I bought my HK brand new. Just doesn't sound as good as the Carver

I don't think the needles ever went above 15W level.
One other thing I forgot to mention, which, however, is essential when comparing equipment. In order for a listening test to be fair, both items must be precisely level matched. This is because a slight difference in volume is subjectively perceived as a difference in quality, with the slightly louder one seeming to have more bass, more treble, and more detail. This nonlinear aspect of human hearing is why loudness compensation circuits are put into so much stereo gear, so that when one is listening at a low volume, one can engage the circuitry to boost the bass and treble in a manner to compensate for this aspect of human hearing.
It is extremely unlikely that your two amplifiers will put out precisely the same power with the same input, and judging from what you have said, my guess is that the Carver puts out more power with the same input.
The proper way to do a listening test would involve using a meter to measure the output of each amplifier, and putting in a volume control to compensate for the difference. And, of course, the listening should be double blind.
In the absence of such things, try listening to the HK with the volume control on your preamp turned higher than when using the Carver, so you can tell that it is barely louder, and then compare that way.