I wouldn't say that's true - I got great results using an Audio Refinement 50-watt integrated with my 2Ce Signatures. Very nice sound and I did not have to turn it up to super-high levels (and I like to rock).
Eventually, though, I did want something with a great phono stage built in, so I opted for a Plinius 8200 MKII, which is quite powerful.
The Plinius sounds better, no doubt about it, but I dunno if that's because of the quality of the components - or something else?