Does one NEED multiple amps?

True Audiophiles would NEED and own more than one amp..this is why they are Audiophiles. Music lovers would own the right amp and NEED none in fact. Truth is it is hard to stop being an Audiophile when one visits Agon everyday or so. Agon is about equipment, not the music. But there is nothing wrong with being in love with audio gear...as long as one knows why one is in this hobby for: gear or music.

I think it is fair to compare this to folks who truly love cars. They usually own a few: a sport coupe, a sedan, a convertible, a vintage but they seldom take their passion to the race track.....if audio gear were as expensive to own as cars, there would be fewer Audiophiles and more music lovers.

From someone currently in rehab'.

One amp for each rig and one backup- that's one right?

I posted that quote from Terry Cain (whose speakers I own). Oddly, at the time he posted that humorous blurb on AA, I owned only one amp thought he was joking (which he half was). Now, I own four or five depending on the week.

My experiences have been that amplification differences tend to be much more readily apparent in the low power/high-efficiency realm than higher powered setups.

Part of my buying spree was due to the fact that I had just made the jump to a low power/high-efficiency system. The odds of buying just one amp and knowing for a fact that it is absolutely the best sound for your own personal preferences in a new system is a long shot at best.

Who can which which design is right for their system without ever hearing a few of them? - Push-pull, SET, SEP, Parallel PP, cap-couple, transformer-coupled, cathode follower, Lofton-White, etc.

Who can say which output tube - 45, 300B, 2A3, 6C33C-B, EL34, EL84, 211, 845, KT-66, KT-88, KT-90, 6550, etc. is the right one without ever hearing them in their own system?

What about the influence of input and driver tubes?

Informed decisions require in-home experience with multiple designs and tube types before settling on something permanently. Now that I've done that, I'm downsizing to just two (or three amps) this month - Art Audio PX-25, Welborne DRD 300B monoblocks, and a DIY fully differential PP amp. Each has it's own special merits depending on the material being played.

Also, I'm not sure any single amp can do it all best - the PX-25 comes damn closests out of the 15 or so amps I've tried the last few years, but even then, a really good PP design is better on large orchestral, hard rock, or percussion heavy music. And the 300B's do ambient/spatial information in a way that is hard to match. Take choral or classical music performed in a large cathedral - nothin like the 300B for that spooky ambient hall sound.

One amp, 3 cd sources of varying flavor, 2 armwands with different flavored cartridges mounted. I suffer from Terry's affliction, but am happier varying the source than the amp to solve it.

I would say there is no such thing...no amp is perfect. You choose which set of imperfections you can live with.
And trust me when I tell you that Terry owns "quality" amps. He has more quality amps than I have fingers and toes! That's one of the reasons it's always fun to go to his place!
Steve