Audio Research SP-8 Mark II Rev 7 (1985) Tube Preamplifier - One Owner

This Audio Research SP-8 Mark II Rev 7 (1985) tube preamplifier is a rare gem that has been meticulously cared for by its one and only owner. The unit is a vintage piece of audio equipment that is highly sought-after by audiophiles and collectors alike. The SP-8 model was manufactured in the United States and is a preamplifier that features a range of inputs and outputs for a versatile listening experience. This preamp is perfect for those who appreciate the warm and rich sound that only tube technology can provide. Bid with confidence on this one-of-a-kind Audio Research SP-8 tube preamplifier.

 

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S/N 65221001

Audio Research SP-8
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.

For those interested in artificial intelligence, ChatCPT characterizes the SP-8 as:

The Audio Research SP-8 is a classic preamplifier produced by Audio Research Corporation, renowned for its high-quality audio equipment. Although it's been a while since its release, the SP-8 is still highly regarded among audiophiles and vintage audio enthusiasts.
Here's a general description of the Audio Research SP-8 preamplifier:
1. Build Quality: The SP-8 is constructed with high-quality materials and components, reflecting Audio Research's commitment to craftsmanship and durability.
2. Design: It features a classic design, typically with a brushed metal front panel and a clean, minimalist aesthetic that blends well with a variety of audio setups.
3. Functionality: As a preamplifier, the SP-8 serves as the control center of an audio system, providing various inputs and outputs for connecting sources like turntables, CD players, tape decks, and more. It also includes volume control and source selection capabilities.
4. Sound Quality: Known for its exceptional sound quality, the SP-8 delivers a transparent and detailed audio performance, with low noise and distortion, preserving the integrity of the audio signal.
5. Tube Design: Like many Audio Research products, the SP-8 may utilize vacuum tube technology in its circuitry, which can impart a warm and musical character to the sound.
6. Features: While vintage by today's standards, the SP-8 includes features such as mono and stereo modes, and even a phono stage for connecting a turntable.
7. Legacy: The SP-8 is part of Audio Research's legacy of producing high-end audio equipment, contributing to its reputation as a leader in the audiophile community.
Overall, the Audio Research SP-8 preamplifier is a prized piece of audio equipment cherished for its exceptional sound quality, timeless design, and enduring appeal among audio enthusiasts.