ART and ARTsa Vacuum-Tube Power Amplifier

The limited edition ART Amplifier 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. Those who do not need the prodigious 275 watt power delivered by the mighty ART mono-blocks will want to consider the ARTsa Stereo Amplifier. Nearly identical cosmetically (one more tube in the front), it is exactly an ART amplifier divided into two channels, each producing a solid 140 watts.

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 simple circuits constructed of the finest available parts. These ART amplifiers exemplify 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. For the ART mono-blocks, four pairs of KT120 output tubes, chosen for their musical accuracy, high power, and reliability, endow this amplifier with a muscular 275 watt output rating. For the ARTsa, two pairs of KT120 output tubes in each channel produce 140 watts of power per channel. A small amount (about 12 dB) of loop negative feedback reduces distortion and achieves a sufficiently high damping factor to control the reactive load typically presented by high-performance 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.

LP140M Vacuum-Tube Power Amplifier

Component parts contribute importantly to the sonic performance of any circuit design. The ART amplifiers maintain the exacting quality standards for which conrad-johnson is internationally known. Resistors are precision laser-trimmed metal foil types. Coupling capacitors are the new Teflon CJD caps, while the power supplies use large value polypropylene capacitors in parallel with CJD Teflons. There are no electrolytic capacitors in the audio circuits or in the related 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 ART and ARTsa amplifiers are built without compromise to achieve a new standard in musical performance, and they are built to last.

Visit a conrad-johnson dealer soon to hear for yourself just how true to the music an amplifier can be.

 

Specifications:

Power:
ART Amplifier - 275 watts from 30 Hz to 15 KHz at no more than .5 % THD or IMD into 4 ohms (also available connected for 8 or 16 ohm loads)
ARTsa Amplifier – 140 watts per channel from 30 Hz to 15 KHz at no more than 1.5 % THD or IMD, both channels driven 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
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:
ART - 1 x M8080, 1 x 6N30P, 8 x KT120
ARTsa – 1 x 6189, 2 x 6N30P, 8 x KT120
Dimensions: 18.75D x 19W x 7.13H inches
Weight: ART - 83 Lbs. ARTsa – 82 Lbs.

Each conrad-johnson component is patiently and carefully hand assembled, then individually inspected and its performance verified by an experienced audio technician. Our confidence in these components is reflected in the three year limited warranty covering labor and parts except vacuum tubes. Service is a top priority at conrad-johnson. In the event that a product does require service, it will be handled promptly and efficiently.