What is the the difference between Onkyo amps,m-504 to,508,5088,509,510 amps and so on.

[Jollygreenaudiophile]

What is the difference between these Onkyo amps? Just because some are more powerfull that doesnt mean better sound and they are all within really just a few watts in power 165 to i believe 220 watts and since the power doubles every 3 decibles isnt it really semantics to say that 35 watts diff would mean double or triple the price?

 

[Jollygreenaudiophile]

I currently use 2 Onkyo m-504's to bi-amp my system but there are m-508s that people say are much better and then the 509 and so on. Not sure what to believe. And then theres the 5088 which was supposed to be exactly the same as the m510, just black. There is one for sale and thinking of getting one. Any Advice? Or suggestions? But then where is the m509 in rank. The # series is supposed to mean something right? Im so confused