If you've never auditioned an Audio Research preamp, forgive anyone who suggests your audiophile journey has peaks yet to be climbed. The SP-6B is a well-refined expression of perhaps the perfect preamp architecture. Cornerstone piece for an endgame system.
- Full 30-point service check
- Cleaned controls, switches, and chassis
Type: Tube Stereo Preamplifier
Frequency response ±.25dB, 5Hz to 30kHz (Line), ±.25dB of RIAA from 30Hz to 40kHz (MM Phono)
Total harmonic distortion Less than .01% at 2V RMS output, 20Hz to 20kHz (Typically about .0005% in midband)
Intermodulation distortion Less than .002% at 2V RMS output
Noise & Hum 86dB below 5V RMS output, more than 90dB below 1V RMS input (Line), 5µV equivalent input noise, wideband RMS, -66dB reference 10mV input(MM Phono)
Gain 60dB (MM Phono), 26dB (Line)
Input Impedance 50kΩ, all inputs (MM 10Ω-100kΩ variable)
Output Impedance Less than 500Ω main output, 1kΩ tape
Recommended minimum load 50KΩ and 250 pF maximum capacitance for maximum audio quality
Maximum Inputs ∞ (Line, essentially overload-proof), 500 mV at 1kHz / 1.5V RMS, 10kHz (MM Phono)
Signal to noise ratio 66dB (MM Phono), 90dB (Line)
Output 2V (Pre out), 60V (Pre out Max)
Tube complement 6 x ECC83
Dimensions 19"W x 5.25"H x 10.25"D
Weight 22 lbs.
ARC SP-6B Owner's Manual
ARC SP-6B Brochure
The History of Audio Research
Audio Research Corporation, affectionately known to fans as ARC, was founded by William Z. Johnson, who began designing custom audio electronics in the early 1950’s and who also operated a specialty audio retail store until the mid-1960’s. Johnson’s efforts almost single-handedly revived vacuum-tube designs at a time...
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While there are a number of high quality preamplifiers available to the audiophile, the SP-6B stands alone in its ability to transmit the listener beyond the reproduction chain to the experience of the live event. The SP-6B achieves this by utilizing a hybrid technology approach to preamplifier design. The SP-6B incorporates massive, electronically regulated, solid-state power supplies coupled with vacuum tubes in the audio amplification stages. While the vacuum tube "lost out" to the transistor in popular consumer electronics where low cost, availability and miniaturization were necessary, the vacuum tube, when incorporated in a classic circuit design with a proper power supply, offers advantages still unobtainable in even the finest solid-state designs.