Music Fidelity M8S-500S Power AmplifierDesign + Build The M8s 500s is a fully balanced stereo amplifier which delivers 500wpc, which almost doubles into 4ohms. The M8s 500s is engineered for very low distortion typically less than . 001% of 1kz and below . 005% at 20kHz. Even at the ridiculous level of 50kHz distortion is a mere 0. 02% creeping up to around 0. 06% at the even more unreasonable figure of 100kHz. These may be measurements of frequencies never encountered in the real world