audio research

Solid state stereo power amplifier

From the ARC website

The Model 100.2 stereo power amplifier sets new standards in musicality and value against all other competitors at or near its price. Rated conservatively at 100 WPC into 8 ohms, the 100.2 produces 200 WPC into 4 ohms and a hefty 360 WPC into 2 ohms -- giving it sufficient drive to handle a wide variety of today’s leading loudspeakers. Both single-ended and balanced inputs are provided for easy connection to any high-quality preamplifier. A.C. power is supplied via a three-pin IEC connector and 14-gauge detachable power cord.

Inside, the 100.2 reflects the latest design strategies from Audio Research engineers. High-impedance (i.e. easy to drive) JFET input transistors feed a single gain stage (for more sonic purity) using selected oversized MOSFET devices in a complementary configuration providing 27.5 dB of gain with tremendous dynamic headroom. This single gain stage is isolated from the power supply via Audio Research's constant current source technology, and directly feeds the MET (Multiple Emitter Transistor) output stage, which is also direct-coupled. A unique (patent pending) limited feedback loop of 6 dB preserves phase linearity, excellent damping characteristics and bass impact and control. The 100.2 is remarkable not only for its tube-like lucidity, but also for its ability to maintain this level of musical composure under demanding dynamic conditions.

The 100.2 also features a fully transparent protection circuit that mutes the output stage whenever the amplifier senses D.C. offset at the input or a shorted connection at the output -- providing an extra measure of protection to loudspeakers. Generous heat sinking provides sufficient dissipation to allow in-cabinet installation, even while the amplifier's overall dimensions are reasonably compact.

The new sonic standard set by the 100.2 must be experienced directly to be appreciated. It possesses a level of midrange transparency until now only achievable by vacuum-tube amplifiers, and delineates a dynamic soundstage that makes conventional solid-state amplifiers seem wooden and diffuse by comparison. Bass speed and harmonic richness are compelling, in large measure because the 100.2 is so liquid and grain-free in its signature. The 100.2 genuinely pushes performance beyond traditional solid-state expectations into new musical territory.





MSRP (US new retail)
$2,995. Increased to $3,495 on Feb 5 2001.


Power output 100 watts per channel into 8 ohms, 200 watts per channel into 4 ohms
Power bandwidth (-3dB points) DC to 160 kHz into 8 ohms
Frequency response  
Input sensitivity 1.3V RMS for rated output. (26.5 dB Gain) single-ended or balanced
Input impedance 150K ohms Single-ended, 300K ohms Balanced Differential
Output taps  
Output regulation 0.4dB 8 ohm load to open circuit
Overall negative feedback 3 dB
Damping factor 20
Slew rate 30 volts/microsecond
Rise time 2.0 microseconds
Hum & noise 150 microvolts RMS (105dB below rated output IHF A-weighted)
Power supply energy storage 130,000 uF total
Power requirements 105-125VAC 60Hz (210-250VAC 50Hz) 390 watts at rated output (100WPC 8 ohms), 700 watts at 200WPC 4 ohms, 800 watts maximum, 150 watts idle
Other Input polarity: Non-inverting at single-ended inputs. Balanced pin 2+ (IEC-268)
Dimensions 19" (48 cm) W (standard rack panel) x 5 1/4" (13.3 cm) H x 11 7/8" (30.2 cm) D (front panel back). Handles extend 1 1/2" (3.8 cm) forward of the 3/8" thick front panel. Output connectors extend 1" behind rear panel
Weight 34.7 lbs. (15.8 kg) Net; 47 lbs. (21.4 kg) Shipping.