Is there such a thing as too much power?

Many years ago, I went to a dealer to audition amplifiers to use with my Acoustat 1+1 speakers.  The dealer, who had sold me my pair, had a big Rowland amp hooked up to his 1+1 speakers.  It sounded okay, but it didn't really quite do it for me.  He then switched in a smaller Rowland amp that was built on a similar design, used the same type of transistors, but, only put out something like 50 watts.  I actually liked the smaller amp more--it seemed more lively.  I admit that I am not a deep bass freak and the Acoustats would not be able to deliver deep bass anyway, but, in other respects, the lower wattage version of the particular design worked better for me.

From my own listening experience, I have heard great examples of different types of amps so I hesitate to say what sort of amps sound best.  I currently own two pushpull amps--one a push-pull triode amp using a 45 tube, the other utilizing the 349 tube (tetrode, I believe).  I also own a parallel single-ended amp that utilizes 2a3 triode tubes.  Of the three, I favor the 349-tube amp. 

Of the candidates for best amp I've ever heard, I would place a custom-built OTL amp at the top--astonishingly dynamic and lively without being hard-edged and brittle sounding.  The only competitor, to me, is a push-pull amp running the exceedingly rare 252 tube.  I heard the 252 amp playing against an Audio Note Kageki (that is the parallel SET 2a3 amp I also own) both driving Audio Note AN-E speakers, and it was no contest--the 252 amp blew away the Kageki.

While my preference is for tube amps, I had a friend's First Watt J-2 in my system for two weeks and liked it very much. I could easily live with that amp even if I preferred my Kageki and the 349 amp.  That same friend built an SIT amp using the schematics supplied by First Watt for DIY amps; I heard that amp in his system and it was a terrific sounding amp as well.  

Tube or solid state, I like lower powered amps combined with high efficiency speakers.

This discussion often becomes an "all-other-things-being-equal" hypothetical discussion.  If nothing else is adversely affected by increasing power, then it probably doesn't hurt to have more power in reserve. 

But, depending on how loud one listens to music, the efficiency of the speakers, and the acoustical environment, having a big reserve of power may not increase sound quality.

Also, being able to deliver a lot of power means that the amp has to be built specifically for that priority, which typically means using a lot of output devices in parallel.  There are some people who say that using multiple tubes or transistors degrades the sound--simpler is purer.

Also, some of the higher output transistors or tubes may not be the best sounding.  I have heard tube amps that can be made to run on different tube types, and I usually end up preferring the lower output tube types (assuming reasonably high efficiency speakers).

Among both tube amps and solid state amps, most of my favorites are low-powered amps.  I like the sound of the two First Watt solid state amps I've heard more I like many ultra expensive high-powered solid state amps (most sound lifeless when playing at modest volume), and I MUCH prefer low-powered tube amps to high-powered ones.  I have fairly high efficiency speakers (99 db/w), and they really sound best with either low-powered push/pull or single-ended triode amps.

Alexberger and atmasphere,

I also agree that low efficiency means more power is needed and this results in thermal compression (as the wire in the voice coil heats up, resistance rises).  That is why high efficiency speakers typically sound more dynamic and lively.  

The reason the industry moved away from high efficiency has a lot to do with the large size of typical high efficiency speakers.  That size became an even "bigger" issue with the advent of stereo and the need for two speakers.  Smaller speakers became a commercial necessity for stereo.

arctikdeth,

Regarding Class D, that was my impression too of several such amps I've heard, but, that seems to be the case with most other solid state amps.  The old adages of solid state sounding grainy don't apply any more, for me it is lifelessness which makes one try to counteract that sense by pumping up the volume.  I like listening at more modest levels, which is why I go with tubes.

Okay,

One does need a lot of power to get to power levels so high as to melt binding posts.  If that is the requirement for a suitable listening level, get a very high-powered amp, because power is relatively cheap to attain, while high quality in other aspects is not so cheap.

I  don't listen at that kind of level and I don't include as a priority the capability to play at extreme levels; I insist on the system sounding dynamic and lively at modest listening levels.  It hardly matter what level the cannon shot in the 1812 Overture should be reproduced at--the dynamic range of the recording limits how loud it will be when the volume level of the rest of the piece is played at realistic levels.