"Klay_Anderson" wrote in message
news:14356237.137.1320865621980.JavaMail.geo-discussion-forums@prnv30...
According to the manual:

"CONSTANT POWER SWITCH Set the rear panel slide switch to match the
impedance of the speakers used. Use the combined impedance value if you are
connecting speakers in series or parallel. Choose the nearest match if the
value is not exactly 4 or 8 ohms. Note that no damage will be done if the
switch is left in the wrong position. However, you may not benefit from the
full capability of the amplifier.
?? Constant power explained The typical amplifier is optimised to produce
full power into 4 ohms and therefore considerably less into 8 ohms. The PA
Series features a unique facility that ensures you get full power output
into either 4 or 8 ohm speakers. It does this by reconfiguring the power
supply for optimum current (4 ohms), or voltage (8 ohms)."

This was hardly unique to Carver. I remember a Sony amp that used such a
system, and there were undoubtedly dozens of others.