M-504

About the M-504

The Onkyo M-504 is a stereo power amplifier produced from 1987 to 1997, known for its robust build and classic design with rosewood side panels and illuminated green power meters. It delivers 165 watts per channel into 8 ohms with a frequency response from 1 Hz to 100 kHz and a total harmonic distortion of 0.003%. The amplifier features a dual-mono construction with two large transformers and discrete output stage circuitry, providing excellent power and sound quality. It has an input sensitivity of 1V, a damping factor of 140, and a signal-to-noise ratio of 120 dB. The unit weighs approximately 22.5 kg (about 50 lbs) and measures 465 x 185 x 422 mm. It supports stable operation into 4-ohm loads and includes an unswitched 100W AC outlet. The M-504 is praised for its authoritative power, clean sound, and vintage aesthetic appeal, making it a sought-after amplifier for enthusiasts of classic HiFi equipment.