SP8

About the SP8

The Audio Research SP-8 is a high-quality all-tube analog stereo preamplifier produced from 1981 to 1988. It features a magnetic phono input designed for moving magnet cartridges and multiple line-level inputs. The preamplifier is renowned for its warm, sweet, and clean valve sound with a high degree of detail and musicality. It includes a volume control, balance, stereo mode selector, tape monitor, and mute functions but no tone controls or loudness switch. The SP-8 uses a combination of vacuum tubes and solid-state elements in its electronically regulated power supplies, ensuring excellent line regulation and low noise. It is built with robust construction, high-quality components, and a professional lab-style aluminum front panel. The unit measures 19" (48 cm) wide, 5¼" (13.4 cm) high, and 10¼" (26 cm) deep, weighing approximately 10 kg (22 lbs). It requires 60 watts of power and supports 100-125VAC 60Hz or 190-240VAC 50Hz operation. The tube complement varies slightly between MKI and MKII versions but typically includes 12AX7, 6922, 12BH7, and 12AT7 tubes. The SP-8 delivers a frequency response of 5Hz to 30kHz with harmonic distortion less than 0.01% at 2V RMS output, and a signal-to-noise ratio of 66dB (MM) and 86dB (line). It is considered a classic valve preamplifier with a slightly soft dynamic edge but excellent detail and openness, making it a sought-after vintage hi-fi component.