PassLabs X-0.2 Owners manual
pass
TM
May 18, 2006
X0.2 Owner’s Manual
X0.2 Owner’s Manual
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Introduction
The X0.2 is an ultra high quality three chassis line-stage audio
pre-amplifier featuring remote control and internal power supply.
It combines a completely new circuit topology with traditional
construction representing thirty five years of preamplifier design.
This pre-amplifier flows from a commitment to create the best
sounding product: a simple circuit with the most natural sonic
characteristics. Derived from US Patent # 5,376,899, the X0.2
integrates power MOSFET and JFET devices in a simple Class A
topology in order to deliver the finest sound possible.
The Super-Symmetric gain circuitry used in the X0.2 is unique in
providing superior flexibility and performance with both balanced
and unbalanced inputs and outputs, converting one to the other as
desired without extra circuitry and without performance degradation.
The X0.2 minimizes the number of components in the signal path,
and yet retains exemplary objective performance specifications. It
pushes the edge of the art in exploring how much subjective quality
is obtainable with a new but very elementary gain stage.
The X0.2 employs a patented new type of volume control that
offers significantly better performance than seen before in an
electronic control. It provides over 60 dB of range, large voltage
swing and very good measured performance. The distortion and
noise is at 1/10 and the dynamic range 100 times the previous state
of the art in active attenuation. Most importantly it is subjectively
outstanding; better than any potentiometer we have evaluated.
The fluorescent display is a very special device. Not only will you
find its blue color highly attractive and readable, it is far more reliable
than the usual LED or LCD display.
Very few people are involved in the production of this product. I
supervise all phases of the construction, and I test each pre-amplifier
myself. If you have questions, comments, or problems, please feel
free to contact me directly.
Thank you for purchasing this pre-amplifier. It is my sincere hope
that you will enjoy its sound as much as I do.
X0.2 Owner’s Manual
Wayne Colburn
Vice President, Design
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Setup
The pre-amplifier consists of three machined aluminum chassis; it
has five sets of input connections, two sets of outputs, both singleended and balanced, a tape loop and a full function remote control
unit that mirrors the front panel functions.
The power supply control chassis has a 5-way binding post that is
used for remote amplifier turn-on. The pre-amplifier’s voltage and
current rating are indicated by the affixed tag on the bottom of the
pre-amplifier’s power supply control chassis. This tag will indicate
either 240 volts, 220 volts, 120 volts, or 100 volts. A 0.5 amp 3AG
slow blow fuse is provided with 100-120 volt units, and a 0.25 amp
slow-blow fuse is provided with 220-240 volt units. The frequency
rating of the X0.2 power supply is 50 to 60 Hz. This pre-amplifier
typically draws 30 watts during operation. Please verify that the input
power rating as indicated on your unit is consistent with that supplied
in your area before attempting hook up.
The remote control is powered by two (2) factory installed AAA
batteries.
The individual gain channels connect to the power supply control
unit with four (4) necessary cables and to each other with one
optional cable. These cables must be installed before the
preamp is powered up. The cable jacks are clearly labeled on
the rear of each chassis and are style and gender specific so as to
minimize opportunity for mis-connection.
Both gain channels are identical electrically, the only difference is the
color of the identifying rings under the RCA connectors. The right
channel is identified by red rings under the RCA’s connectors and
the left by white rings. Additionally the right gain stage chassis has a
female XLR marked “mono” and the left gain control chassis has a
male XLR marked “mono” as a further identifier.
The X0.2 takes maximal advantage of four identical gain paths
(two identical paths per channel) very much unlike the typical two
gain path (one signal path per channel) pre-amplifier you may be
familiar with. Almost without exception traditional consumer audio
pre-amplifiers, unlike their science and industry counterparts have
maintained a single signal path per channel (two identical aths in a
stereo pair).
In order to manage balanced signals these two gain path preamplifiers must utilize phase combining networks to process
incoming signals and subsequently drive outputs via phase splitting
circuits to re-establish a quasi-balanced signal. This manipulation of
X0.2 Owner’s Manual
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signal typically adds additional gain stages and degrades the inherent
noise and distortion superiority of balanced signal, coloring what you
eventually hear.
Pass Labs, through its unique patented “Supersymmetry” topology,
maintains the advantages of a true balanced signal throughout
the electronics chain. The salient point of this approach affords
significantly less signal manipulation, higher input impedance, as
much as a 100:1 (20dB) reduction in distortion while providing
greater gain, and twice the dynamic headroom of identical circuits
running single ended.
The X0.2 maintains the integrity of its received signal by treating
all sources internally as balanced signals and converts seamlessly
between balanced and unbalanced inputs and outputs without any
additional components in the signal path. This was a conscious
effort by Pass Labs to enhance the consumer’s ability to integrate
source components and power amps with otherwise incompatible
requirements through a virtually transparent control center.
It is not absolutely necessary to have the “mono” cable installed
between these connectors unless you plan to operate the X0.2
in mono mode. You may use our supplied “mono” cable or an
aftermarket male - female XLR of your choosing. If you choose an
aftermarket cable, length should be consistent with the placement of
your equipment and not excessively long.
The DIN connectors plug into their mating jacks and then screw into
the rear panel on all three chassis. These connectors are intentionally
a snug fit, but should never be forced. The single unmarked DIN
jack on the right rear of the power supply control chassis is currently
unused, we have reserved it for future performance enhancements.
We have provided a standard IEC AC power cord that fits into the
IEC line receptacle at the rear of the pre-amplifier power chassis.
The pre-amplifier is equipped for operation with an earth ground
provided by the user’s AC outlet. Do not defeat this ground. The
chassis and circuit ground of the pre-amplifier are connected to earth
through a power thermistor, which gives a ground connection for
safety but helps avoid ground loops.
As a safety issue we suggest that the power cord should be
the last cable installed on your pre-amplifier. The power
cord should be attached to the pre-amp power supply prior to
plugging into “house power.”
X0.2 Owner’s Manual
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