Pass Laboratories XP-20 User manual

XP 20 Owners Manual Rev 0.4 16 November 2010
PASS®

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For your protection please read the following:
Water and moisture: Electrical devices should not be used near water (as per
example, near a bathtub, washbasin, kitchen sink, laundry tub, wet basement or
swimming pool ). Care should be taken such that objects do not have the opportunity to
fall, and that liquid is never spilled onto or into the device enclosure through openings.
Power Sources: An electrical device must be connected to a mains power source in
strict accordance with the supplied product owner’s manual. Please verify that the AC
mains voltage specified in the product manual matches those requirements indicated on
the unit and the AC voltage provided to your location by the power company.
Grounding: Adequate precautions should be taken so that the grounding provisions
built into an electrical product are never defeated.
Power Cords: Pass Laboratories provides a power supply cord that meets all
legislated requirements for the market in which the product was originally sold. If you
choose to substitute an after-market product we urge you to choose one that is fully
safety rated by the necessary local authority.
Power Cord Protection: Power supply cords should be routed so that they are not
likely to be walked on, abraded, or pinched by items placed on or against them, paying
particular attention to cords where they enter plugs or exit from a device. Never under
any circumstance insert a cut or damaged power cord into a mains power socket.
Power and Signal: Cables should never be connected / disconnected with equipment
powered up. Failure to heed this warning may damage or destroy equipment.
Ventilation: Power-amplifiers run hot, but you should be able to place your hands on
them without discomfort. You must allow for this heat in installation, by providing for
free air circulation around the product. Electronics should not be subjected to sources
of excessive radiant heat. Excessive heat can shorten the life of the product and may
cause the electronics to self-protect and shut down.
Servicing: To reduce the risk of fire, electrical shock or other injuries, the user should
not attempt to service the device beyond that which is described in the operating
instructions. All other servicing must be referred to qualified service personnel.

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Introduction
The XP-20 is an ultra high quality line-stage audio preamplifier featuring an improved
hand held remote control and external power supply electrically isolated from the analog
circuits of the preamplifier in a cosmetically matched second chassis.
The XP-20 like all Pass Laboratories products attempts to minimize the number of
components in the signal path, and yet retain exemplary objective performance
specifications. This pre-amplifier pushes the edge of the art by exploring how much
subjective quality is obtainable with unique circuit elements applied in innovative ways.
The Pass Laboratories XP-20 along with the XP-10 pre-amplifiers are the natural
descendants to the highly acclaimed and successful X series of Pass Laboratories line-
stages represented by models X0.2, X1 and X2.5.
The X series pre-amplifiers have received many highly respected and well-deserved
accolades since their introduction in 1997…. justifiably so. More importantly they have
provided a solid foundation from which the current and newest product has evolved.
These new pre-amp offerings from Pass Laboratories objectively sound and measure
significantly better than their immediate predecessors. These are the finest pre-
amplifiers Pass Laboratories has built to date, without question! Thank you for your
purchase of the XP-20.
The new XP series pre-amplifiers are more true to state of the art recordings than our
previous product. Given quality recordings, these pre-amplifiers sound more dynamic,
bass lines are more clearly, cleanly, and accurately delineated, helping eliminate un-
necessary one note bass; instruments and voice are presented in a more refined spatial
envelope, and with better spectral balance. Fine nuances and details, which frequently

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go un-noticed, now become apparent -- even in loud and highly complex musical
passages.
The simple truth is that a decade of knowledge and experience gained, coupled with
new component technology, has enabled both enhanced performance and listening
satisfaction over the building blocks we had available when the original X series pre-
amplifiers came to market. Pass Laboratories has not been shy about taking
advantage of these circuit innovations and new components in these new pre-
amplifiers. You will hear, and appreciate, these significant sonic improvements in the
XP series product.
Collectively, audiophiles tend to listen quite a bit differently today, than they did when
the original X preamps were created, and the XP line of product have all been designed
to reflect those changes in listening style.
Pass Laboratories has redesigned the remote control to allow direct access to the most
frequently wanted control functions, thus simplifying and enhancing product operation.
The new remote control codes have been carefully selected to minimize the impact on
other remote controlled electronic devices, allowing for more carefree product
placement. Volume control steps on the new pre-amplifiers are more numerous and
generally of smaller increments, giving the listener a wider choice of listening levels to
better accommodate the wildly-fluctuating signal levels of current, verses legacy,
recordings.
Changing lifestyles dictate that many audiophiles now share family space where music
may be an adjunct to other activities. To better serve the needs of these listeners, the
newest Pass Laboratories pre-amplifiers allow for significantly more precise volume
steps and greater attenuation at the very lowest volume levels.

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So that these very low-volume listening levels have real world practicality, the noise
floor and very fine detail retrieval of these new pre-amplifiers is dramatically superior to
our previous product.
Frequently, the perception of increased detail comes at the cost of equally increased
grain or edginess in the music. With this new pre-amplifier, hundreds of hours of
thoughtful listening and careful adjusting have produced a product where the enhanced
detail simply comes through as greater spatial refinement and dynamic accuracy;
without any loss of musicality.
Bass definition is better than in pervious models, highly dynamic passages typically
have more weight, a more accurate leading edge with increased control and the
spectral balance is more finely integrated top to bottom.
As good as the XP-10 is, the XP-20 performance metrics are enhanced over those
available in the XP-10 by virtue of a separate and additionally regulated power supply.
For the listener these circuit enhancements will convey musical bass with significantly
more impact, articulation and timber accuracy. With well-recorded material the XP-20
will present a more refined sound stage than the XP-10 with greater ability to accurately
delineate instruments in their proper spatial perspective of depth, width and height.
We sincerely believe these are simply the best sounding pre-amplifiers Pass
Laboratories has ever built! Simply put the XP products deliver the experience of a past
musical event in a more believable sonic panorama than anything we have previously
brought to market. Thank you for listening and giving us the opportunity to prove this
claim.
ADVISORY
There is an Extremely Small (but Non-zero) Chance That, Through a Process Know as
Tunneling, This Product May Spontaneously Disappear from Its Present Location and

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Reappear at Any Random Place within the Universe, Including Your Neighbor's
Domicile.
The Manufacturer Will Not Be Responsible for Any Damages, Inconvenience or Mental
Anguish That May Result.
There is a much higher probability that when you first plug your new pre-amps power
supply into the wall and listen to your favorite selections that you will not be
experiencing the full measure of performance this product is capable of. These are high
bias Class A topology circuits and their performance is largely temperature dependent.
We expect these circuits to heat up slowly through normal operation, do not attempt to
augment that heating by any artificial means. Temperature and performance will slowly
stabalize over the first 24 - 48 hours of operation and thereafter be at their sonic best.
Be aware however that if you unplug or otherwise remove power from the unit that the
warm up period starts afresh. Please give this product at least 24 hours initial warm
up time before attempting any critical listening.
A typical current draw for this product is 25 watts or less; the XP-20’s are designed to
be powered up 100% of the time.
SET-UP AND OPERATION
So much for the philosophy, physics and advantages, lets play music.
Please read and understand the operational instructions and safety issues associated
with this product. We go through great effort to make a soundly engineered, and
supurbly performing rugged product of lasting duribility. We understand that things
infrequently go wrong, if you have any questions or problems please contact either your
dealer or the factory, we are here to support the product and you, the user.
As with all audio electronics the power cable should be the last thing attached and the
first one removed any time you hook up or remove equipment from the signal chain.

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The DIN-25 umbilical cable should never be connected or removed with the power
supply chassis plugged into house power.
The preamplifier has five sets of stereo input connections, both single-ended and
balanced output connections and a full function remote control in addition to the normal
complement of front panel control functions.
The preamplifier's voltage and current rating are indicated by affixed tag on the rear of
the preamplifier’s separate power supply. It will indicate 240 volts, 220 volts, 120 volts,
or 100 volts. A 1.0 amp 3AG slow blow fuse is provided with 100-120 volt units, and a
0.50 amp slow blow fuse is provided with 220-240 volt units. The input frequency rating
of the power supply is 50 to 60 Hz. The preamplifier typically draws approximately 25
watts of power from the utility mains during operation.
Please verify that the indicated voltage requirement of this preamplifier’s power supply
is consistent with the utility voltage at your location.
We have provided a standard IEC AC power cord that fits into the IEC 320 line
receptacle at the rear of the power supply chassis. The preamplifier and power supply
is equipped for operation with an earth ground provided by the users AC outlet. Do not
defeat this safety ground. The chassis and circuit ground of the preamplifier is
connected to earth through a power thermistor, which gives a ground connection for
safety but helps avoid ground loop related noise issues. Please connect the power
supply to the preamplifier chassis by the supplied umbilical before plugging the
power supply into the wall. Conversely please unplug the power supply from the
wall before disconnecting the umbilical cable.
IN’S AND OUT’S
There are a total of five inputs. Two of the five inputs are balanced XLR only. The
other three inputs are single-ended only. The XP-20 also has a “Tape Loop” with single

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ended inputs and outputs. There are three pairs of outputs available with identical gain
structure. One pair Balanced, two pairs single-ended. You may use more than one
output at a time.
The single ended outputs are paralleled, but under most circumstances will drive
several devices at once, with no anticipated ill effects by virtue of the XP-20’s low output
impedance and high current capability. The balanced outputs are derived from their
own circuit elements, independent of the single ended outputs. Tape input
communicates back to the input bus, independent of the XP-20 volume control.
Balanced inputs and outputs are via XLR connectors. Single-ended inputs and
outputs are via RCA connectors. On the XLR connectors, pin 1 is grounded, pin 2 is the
positive signal, and pin 3 is the negative signal. Left channel RCA connectors are
marked with "L". Right channel RCA connectors are marked with "R". In a similar
fashion balanced XLR inputs and outputs are marked with "L" for left and "R" for right
channel.
The main outputs are located at the left-hand side (viewed from the rear) of the rear
panel, two male XLR connectors, and four RCA connectors, "R" (right) and "L" (left).
The RCA connector's ground (shell) is in parallel with pin 1 of the XLR outputs and the
RCA hot is fed from an independent summing junction that maximizes the X circuit
benefits. The RCA, single-ended, outputs are buffered from the balanced outputs.
You may use both the single ended and balanced outputs at the same time. On the
XLR, pin 1 is ground, pin 2 is positive, and pin 3 is negative.
The XP-20 has an onboard tape loop for those of you who like to record, add a signal
processor into the chain or simply need one additional pair of RCA inputs to complete
your music system. The tape loop is available only from the remote control and is
selected or deselected by a single keystroke of the “Tape” button on the remote. When
you select Tape from the remote the display shows a lower case letter “t” on the right

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hand side. When the letter “t” is showing tape input is selected and other inputs are de-
selected, regardless of other settings you may have chosen.
Input and output connectors were carefully selected to withstand a lifetime of frequent
use.
HANDY FEATURES
The XP-20 gain chassis has a single pair of binding posts labeled “Ext. Amp Turn-on”.
A 12-volt signal is available at these binding posts to control additional entertainment
electronics. This External Turn On feature was specifically intended to control Pass
Laboratories power amplifiers but may in fact control competitive product with similar
features. Check your power amplifiers owner manual and specifications for particulars.
This function is only active from the hand held remote control.
Description of Operation
In application the XP-20s front panel controls and alphanumeric display are quite
straight forward, and intuitive. We encourage you to become familiar with their
operation prior to establishing any input connections with this unit. Experience indicates
that engaging in a few minutes of exploration will add much to your ultimate enjoyment
of this exceptional Pass Labs product.
The left most button on the front panel is Mute. Pressing this button toggles between
mute on and mute off. Mute on removes signal from the output of the preamp.
The second button from the left is Mode. The front panel mode switch cycles the
preamplifier control chassis display through 3 different levels of illumination, Bright, Dim

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and Off. Default setting is Bright. Manually selection of illumination levels over-writes the
default setting. Removing power re-boots the system and re-establishes the default
settings. When in Off the display will illuminate at the Dim level only as control
selections are being made. Six seconds after the last control command the display will
blank, returning to Off.
The two input elect switches (designated by left and right pointing arrows) toggle
through inputs 1-5 in sequence.
When selecting an active input, as previously indicated, the left and right arrows select
for inputs 1 through 5. Input 5 is unique in that it is linked with the PASS THRU (Home
Theatre) function. (The HOME THEATRE / PASS THRU FUNCTION is discussed at
length below.)
The theater “Pass Thru” function bears special attention, this function is only available
as direct access through the hand held remote control. This function is associated only
with input number 5 and has two positions selected with the “pass thru” button on the
remote; those two positions, on and off. This function is useful in that it allows the
preamplifier to function as a unity buffer (0dB gain at volume step 75) for use with
components that best function with their own volume controls, such as surround
processors. When the right-front and left-front outputs of the processor are routed
through input 5 of the XP-20 (with the gain of the XP-20 set for step 75), the volume will
be under full control of the processor and the XP-20's action will be totally transparent.
When the user chooses this setting the software sets the XP-20's gain to step 75 and
displays the setting as 75P for both right and left channel, regardless of how it was
previously configured. When at unity gain in the home theater mode (Pass Thru) both
left and right level controls on the XP-20 will have a displayed value of 75P (0 dB), and
any previous balance settings will be over written, allowing total control by the