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ARTsa Stereo Vacuum-Tube Power Amplifier (Pre-owned)

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This product is currently unavailable.


We are pleased to be able to offer a little used example of this fine stereo power amplifier on behalf of one of our long standing customers.  Immaculate condition thoughout supplied complete with original packaging and accessories.


Supplied with 18 month warranty.

At conrad-johnson, their 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 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.


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 enables them to extract the full potential from our circuit designs and ensures that their 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.



Power:  – 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: 
 – 1 x 6189, 2 x 6N30P, 8 x KT120

Dimensions: 18.75D x 19W x 7.13H inches

Weight:  – 82 Lbs.

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