The BGW Systems Model 85 (1985) Broadcast Power Amplifier is a 19-inch rack-mount unit designed for broadcast, recording studios, theater sound systems and other demanding applications. Pulled from working environment so we know it works! Designed for any load impedance equal to or greater than 4 ohms as follows:

Mono: 90 watts into 8 ohms.
Stereo 45 watts per channel. into 4 ohms.
Stereo: 35 watts per channel into 8 ohms.

Frequency Response: 20Hz to 20kHz.
Total Harmonic Distortion: 0.05%.
Damping Factor: 300.