Audio Research SP-8 All Tube Analog Preamp with Phono Stage

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One of our best selling preamps from Audio Research. Full featured and capable of working with your turntable.

This example was also factory upgraded to REV6

In overall very good cosmetic condition showing very little signs of wear.

Also comes to you in it's rare original packing!

Audio Research SP-8 - Manual

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

The SkyFi Testing Process for Preamplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.

At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.

Final testing involves putting actual music through the preamplifier. We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.