Look i think it was actually the heroin, and it made him bad at covering how shit of a person he is. Having someone spraypaint clapton is god on a wall in the 1960s really went to his head
Consider, if you will, the Fender ProSonic. The ProSonic is heavily based off of the Mesa Boogie Rectifier series, which is itself a modified '59 Bassman circuit. Fender copied a copy of a Fender.
Off-topic but, incidentally, the Fender Princeton Reverb is the best Marshall Plexi as long as you don't want things like "subtlety" or "a tone stack that makes a damned lick of sense." If you ever get to try one out -- from any era (mine's a mid-70's CBS silverface) -- run a Rat into the front end, dialed in as a low-to-mid gain, maxed-out volume midrangey boost. Set the volume on the amp to 9 or 10. Set the bass to zero. Set the treble to about 8. Run the output of the amp to a cab loaded with Celestion greenbacks (or similar). Play any Metallica - Kill 'em All riff that you can come up with off the top of your head. Bask. Repeat.