passTM
XP-20 Owner’s Manual
November 25, 2011
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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.
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.
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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.
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 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.
Advisory
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
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.
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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. 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.
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 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.
In’s and Out’s
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
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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 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.
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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 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.)
Before selecting the theatre pass through (pass thru) option, it is
imperative that the input device on input number 5 has its gain set
to minimum. Failure to follow this precaution could result in a
volume level intolerable to both ears and speakers. (The standard 2
volt source component, with the pre-amp set to 0 dB, will drive most
power amps to full rated output.)
As an added precaution when “pass through” is selected the volume
ramps upto 75. This is to prevent nasty surprises when “pass thru”
is selected accidentally. The ramp up sequence can be stopped at any
time by hitting any button on the remote.
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
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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 processor. Both of these default conditions are
intentional, and intended to make the most advantageous use of your
source electronics.
You may also set any input to unity (0 dB) by setting the volume at
step 75 from the remote or front panel control.
When “Pass Thru” is de-selected the XP-20 reverts back to the
previous input, volume and balance settings.
Input 5 may be manually selected and used without the “pass thru”
function, in which case its behavior will be identical to inputs 1-4.
The electronic volume control allows greater than 80 dB range and is
driven by a micro-controller that reads the optical encoder serving as
a front panel volume control.
In this manner tracking of the volume of the two balanced channels
is possible with accuracy unavailable on any ordinary analog volume
control, assuring precise level steps and high common mode noise
rejection in balanced circuits. Wayne Colburn’s exceptional volume
control in conjunction with the fluorescent display give the user
ability to replicate volume levels with absolute accuracy in steps of
roughly 1 dB or less.
The remote control uses a multi-button direct access architecture.
This remote is designed to operate several pieces of Pass Labs
electronics, not all of the functions available on this remote will be
applicable to all of your Pass Laboratories electronics. Specifically
the uppermost left hand button marked “power” does not work with
the XP-20. The XP-20 is designed to be powered continuously and
therefore this button will not affect the pre amplifiers operation.
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The Remote control operation is, or should be very intuitive in
operation; we have attempted to make its operation as familiar as
possible. Where applicable the remote mirrors the front panel
controls.
POWER: As previously mentioned has no reality with the XP-20.
This specific control functions has no effect on this product.
EXTERNAL AMP ON: The “external amp on” button supplies
a 12-volt trigger voltage from the rear panel of the XP-20, which
will control various pieces of auxiliary equipment. This function is
intended to control Pass Laboratories power amplifiers. For specifics
please see the instructions that accompany your power-amplifier.
You may also call the Pass Laboratories factory for specifics.
MUTE: pressing mute once will quiet the pre-amplifier outputs;
pressing mute a second time will return you to the previous volume
control setting.
INPUT SELECTION: Pressing. 1,2,3,4,5 will immediately move the
input selection to that input selection; volume and balance settings
will not be disturbed.
BALANCE: Pressing balance left (<) or balance right (>) will
increase the level in the left or right speaker, depending upon which
button is pushed.
VOLUME: Pressing the increase (^) button or the decrease (v)
button will shift the volume setting 1dB, holding a button down will
increase or decrease the level until such time as you either release
pressure on the button or reach the limits of the volume control.
PASS THRU: Pushing this button twice, sets the pre-amplifier to
volume step 75 (0 dB) and input 5. As an added precaution when
“pass through” is selected the volume ramps upto 75. This is to
prevent nasty surprises when “pass thru” is selected accidentally. The
ramp up sequence can be stopped at any time by hitting any button
on the remote.
The button must be pressed again to exit “Pass Thru” and unlock
the other command selections.
TAPE: Pushing this button once selects the single ended “Tape” as
your sixth input, pressing a second time deselects the tape input and
defaults back to the indicated input. When “Tape” is selected a lower
case letter “t” will appear on the right hand side of the display.
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DISPLAY: The default setting for the display is “bright”, pressing
the “DISPLAY” button once changes the display to it’s “dim” or
“low intensity” setting, pressing the button a second time selects
“off” for the display. When “off” is selected any other control
function will cause the display to indicate product operational status
for approximately 7 seconds and then the display will once again
blank.
Pressing the “DISPLAY” button a third time cycles back to a “bright
display”.
We recommend the use of the balanced output mode where possible.
Balanced input to power-amplifiers will typically retain the character
of the input mode, but offers less distortion, less noise, more gain,
and more voltage swing, without compromising the sound.
With balanced operation, the common mode rejection of the preamp
reflects the intrinsic common mode rejection of the topology, the
matching of the gain devices, and the matching of the attenuator
channels. In this case we have been able to keep the total mismatch
to about .1%, for a common mode rejection of approximately -60
dB.
The input system of the preamplifier will exhibit full common mode
noise rejection with passive balanced sources, where the negative
input is connected to ground at the source through the appropriate
source impedance. This allows adaptation of unbalanced sources to
balanced operation with passive cable connections in a manner that
achieves the superior noise rejection of active balanced sources.
The use of a micro-controller allows all of the preamplifier functions
to be repeatable and accurately controlled. The microprocessor only
controls the functions of the preamplifier. At no time does any of
the input or output signal come into contact with the digital control
signals.
The digital circuits are powered by a power supply that is isolated
from the analog supply. Should it ever be necessary to update
the software that controls the functioning of the preamp only the
socketed micro-processor need be changed.
Rugged mechanical muting relays, which delay connection during
turn-on and shut off the output when insufficient power supply is
available to maintain regulation, guard the output of the preamplifier
and offer protection to the power-amplifier and loudspeakers.
The XP-20 consists of two chassis, shipped in a single box.
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“Pass”, “pass”, “Pass Labs”, “Pass Laboratories”, Supersymmetery”,
“Aleph”, and “Zen” and are all registered trademarks of Pass
Laboratories, Inc., and all rights thereto are protected by law.
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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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All Pass Laboratories products purchased new from an authorized
Pass Laboratories dealer in North America are covered by a
transferable, limited 3-year warranty. This warranty includes all parts
and labor charges incurred at the factory or factory specified repair
facility, exclusive of any subsequent or consequential damages.
Damage due to physical abuse is specifically excluded under this
warranty.
Pass Labs Warranty
For this warranty to apply the customer is responsible for returning
the product unmodified to the factory within the specified warranty
period. The customer assumes all responsibility for shipping and
insurance to and from the factory or a factory specified repair facility.
The conditions and stipulations of this Pass Laboratories warranty
only applies to units originally sold new through an authorized dealer.
Warranty on factory repair is 60 days and covers only the scope of the
original repair.
Non-North America customers should consult with their original
Pass Labs dealer or distributor for warranty repair instruction prior to
contacting the factory or shipping product to the factory for repair.
Non-North American product must be returned to the country of
origin for warranty service. Foreign distributors are only required to
offer warranty service on Pass Laboratories product that they have
imported, verifiable by serial number.
Please note: Conditions of warranty service and customer rights for
product purchased outside the United States may vary depending
upon the distributor and local laws. Please check with your local
distributor for specific rights and details.
Any modifications to Pass Laboratories products that have not
received written factory approval nullify all claims and void all
provisions of the warranty and liability by the maker or authorized
distributor. Should a modified product be returned to the factory for
repair the owner will be required to pay all necessary charges for the
repair in addition to those charges required to return the product to
it’s original configuration.
In the case of safety issues, no product shall be returned to the
customer without those safety issues being corrected to the most
recent accepted standards.
Removal or alteration of original Pass Labs serial numbers voids the
factory warranty. Product with altered or missing serial numbers will
be suspect as counterfeit or stolen product.
Pass Laboratories will not repair or in any way indemnify any
counterfeit or cloned product. Pass Laboratories does not offer
products in voltages intended for international markets either to
authorized Pass Labs dealers or to third parties located in the United
States or Canada.
For more information please contact: Pass Laboratories Inc.
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pass®
Pass Laboratories Inc.
PO Box 219, Foresthill, CA 95631
voice: 530.367.3690 - fax: 530-367-2193 - web: passlabs.com
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