Re: Why are some kind of amps hard to play ?
Seems like a lot of players who play clean all the time don't know how to use distortion, and the players who use heavy distortion can't get a decent clean tone. Definitely something in the fingers.
I played clean for years on a high-powered SUNN SS combo, then went back to using a tube amp...BF Fenders and a Marshall for more pushed tones. VERY different feel; I won't say one style is better than another. But when I got my first Mesa, it was like it all came together for me: a great clean tone, and the drive tone I'd been searching for.
The big Mark III had incredible headroom, but at the same time...a very liquid feel under my fingers. I became a better player almost instantly. It had the flexibility I needed, and it was just inspiring to play. A lot of amps just can't do that. There are companies whose amps I want to like, but every time I play one, it sounds dry, clinical, sterile. No thanks.
Volume is another issue. If you're used to playing quietly at home or in a club, you get used to the amp's response at that level. Move onto a big stage where you're cranking the volume...the tubes work harder, you're pushing more air, and all of a sudden the guitar feels alive in your hands. You're totally out of your comfort zone, trying to deal with the extra compression and sustain while on the verge of feedback. Though, when you get used to that, it can be addictive. That feel of a pushed amp is one of the reasons so many players have moved from the 100-watt behemoths to smaller 15-to-35-watt amps. That said a BIG pushed amp can be a lot of fun, when you get used to it.
Pickups can play a role too. It can be miserable playing a screeching microphonic pickup at high volume, but a mildly microphonic pickup can be a good thing.
I don't practice on a little practice amp. It's better for me to play the amp I'm going to be gigging with, with the features and tones I'll be using. Makes no sense to me to spend hours fiddling with a tiny, tinny amp....when I could be fine-tuning the amp I'm going to play with.
So I'd say, practice on that Plexi. Learn to run it at the volume(s) you'll be playing at, and you will learn to play with the right feel.
And a loud Plexi? Better invest in some serious ear protection!
Good luck.
Bill