They used JMP Super Leads for the recorded stuff. They used empty 800's for stage and not sure what they used live. On Love At First Sting tour, it sounded like some kind of Marshall; not too overly saturated.
All the great albums, they used stock Gibson pickups through cranked Super Leads. The best sound on the planet!
They started touring with Soldanos late 80's into the 90's, then came all the other slew of amps.
To get classic Scorpions sound from Lovedrive on up, Marshall JMP Super Lead non master volume heads.
Nowadays there are plenty of builders making replicas of all late 60's JTM and JMP Super Leads.
note: I record only with a 50 watt replica of a 1968 Plexi SL.
Use an overdrive or boost in front of the amp to get super saturated modern tones. Though plugging straight in still sounds best.