Conrad Johnson ACT2 Series 2 Tube Preamplifier, Complete Set, $16,500 MSRP

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Conrad Johnsons best looking preamp, and one of the best ever made. This is also the later and more advanced Series 2 model.

The only shortcoming is that this does not have a phono section, so it's perfect for those all-digital folks or someone with a kick-ass outboard phono preamp.

This was thoroughly tested in our lab where we replaced a few components in need. It is working and sounding perfectly.

Condition is near perfect with no signs of use or abuse. The remote does show some wear in the lettering, but is very clean otherwise.

Comes complete will all accessories and packaging as the day it left the factory.

The matching CJ amplifier is also available by clicking here

Conrad Johnson ACT2 Series 2 Tube Preamplifier - Owner's Manual

More from Conrad-Johnson:

ACT2 preamplifier
Introduced July 2004
THE ACT2 PREAMPLIFIER EMBODIES CONRAD-JOHNSON’S LATEST ADVANCES IN LINE-STAGE PREAMPLIFIER TECHNOLOGY.
It is the successor to the legendary ART preamplifier that has been widely recognized as the reference standard for line-stage preamplifiers since its introduction in 1996. The ACT2 incorporates the breakthrough concept of the composite triode circuit (which has garnered more than a dozen international awards for conrad-johnson preamplifiers). The ACT2 refines this approach by implementing circuit upgrades and by taking advantage of recent advances in materials technologies. The end result is a line-stage preamplifier that we believe will quickly be recognized as the new industry-wide reference standard.

The ACT2 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 ACT2 Preamplifier is elegant in its simplicity.
The audio circuit consists entirely of a single amplifier stage incorporating one composite triode comprised of four paralleled sections of ultra-high transconductance miniature dual triodes. This arrangement achieves a low output impedance while reducing the number of active stages to the absolute minimum of one, resulting in unparalleled sonic purity. DC voltage is supplied to this stage by cascaded discrete voltage regulators that absolutely isolate the audio circuit from the power line by maintaining virtually zero 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. Critical audio circuitry is mounted on a subchassis that is isolated by a suspension system designed to minimize microphonics. The dramatic casework features an attractive clear Lucite tube guard 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 ACT2 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 Teflon and polystyrene 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, polystyrene, and Teflon – there are no electrolytic capacitors in the audio circuits or their related power supplies. Switching relays are sealed and have gold plated silver contacts. Input and output connectors are machined from oxygen free copper, and are gold plated.

The ACT2 is built without compromise to achieve a new standard in musical performance, and it is built to last.

Specifications:
• Gain:
21.5 db

• Maximum output:
10 vrms

• Output impedance:
under 500 ohms

• Distortion:
less than .1% THD

• Frequency response: at unity gain:
2 Hz to more than 10OKhz

• Hum and noise:
100 db below 1.0 v

• Tube complement:
4 x 6N30P

• Mechanical:
• Dimensions:
19 W | 5.375 H | 5.75D inches

• Weight:
30 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.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.