I noticed that the 755 specs show a damping factor of 850. After monkeying around with various speaker cable lengths and speaker load ratings, I was able to come up with the following at the amp's 200W rated power:

Speaker Wire gauge Wire Length Damping
8ohms 12 6ft 282
8ohms 12 8ft 230
8ohms 12 10ft 195
8ohms 12 10ft 169


and speakers with a lower load seem to fare even worse....I assume 300W into 4ohms.

4ohms 12 6ft 169
4ohms 12 8ft 133
4ohms 12 10ft 110
4ohms 12 12ft 94


I'm not an amplifier expert, but how much damping factor is considered "enough"??? I hadn't realised that the minute change in resistance (a few hundredths of an ohm) due to speaker cabling could have such a dramatic effect. What can be done to increase damping other than cutting an amp's output impedence to vanishingly small numbers...and is that even an important thing to worry about?

Maybe someone with a bit more real world knowledge can help me understand this...

Cheers,