People buy them for various reasons, including but not limited to the following:
- they need the rated output.
- they have no need, but like the look, feel, build quality, extra output to standby if ever need the extra.
- heard, or read from others, on forums, dealers, friends, reviews including Youtubers, all hearsay stuff...
- misread and/or misinterpreted specs, so thought the larger amp will give them better sound quality.
- heard the better sound quality with those amps, but it's just in the head, no better sound if done in blind tests.
On the last point, of course, many actually heard the better sound but in most (but not all) cases, it could be due to other factors than the actual amp, in other words, if listen to their own smaller amps, or even their AVR, the sound quality will be the same or only subtly different, if compared under the same conditions.
Don't believe forum members like us, read expert opinions, such as those from Dr. Gedlee, Olive, Toole, they all will tell you people should pay more attention to speakers and rooms, not amplifiers that are on the right side of the curve of diminishing return.
The R7's nominal impedance according to KEF is 8 ohm nominal, but many of us would say treat it like 4 ohm nominal for the purpose of sizing your amp.
Amp power recommended (by KEF) is 15-250 W, so the SR7011 should be adequate but if you want to cover all conditions of use, any amps rated for 250 W/350 W 8/4 ohms should have you covered. If you currently listen to music/movies with volume of the SR7011 no higher than say -15 90% of the time, then I doubt you will hear "better sound quality" using external amps but you will, unless you compare them without being subjected to the unavoidable bias/Placebo. People will say the difference they heard was so obvious that there is no need to do it "blind", but in all available serious studies, even people who were so confident, failed.
I think by now, your question
"I'm I just wasting money or would this be beneficial enough to really make a difference in sound quality. I would say decibels as well, but really you only gain roughly 3db for ever 100 watts per channel. " It is of course up to you to believe, or not.... My suggestion is, go and get that amp you like, just don't expect to hear "better sound quality", and if you do hear, or think you hear better sound quality, you will be very happy. If not, it is not a waste of money because there are other reasons aide from audibly better sound quality but then worth it or not is a subjective matter.
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