Too powerful of an amp!?

@kld10 wrote:

I always had over powered amps with lots of headroom. It’s always been beneficial I find. I am now at an extreme point where I already had a Mcintosh 300 watt per channel and I bought Avantgarde speakers at 107 db efficiency.
That means that I hardly use two watts. I am not bothered by the amp not working hard, but rather the question always goes through my mind that the preamp volume is always in the lower area. I keep hearing that a preamp works best between 75% and 100% (unity gain).

So to your question, I would say, an over powered amp yes, but are we getting the best out of our preamps that are always in very low volume setting?

I do understand that there are many ways of attenuating signal but speaking in general here, I believe most preamps work best between 75% and unity gain

With very high sensitivity speakers like yours, depending to some degree on amp gain/input sensitivity, you’d likely always be in the lower end of the attenuation scale, be that with low or high wattage amps. The real impact of more amp power shows its face in the other end of the scale, certainly volume-wise and in regards to the cleanliness of sound, but indeed - as you imply - it also comes down to the chosen volume control implementation and whether it’s a linear or logarithmic variant (with the latter being the more appropriate choice here).

I very much adhere to the importance of headroom as well with prodigious amp power at hand in my own setup (>2kW per channel divided over 3 stereo power amps, fully actively), and that with an effective speaker segment sensitivity range sitting between 100 to 111dB’s. As to how that applies to the debate on "the importance of the first watt" I believe it has a tendency to be (over-)simplified into a matter of wattage capacity mainly and how low wattage amps shine here, but it doesn’t follow through in my own experience of comparing lower vs. higher powered amps in my specific setup context. As a matter of fact I use a class A/B ~600W/8 ohm power amp over the top horn section @111dB sensitivity, and compared to the previous 30W class A amp used here it’s no less refined or capable at lower SPL’s.

Other than the amp itself is the context of its use; does it look into a heavy or easy load, and how do those conditions affect the amp to perform nearer its peak? Active config. sans passive crossovers, that would otherwise meddle with the control over drivers, is an important factor here, and many would be surprised at how much active config. levels out the differences between amps, differences that would be more obvious via a passively configured speaker setup.

People sometimes get too hung up on wattage numbers and what a general, accepted stance could point to as being the best practice. Just use the amp(s) one feels has the better sonic merits overall, preferably with sufficient power to boot, but if that turns out to be a 28W class A Sugden that sounds great over a pair of low eff. Harbeth speakers, then so be it. Conversely using a several hundreds watts amp on very high eff. horns can be a sonic delight, at lower SPL's as well, although obviously this scenario has more in store for it wrt. headroom. 

Yes you can as long as your are use the volume control diligently. Also many often overlook the input sensitivity of an amplifier and when using preamp, this is where synergy come into play. Keep in mind that this applies to separates and not much into integrated amplifiers.

Great point on running your pre-amp in its comfort zone was made by @kld10  and it gets to what I read elsewhere recently.

I recently read somewhere on this site about running an amplifier within its ideal power range.   Not running 12watts into Maggie's at low volume, you're still pushing it some and out of its comfort zone. Not running 600 watts into horn speakers, using the opposite end of the power band with its own issues.

It would seem advantageous to me. Individual components might vary in their zones, but it's the general idea we're bringing up.  (If I have to go up or down, I'll always have more power, never less though.)

I always had over powered amps with lots of headroom. It’s always been beneficial I find. I am now at an extreme point where I already had a Mcintosh 300 watt per channel and I bought Avantgarde speakers at 107 db efficiency.
That means that I hardly use two watts. I am not bothered by the amp not working hard, but rather the question always goes through my mind that the preamp volume is always in the lower area. I keep hearing that a preamp works best between 75% and 100% (unity gain).

So to your question, I would say, an over powered amp yes, but are we getting the best out of our preamps that are always in very low volume setting?

I do understand that there are many ways of attenuating signal but speaking in general here, I believe most preamps work best between 75% and unity gain

@carlsbad2  +1 - Carls is right - we typically use very little power for most listening.  A clean amplified signal is better, even if it is 'only' 100 watts.  In my system I bet I only use the first 20 watts before it is too loud.  

All great advice.  An important aspect of matching amps and speakers is synergy.  The watts alone won’t tell the full story on how they’ll pair together.  Another poster brought up Horse Power under the hood which is a good comparison, it’s not just HP though, it’s Torque, it’s how a car is geared and various other factors, it’s when the engine in a car has synergy with the rest of the car that true magic happens.  Same with speakers and amps.  Research what mates well with your speakers, Tube or SS, do they need headroom to really shine?  Are the speakers on the brighter side?  Pairing Tubes or Class or SS amps known for warmth like Macs, Pass, Krell, Parasound, Cod to name a few.  Your speakers will likely do very well with amps that have some headroom, provide stability.  If you like Mac’s, a great place to start with their power / autoformer technology.  Good Luck, enjoy the journey! 

True @carlsbad2 !  

So very true.  I powered KEF LS50s with a 300B amp! (8 watts)

If you don't listen loud, a low powered amp won't be harmful. The other consideration with a low powered amp is lack of headroom.

@jbhiller 's advice above struck me wrong until I kept reading.  You won't damage an amp with a low power signal unless it is clipping/distorting.  So buying a low power amp AND turning it up too loud will damage speakers.

Jerry

Great advice above.  We are all reconciling the following truisms: 

1. Never under power loudspeakers if you can avoid it.  Too little power can damage speakers. 
2. When buying amps, don't forget when you buy a 400W mono block, or the like, that it's the first few watts that matter. 

When an amplifier clips, nasty stuff typically happens to what the loudspeaker gets fed and pushes back.  

When we listen, even at loud volumes, the first 1-8 watts are most of what we use and hear.  A 9 watt tube guitar amplifier will blow you out of the room, compared to these massive wattage amps we see today.  

Sorry, don't mean to confuse you.  It's all good advice above. It's a delicate balance.  Going over with a good quality amp is usually a good thing!

Just don't trade quality for power, which often happens.  Most of the time, even with your less sensitive speakers, you'll be listening under 25 wpc--maybe even under 5 wpc.  I'd recommend spending your money to get the best amp you can get and if you have to pay more for a 500 wpc amp, you'd be better off getting a higher quality 100 wpc amp for the same money.

Jery

That's like too much HP under the hood. Only if you can't handle it.

Absolutely yes you can go higher. In general it is safer than having a too high versus underpowered amp. Running out of juice will fry speakers more easily. Now, on the other hand if you run at ear bleeding sound levels you should be a bit carefull. But most speakers will play very loud, and will give notice that they are under stress before you damage them. 
 

I have probably had amps twice as powerful as max for the first thirty years of my audio career and never damaged a thing. 

 Yes you can go higher. In fact if it’s a high current amp, it will be more beneficial. I run my Pass 250 with many bookshelf rated less than 250w rating. No issue what so ever.