provided by gisewhcs from the Hififorum

Rated power measured according to DIN 45500 up to 1% distortion factor in 13,5V

JBL GTQ400

1 × 113 Watts channel 1 at 4 Ohm
2 × 108 Watts channel 1 + 2 at 4 Ohm
4 × 93 Watts channel 1 up to 4 at 4 Ohm

1 × 324 Watts channel 1 + 2 bridged at 4 Ohm
2 × 256 Watts channel 1 + 2 and 3 + 4 bridged at 4 Ohm

512 watts total power