Pass Laboratories XP-30 User manual

XP-30 Owner’s Manual
Rev. 0 - Oct 3, 2011

Introduction
In an area of electronics where it is often thought that everything that can improve
the sound has already been done, where other designers are concentrating on
mechanicals and eye-candy, we offer better sound.
The XP-30 is the best preamplifier line stage ever made by Pass Labs. By
extension it is possibly the best line stage ever made. It is the result of several years
effort by Wayne Colburn and staff at Pass Labs and has undergone numerous
designs, redesigns, revisions, more revisions, adjustments and tweaks; more than
any preamp product with the possible exception of the XP-25 phono stage.
Measurably the XP-30 generates less noise, less crosstalk, less distortion. It
delivers greater dynamic range, gain, output voltage and output current. This is not
why it is a breakthrough product.
We value technical excellence, but it is always the sound that is paramount. Many
audio products have measured spectacularly well but have not gone down as
classics because they have not delivered subjective qualities that keep listeners
happy beyond the occasional initial excitement.
With this uppermost in mind we set out to create a new preamplifier that simply
invites you to listen. We want you to anticipate listening to your entire record
collection, again and again.
As part of the process in developing the XP-30 we began by uniformly upgrading the
playback systems of our listening group. We do not do AB or ABX testing – our
people live with prototypes as long as they like in their own system, and only one
component gets changed at a time. This allows a close duplication of our
customer's experience and makes it easier to hear differences over extended time,
with our focus remaining on the quality of the sound.
Several set of prototypes were evaluated and refined over a period of three years.
This period also saw the final development of the XP-25, and its presence allowed
us to work in as much synergy between the components as possible. Several
different power amplifiers also participated, including XA.5 amplifiers,
prototype “Concept” amplifiers, SITs, and even tubes.
In the end everyone agreed on the sound - music flows through the XP-30 with
greater ease, spatial development and dynamic contrast than anything else we have
heard. Wayne even managed to fit in a couple of my requested features –
enhancements for bi-amping, and enough gain and voltage swing that the XP-30
can drive power amplifier output stages all by itself.
All that remained was for Desmond to turn it into eye candy as well.
Me, I wrote this introduction because Wayne was too modest to.
- Nelson Pass

Description
The XP-30 is a modular preamplifier consisting of one control / power supply chassis
and additional gain chassis, each containing the analog circuits of a single channel.
The XP-30 is meant to typically be used as a two-channel product, but you can use
the control chassis to serve up to six channels.
Each channel individually provides master and slave outputs. The relative level
between the master and slave outputs of each channel is adjustable by a knob on
the front panel of each individual gain chassis. If you have ever wanted to bi-amp
your loudspeakers, you might appreciate that this feature allows easy use of
different types of amplifiers for the low vs the high frequencies, adjusting the relative
levels as needed. If you need big power and control on the bottom but want the
sweet character of tubes on the top, you may wonder how you ever got along
without this. Or why other companies don't offer it.
It is even useful when the same types of amplifiers are used – typically without the
full load on each amplifier the subjective balance still needs minor tweaking.
All connected gain chassis respond to the master level adjustment on the main
control chassis through a completely new volume control covering a range of 100 dB
in precise 1 dB steps.
Both outputs of each channel are offered as single-ended and balanced outputs
having the same gain and impedance and both may be used simultaneously with no
degradation.
There are five (5) regular inputs, a special home theater bypass input and tape input
for those needing any side loops for recording or signal processing.
The control chassis also supports a mono function between the separate different
analog stage chassis.
The power supply in the control chassis is large enough for somebody else's power
amplifier. It contains a pair of highly efficient, low-noise Plitron transformers in dual
mono topologies, emi filtering, large capacitance reservoirs, and of course the
isolation that comes with being in a different chassis from the analog gain stages.
Something else that was on Nelson's wish list – the ability to drive an amplifier
output stage by itself: Do you require a preamplifier deliver a fraction of a volt to the
power amplifier or peaks in excess of 50 volts to a balanced no-feedback follower
output stage?
The XP-30 is fully capable of both tasks at once. The internal gain of each stage
can be boosted another 16 dB via an internal jumper and the preamp can serve as
the low source impedance front end to the new generation of Class A power
followers. Don't laugh – they already are for sale, and there are more coming your
way. If you have an XP-30 you won't have to buy a new preamp...

The output impedance of each output is quite low and thus able to better drive long
cable runs or cables with greater capacitance or amplifiers with low input
impedances.
XP-30 volume control is totally new and sonically unique. It's measured
performance - distortion, bandwidth, noise, and resolution is beyond reproach. It
preserves the dynamics and detail of the music passing through it, and scales this
performance over its 100 dB attenuation range.
Wayne Colburn has further refined his thinking of how the active circuit should serve
the music. Like Nelson, Wayne looks at parts and sees not applications but
potentials. The XP-30 uses a new and more advanced version of the gain modules
that have been popular in Pass products for the last ten years. It has lower
distortion and wider bandwidth than its predecessor and also features a dramatically
higher input impedance. This improved version of our symmetric topology sounds
so exquisite that that it has also been adopted in the new “Dual Chassis Amplifier”
prototypes. Pass Labs has made large purchases of discontinued Toshiba Jfets and
Mosfets to support production of this new gain stage for the next ten years.
Each of these efforts have contributed to a preamp that is more resolving, dynamic,
spatially accurate and closer to the real joy that is music.
To summarize:
The XP-30 is a time machine, offering a greater “look-back” at the original musical
performance and conveying additional insight to the artist’s creative intent. The XP-
30 will help you rediscover the joy of your record collection.
It's measured performance is our best yet.
It has some features that will help you get more out of your system – things that you
may not yet appreciate.
The XP-30 is the preamplifier that we built for ourselves.

Setup and Operation
So much for self-congratulation. Lets play some music!
On a more sober note, please read and understand the operational instructions and
safety issues associated with this product.
All of us at Pass Laboratories put great effort into building a soundly engineered and
superbly performing rugged product of lasting durability and value. We understand
that things occasionally go wrong, but we are here to support you if that happens. If
you have any questions or problems, please contact either your dealer or the
factory.
The support email address is:
[e-mail]
If you don't get a good enough answer, you can appeal to
[e-mail]
or even
[e-mail]
It is usually helpful to have your product's serial number available when you contact
the factory. It is by serial number that we track all hardware and software details
and history of an individual product unit.
Power Connection
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.
First
The preamplifier's voltage and current ratings are indicated by affixed tag on the rear
of the preamplifier's power supply / control module. The tag will indicate 240 volts,
220 volts, 120 volts or 100 volts.
A 2.0 amp 3AG slow blow fuse is provided with stereo 100 –120 volt units and a 1.0
amp 3AG slow blow fuse is provided with stereo 220 – 240 volt units.
Additional channels beyond the normal two may require a different fuse value,
please contact the factory for your specific application.
The input frequency rating of the power-supply is presumed 50-60 Hz in all
instances. Some individuals may wish to use a power regeneration apparatus, and
slightly higher lines frequency is presumed acceptable. The preamplifier typically

draws 45 watts of power from the utility mains during operation as a 2 channel
preamplifier. Additional channel demands increase the demand for line wattage by
approximately 15 watts per channel.
We have provided a high quality standard IEC AC power cord that fits into the IEC
320 line receptacle at the rear of the power supply / control chassis. This is the
power cord we use for all product evaluation. You may substitute an equivalent
“after market” power cord of your choosing; however, we strongly suggest that any
cord you select must carry all appropriate government certifications for your location.
Under no circumstances defeat the safety ground provided by the power cord. We
have provided internal isolation to help prevent ground loops. If ground loops exist
in your system which suggest to you that you might want to disconnect this earth
ground, please contact your dealer or the factory first. Be aware that some of the
internal noise filters of this product presume a good earth ground through the power
cord. Removing that ground may compromise system performance.
Do not plug in the power cord yet.
Second
Place the components that comprise the XP-30 in the locations where you plan to
use them. They don't need a lot of ventilation, but a little is helpful.
On the rear of each control chassis are two identical DIN-25 sockets in parallel with
one another. You may connect either socket to the control chassis, as previously
indicated they are identical. The second socket provides daisy chain capability for
additional gain channels.
The DIN-25 connecting cables only communicate power, and control commands to
the gain stages. At no time does audio signal cross the DIN-25 umbilical cables.
Keeping each gain channel chassis 100% isolated from every other gain channel
chassis reduces channel cross-talk to a near theoretical minimum.
Connect the power supply / control chassis to the gain stages by the supplied DIN-
25 umbilical cables. They must be pressed firmly into the receptacles, keeping in
mind that the connector shell is trapezoidal, which keys the proper orientation.
Finger tighten the screws on either side of the connector shell. Do not use
excessive force, take care not to cross thread the screws.
Third
There are a total of seven inputs on each chassis. The first inputs are numbered 1-
5. Input 6 has been named “Pass-Thru” and is intended for use with a home theater
processor (see the later notes on use of input 6). Input 7 is the tape loop.
The XP-30 is shipped with shorting plugs on the input XLR connectors which
connection the (-) pin 3 input to the ground pin 1 input. Save these jumpers. They
are not only gold plated and thus valuable, but you will need them when you wish to

operate an input with RCA (single-ended) connections. The XLR pins are
numbered, but you’ll have to look close, maybe with a hand lens.
There are two sets of balanced and single ended outputs on each channel,
designated “master” and “slave”. You may connect and use as many of these
outputs as you wish without degradation of signal. Each output is derived from it’s
own circuit element and is totally independent of any other outlet. On the XLR, pin 1
is ground, pin 2 is positive and pin 3 is negative.
The XP-30 also incorporates a “tape-loop” for those users who either record or wish
to insert a processor loop as a side chain. Tape out communicates directly back to
the input bus, bypassing the volume control. Tape out is always active, with one
exception, where Tape Out is isolated from Tape Input to avoid a feedback loop.
The tape loop is only available from the remote control and is selected or deselected
by a single keystroke of the “Tape” button on the hand remote. When tape is
selected from the hand remote, the display on the power supply shows a lower case
“t” on the right hand side of the display. When the letter “t” is showing, the tape input
is “selected” and all other inputs are “deselected”, regardless of any previous
settings you may have chosen. Pressing the “Tape” button a second time, cancels
the command.
Handy Features
The home theater “Pass-thru” command is simply a software setting that selects
input 6 and sets the gain to 0 dB with a minimum of keystrokes. The keystroke
shortcut selects input 6 and slowly advances the volume control to step 89, starting
from 0. The slow advance of level is intentional; 0dB (step 89) is appropriate for a
home theater processor, it is however dangerously high for most source
components. As the level advances the display will indicate each volume step with
the step number and the suffix L & R (Left and Right). Once the 0dB point is
reached the L & R suffix are superceded with a letter P (Pass-Thru).
At any time the volume advance for the Home Theater Bypass may be interrupted
by pressing any button on the hand remote other than the Pass-Thru button. Once
halted the volume may be manually set from either the front panel volume control or
from the volume up ^ and volume down v arrows on the remote.
Pass- Thru functionality may be over ridden allowing this input to be treated as
simply as an additional user addressable input. The slow advance of level allows
the user to safely cancel the incremented volume increase command and assert
manual control over the preamplifier output level.
When selected as an additional input the control chassis display will show this
selection as input 6 with the letters L (left) and R (right) as suffix’s to the level
setting.
The XP-30 has a single pair of binding posts on the power-supply / control chassis
which are labeled “Ext. Amp Turn-on”. A 12-volt DC signal is available at these

binding posts to control additional entertainment electronics. The External Turn-on
feature was specifically intended to control Pass Laboratories power amplifiers, but
may in fact control items from other makers with similar features.
The binding post red terminal conveys a 12-volt positive voltage and the binding post
black terminal is a ground reference voltage. Please check the owners manuals of
your ancillary equipment for particulars of compatibility. If you have a question,
please contact the Pass Laboratories factory.
Specific to Pass Laboratories power amplifiers is the requirement that the power
amplifier be placed in standby from it’s front panel control before using the remote
turn on function. The power amplifier’s onboard stand-by switch over rides the pre
amplifier control with respect to the “on” command. This is intentional so that the
power amplifiers may also be controlled manually.
The monaural function is selected only from the front panel, it is not available from
the hand remote. When mono is selected, rather than creating a true mono signal it
creates a frequency dependent blend of signal from two chassis. The blend has
been chosen such that it minimizes noise while maximizing information transfer.
The two blended gain chassis are joined to one another by a special XLR cable The
blend function was intended to address the special needs of professional audio
archivists who frequently work with recordings of historical importance and dubious
quality.
These professional archivists require circuits that transfer the last iota of intelligible
detail combined with the smallest percentage of unwanted artifact (spurious noise).
The blend circuit specifically addresses this professional need.
As a casual listener you may find the “mono” function of value when listening to any
recordings that presumed a single point source reproduction rather than two-
channel. The high frequency blend of the mono control frequently reveals
performance nuances in these recordings that would otherwise go unnoticed on a
two-channel system.

For your protection please read the following:
Water and moisture: Electrical devices should not be used near water (for 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 high quality power supply cord that
meets all legislated requirements for the market in which the product was originally
sold. These are actually the power cords with which we evaluate the sound of our
amplifiers. If you choose to substitute an after-market product we advise you to use
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 equipment.
Ventilation: Power-amplifiers run hot. You must allow for this heat in installation, by
providing for free air circulation around the product. You should be able to place
your hands on the heat sinks for 5 to 10 seconds without discomfort. This
corresponds to about 50 to 55 degrees C. Electronics should not be subjected to
other sources of excessive 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.
If you have any questions whatsoever about product safety, please contact your
dealer, distributor, or Pass Labs by email: [e-mail]

Specifications
Gain 10,16 or 24 dB / Maximum attenuation of –90dB
Volume control 100 individual 1 dB steps
Freq. Response 20Hz – 20kHz +/- 0.05 dB
Distortion < .1 % THD at 1 kHz typically
<0.001% THD @ 1V rms
<0.01% THD @ 14V rms
Output Impedance
Main balanced 120 ohm total, 60 ohm per phase
Slave balanced 200 ohms total, 100 ohm per phase
Main RCA 120 ohm
Slave RCA 120 ohm
Input impedance 42 k-Ohm
CMRR typical -65 dB, 1KHz
Crosstalk broadband, typical -100 dB, 1KHz
Signal to Noise Ratio -110 dB, Ref 5V
Residual Noise 20 Hz – 20 kHz < 20 uV un-weighted max
Power Consumption 45 watts as two channel, 15 watts additional per additional
channel
Dimensions chassis 17”W x 12”D x 4”H
Shipping Weight 74 pounds in packing carton.

Warranty
Please check with the factory authorized distributor in the country where you are
purchasing this product for specific warranty information.
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.
For this warranty to apply the customer is responsible for returning the product
unmodified to the factory within the specified warranty period. SPECIFIED
WARRANTY PERIOD COMMENCES UPON THE PRODUCT’s FACTORY SHIP
DATE.
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 Authorized Dealer Refurbished product is 1 year and does not cover
cosmetic condition of the product.
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 warrantee
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 suspected as
counterfeit 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.
© 2011 Pass Laboratories Inc..
“Pass ”,“PASS ”,“Pass Labs ”,“Pass Laboratories ”, Supersymmetery ”,“Aleph ”,and
“Zen ” are all registered trademarks of Pass Laboratories, Inc., and all rights thereto
are protected by law.