Heat losses are the thermal emissions from an amplifier while it is operating. It comes from dissipated waste power—i.e., real AC power in minus audio
power out. Measurements are provided for various loads at idle, 1/8 of average full power, 1/3 of average full power, and full power, with all channels
driven simultaneously. For typical usage, use the idle and 1/8 power figures. This data is measured from representative samples; due to production
tolerances, actual heat emissions may vary slightly from one unit to another. Bridged mono into 8 ohms is equivalent to 4 ohms per channel; into 4
ohms is equivalent to 2 ohms per channel.
BTU/hr
Idle
CXD 4.3
225
CXD 4.5
286
Load per Channel
BTU/hr
1/8th Power
CXD 4.3
684
CXD 4.5
811
1/3rd Power
CXD 4.3
983
CXD 4.5
881
Full Power
CXD 4.3
2498
CXD 4.5
3116
Idle
Thermal loss at idle or with very low signal level.
1/8 Power
Thermal loss at 1/8 of full power is measured with pink noise. It approximates operating with music or voice with light clipping and represents the
amplifier's typical "clean" maximum level, without audible clipping. Use these figures for typical maximum level operation.
1/3 Power
Thermal loss at 1/3 of full power is measured with pink noise. It approximates operating with music or voice with very heavy clipping and a very
compressed dynamic range.
Full Power
Thermal loss at full power is measured with a 1 kHz sine wave. However, it does not represent any real-world operating condition.