McIntosh MA5100 Integrated Amplifier

The McIntosh MA5100 is a vintage 2-channel solid-state integrated amplifier manufactured between 1966 and 1972. It is highly regarded as McIntosh's first fully solid-state integrated unit. [1, 2] Key Specifications Power Output: \(45\) Watts RMS continuous per channel into 4, 8, or 16 ohms Total Harmonic Distortion (THD): Does not exceed \(0.25\%\) at rated power from 20 Hz to 20,000 Hz Frequency Response: 10 Hz to 20,000 Hz (+0, -0.5 dB) at rated power Damping Factor: 100 into 8 ohms Input Sensitivity: 2mV (Phono/Tape Head), 300mV (High-Level Inputs) Signal-to-Noise Ratio: 70 dB (Phono), 75 dB (Line) Semiconductors: 34 transistors, 23 diodes, and 2 TRIACs Dimensions: 16" Wide \(\times \) 5-7/16" High \(\times \) 14-1/2" Deep (including connectors) Weight: 25 lbs (11.3 kg) [1, 2] Features & Controls Dual concentric bass and treble controls (adjustable \(\pm 18\) dB) High and Low-frequency filters (LF: 50Hz, HF: 5kHz) Selectable Phono equalization (RIAA or LP) Phase switch (0 or 180 degrees) Headphone jack and Loudness switch