Audio Research SP-14

Original owner. Great sounding tube preamp. 

Description: Hybrid (tube/FET) stereo preamplifier with one phono input, six line-level inputs, and two tape loops. Specifications: Frequency response: 30Hz–40kHz ±0.3dB (RIAA phono), 5Hz–50kHz ±0.5dB (line). Distortion: less than 0.01% at 2V output. Input impedance: 47k ohms standard, with user-adjustable resistance and capacitance (600pF as supplied) (phono); 50k ohms (line). Output impedance: 250 ohms (main), 1000 ohms (tape-out). Recommended load: 60k–100k ohms in parallel with 100pF (20k ohms minimum and 1000pF maximum). Phono stage gain: 66dB (to main out), 46dB (to tape-out). Phono sensitivity: 0.25mV at 1kHz for 0.5V output. Line stage gain: 20dB (to main out), 0dB (to tape out). Line sensitivity: 50mV RMS at 1kHz for 0.5V output. Output level: 2V RMS 5Hz–50kHz, all outputs into 60k ohms (maximum from main output, 50V RMS at 0.5% THD at 1kHz into a 100k ohm load with 5V RMS high level input). Phono overload: 200mV RMS at 1kHz (1000mV RMS, 10kHz). Maximum input level (line): 20V. Noise: 98dB below 5V RMS output, greater than 100dB below 1V RMS input (line), 78dB below 1mV input (phono).
Dimensions: 19" W by 10¼" D by 5¼" H. Weight: 12 lbs.