ORIGINAL: Platano
Believe he used the SG for the first album (and Woodstock), then on Abraxas (Black Magic Woman days) he played a Les Paul through a modded Fender. The modded Fenders blossomed into Mesa Boogie. He then played a Yamaha guitar for several years and they made a Carlos Santana model. My buddy Stratton had one and a Mesa Boogie. Tone for days.. Then he moved on to PRS..
Hi Joe, yep, I bought the gear as close as I could get to the rig Carlos had at the time, a Yamaha SG2000 (weighs over 10 lbs., still have it) and a Mesa Boogie Mk1. Found that I had to CRANK the amp to get close, which was paint-peeling loud. Much of Santana's tone comes from the interaction of guitar and amp at high volumes. Ulitmately not practical for those of us not playing stadiums.
You can get into that tonal territory with more moderate volumes in a variety of ways, but I think that American voiced amps (blackface Fender, Boogie, Dumble, Fuchs) with either a really good OD Channel or a smooth OD pedal will be a good start.
I LOVE the Abraxas album. My favorites of all his tones.