Audio Research SP-8

 The single greatest requirement of a preamplifier is to amplify the given signal input without adding or subtracting musical information. This extremely complex, intricately defined, highly dynamic signal creates heavy demands on a preamplifier. Only Audio Research preamplifiers so accurately meet these demands that they transmit the listener beyond the reproduction chain to experience the "live event".

For optimum signal amplification the SP-8 utilize vacuum tube audio circuitry. While the transistor has replaced the vacuum tube in most popular consumer electronics, the vacuum tube still offers a number of design adventages over solid-state devices.  The vacuum tube has ceratin unique electrical properties that make it highly attractive for use in quality audio electronics.

Audio Research continues to incorporate the vacuum tube in its designs many years after tube technology was considered impractical. However, experience dictates that for state-of-the-art. Music reproduction the vacuum tube is difficult to surpass. Because of its long-term involvement in vacuum tube design Audio Research  is regarded as the leader in vacuum tube technology.

Features

Automatic muting for continuous protection

Manual muting for repeat settings,interruptions, etc.

Front panel power switch for activating 1600 watt capacity back-chassis, plug-in power receptacles.

High accuracy, close tracking segmented gain control

Sonically selected components for optimum sound performance

Near military grade construction used throughout.

Specifications

Frequency Response:

High Level :  + .25 dB; 5 Hz - 30 kHz

Magnetic Phono :  + ,25 dB of RIAA, 30 Hz - 40 kHz

Harmonic Distortion:  less than ,01% at 2V RMS output, 20 Hz -20 kHz

Input Impedance:  50 k Ω, all inputs

Noise:

High Level :  250 µV RMS maximum residual unweighted wideband noise

Magnetic Phono :  5 µV maximum equivalent input noise, wideband RMS

Dimensions (W x Hx D):  19" x 5,25" x 10,25"