Is there such a thing as too much power?

   I downgraded power from 300 watts per ch to 70 and I like the sound better! I always thought more power is a good thing, but could that be wrong?

Please enlighten me...
Answering your title question...NO!  You can never, ever,ever have too much power!!  You just have to be careful to never overcrank the volume control.  Always keep your system well fed! (quality and quantity)
OP seems to imply that an amplifier's contribution to SQ is theoretically solely based on watts and not circuit design and a bazillion other factors.
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.
+1 @larryi & @three_easy_payments

I would add a couple of things:

1) Within a given class of operation (A, AB, D), and if everything else is equal, more amplifier power tends to mean greater cost. So for a given investment in an amplifier choosing a lower powered design tends to mean that a greater percentage of that investment can go toward quality rather than toward watts.

2) Some excerpts from posts by Atmasphere in this thread (the rest of his posts in that thread are also well worth reading):

Its important with any system to avoid distortion but in fact distortion is the name of the game as the human ear translates distortion into tonality....

... A lot of push-pull amplifiers will actually make more distortion below a certain power level, so for those amplifiers its helpful to have a speaker that is a little less efficient, so the distortion is happening at a lower level and is hopefully less noticeable. But this is why some amps seem to lack detail at lower power levels.

There is definitely more to this than meets the eye!

... There is something to the idea that smaller amps sound better. In the case of push-pull tube amps, this has almost entirely to do with the output transformer itself. The reason for this is that the more power the output transformer can handle, the less bandwidth it has. So in the larger designs, usually the designer has made a tradeoff based entirely on what he thinks is important....

... Now the problem with push-pull is often that there is a phase-splitter circuit that introduces some distortion. This is not true of all P-P amps, but it is true of most of them. This generally is not an issue until you get into the lower power regions of the amplifier, at which point the distortion of the phase splitter comes into play. For this reason a highly efficient speaker (+98 db or so) may not be the best choice with a plus-100 watt amplifier as you may never get the amp out of that region of higher distortion at lower power levels.

-- Al
yes, spending money that could be spent on content, other equipment, better speakers ...

a ton of SS power or some tube power, I say, get efficient speakers, get tube amp.

and, avoiding size, weight, heat, electrical use is good! optional locations if smaller/lighter/less heat!

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.
Horses for courses
You don't need 20 tons air-conditioner to cool down 2000sq-ft house.
I can think of plenty of reasons why a 70 watt amp can sound better than a 300 watt amp. This should come as no surprise whatsoever!

The most important thing to know when it comes to power is the great Robert Harley quote, "If the first watt isn't any good, why would you want 200 more of them?" 

Ya, there's a reason Nelson calls his stuff "First Watt".

It applies to both tubes and transistors.
A few more comments:
0. as other have noted, with details your question is academic and no one can explain why. If they try they lie or are fools.
1. more power is better. You may not use it, but occasionally it will allow for un-distorted dynamics etc. And there is  certainly no penalty - with the great, impractical caveat "all things being equal" - since they rarely are.
2. But things are not equal.  Building a powerful amplifier requires money to be spent on things that don't contribute to better sound.  That's the trade-off.  A giant metal chassis, giant transformers, blah blah - that are only useful if you need them. They could have gone into better parts or ????
3. one person wrote: "There are some people who say that using multiple tubes or transistors degrades the sound--simpler is purer." I strongly disagree with this. I have designed lots of amps, preamps, etc. commercially and have never ever heard such, never thought such, and in fact there is plenty of theory that indicates that many devices of ANY KIND in parallel perform better for myriad reasons that would require lots of explanation. resistors' errors average out. Capacitors see lower effective ESR. Transistors non-linearities average out.  In fact i do it all the time, on purpose, even when i could get by with one device. I do it for better sound, and so does Nelson. (he has a power amp with like a billion tiny jfets on the output, all moving about a milliamp in parallel like ants).

All that said, since we are all constrained by size, budget, etc. i have much more freedom to design an awesome 20 wpc amp than if you rally need 200w or 400w.  But only if it needs to be at the same price. My best sounding component set ever is still the same - my lower powered class-A amps run in pairs, fully balanced.  Effortless power.  Just a sense of ease, never straining, never strident.  And since they are fully balanced from the preamp on, quieter and more revealing too.  QED. Same product.  EXACT SAME. More power. better sound.  but, God only knows what it would take to build and sell that complete solution profitably today. Probably in excess of $15k --  maybe $20k. I shudder to think.
So, in theory? No - the opposite.  In reality, quite often the less powerful product can sound better because that was the goal.

The omly important thing for you is that your new amp sounds good and makes you happy.
If you don’t have enough power you clip.  When you clip good watts go bad no matter how awesome they were to start with. 

Clipping is hifi public enemy #1 to avoid at all costs.  Wats in reserve are your insurance policy.  Make your amp work too hard and all else is lost. 
You can never have too much power. Full stop.

However, do not confuse power with ’loudness’. The latter is measured on a logarithmic scale. That means to get a tone twice as loud, you need 10 times the power (approx). A 100 watt amp is only twice as loud as a 10 watt amp.

However, also note that the supply of an amp, especially how quickly it can source current, almost exclusively determines the impactfulness and the transient response.

A good amp usually has power supply rated at about 2 times the power for class AB and at least 3 times as much for class A (Pass Labs).

In addition, a lower power amp will almost certainly clip much sooner than a higher power amp. So, to get a good higher power amp, its supply must be ready for the instant square wave response.

So in summary.... no you can never have too much power.

It is almost like a car. Would you rather have a 500hp car which you do not stress, or a 150hp car which is almost always working at its limit.

Would you rather have a 500hp car which you do not stress, or a 150hp car which is almost always working at its limit.

Lol! I would rather have a car with superb throttle response.

Awful example. My 1979 Porsche 911SC has only 180 hp and I can assure you it will do 150 mph and is hardly ever working at its limit. Which even if it is, that is what its designed to do! Run flat out! Its just an awful comparison.

I went for a autocross ride one time in a Corvette that had been stripped down, roll-caged, and NASCAR engined to something like 700-800 hp. Who knows maybe 900. Whatever. Instant that car came on the cam both monster fat Hoosier slicks started smoking laying down the biggest fattest burnout stripes you ever saw in your life. The car was all but uncontrollable.

You can never have too much power- if all you want is power. If what you want instead is control, well then its very easy to have too much power. Its all a matter of priorities.
already mentioned above but worth repeating - watts has nothing to do with sound quality.  Class A, A/B, Class D all sound different for a reason.

It depends on a lot of things but probably no.
You don’t state the amps you dealt with so I’m guessing they aren’t from the same manufacturer. Did you go from a class a/b amp to a class a amp? Both SS or both tube?  If you have very efficient speakers, then you might have a better shot at having a low power amp be better compared to having a 85db speaker which would be hard to drive with such low power
Yep... awful comparison (lol)
Nice car though (the Porsche that is). I think the comparison vehicle should be a little better controlled like a later Porsche 911 GT3 RS, or better the 918 Spyder 😁
Roger Modjeski argued that except in the case of very sensitive loudspeakers, all amplifiers are occasionally driven into clipping. He went on to say that how an amp behaves while clipping (stability, generation of distortion) is a result of the quality of it’s design, and that behavior an important contributor to the amp’s sound quality.
No such thing!
 More power the better.
this is a dead horse mention.

  More power is always better.
no,clipping, no reserve loss.
  Headroom is your friend!

 300+ RMS is the answer.

 Make sure their good!

 If the first 2 watts are trash, why have 299 more?

 Get good amp, and don’t look back!
My 2 amps are Onkyo Integra pre and power 300 watts per ch., and the Marantz surround sound 7.1 70 watts per ch. 

I know this is not the level most of you all are used to but, it's my second system (my main is Krell). 

I am surprised at the amount of enjoyment I am getting from Paradigm Studio speakers connected to Marantz surround receiver - considerably more than I was with the Onkyo Integra separates...Marantz is not what it used to be but they still make listenable gears I guess.

The music sings more with less power - go figure that. 

Thank you for all those posted - you guys are a great source of info!

Stay safe and enjoy concerts at home...

I thought it was important to use at least 25% of the preamp. I had a marsh Sound Design A400s which is 200 WPC-push pull. I always thought is was a little under detailed unless you really turned it up. I switched to the 100 wpc version and it sings like a canary even at very low volume. My speakers are 89 efficiency. I had three of the A400s amps so I had three to test. I love all car’s so I understand the examples. I really love Ferrari’s and Mustangs. I wish Mustangs could get that horsepower to the wheels. For some reason the 350 was always faster than the 500. Lighter and more control on the throttle I don’t know. I truly love my system now. Sorry, no one was talking about the preamp or maybe using a TT with it as a source which I thought was important. 
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.
Sure more power is better , for some speakers.  I have begun to gravitate towards higher sensitivity speakers along with higher quality electronics.   That recipe has worked well.  I have been using the same 40 w PP mono amps for five years with several pairs of speakers that are easy to drive . I love those amps and swap speakers out every now and then

I subscribe to the “First Watt” school of thought .   
McIntosh Amps, power indicator meters, if showing a scale of watts, hardly move. That is literally the first watt. Juice the volume all the way up to reach/show avg. 5 watts, lots of sound!

You need to push a button, change/minimize the measurement scale to get them to actively move. They tell you a lot about how little power your speakers need, or how much, but still not much for inefficient ones.

They have a peak hold option on some meters, to show you how much (maximum) was needed for the most demanding part of that musical track.
For me all dynamic speakers that need more power that gives EL34 push-pull amplifier have compressed sound.
You can use 1000 Watt amplifier with these speaker but it wouldn't change this character.
You can never have too much power. Full stop.
This statement is only true in theory.  In the real world where we all live, there are practical considerations that cause this statement to be false.

Apparently there is a need to explain why as I see a lot of myth in the posts above. If you look at the distortion curve of many amps, you will see the distortion starts at a certain level, **drops** as power is increased to about 5-7% of full power, then rises at power levels above that until it takes off at clipping.

Now the simple fact is that most of the time the music you hear is not requiring a lot of power- that power is needed mostly for transients.

If the speaker you have selected is very easy to drive, and the amplifier is very powerful, then you might say you have unlimited power since you can't clip the amp and stay in the room. But you won't be hearing what the speaker or amplifier can really do, since you'll be operating the amplifier 97% of the time **below** that minimum distortion point. Below that point, noise and distortion obscure detail due to the ear's masking principle. There will also be tonal aberrations as the ear converts distortion into tonality, and favors that over actual frequency response.

So there is a reason why matching an amplifier to a speaker on a simple power basis is good if **sound quality** is your goal!  A very powerful amplifier works best on a speaker that is less efficient, so that you can operate at power levels where the amp is making less distortion. Conversely this is why a lower power amp sounds best on a higher efficiency speaker.

Now *some* amplifiers have a distortion curve where the distortion drops linearly to unmeasurable as power is decreased. If you have one of those amps, then you can have a lot of power on an efficient speaker and get away with it- have your cake and eat it too.

But there aren't many amps that do that, and most of them don't make a lot of power- being SETs. Now we make an amp that gets around this problem, because of our topography (and the lack of feedback) we are able to get this type of distortion curve. We're not the only ones- Nelson Pass is successful with this approach in some of his designs. Its tricky- the amp has to be linear at low power levels. Amps with feedback often have the feedback poorly applied (and so is not always able to correct the way it should) and so you see the distortion rise at lower power levels. One of the few solid state amps I can think of that has a better feedback setup is the Benchmark, and there are a few class D amps as well.

The point here is saying that higher power is better without taking into consideration how the amp behaves is the same as suggesting that flushing $$$$$ down the loo is a good idea. Its isn't. You have to take into consideration how it is the amp makes all that power. Now I happen to agree that paralleled devices to get more power is a good thing- that's how we do it as well. I've already outlined where I think the problem lies, although I've only nutshelled it for the sake of brevity and this is already a too long post.
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.
Stand by- Krell is currently working on the answer. 

Current-ly. Get it?

Admittedly not much of a joke. But then neither is this subject. I mean, the idea anyone still thinks power correlates with quality is mildly entertaining.  But its no joke. Its just funny anyone still thinks that way.
@millercarbon Hey I own a 78 911 SC ! Not the fastest car out there, but like you said well designed to use the power that it has all day long! To the extreme I just sold my 96 911 993 Turbo that was modified 600,hp/595 lb of torque 
That car was amazing! Did I do the stop speed of 200mph......never! Did I race every boy racer out there.......never. But there is nothing like a owning a piece of well engineer equipment that will do everything that you want, and then some at anytime!
I own a Tube amp in triode 35 watts and sounds magical and also own a D class amp that has 550 watts@8ohm 650@4ohms&1,200@2ohms 
When I use the D class to drive my Maggies, they really come alive with soundstage,  inner detail and micro dynamics, even at the lower volume levels. I think I'm a power junkie!!

Not all Watts are equal.  That's why one 50watt amplifier may sound better than another 50watt amp.  We drove a pair of Dahlquist DQ10s with a pair of 80wpc Stax amplifiers to uncomfortable levels that a 300wpc Kenwood could not achieve.  Of course, in 1980s dollars, the Stax was $3000 more then the Kenwood.

I have experience on damaging speakers with Too little watts.  Driving them into distortion and all of a sudden, no tweeters.

The Watt wars has been going on since the intro of solid state and went off the charts with the Japanese solid state invasion in the 80’s. Manufacturers have convinced just about everyone that if you have an 80 watt amp and a 100 watt amp the 100 watt amp is "better" and louder. In general the maximum watt rating of an amp is a worthless number for comparing amps within 2x (or more) the power rating. As someone mentioned dBs use a logarithmic scale so to increase the loudness by 3dBs (not much) you need double the power. So comparing that 80 and 100 watt amp there will be about a 1dB theoretical max increase at full power. You will never hear this!

More important is the design of the power supply and its power reserves. The watt rating is calculated with a constant tone played till it clips. But if a power supply has ample reserves it can deliver many times the wattage rating for short peaks without clipping. For most listening this is more desirable than having an amp with a marginal supply that barely covers its rating. To get a better idea about the real power output and how well it can drive a difficult load check the specs and see if it can double down (or come close) the watts going from a 8 ohm to a 4 ohm load. If it goes to 2 ohms even better. This gives a good approximation of how good the power supply is. I would take a 70 watt amp that doubles down over a 300 watt amp that only has a small increase in watts at a lower ohm load  any day.
300W RMS per channel minimum!

 Or go home!
  O substitute for power and headroom
Used amps w 100W 150 W!, 200W, 300W, AMD my current amp are 650W RMS.  

the 650 W and 200W are the best amps. I’ve used!

1 watt, 80 watts. Waste!

 Buy power for crescendos,, and headroom!

dont look back
@millercarbon Hey I own a 78 911 SC ! Not the fastest car out there, but like you said well designed to use the power that it has all day long! To the extreme I just sold my 96 911 993 Turbo that was modified 600,hp/595 lb of torque
That car was amazing! 

Careful readers will notice I said you can have too much power in an amp, and you can have too much power in a Corvette. But I never said you can have too much power in a Porsche. Porsche actually even has a name for it: GT2.
993 GT 2 ??? I can get one for $1.6 million
I don't want my amp to clip, but do want my Porsche to clip.....the apex that is!
My amp has more that enough power, but it is also capable of 65 amps for 500 miliseconds 

All this super power amplification is worthless. It overheat driver voice coil caused to increasing drivers impedance and huge dynamic compression. 
It is even worse -  this dynamic compression has memory, because driver voice coil can't be cooled quick enough. It also cause bad frequency response around crossover points, as result of increased drivers impedance. 
It was the biggest mistake in history of audio industry to go to low sensitive speakers with high power amplifiers.
What I hate most in audio industry - when producers, sellers and reviewers are selling cheap stuff with expensive price tag and try to brainwash people that this cheap stuff is exclusive and expensive.
Audiophile you have to know -
Low sensitive speakers are cheaper to build compared to high sensitive speakers.
High sensitive drivers have bigger magnets and light cones made from more expensive
material compared to heavy cons and weak magnets in low sensitive drivers.
Also to build boxes for high sensitive speakers much more expansive.
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.
I dont still understand the arguments against LOL....

ALL OTHER THINGS BEING EQUAL (That is the part people seem to be missing) a higher power amplifier will always be preferable.  It will run less stressed and have much more headroom.

As for the higher distortion at lower levels of a power amp, even those higher levels of distortion is still well BELOW anyone's hearing so it is a moot point.

This thread is worth a read (you can get the gist from the first two posts). By following the instructions you can work out how much power you need. If you look at the poll results you can see that  >70%  indicated 25W or less with nearly 40% needing only 4W.
Power in itself is not a bad thing but assuming you are working to some kind of a budget then it would be best to find the highest quality amplifier that meets your needs within your budget. Power adds significantly to the production cost of a product (less so with class D) because some of the most expensive components within a power amp are the power supply and heatsinks the size of which are proportionately related to the rated output power.
A lot of the stuff people believe about power makes an awful lot of sense. The only problem is that while the reasons make sense on paper they don't work out nearly so well in the real world. 

Point of order: one low-powered amp that sounds better than one high powered amp is by simple logic proof that power isn't everything. We have not one but hundreds of low powered amps that sound hugely better than thousands of much higher powered amps. So clearly something else is going on. 

What I think is going on, power is but one small item on a very long list of things that matter. In fact its kind of weak and pointless to qualify that. Its what I know is in fact going on. The list of things that affect sound is so much greater and longer than we know that it often strikes me as pointless to even be talking about them. 

I mean to talk about how many watts an amplifier puts out, in terms of sound quality, we might as well be talking about how many grains of sand in judging the beach at Cancun. Which would be a pretty nice beach... anywhere else but Cancun.

Hi @larryi ,

I'm not against to use, for example, small monitor speakers with sensitivity ~88-90dB/1W in 100-150 sq ft room. But in this combination even 300B SET will be enough.

I think the very popular but wrong way to do - using big low sensitivity  (< 88dB/1W)  big tower speakers in a big room.
In this situation need a huge amplification power and a result a strong and ugly compression.