A few years ago I had an SLO with all of the various mods, KT66 tube upgrade, etc. Great amp that I now regret selling. I want to buy another and have heard the early amps were built better than the current ones. Is there any truth to this? Is there a certain year or period to look for? I didn't find the various mods my previous amp had to be all that big a deal and my next SLO won't have them. I think the less "stuff" cluttering the circuit provides the purest and best tone. Comments appreciated!