We are offering a fully tested and serviced Audio Research SP-8 Tube Preamplifier. We acquired this preamp along with an AR D60 (For sale as well) also with a black faceplate. We hooked up the two units in one of our systems for a week and they sounded fantastic, we especially liked the phono stage. Cosmetically the unit is in excellent condition with only a few scuff marks on the back of the top cover.
From Audio Research
Specifications
FREQUENCY RESPONSE
High level section: ±.25dB, 5Hz to 30kHz. -3dB points below 1Hz and above 100kHz. Magnetic phono: ±.25dB of RIAA, 30Hz to 40kHz
DISTORTION (THD)
Harmonic distortion: Less than .01% at 2V RMS output, 20Hz to 20kHz (Typically less than .0005% in midband). Intermodulation distortion: Less than .002% at 2V RMS output
NOISE & HUM
High level: (1) 250µV RMS maximum residual unweighted wideband noise at main output with gain control minimum (86dB below 5V RMS output) (2) More than 90dB below 1V RMS input (less than 20µV equivalent input noise). Magnetic phono: 5µV equivalent input noise, wideband RMS (-66dB reference 10mV input) (Approximately 1µV above 200Hz or -80dB reference 10mV input)
GAIN
Magnetic phono input to tape output: 34dB. Magnetic phono input to main output: 60dB. High level inputs to tape output: 0dB. High level inputs to main output: 26dB.
INPUT IMPEDANCE
50K ohms, all inputs (Magnetic phono may have any value from 10 ohms to 100K ohms substituted. Also has provision to add to the 40pF input capacitance for matching certain magnetic cartridges.)
OUTPUT IMPEDANCE
1000 ohms main output and tape output. Recommended minimum load for maximum audio quality 20K ohms and .001µF maximum capacitance.
OUTPUT POLARITY
-
MAXIMUM INPUTS
Magnetic phono, 900mV at 1kHz. (3.5V RMS, 10kHz) High level inputs essentially overload-proof.
RATED OUTPUTS
2V RMS 5Hz to 30kHz, all outputs; 60K ohm load (main output capability is 60V RMS output at ½% THD at 1kHz into 100K ohm load with 3V RMS high level input)
POWER SUPPLIES
Electronically-regulated supplies utilizing both vacuum tube and solid state elements. Line regulation better than .01%
TUBE COMPLEMENT
SP-8 MKI: (2) 12AX7, (3) 12AX7, (2) 6922, (1) 12BH7. SP-8 MKII: (2) 12AX7, (2) 12AX7, (2) 6922, (1) 12AT7, (1) 12BH7
POWER REQUIREMENTS
100-125VAC 60Hz (190-240VAC 50Hz) 60 Watts
DIMENSIONS
19" (48 cm) W x 5¼" (13.4 cm) H (standard rack panel) x 10¼" (26 cm) D. Handles extend 1 ⅝" (4.1 cm) forward of front panel. Rear chassis fittings extend ⅞" (2.3 cm).
WEIGHT
22 lbs. (10 kg) Net: 30 lbs. (13.75 kg) Shipping