Pass Labs XA200 User Manual
pass
TM
May 18, 2006
XA200 Owner’s Manual
XA200 Owner’s Manual
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Introduction
Analog designer Nelson Pass has over the years produced some truly
great solid-state ampliers, each unique in it’s own way. Not surprisingly, the Pass Laboratories ™ XA200 monoblock amplier is no exception. The XA200’s sleek industrial design is a stunning understatement of artistic form integrated with state of the art function.
Since the introduction in 1997, the X amplier series using the patented Supersymmetry™ circuit topology have been the mainstay of
amplier offerings from Pass Laboratories™. These ampliers 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 ampliers achieve very high power with outstanding subjective
and objective performance.
With the introduction of the XA200 Pass Laboratories™ signicantly
raises the performance standard of excellence by introducing an entirely new series of power ampliers. The new “XA” series of ampliers feature a rened 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 ampliers and the highly rated “Pass Laboratories
Aleph™”. The XA series is the marriage of a highly rened Aleph™
output stage with the patented Supersymmetry™ “X” front end.
The emphasis of the XA series is to accentuate performance 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 denitive bass control of the X series ampliers.
The XA 200 is packaged in an artistically rened variant of the massive chassis previously reserved for the 1000 watt X-1000.5 monoblock amplier, but running more than twice the Class A bias current
of our other ampliers.
The Pass Labratories™ XA200 will deliver 200 watts rms into 8 ohms
of impedance. This is the ampliers class A limit, driving the XA200
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 aws in the XA200, but
rather a condition of the very highly biased Class A operation. However; as an interesting point of reference, 200 watts driving a 87dB/
1W/1m speaker will deliver a 112 dB (very loud) average acoustic signal in a 100 cubic meter room, peaks will be somewhat higher.
XA200 Owner’s Manual
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The XA200 has a massive toroidal transformer coupled to a high
current DC reservoir. Recognizing that the XA200’s ability to resolve
microdynamics is best experienced with clean power, the extreme lowlevel resolution of the XA-series benets from a specially designed
power supply that signicantly reduces and rejects power line borne
noise.
The XA amps open the sonic soundstage to the very limits of the recording format. Through the XA200 complex musical passages reveal
themselves in the most dramatic manner. With the XA200 you will
hear everything within the upper octaves, which includes any recording, source or loudspeaker issues. Keep this in mind when choosing
complementary equipment, remembering that recordings and the
other components in the signal chain will strongly dictate soundstage
width and imaging and likely be the limiting factors in your listening
environment. The room itself will also add its acoustic signature, and
should be considered an audio component.
Speaker selection should be strictly a matter of personal taste. The
XA200 is unconditionally stable into any load presented by a loudspeaker, but will provide less power into other than 8 ohms. The
XA200 accommodates both single ended (RCA) and balanced inputs
(XLR). Input impedance’s are 11 kohm unbalanced and 22 kohm
balanced to permit integration with the widest possible range of upstream components.
Requirements
You can position this amplier anywhere you wish, but it must have
ventilation. We do not recommend placing it in enclosed cabinets or
small closets without means for air to circulate freely. Stacking these
power ampliers directly upon each other is not recommended for
the same reason. This amplier idles at approximately 650 watts, the
equivalent of a small hand held hair dryer. At idle most of that energy is dissipated across the heat sinks, so the heat generated by each
XA200 is equivalent to a small hair dryer. To dissipate this heat the
product should have about 6 inches clearance to the top and sides for
adequate air circulation.
Let’s talk about power requirements. The amplier draws about 5-1/2
amps (continuous rms) at 120 volts out of the wall during operation,
and this reects mostly the idle current that we run through the output
stage. When not actually intending to play music the XA200 should be
left in standby mode. In standby mode it draws only a few watts of
power, that necessary to keep the capacitors charged.
We have provided a standard IEC power cord that ts into the stan-
XA200 Owner’s Manual
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dard 15 amp IEC receptacle at the rear of the amplier chassis. Two
XA200’s may be run on a single 15-amp circuit. This amplier is
equipped for operation with an earth ground provided by the users
AC outlet. Never defeat this ground connection. The signal ground
of this amplier is connected to earth through a power thermistor,
which provides a safety ground but provides protection from irritating
ground loops.
As a safety issue we suggest that the power cord should be the last
cable installed on your power-amplier. You may, if you wish, substitute a 15-amp aftermarket power cord for the one we have supplied.
Only use power cords, which meet all local safety standards and carry
acceptance marks from the local regulatory authority. The power cord
should be attached to the amplier prior to plugging into house power.
Place the rear mounted switch in the off (down) position before plugging in this amplier.
The amplier’s voltage and current rating are indicated on the rear
panel. It will be either 240 volts, 220 volts, 120 volts or 100 volts, all
with a restorable type circuit breaker of the appropriate ampacity. The
inclusion of this re-settable circuit breaker does away with the need for
disposable fuses. The frequency rating of the AC line source is 50 to
60 Hz in all cases. Please verify that the ampliers indicated voltage
requirements are consistent with the supplied voltage and current at
your location. Transformers are input voltage specic and their change
is not a trivial matter.
Setup
XA200 Owner’s Manual
Looking at the rear panel you will see the AC power cord receptacle,
a power switch / breaker, two pairs of output connectors which allow
for speaker bi-wiring, a single pair of 5 way connectors for remote
turn-on, a single RCA input connector and a single XLR balanced input
connector.
Make sure that the rear panel power switch/breaker is off (down).
Plug the AC cord into the back of the amplier, and then into the wall.
Then turn the power switch/breaker on (up). The lights in your house
will blink when the power supply charges the capacitors. (Note: The
power switch/breaker is never to be used as a “safety device” or “emergency disconnect” for this product. This device provides current limiting which will protect the amplier, it will not provide personal shock
protection in the event of a reversed hot / neutral, lack of grounding
or other improper wiring in the supplied mains voltage.)
On the front panel, the “Standby” LED indicator should be glowing
blue, indicating that AC power is available and the capacitor banks are
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charged. The “Power” LED should not be on. If the “Power” LED
is on, don’t get excited, just use the front panel stand-by button to go
to stand-by mode, with the “Standby” LED on and the “Power “ LED
off.
OK, so the amplier is sitting there in stand-by mode with just the single
blue LED lit. No speaker connected yet. You can go ahead and connect the source and speakers. Make sure you are in standby mode to
protect your speakers from transients. The prudent installer will unplug
the XA200’s power cord from the mains while attaching speaker cables.
To avoid the possibility of short circuits always connect speaker cables
to the speakers prior to connecting to the amplier. The output binding posts will accept either bare wire or spades. (Regulatory agencies
in many countries have banned binding posts that will accept a banana
plug, forcing us to abandon this option.) Make sure that your speaker
wires only attach to the outputs of the amplier, not to each other and
never to the amplier case.
Some powered subwoofers require an audio signal ground reference and
their makers may suggest that a black speaker terminal is where this voltage reference might be found. On complementary designs, which would
be typical of all power amps produced by Pass Laboratories™, this is
an incorrect and unsafe assumption. On all Pass Laboratories™ power
ampliers a reference of 0 volts will be found only at pin 1 of the XLR
input or at the shell of the RCA input.
Reference connections for these devices require special consideration
when used with our product. If you have such a device, and wish to use
it with our product, please contact our Foresthill, California factory for
specic instructions.... you have been warned.
The amplier may be driven single-end or balanced, your choice. Singleended input will always occur through the RCA connector and balanced
input will always occur through the XLR connector. If driving the amplier single-ended leave the supplied jumper in place between pins 1 &
3 on the input XLR. On the XLR connectors pin 1 is ground, pin two
is positive input and pin 3 is inverted (negative) input. Pin numbers are
marked on the XLR. If you re-install the jumper incorrectly or leave
it lying about, the amplier will not work properly. You must choose
either XLR or RCA inputs it is not advised to try and run both concurrently.
XLR input connector showing proper
placement of jumper pin for use with
single-ended (RCA) input.
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