I'm just confused about it is all. I read about external amps being better, so I got one. It's cool. People who don't know much come on forums for help, not to be belittled and berated. Thanks.
Well, I see you've run into the Marks, two of our resident grumpy old men. Especially markw. They mean well, but sometimes they get impatient with anyone who doesn't care to get at least an associates degree in electronics before asking questions.
What they're trying to tell you is that amplifiers don't work the way you think they do. Think of an audio amplifier like a black box that multiplies an input signal by a given, fixed, amount. Yes, fixed. Let's say that for one particular amplifier the multiplier is 26. That means that any signal you feed into the amplifier comes out 26 times bigger. Let's say another amplifier has a multiplier of 32, which means that any signal you input will be 32 times bigger at the output. This multiplier is the gain structure TLS Guy is talking about. And here's a curve ball... the multiplier has absolutely nothing to do with the potential power output of the amplifier. That's a separate design consideration. And the volume control, that's just a way to adjust the signal level up or down that's fed by the pre-amplifier, in a receiver or an integrated amp or a separate pre-amp, into the power amplifier inputs. That's all a volume control is.
So, the bigger the multiplier the more sensitive the amplifier is, and the louder that any given input signal will sound. And it also means the volume control won't have to be turned up so high, because the amp is just more sensitive. So a 30 watt per channel amplifier that's more sensitive can sound louder, within its power output capability, than a 300 watt per channel amplifier that is less sensitive, assuming a similar input signal.
In reality, I've over-simplified things a bit to make it easier to understand. In reality the multiplier is measured in decibels, which uses a logarithmic scale in which every 3 decibels represents a doubling of the signal level, so the typical gain range for home audio power amplifiers is between 26db and 32db, so the real signal multiplication factor is huge. For 26db of gain you're doubling the input signal 8.6 times compounded, and for 32db 10.6 times compounded.
The gain of the Rotel amp is about 28db, which puts it at the low end of the home audio sensitivity range, and that may or may not be compatible with the output capability of the Yamaha. Regardless, having to turn up the volume control to achieve a similar in-room volume level isn't all that surprising.
