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XA60 Owner’s Manual
Analog designer Nelson Pass has over the years produced some
truly great solid-state amplifiers, each unique in it’s own way. Not
surprisingly, the Pass Laboratories™ XA60 monoblock amplifier
is no exception. The XA60’s sleek industrial design is a stunning
understatement of artistic form integrated with state of the art
function.
Since their introduction in 1997, the X amplifier series using the
patented Supersymmetry™ circuit topology have been the mainstay
of amplifier offerings from Pass Laboratories™. These amplifiers
are heavily biased Class A/B designs with only two gain stages and
an absolutely minimal component count in the signal path. In spite
of this simplicity and thanks to the unique characteristic of the X
topology, these amplifiers achieve very high power with outstanding
subjective and objective performance.
With the introduction of the XA60 Pass Laboratories™ significantly
raises the performance standard of excellence by introducing an
entirely new series of power amplifiers. The new “XA” series of
amplifiers feature a refined and elegantly simple, very highly biased,
pure Class A mode of operation. This is a new and unique circuit
topology that we descriptively characterize as being Single-ended
Class A. This new topology combines the very best characteristics of
Pass Laboratories™ “X” series amplifiers and the highly rated “Pass
Laboratories Aleph™”. The XA series is the marriage of a highly
refined Aleph™ output stage with the patented Supersymmetry™
“X” front end.
The emphasis of the XA series is to accentuate performance and
sonic refinement over power. The XA series has the characteristic
warm midrange and sweet top end of the Aleph™ product
conjoined with the extreme dynamic range and definitive bass
control of the X series amplifiers.
The XA60 is packaged in an artistically refined variant of the massive
chassis previously reserved for the 150 watt X-150.5 two channel
stereo amplifier, but running more than twice the Class A bias
current of our A/B amplifiers.
The Pass Laboratories™ XA60 will deliver 60 watts rms into 8
ohms of impedance. This is the amplifiers class A limit, driving
the XA60 harder or reducing the impedance of the load will not
convey any additional power. Driving into a short will not convey
any additional power. These are not design oversights or flaws in
the XA60, but rather a condition of the very highly biased Class A
operation. However; as an interesting point of reference, 60 watts
driving a 87dB/1W/1m speaker will deliver well in excess of 100 dB
Introduction
