Pass Labs
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XA200
XA160
XA100
XA60
XA30
XA amplifiers
ver the years Pass has produced some
O
truly great amplifiers, each design unique
in some way. The XA power amplifiers offer
the marriage of two classic examples of
these designs - the Aleph single-ended Class
A output stage and the X Super-Symmetric
front end circuit. Each of these designs is
covered by basic patents and stands alone in
defining Nelson Pass’s simple but powerful
approach to amplifier design. Together, the
two topologies complement each other in a
way that represents a near perfect synergy,
resulting in the newest, highest standard in
audio amplification.
Compared to the X series, the XA
amplifiers have more emphasis on audio
perfection over power. Dissipating the
same power at idle, the XA series trades
efficiency for the warmer midrange,
sweeter top end, and better defined bass
of a pure Class A amplifier. If you need
raw power and very high current into a
low impedance load, an X amplifier is the
appropriate choice. If the purest quality
into a reasonable loudspeaker is your
choice, you want an XA model.
The XA series amplifiers run pure
balanced single-ended Class A with an
enormous bias current - they do not
fall back on Class AB operation. This
extraordinarily over-the-top Class A
is responsible for an effortless threedimensional presentation of the sonic
landscape. This in combination with
exceptional resolution of minute detail
and dynamic contrast creates the illusion
that through these amplifiers you could
touch the performers, as if the last veil
was removed, but without a trace of glare
or harshness.
The XA’s retain the sweet warmth and
lushness of the Aleph series without fluffy
coloration, and the dynamic contrast is
X A 2 0 0
Mono design
200 watts
Gain: 26dB
+/- 60V Max
+/- 9A Max
19W x 11.5H x 28D
175LBS
Mono design
160 watts
Gain: 26dB
+/- 50V Max
+/- 7A Max
19W x 11.5H x 22D
150LBS
X A 1 6 0
Mono design
Mono design
X A 1 0 0
100 watts
Gain: 26dB
+/- 20V Max
+/- 5A Max
19W x 9.5H x 22D
100LBS
X A 6 0
60 watts
Gain: 26dB
19W x 7H x 20D
70LBS
even better than the X series - transients
leap from black to crescendo and back
again with no telegraphing or hangover.
There is as much bottom end control as
the original X amps, but carries more
subtle nuance. The midrange is a little
deeper and the soundstage wider than
the either the Aleph or the X amplifiers
alone.
The XA’s sleek industrial design is a
stunning understatement of artistic form
and function - an appropriate temple for
the best amplifiers that money can buy.
There are four different XA monoblock amplifiers, plus one stereo power
amplifier, with power levels ranging from
60 to 200 watts in the mono-block units
and 30 watts per channel in the stereo
version.
These power ratings are specified into
8 ohms of impedance. Single-ended
Class A output stages are biased to a
particular impedance, and they do not
increase in power at lower impedances,
unlike conventional amplifiers. They do,
however, perform well at any impedance,
and are reliable into a dead short.
The XA series amplifiers all have massive
toroidal transformers and high speed/
soft recovery rectifiers coupled to four
high capacity DC reservoirs with passive
CRC or CLC filters to remove incoming
and outgoing ripple. The AC line
connection has EMI, spike, and inrushsurge conditioning to remove noise
from the outside world and prevent the
amplifier from sending noise out.
As a breed, exotic single-ended Class
A amplifiers with only two stages and
almost no feedback are known for
wonderful sound, but not for particularly
good objective specifications. There is a
common belief that good sound does not
correlate well with measured performance,
but at Pass Labs we do not see a conflict
- the question is not whether the amplifier
measures good, but the approach the
manufacturer has used to achieve that.
The XA series excels on bench tests, with
measurements as good or better than
amplifiers with 9 gain stages in series and
tons of feedback, but does so with the ease
and stability of a simple 2 stage device with
minimal feedback that naturally combines
high power and subtle precision.
For amplifiers drawing as much as 700
watts, they possess a remarkably low
output noise at about 10 nanowatts,
a figure less than 1 part in 10 billion
compared to the output power.
X A 3 0
Stereo design
30 watts/ch
Gain: 26dB
19W x 7H x 20D
70LBS
The bandwidth is more than 5 times the
audio spectrum at each end, and the
maximum speed of the circuit is about 100
times that of the output of a digital or vinyl
source.
The low distortion character is monotonic,
with low order harmonics declining with
power until they disappear beneath the
waves of the 2 microvolt random noise
floor.
Specifications only tell a small part of the
story. If you are looking for a musical
experience that brings you as close to the
performance as possible, the XA series
from Pass Labs is as good as you can get.
Other companies make products that
compare in one respect or another, but
nobody else delivers this level of sound,
design, hardware, reputation, reliability and
service in a single product.
Pass Laboratories, PO 219, Foresthill, CA 95631 - Voice: 530.367.3690 - Fax: 530.367.2193 - www.passlabs.com
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