The ART300 amplifier embrace our firm belief 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 audio circuit of these amplifiers 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 KT150 output tubes, chosen for their musical accuracy, high power, and reliability. Two pairs are used to produce 300 Watts in the mono ART300. 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 adjustment tool.
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.
The ART300 amplifier maintain the exacting quality standards for which conrad-johnson is internationally known.
Resistors are precision laser-trimmed metal foil types. CJD Teflon dielectric capacitors are used for coupling the inverter stage to the output stage, and to bypass the large value polypropylene capacitors in the regulated power supplies. Proprietary wide-bandwidth output transformers contribute to excellent high frequency performance. Even the machined gold plated OFC connectors and the internal wiring have been carefully selected for optimal sonic performance. Attention to every detail enable us to extract the full potential from our circuit designs and ensures that our products will perform to this potential for years to come. The ART300 is built without compromise to achieve a new standard in musical performance, and they are built to last.
Power: ART300 Amplifier
300 Watts rms from 30 Hz to 15 KHz at no more than 1.5 % THD into 4 ohms (also available connected for 16 ohm loads)
1.0V rms to rated power
Frequency Response (at 10 watts)
20 Hz to 20 kHz, +/- .25 dB
Hum and Noise
108 dB below rated power
ART300 – 2 x 6922, 4 x KT150
16.3125D x 19W x 8.75H inches
ART150 80 lbs.
ART300 73 lbs.