Preview: Audio Research Reference 75
At first listen, I almost found re-incarnation a possibility. This new tubed, 75 watt stereo amplifier from Audio Research bears a more than passing resemblance to the classic D-79 tube amp of William Z. Johnson design, which was, in my opinion, the best sounding amplifier of the Seventies — and a landmark in its day.
It sounds like that legendary amplifier, yet even better – it has a more neutral bottom end, thus a sense of more power, indeed, it sounds as if it could drive any modern speaker system, and to that test we shall put it. Its ability to handle musical transients and dynamics exceeds any of its ancestors and it is decidedly better looking.
When I say it sounds “better” I mean it sounds as if its design has been perfected, but it still has all the strengths of, say, Johnson’s classic D-79 and then more, much more.
I was knocked out.
Review to come…
Audio Research Reference 75 stereo amplifier
Specifications from the Audio Research website:
POWER OUTPUT: 75 watts per channel continuous from20Hz to 20kHz. 1kHz total harmonic distortion typically 0.6% at 75 watts, below 0.05% at 1 watt. Approximate actual power available at ‘clipping’ 76 watts (1kHz).
POWER BANDWIDTH: (-3dB points) 7Hz to 60kHz.
FREQUENCY RESPONSE: (-3dB points at 1 watt) 0.7Hz to 75 kHz.
INPUT SENSITIVITY: 1.4V RMS BAL for rated output. (25 dB Bal gain into 8 ohms.)
INPUT IMPEDANCE: 300K ohms Balanced.
OUTPUT POLARITY: Non-inverting. Balanced input pin 2+ (IEC-268).
OUTPUT TAPS: 8 ohms, 4 ohms.
OUTPUT REGULATION: Approximately 1.0dB 8 ohm load to open circuit (Damping factor
OVERALL NEGATIVE FEEDBACK: 15dB.
SLEW RATE: 10 volts/microsecond.
RISE TIME: 4.0 microseconds.
H U M & N O I S E : Less than 0.06mV RMS – 112dB below rated output (IHF weighted, input shorted)
POWER SUPPLY ENERGY STORAGE: Approximately 520 joules.
POWER REQUIREMENTS: 105-125VAC 60Hz (210- 250VAC 50Hz) 410 watts at rated output, 500 watts maximum, 230 watts idle.
TUBES REQUIRED: 2 – Matched pair KT120 – Power Output; 2 – 6H30 Driver.
DIMENSIONS: 19″ (48.3 cm) W x 8.75″ (22.2 cm) H x 19.5″ (49.5 cm) D. Handles extend 1.5″
(3.8 cm) forward.