Always have the compressor off when your playing. Not only because of the 3 to 8 hp you loose. Compressors are pullied/geared to work well in the 2,000-3,000 rpm range. Running them at 6,000 can be expensive. A few of the police car models I worked on had cutoff switches based on throttle position.

Darryl, Hill
350sl
74 450 se

Chevota Landcruiser