The SPA4-100 four channel amplifier delivers 100 watts rms per channel into 4 or 8 ohms; the four channels can also be bridged in pairs, each pair providing up to 200 watts rms into 4 or 8 ohms. The SPA4-100 bridged pair channels can be switched into 70V or 100V direct drive mode providing up to 350 watts rms into a 70V or 100V output; when in 70V or 100V mode the 80Hz highpass filter is automatically engaged.