My 30 Watt class A is louder than my 100 Watt Class AB?

I tried to use a Schiit Saga preamp (unity gain) with their Aegir power amp which is on the low side of amp gain. I had to turn the volume up to near max on most recordings to get an average listening level.

The Sega has no gain, your source has to be high voltage such as a CD player to drive an amp with enough voltage. If you were hooked to a low voltage source like a record player, you would run out of steam. And that is why active pre-amps exist. 

Volume isn’t my problem :)

Using 4ohm 84db speakers, I never go past 11 o’clock on the dial :)

@russ69 -- I know the Saga has no gain (that's what "unity gain" means.) And I was using a DAC with the typical 2 volt output, so nothing amiss there. While most of the time I got the desired playback volume, the problem was when the recording itself was recorded at lower than normal volume. Certainly not a problem with most pop/rock material, but there are some recordings out there where this can be an issue.  Its not an issue limited to certain turntables/phono preamps.

I went from a tube preamp with 3-5 db of gain into a ZMA and always had the preamp up more than half way to get reasonable volume from 96db sensitive speakers. When I got a Backert preamp with 9db of gain now all of the sudden the ZMA is a  power house and never needs the pre up nearly as much to reach very robust listening levels. Gain staging is crucial and of course component synergy.

Watts per channel are only the out put measurement ( horse power). There is so much more (torque) inside the an amp that produces the watts per channel. They did not name the company “First Watt” because it was catchy!