SP11 MkI

About the SP11 MkI

Introduced in 1985 at a price of the SP-11 mki is a complex and sophisticated hybrid preamplifier that uses six 6DJ8/ECC88 tubes in every active stage combined with FETs, delivering the warmth of tubes with the low noise and distortion of solid-state technology. It features a dual chassis design with triple-regulated power supplies, separate level and gain controls for ultra-fine volume tuning, and front panel selectable phono input impedances (47K, 100, 30, 10, 3 ohms). The unit offers a frequency response of ±1dB from 0.2Hz to 100kHz for high-level inputs and ±0.2dB RIAA from 20Hz to 40kHz for phono inputs. Distortion is impressively low, with harmonic distortion less than 0.005% at 2V RMS output and intermodulation distortion less than 0.003%. Noise levels are also very low, with IHF weighted output noise at 6µV. The SP-11 mki has 250 ohms output impedance on main outputs and supports recommended loads of 60K ohms. It was highly regarded for its tonal balance, resolution, and musicality, and remains a sought-after classic preamplifier today. It does not have balanced XLR outputs, reflecting its era. The design foreshadowed modern hybrid preamps by blending tube sound with solid-state reliability and precision.