What is your experience with amp power?

Okay. The OP is asking for experience with amp power, so here’s one.

About 10 years ago, my "rig" was running an amp with just north of 100wpc. We serviced equipment full time, also providing performance upgrades. After "hot rodding" an amp with 600+wpc I decided to do a "field test" in my home. The speakers are of my own design, are approx 97db efficient and have "sufficient" cone area.

After a little warm up period and determining where to dial in the volume control on the preamp to get max power without clipping, I queued up one of my favorite demo pieces: Foreplay: Between the Sheets and got comfortable in my listening chair.

Those familiar with the cut understand that things happen pretty quickly, so I braced myself for the anticipated impact to follow. I pushed the "play" icon on the remote .... and ...

I felt the bass hit my chest. Not the first time this had happened, but not at this level of intensity. I then felt the bass go through my chest, hit the cushion behind me, which caused it to vibrate. If felt the recoil of the cushion hiting my back. It was startling to say the least.

The amp was returned to the owner (accompanied by a big "thumbs up"). I’ve never had an experience even close to this in my home. The additional 8db (+/-) of headroom was clearly "audible." You may be asking why I haven’t purchased an amp to duplicate this experience in my home? I have hot rods in my garage. Doing a smoky burnout once in my lifetime is enough.

It varies wildly depending on the speaker and the amp.  Certain brands are best with huge amounts of power and are not just low efficiency low impedance as your rightly pointed out.  

That said, with speakers of even modest efficiency, amp quality is often more important that power.  I run Wilson-Benesch Discovery 3Zeros with a pair of 55w mono blocks.  I have run with more power (200w) into 8ohms via excellent SS amps and do not feel they outperform my better tube based monos.  

I just did an extensive test between my Canor tube monos and the AGD Gran Vivace.  AGDs delivered slightly better bass response.  Canors sound slightly more natural.  But these are small differences and most people would walk away saying both were great and a great match for the speakers.  

To be honest, there are a lot of inaccurate statements in this thread. I am guessing that only a few people here know design and have experience in building an audio component.

Are there really inaccurate/false statement in this thread, or is it just perspectives and experiences that don’t match with yours? If it’s truly a false statement, it can be decisively refuted with math & physics.

One of the common perspectives I disagree with is (paraphrasing) - "doubling power is only 3dB and that’s not much anyways". 3dB is a lot! You can TOTALLY hear a huge difference in 3dB. Find your "preferred" listening volume, then adjust up or down by 3dB - it sucks! 1dB was loosely determined as the "audibility threshold" a long time ago, but the subtext there is *for casual listeners*. It’s more meaningful for a seasoned audiophile. When dealing with say L/R channel imbalances, you can certainly notice down to a third of a decibel, at least.

Another perspective I don’t share is that paralleling multiple outputs (tubes, transistors) imposes some kind of sonic penalty. Definitely NOT in my experience. If anything, the aberrant characteristics of one particular device can get averaged/smoothed out by the others (that’s good). The choice of device itself matters a lot (of course), but if the PSU and OPT and driver circuitry can handle it then the more the merrier I say. Bridging is a different story, as is stacking extra gain stages - both of these can certainly impose performance penalties in the pursuit of higher power and higher volumes.

I definitely get folks who prefer the sonic character of say 6L6 or EL34 (I love both of those tubes) over the more austere KT88/KT120, but I bet a properly done high power amp with lots of paralleled (say) 6L6GC would be pretty amazing - you just don’t see those on the market. Manley does have their NeoClassic with lots of EL34, but I haven’t heard it yet - looks interesting.

I agree that 3 db is quite a bit of difference in sound level and I share your experience with channel balance.  I use to run a Levinson No.32 linestage that allows for 0.1 db changes in volume.  That gradation seemed ridiculously fine.  With most musical sources (i.e., not a steady test signal) it is a bit hard to hear a 1 db change in volume.  But, in terms of channel balance, it was quite easy to hear a 0.2 db change to one channel.  That explains why Levinson offered such small changes.  I don't like stepped attenuators which have so few steps that there is more than a 1 db change between steps--the right volume level always seems to be between the two offered steps.  It is amazing how small is the window on the ideal volume level.  That is another reason why remote control of volume seems essential to me--you cannot, practicably speaking, find the right volume by getting up to manually adjust the volume even if you are not lazy.

bigkidz is correct.

Do not concern yourself with amount of amplifier power, concern yourself with quality of amplifier power.