The GAT Preamplifier embodies
conrad-johnson's latest advances in line-stage preamplifier technology.
We believe that it will quickly be recognized as the new industry-wide
reference standard for line-stage preamplifier performance, a role
filled for more than a decade by its legendary predecessor, the ART
preamplifier. Like the ART, the GAT Preamplifier will be available in a
numbered, limited edition of 250 units which will be sold through
selected conrad-johnson dealers.
The GAT
Preamplifier is a vacuum-tube, line-stage preamplifier that looks as
good as it sounds. It is also notable for convenience and ease of use.
The unit features input selection and level adjustment by
microprocessor-controlled relays. Level and balance can be adjusted in
100 steps of approximately .7 dB per step. All functions can be
controlled by the hand-held wireless remote control.
The
circuitry of the GAT Preamplifier is elegant in its simplicity. The
audio circuit consists of a single amplifier stage incorporating one
composite triode comprised of paralleled sections of a
high-transconductance miniature dual triode vacuum tube. This amplifier
stage is coupled to the preamplifier outputs through a high-current
MOSFET buffer, which achieves a very low output impedance, making the
GAT extremely flexible in the choice of interconnect cables and
amplifiers. DC voltage is supplied to the circuit by our latest discrete
voltage regulator that isolates the audio circuit from the power line
by maintaining negligible impedance across the audio frequency band.
Infrasonic noise is minimized by operating the tube filaments (heaters)
on a dc voltage supplied by another discrete regulated power supply.
Considerable
care and attention have been paid to the physical aspects of the design
as well. Microprocessor controlled relays, used for selecting sources
and level setting, are located right at the input connectors, keeping
signal paths short to minimize crosstalk between channels and inputs.
The vacuum-tubes are isolated by a suspension system designed to
minimize microphonics. The dramatic casework features attractive clear
Lucite tube guards outside the chassis, allowing for easy access for
tube replacement.
At
conrad-johnson we have long appreciated that the full potential of any
circuit can only be realized by using the finest available parts. Each
part for the GAT has been selected on the basis of both sonic
performance and durability. The audio circuit (including the level
control) is executed entirely with precision metal foil resistors and
proprietary CJD Teflon capacitors. Tubes have been carefully hand
selected for minimum noise and microphonics. The dc regulated power
supplies use the same quality resistors as the audio circuits.
Capacitors for the power supplies are exclusively polypropylene and
Teflon. There are no electrolytic capacitors in the audio circuits or
their related power supplies. All signal switching is done by special
relays designed for signal applications. These relays are sealed and
have gold plated silver contacts. Input and output connectors are
machined from oxygen free copper, and are gold plated. The GAT is built
without compromise to achieve a new standard in musical performance, and
it is built to last.