Pass Labs X2.2 User Manual

pass

TM

Aug 10, 2006

X2.2 Owner’s Manual

X2.2 Owner’s Manual

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Introduction

The X2.2 is an ultra high quality non-remote linestage audio
preamplifier with internal power supply. It combines a completely
new circuit topology with traditional construction representing thirty
five years of preamplifier design.

This preamplifier 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 X2.2
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 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 X2.2 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 X2.2 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 X2.2 may be factory upgraded to the X2.5 which will convey
several operational functions and remote control which are absent
from the X2.2. The upgrade will also change the front panel display
to the more informative vacuum fluorescent alpha-numeric display.
Very few people are involved in the production of this product. I
supervise all phases of the construction, and I test each preamplifier
myself. If you have questions, comments, or problems, please feel
free to contact me directly.

Thank you for purchasing this preamplifier. It is my sincere hope
that you will enjoy its sound as much as I do.

Wayne Colburn

X2.2 Owner’s Manual

Vice President, Design

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Setup

The preamplifier has four sets of input connections, both single­ended and balanced output connections, and a separate tape loop.

The preamplifier’s voltage and current rating are indicated by affixed
tag on the bottom of the preamplifier. It 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
power supply is 50 to 60 Hz in all cases. The preamplifier typically
draws less than 30 watts during operation. Please verify that the
indicated voltage requirement of this preamplifier is consistent with
the voltage at your location.

We have provided a standard IEC AC power cord that fits into the
IEC line receptacle at the rear of the preamplifier chassis. The
preamplifier is equipped for operation with an earth ground provided
by the user’s AC outlet. Do not defeat this ground. The circuit
ground of the preamplifier is connected to earth and power ground
through a power thermistor, which gives a ground connection for
safety but helps avoid ground loops.

There are a total of four inputs and a separate tape loop. Two of
the four inputs can be used single-ended or balanced. The other two
inputs are single-ended only. The tape loop has both single-ended
and balanced inputs and outputs. 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” from below. Right channel RCA
connectors are marked with “R” from below. Balanced XLR inputs
and outputs are marked with “L” for left and “R” for right channel.

If your signal source is unbalanced, input will occur through the
RCA input connector, which is in parallel with the XLR connections
1 and 2. When single-ended inputs are used on input 1 and input
2, a shorting plug is provided between pins 1 and 3 of the XLR
connection, shorting the negative input to ground, and providing
optimal performance.

The unbalanced input impedance of the preamplifier is 33 kOhms.
In balanced mode, the input impedance is higher, with a differential
impedance of at least 66k Ohms.

Next to the inputs on the rear panel, the preamplifier offers tape
inputs through both XLR and RCA connectors. This output is a
direct connection to inputs 1, 2, 3, and 4 when they are selected from

X2.2 Owner’s Manual

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