Mapletree Audio Design

A high definition RIAA phono preamp plus line preamp in a compact chassis with separate power supply. Low distortion NOS octal tubes (2 x 12SC7, 2 x 12SN7GT switchable for 6SN7GT). Hybrid passive/feedback RIAA equalization. Low impedance cathode-follower outputs. Two line inputs with 20 dB gain. Parallel line outputs for bi-amping or driving a headphone amplifier. Source selector switch, volume, and individual channel level controls. All point-to-point wiring using silver-plated Teflon wire. Includes PS 2 power supply. High quality components are used throughout: precision metal film resistors, Auricap and Black Gate signal capacitors, and plastic element volume control. Specifications: Input resistance: phono - 47 kOhms, line - 500 kOhms. Output impedance: less than 500 Ohms. RIAA equalization: within 0.5 dB 20 Hz–20 kHz. Gain: phono - 50 dB at 1 kHz, line - 20 dB. Line input frequency response: 15 Hz–130 kHz -1 dB. Hum and noise: phono - less than 1.5 mV for gain of 40 dB (60 dB below 1.5 V output), line - less than 0.5 mV for 20 dB gain.