The first proper rig I had was a secondhand HH from a friend of a friend. 1x15, 2x10, and supposedly a 600w head. Whenever he played through it it sounded full, rich, and clear, with loads of headroom. Whenever I used it, it would be woolier than a wooly mammoth. And barely audible. So quiet. I then sold it back to him, at which point he said "had I used the input bridging to get the volume output?" Doh!
I then bought a massive trace rig. 2x15, 4x10, brightbox, and the 1000w head. It was stunning if I could turn it up past 1, which was very infrequently. Too big for small gigs, then couldn't use the potential on big gigs because nobody else on stage could hear themselves. It was capable of killing the front row. Awesome piece of kit.
I have been doing sound for a local band for the past 10 years, the bass player had this god awful Ashdown combo. Took no care of it at all. Just no tone or power at all. It was only when we did a local music festival, with back line provided, that I got him a bass sound. Ampeg STV and 8x10. What was killing his sound was his small pedal board with a compressor and a limiter on it turned pretty much to max which he didn't use through the Ampeg. Next gig back on the Ashdown, no pedalboard, no difference. Still dirge.