Pass XP-27 Owner's Manual
PASS
TM
XP-27 Owner’s Manual
XP-27 OM Prelim
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INTRODUCTION:
Pass Laboratories, specically Nelson Pass and his co-designer,
Wayne Colburn have a long history of imagining and successfully
bringing to the discriminating consumer some of the nest phono
stage pre-ampliers ever offered. Each new incarnation of the
Pass Laboratories phono preamps has pushed their personal limits
as to what level of acoustic bliss is realistically achievable from
“Streaming Analog”©.
Since 1997 the guiding credo for these phono pre-amps remains
the vision that music must ow effortlessly from LP surface to listeners
ear. With each evolution of product that effortless ow should
issue forth with greater detail and clarity while never forgetting
or sacricing the soul of the music and the artistic intent. The Pass
Laboratories XP-27 does not disappoint.
The XP-27 was brought to market both by copious measurements
and extensive listening through a multitude of tone arm and
cartridge combinations. Listening was given precedent over the
numbers but never at the expense of measured performance.
The result is a dynamic, lush and smooth sound with dramatic
detail and spectacular layering. Those listeners familiar with Pass
Laboratories previous phono pre-amps will be struck by the clear
delineation of bass notes in the XP-27 and the greater sense of
music in a real physical space.
Like some great musicians we get requests! You spoke and we
listened… so that you can listen better. Now the XP-27 a product
designed at the intersections of excellence, adaptability and
convenience.
The twin chassis XP-27 eclipses the already exceptional
performance of the well-reviewed and well-received XP-15, XP-25
& XP-17: delivering enhanced RIAA performance at a fraction of
the previous distortion. With the XP-27 you are going to discover
a whole new dimension of dynamics, inner detail and spectral
richness on your favorite LP’s.
The XP-27 brings all control and cartridge loading functions to the
front panel and presents them in a clear easy to understand layout.
The XP-27 boasts two separate and selectable inputs, ample
adjustable gain along with generous resistive and capacitive
loading choices.
Those listeners and archivists with the desire or need to sample
music from two tone-arms or turntables will be able to do so
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instantly with a single XP-27, thus simplifying their complement of
analog equipment and removing one more variable from their
listening chain.
The addition of a user selectable high pass (low cut) lter makes
possible the playing of recordings with excessive subsonic
information.
The addition of a user selectable mute control makes possible the
cuing of records and needle drop in absolute silence.
The XP-27 is an uncommonly ne match with very low output
moving coil cartridges which would normally require a transformer
rst stage.
By the early 1980’s it was generally acknowledged that lower
output moving coil cartridges were capable of retrieving
signicantly more ne detail from record grooves than higher
output moving magnet cartridges. In many instances this was
simply a case of having lower moving mass to accelerate in the
electrical generator mechanism of the phono-cartridge. Moving
coils with 3 or 4 turns of the nest wire attached to the lightest and
stiffest cantilevers were capable of accurately tracking complex
musical passages that a few years prior would have seemed
impossible tasks to engineer and listener alike.
The really astute cartridge makers had clearly taken a page
from the automotive and motorcycle racing cognoscenti, whose
engineers were doing everything in their power to lower “un-sprung
mass” in an effort to get tires to say in intimate contact with the
roughest terrain at the highest possible speeds. In both worlds
the ability to accurately track the impossible landscape is the
ultimate goal….. minimal moving mass associated with a compliant
suspension is a big part of the answer.
Unfortunately the active electronics that were capable of
extracting signal at those low levels, frequently then buried much of
that signal in their own noise oor. Step-up transformers generally
addressed the noise issues, but frequently lost the very ne detail
somewhere in the transformers iron core. For the time, the promise
of the best moving coil cartridges went un-realized
The XP-27’s high gain and exceptionally low noise gure allow for
ample output and detail from cartridges providing as little as 40 uV
(micro-volts) of signal at the phono input.
The adjustable gain options of the XP-27 make this unit immune
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from overload with any high output cartridge of which we are
familiar.
The XP-27 is as much a pleasure to use as it is to listen through,
thank you for trusting your ears and your vinyl collection with us.
Before you sit back and listen, take time to read and understand
cartridge loading. When you nd the desired setting, please
record that setting so that you can come back to it in the future.
For your convenience we left space at the end of this manual for
just these sorts of details.
TECHNICAL DETAILS:
As previously indicated the XP-27 is a twin chassis design. One
chassis holds the fully ltered and regulated power supplies and
the second chassis houses the analog gain circuits, input switching,
loading and all those details and features normally associated with
a reference RIAA phono stage.
The two chassis are interconnected with 9 conductor cable. This
cable only carries power, never analog signal.
Consumers frequently ask us if they may substitute a cable of their
choice for the one Pass Laboratories supplies. The answer is yes,
provided that cable carries all the necessary legal approvals.
Never attach or detach the 9 pin cable with the power supply,
powered up from the wall. Always unplug your XP-27 from line
voltage prior to attaching or removing the cable.
If you substitute an aftermarket power cord you need to be aware
of the following. The ground pin on the power cord provides this
product’s safety ground, for your safety and the integrity of this
product the safety ground must never be defeated. Additionally
this product has lter components in the AC line that are designed
to shunt unwanted noise from the power-line to ground. Defeating
the safety ground will ultimately defeat some of the performance
advantages built into this product.
To insure maximum performance and maximum safety use only
power cords that are grounded and carry all the necessary
approvals and directives from the local regulating authorities.
XP-27 OM Prelim
Lets talk about AC power requirements. Your new XP-27 is built
voltage specic to your market. Line voltage is determined at the
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