Saw and heard the Jeff Beck Group at the boston Tea Party in ~'70. Ron was on his Tele bass and Marshall Major rig. The greatest live rock band I have ever heard.
Earlier, in 1969, I got a Marshall Major 200 watt tube head and the obligatory 812's (two 412 cabs, the top one being a slant face) from Manny's in NY. I had a friend who got a Sunn 2000s about 1970. I soon realized that the 2000s had tons of sweet low end, but the Marshall was thin and wimpy down low. The "green back" Celestion equipped cabs did not do the job.
@amusicalperson — I took that Marshall rig on the road to Fairbanks, Alaska in 1971, and when I got back I sold the cabs and got a lightly used Acoustic 301 118 cabinet. So much better for everything.
The Marshall Major head was nice, but I don't miss it much. 84 lbs and not very reliable. Pushed, it was loud, not very flexible, and kind of harsh. To be honest, you can get that sound easily with a pedal or two and a clean loud amp/cab pair. I hate to sound jingoistic, but the English have never produced a bass amp that I really liked. YMMV. Then again, I don't like SVTs, either.