How Much Difference Does a More Powerful Amp Make?


When would you notice a real difference in sound quality with a more powerful amplifier?

I have a Simaudio W-7 driving Dynaudio Sapphires, and at some point, I may upgrade to Sonus Faber Amati Futuras.

My W-7 is 150 watts at 8 Ohms, and Simaudio makes the W-8 at 250 W at 8 Ohms. Would I notice any difference if I moved to the more powerful amp in a medium-sized room (14' x 22' x 8')?

The Sapphires are 89 db efficient, the Futuras are around 90 Db, but I've read that with most speakers, the more power the better.
level8skier
Maril555 - Imagine 100W class AB transistor monoblock that dissipates 100W of continuous power into heatsink while driven with the sinewave test signal.

Now, get rid of this large expensive heatsink and replace it with 25W heatsink and use saved money to oversize power supply and up the voltage. You'll get an amp that is rated only 25W continuous but is louder with better control of the speakers at the expense of continuous power rating that is useless since average music power is only few percent of peak power. Peak power is what counts.

Most likely it will not sell very well since most of people, you including, believes that higher continuous power rating means better sound. Tubes might be different story - we need to ask Atmasphere (he knows tubes).
I have a 100 watt solid state amp that controls my speakers better than a 150 watt solid state and a 400 watt digital amp that I tried.
Approaching your question from the speaker side.
Sensitivity is not the end of the amp/speaker problem. 'goodness' of load is more about phase angle then just sensitivity. A very highly reactive load will be worse, even if much more 'sensitive'.

From the amp side. IF....you were driving just a resistor, the more powerful amp would indeed be slightly louder. Not even 3db, which would hardly be worth it. But, the load you are driving is not a resistor so as it turns out, amps vary in ability to drive such non-resistive loads. It is just possible that the lower power amp will be a better electrical match for your current or proposed speakers.

For the above reasons, 'hi-current' amps may be a red herring non-spec. Since speakers are not a resistor, the real measure of an amp is how well it does into a real load. Which the published specs don't help with.

As for 'real world' performance? Read Kijanki post above. 10x power=2x loudness. Not much for such a huge increase in power. If all speakers were of the sensitivity they advertised, much better leverage could be gotten with more sensitive speakers than the amount of amp power you are talking about.

Check out this link for real-world amplifier testing.

http://www.sonicdesign.se/amptest.htm
IMHO, and perhaps more so with ss amps, having some extra power beyond actual use, is worthwhile in that it can keep an amp from stressing near it's clipping point.
I had a Classe CA 300 on a pair of PMC MB2 once and turned the amp up to its limit and then put on a Classe CA 400(only 100w more But 1kv bigger transformer)and that made a huge difference when pushing a great song up into the bigger SPL's.
I have had a Simaudio Titan(200w/ch) and it would hold its own..
The $$ value vs power may not be worth it...maybe W7M's