If I manufactured an amp with low output impedance, I would certainly tout its high damping factor as a positive attribute. But, for anything other than really high output impedance amps, like some SET and triode pushpull tube amps, playing into speakers that present a particularly difficult load (low impedance at critical frequencies), the numbers are usually meaningless. Personally, I would not be that concerned unless the output impedance of the amp exceeds 2 ohms (nominal damping factor of 4) for any speaker that is reasonably rated at 6-8 ohms.
Amp damping factor?
OK need some technical info. I was told by a reputable source that I should buy an amp that had a high damping factor >100 and preferably closer to 150-200. In looking at this in the specs for many units it seems this might be over-rated. I have been looking at some vintage Mac gear and their numbers are like 10-40? Is that an age thing and modern equipment is just that much better? Or is there a tradeoff I dont know about?