Audio Research is one of the most dependable brand names when it comes to high-end audio systems. For years the brand has been recognized by audiophiles throughout the world as equipment that delivers clear and consistent quality in music.

What are the specs for the Audio Research SP-11 / SP-11PS?

Frequency Response:
High level input: ±1dB 0.2Hz to 100kHz. -3dB below 0.1Hz and above 200kHz. Phono input: ±.2dB of RIAA 20Hz to 40kHz. ±1dB of RIAA 1.0Hz to 100kHz.
Harmonic distortion: Less than .005% at 2V RMS output, 5Hz to 20kHz (Typically less than .001% at midband, phono or line input). Intermodulation distortion: Less than .003% at 2V RMS output
Noise and Hum:
IHF weighted, shorted input: Output (Gain down): 6µV (110dB below rated output). Input (High level): 3µV equivalent input (110dB below 1V input). Phono: 0.15µV equivalent input (76dB below 1mV input)
At 1kHz, bypass mode: Phono input to tape output: 46dB (0.2V output from 1mV input). Phono input to main output: 75dB (0.175mV input for 1V output). High level input to main output: 29dB (36mV input for 1V output).
Input Impedance:
Phono: Front panel selectable 47K, 100, 30, 10, 3 ohms. Phono input capacitance: 150 pF at 10kHz. High level: 20K ohms or higher, depending on switch functions.
Output Impedance:
250 ohms main, direct, inverted outputs. 500 ohms tape output. Recommended load 60K ohms and 100pF (20Kohms minimum, 1000pF maximum)
Output Polarity:
Tape outputs, direct output: Non-inverting. Invert output: Inverting. Main outputs (2): Selectable non-inverting or inverting. All outputs may be used simultaneously.
Maximum Inputs:
Phono: 350 mV RMS at 1kHz, 1200 mV RMS at 10kHz (0.1 second maximum duration, 6dB less if continuous). High level: 25V RMS.
Rated Outputs:
2V RMS 1Hz to 100kHz main, direct, inverted outputs. (Maximum 80V RMS at 0.2% THD at 1kHz into 60kOhm load with 2.85V RMS high level input).
Power Supplies:
Tube Complement:
(6) 6DJ8/ECC88
Power Requirements:
95-135VAC 60Hz, 190-270VAC 50/60Hz, 130 Watts maximum
Filter: 25Hz Hi-pass phono subsonic 6dB/octave rolloff (to eliminate ringing) with transition to 12dB/octave at 10Hz. Front panel switchable phono only. Controls (6): Gain, Level (to set gain range), Balance, Mode, Input, Impedance. Switches (8): Tape monitor, Copy, Tape 1/2, Tape 1to2 / 2to1, Mute, Invert phase, Bypass, Filter.
(Each chassis, EIA Rack panel mounting) 19" (48 cm) W x 5 ¼" (13.4 cm) H x 10 ¼" (26 cm) D. Handles extend 1 ⅝" (4.1 cm) forward of panel. Interconnect cable extends 4" behind rear of chassis.

What else to know about the Audio Research SP-11 / SP-11PS?

The SP11 is a hybrid unit, utilizing both vacuum tubes and Field Effect Transistors (FETs). It is not intended that this product should somehow continue the controverso of "vacuum tubes" vs "solid-state". Rather, in keeping with Audio Research's design philosophy of advancing the state-of-the-art, each type of device is used where it performs best. One important result, aside from the dramatically improved quality of sound reproduction, is the use of only six vacuum tubes - tubes which need not be selected low-noise types. A significantly longer time between tube replacement is also expected. As a last word, this preamplifier may well change your thinking about music reproduction. Because it is so incredibly "open" sounding, much information not previously audible is available, providing new insight and enjoyment. To be appreciated, the SP11 Preamplifier must be personally experienced; it cannot otherwise be adequately related.

Brief History of Audio Research

Other Audio Research Products We Often Buy

Typically, StereoBuyers purchases mostly used amplifiers, especially the vintage amps and high-end Audio Research models.

StereoBuyers has purchased tens of thousands worth Audio Research brand equipment since 2014, with individual buys ranging from $100 to well over $50,000. If you are moving, ready to upgrade, or have Audio Research equipment you do not or will not be using, why not contact us today to find out if it is worth good money?

If you are interested in selling your used Audio Research equipment to us in the greater NYC area or Colorado, please click here to fill out a Free Quote Form and we will get back to you. If we agree on terms, we come to meet you where you want, and pay cash.

The following images show actual Audio Research equipment purchased by StereoBuyers.