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.
