Pass Laboratories XP-12 User manual

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PASSTM
XP-12 Owner’s Manual

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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 specied
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-ampliers 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 re, 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 qualied service personnel.

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Introduction:
At Pass Labs we don’t change our products unless we feel that
the changes are signicant improvements over previous versions.
Because of this we see typical product life spans of seven to eight
years.
We are constantly working on and listening to new things and
increasing our knowledge of circuits and components on sound.
Eventually we nd some things worth putting into production
because they are signicant enough. That time has come with a
new series of preampliers.
The new XP-12 starts with a new power supply. It uses an efcient
toroidal design with both an electrostatic and Mu metal shield
along with vacuum impregnating and epoxy ll. This gives us a very
quiet transformer both electrically and mechanically.
The power supply circuitry itself is also lower noise and has
additional ltering, a little more complicated but worth it.
The XP-12 uses the single stage volume control borrowed from the
XS line preamp. This gives us one hundred 1 dB steps with lower
noise and distortion while removing some signal path parts.
The gain circuitry continues to use our favorite transistors from
Toshiba but has a larger higher biased output stage similar to the
XS preamplier auto bias. This makes longer and multiple cable runs
easier to drive and gives us the advantage of simplifying our single
ended output circuitry while increasing performance.
Overall this makes for a quieter more neutral, musical and versatile
control center for your system.

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Setup:
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 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 rst one removed any time you hook up or
remove equipment from the signal chain.
The preamplier’s voltage and current rating are indicated by
afxed tag on the rear of the preamplier. The preamplier
typically draws 30 watts during operation. Please verify that the
indicated voltage requirement of this preamplier is consistent with
the utility voltage at your location.
We have provided a standard IEC AC power cord that ts into
the IEC 320 line receptacle at the rear of the preamplier chassis.
The preamplier is equipped for operation with an earth ground
provided by the users AC outlet. Do not defeat this ground.
There are a total of ve inputs. Two of the ve inputs are balanced
XLR only. The other three inputs are single-ended only. There are
two pairs of outputs available with identical gain structure. One
pair Balanced, one pair single-ended.
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 two
RCA connectors, “R” (right) and “L” (left). The RCA connector’s
ground 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 benets. 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.

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Operation:
In use the XP-12’s 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.
After the all the inputs and outputs are connected and double
checked, you can now turn on the preamp by means of the power
switch located next to the AC inlet.
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 front panel mode switch cycles the preamplier display through
2 different levels and off. These two functions are as follows:
Bright, Dim and Off. Using any functions with the display “off” will
momentarily bring the display back up to its dim setting.
The two Select switches (designated by left and right pointing
arrows) then alter the displayed active input, 1 through 5.
Input 5 is unique in that it is linked with the Home Theater (Unity
Gain) function. (The HOME THEATRE FUNCTION is discussed at
length later in this manual.) The two select arrows logically control
selections of the various inputs to the preamplier.
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 89. 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 through 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 preamplier to function as a unity
buffer (0dB gain at volume step 89) for use with components that
best function with their own volume controls, such as surround
processors.

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When the right-front and left-front outputs of the processor are
routed through input 5 of the XP-12 (with the gain of the XP-12 set
for Unity), the volume will be under full control of the processor
and the XP-12’s action will be totally transparent. When the user
chooses this setting the software sets the XP-12’s gain to the unity
gain setting, regardless of how it was previously congured.
When at Unity both left and right level controls on the XP-12 will
have a displayed value of 89 (0 dB), You may also set any input to
unity (0 dB) by selecting low gain and setting the volume at step 89.
We have designed this product, so that the volume setting of the
preamplier will always revert to the values in the temporary register
as you exit from Pass Through. With the rarest of exceptions this is a
very safe transition, very infrequently will the normal chosen level be
higher than 0 dB.
The electronic volume control allows greater than 70 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 volume control, assuring precise level
steps and high common mode rejection in balanced circuits.
Wayne Colburn’s exceptional volume control in conjunction with
the uorescent display gives the user ability to replicate volume
levels with absolute accuracy in steps of roughly 1 dB.
The remote control uses 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 your Pass Laboratories XP-12.
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, tape and ext. amp on (external amplier turn-on) are not
used with the XP-12. These specic control functions are for other
products and have no effect on this product.
MUTE: pressing mute once will quiet the pre-amplier 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.

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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-amplier to
volume step 89 (0 dB) and input 5. As an added precaution when
“pass through” is selected the volume ramps upto 89.
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.
DISPLAY: The default setting for the display is “bright”, pressing
the display button once changes the display to its “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-ampliers 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 reects 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 preamplier 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 noise rejection of active
balanced sources.

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The use of a micro-controller allows all of the preamplier functions
to be repeatable and accurately controlled. The micro processor
only controls the functions of the preamplier. 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.
Muting relays, which delay connection during turn-on and shut
off the output when insufcient power supply is available to
maintain regulation, guard the output of the preamplier and offer
protection to the power-amplier and loudspeakers.
XP-12 Specs:
Power consumption 30 Watts
Gain 9.3dB Balanced
Frequency response: +/- 0.05 dB 10Hz to 20KHz
-1dB @ 100KHz
Crosstalk > 100dB
Residual Noise 15uV 10 – 30Khz
THD < 0.001 @ 1V 1Khz
Dimensions: 17”w x 12.5”d x 4”h
Weight: 20lbs

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Warranty Information
We go through great effort to make a soundly engineered, and
supurbly performing product of lasting duribility. But we also
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.
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 specied
repair facility, exclusive of any subsequent or consequential
damages. Damage due to physical abuse is specically excluded
under this warranty.
For this warranty to apply the customer is responsible for returning
the product unmodied to the factory within the specied warranty
period. The customer assumes all responsibility for shipping and
insurance to and from the factory or a factory specied 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, veriable 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 specic rights and details.
Any modications 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 modied 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 conguration.
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.

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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.
“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.
PASS®
Pass Laboratories Inc., 13395 New Airport Rd., Suite G, Auburn, CA 95602
voice: 530.878.5350 - fax: [phone] - web: passlabs.com