's impedance will be very
low (typically 2 ohms) at high frequencies.
So the relatively high output impedance (4
ohms for example) of a tube amplifier will
cause non-linear frequency response in an
ESL.
Second point is that in order to obtain good
sound from an electrostatic, we need
undistorted power and flat frequency
response across the entire audio band. This
can only be obtained with high-power,
transistor amplification.
To my question, "Isn't your amp too powerful
for my Quads?" Roger answered that in my
case, in order to play well, I need much
more power than I think I need. He has sold
several of his powerful ESL amps to Quad
owners and none had ever returned the
product or had problems with their Quads
because of the amplifier. They all thought
the ESL amp worked beautifully.
According to Roger, the most important
parameter in an amplifier is sufficient
power. The amp simply must not clip under
any circumstances as doing so will cause
loss of dynamic range, distortion, and loss
of detail. It is for these reasons that it
is better for an amp to bring the
loudspeakers to their limit rather than
going into clipping before reaching that
limit.
For details on the Sanders Philosophy you
can visit his web site (www.sanderssoundsystems.com)
where you can find many articles on
amplification, electrostatic panels, and on
hifi in general.
Despite Igor's doubtful thinking, "Be
careful your panels will go on fire!", I
couldn't wait to try the ESL amp. When the
package arrived safely from the U.S., I
dragged it to the attic and hooked it up to
my Quads, being sure that they were placed
on the anti-resonance base (STAB 1) designed
by Gregorio Giust.
First, some comments on specifics and build
quality. The pictures are quite explicit of
all but an artisan built object made in USA.
The amp has a very high quality external
finish. The internal and connection
components are superb (WBT connectors for
the loudspeakers, 1% tolerance components,
RCA connectors in rhodium, 18 transistor
power for each channel, machined aluminum
chassis, shielded toroidal transformer,
etc.).
The amplifier has excellent performance
specifications with 360 watts/channel at 8
ohm, 600 w/c at 4 ohms, and over 1000 w/c at
2 ohms. The amp can produce 2000 VA per
channel when driving an ESL. It has 26 dB of
gain, 500 volts/microsecond Slew Rate, and
an input impedance of 50 kohm. Distortion is
vanishingly low at around 0.002%. It weighs
23.5 kilograms (52 pounds).
The designer recommends keeping it always on
as it runs cool and consumes very little
electrical energy at idle. Leaving it on
contributes to high reliability, long life,
and the unit will always be warmed up so
will operate at its best the moment you wish
to use it. For this reason, I started my
listening after a warm-up period of 48 hours
with the power line filtered by DOCET of
which I spoke in the most recent issue of
this magazine.
I used SONIC EUPHORIA and ZOE by Lector as
preamps. My source was a CDP OPUS 21 by
Resolution audio. The usual cables: Dual
Connect for the loudspeakers, YBA Crystal
between the preamp and power amp, the great
SILTECH COMPASS LAKE G6 SATT VERSION between
CDP and preamp, AC cables by Siltech for the
Quad and by Crystal Cable for the other
components.
When I first started listening, I was quite
traumatized. The Quad protection circuitry
kept triggering. But once I figured how it
worked, I found just the right volume to
avoid the triggering the protection
circuitry. Thereafter everything went
smoothly so I could start critical listening
of my made-in-Colorado amp.
I immediately was struck that Quads have a
greater extension across the entire audio
band when being driven by the ESL amp than
when driven by my reference OTL tube amp.
The low frequencies are definitely deeper
and much more controlled, and the high
frequencies seem endless to the point that I
had to remove the supertweeters by Mark &
Daniel, which were no longer needed.
When driven by the ESL amp, the Quads
produce high frequency response that I have
never heard before. The highs are not at all
tiring. Rather the information is much more
complete and produced with more coherence
than before.
Mid-range and voice have the usual Quad
magic, but are now softer with richer
harmonics up and down that give the sound
great realism. Compared to the OTL tube amp,
response speed on transients is definitely
greater. The imaging maintains good
proportions but now appears deeper and
richer with more micro-ambient information.
Instrument positioning is realistic and
differences in registration is much more
defined than previously. Resolution is
greater, which makes differences in speaker
positioning and electronics easier to
analyze and evaluate.
I might say that the ESL amp is a little
less "warm" compared to the OTL amp, but it
gets along well with Quads, which produce
better coherence and a clearer and more
realistic sound than that produced by the
OTL amp.
The interface of the ESL amp with my two
preamps was excellent. The Sonic had a
chance to show its legendary adaptation to
the new amp showing all its best assets,
especially in sound stage reconstruction and
voice rendering. ZOE made reproduction a bit
more aggressive when necessary thanks to
greater speed and gain, ending up to be my
favorite between the two in an interface of
tubes and transistors of rare efficiency and
magic.
I had tried other amps in the past with the
Quads, but not even the Threshold amp gave
me the performance of Roger Sanders' ESL amp
in terms of comprehensive performance. Until
the arrival of the ESL amp, no previous amp
behaved better than the OTL amp with the
Quads.
But there is a first time for everything.
The obvious conclusion is that I decided to
buy the ESL amp as it made a great
improvement in the overall quality of my
system. Maybe I could find something better
for the Quads but I doubt it would cost less
than the 2900 euro I spent to buy this
amazing music machine in the USA.
I realize I was privileged to be able to try
in my home the ESL before deciding to buy
it, and I can understand that the lack of an
Italian distributor is an obstacle to its
distribution in the Italian market. But
still, I must recommend it as a great
price/quality bargain and as a
well-engineered and quality-built product. I
usually don't recommend or approve blind
purchases but . . . exceptions can be made.
--------------------------
Manufacturer's note: Sanders Sound Systems
offers risk-free, 30-day, in-home equipment
trials to any customer, anywhere in the
world. If you are not completely satisfied
with any of Roger's products, he insists
that you return them for a full refund --
and this offer includes free round-trip
shipping!
We
sell direct world-wide