Audiophiles Choice
Vacuum-Tube Power Amplifier


Power: 275 watts from 30 Hz to 15 KHz at no more than 1.5 % THD or IMD into 4 ohms (also available connected for 8 or 16 ohm loads)
Sensitivity: 1.8V to rated power
Frequency Response (at 10 watts): 20 Hz to 20 kHz, +/- .25 dB
Hum and Noise: 108 dB below rated power
Input Impedance: 100 kOhms
Tube Complement: 1 x M8080, 1 x 6N30P, 8 x 6550
Dimensions: 18.75D x 19W x 7.13H inches
Weight: 83 Lbs.

The ART Amplifier is our first limited edition power amplifier, and only the third of these very special limited edition products that we have offered in our more than thirty years in business. It is designed to be a reference amplifier for the use of industry professionals as well as dedicated audiophiles. Like its companion GAT Preamplifier, the ART Amplifier will be offered in an edition of just 250 units (125 pairs) to be sold through selected Conrad-johnson dealers and distributors.

At conrad-johnson, our approach to circuit design is predicated on the principle that the surest path to both state-of-the-art musicality and exceptional reliability is to keep the circuits simple and build them with the finest available parts. The ART amplifier exemplifies this basic principle. The audio circuit has just three elements, each as simple as possible, and each essential to the operation of the amplifier. A voltage gain amplifier (a single triode) is direct-coupled to a cathode coupled phase inverter (each phase handled by a single triode), which in turn drives the output stage. Power is developed by 6550 output tubes, chosen for their musical accuracy, high power, and reliability. Four pairs are used to comfortably and reliably achieve the 275 watt power rating. A small amount (about 12 dB) of loop negative feedback reduces distortion and achieves a sufficiently high damping factor to control reactive loudspeaker systems. To assure continued peak performance, the owner need only make a simple bias adjustment when new tubes are installed. Built in LED bias indicators allow the user to make this adjustment using only the supplied screwdriver.

Separate, low impedance, discrete dc power supply regulators are provided for the input and phase-inverter stages, thoroughly isolating these stages from the power demands of the output stage. These power supplies are designed to maintain a rock solid supply at all audio frequencies.