Reference 80S Stereo Power Amplifier The Reference 80S stereo amplifier continues Audio Research’s latest design effort in creating a vacuum-tube amplifier that not only redefines ultimate music reproduction, but does it in an incredibly beautiful package. The 80S was created with as much spirited authority as we can pack into a compact circuit with 2 KT150 tubes per channel for music lovers who want Reference-level performance at the lowest possible barrier to entry. Like every Reference amplifier before it, the 80S is a fully-balanced differential design, delivering the highest performance and lowest distortion. A four-layer circuit board is used to provide a separate ground plane, better circuit layout, and fewer noise-inducing point-to-point connections. Music is projected against a quiet, jet-black background—like looking at the stars out in the country, removed from light pollution. It is magical and enveloping. The finest details are heard, with rich harmonics, incisive bass, and full dynamic contrasts, showcased with the ambience of the original acoustic space. a fully-balanced differential design that provides the highest performance & lowest distortion Outwardly, the 80S shares the same dimensions as the 160M. A single shallow whisper fan is built into the bottom plate. Flexibility is built-in, too, with XLR and SE inputs, 4-8-16 ohm output taps, 12V input and output triggers, RS232 input, tube hour meter, switchable fan speeds, and defeatable auto-off function. The feature set is the same as the 160S, including a proprietary auto-bias circuit that adjusts for not only tube age, but for powerline voltage swings. There is fusing of the output tubes for safety and stability, single-ended and balanced inputs for flexibility, switchable Triode/Pentode operation – distinguished from the Triode/Ultralinear modes in the 160 models – to accommodate loudspeakers and personal preference, output tube monitoring, and inclusion of an hour meter. This is a tube amplifier that does not require fiddling and is meant to be enjoyed. The built-in 12V trigger turns the 80S on or off when connected to a modern preamp. Built by hand, from the ground-up in our Maple Grove, Minnesota facility, the 80S can fool you into feeling you are in the presence of the musical performance. Whatever your reference speakers may be, whether they are from Wilson, Magnepan, Vandersteen, Focal, Sonus faber, B&W, or countless others: the Reference 80S will elevate their performance to a new plateau. TECHNICAL SPECIFICATIONS Power Output 70 watts continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 1% at 140 watts, below 0.04% at 1 watt. (Note that actual power output is dependent upon both line voltage and “condition” i.e.: if power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not critical) Power Bandwidth (-3dB Points) 7Hz to 68kHz Frequency Response (-3dB points at 1 watt) 0.7Hz to 94kHz Input Sensitivity 1.4V RMS Balanced for rated output. (25.5 dB gain into 8 ohms). RMS SE for rated output. Input Impedance 300k ohms Balanced; 75k ohms Single-ended Output Polarity Non-inverting. Balanced input pin 2+ (IEC-268) Output Taps 4, 8, 16 ohms Output Regulation Approximately 1.0dB 16 Ohm Load to Open Circuit (Damping factor approximately 8) Overall Negative Feedback 15dB Slew Rate 10 volts/microsecond Rise Time 4.0 microseconds Power Requirements 105-130VAC 60Hz (210-250VAC 50Hz) 420 watts at rated output, 280 watts in Triode mode, 221 watts at “idle”, 3.6 watts off Units for Japan: 100VAC 50/60Hz Tubes Required 2 matched pair KT150 (Power output V1-V4); 2 6H30 (Gain stage V5, V6) Weight 62 lbs. (28.2 kg) Net; 73 lbs. (32.7 kg) Shipping Dimensions Width 18.5” (47 cm) chassis; 19.0” (48.26 cm) faceplate. Height 10.5” (26 cm) Depth 18.5” (47 cm) With handles & connectors: 21” (53.3 cm)
