Conrad Johnson GAT Series 2 Reference Tube Preamplifier

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This is the flagship tube preamp from Conrad Johnson and possibly the best tube preamp we've seen.

Tubes were just replaced with a NOS matched pair of Philips PCC88. Plus this example just came back from C-J in January of this year where it received a clean bill of health (confirmed in our own lab).

This is a complete kit and will present like new. There not a scratch or finger print on it as you can see from the pictures. It's not often we give something a 9 condition rating.

Your purchase includes the original shipping carton with all internal packaging, the remote in its C-J case, plus the original manual and tube boxes.

** This is a line stage preamplifier meaning the PH/AUX input is not a phono (RIAA) input. You can connect a C-J or any other branded dedicated phono preamplifier to this input.

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - Power Cords 

More from Conrad Johnson:
Winner - 2019 The Absolute Sound - Editor's Choice Awards

GAT Preamplifier
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.

Conrad Johnson GAT Series 2 Reference Tube Preamplifier - Manual

GAT Triode Preamplifier Specifications
Gain:
25 db

Maximum output:
20 vrms

Output impedance:
under 100 ohms

Distortion:
less than .15% THD

Frequency response:
at unity gain
2 Hz to more than 100Khz

Hum and noise:
100 db below 1.0 v

Tube complement:
2 x 6922

Dimensions
15.375 D x 19 W x 4.81 H (inches)

Total Weight
35 lbs.

The SkyFi Testing Process for Preamplifiers:
We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.

At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.

Final testing involves putting actual music through the preamplifier. We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.