Thanks, I apreciate your reply.
I already have an ARC D200, predecessor of the 100.2 (same output MET transistors, dimensions, wattage, etc) purchased with an ARC SP9 MkIII preamp in 1994.
I thought that both are now as when were new. Not a trace of hum or unbalanced channels, distortion, etc.
It is possible that I have not noticed a decrease in quality of my amps over the years.
I can replace capacitors, but if transistors are with some deterioration, thats other thing and maybe is better not to buy a relatively old solid state amp.
Best regards