Digging into the early Zep tones and info, I don't think it was the Supro Thunderbolt. It was the Supro 1690T Coronado, a 35 watt 2x10 combo. But if the info I gathered is correct, Page had his modified as a 1x12:
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Or like a young Eddie Van Halen telling people that he used a variac to increase the voltages to his Marshalls for the EVH Brown sound... what a Butthead! I wonder how many amps were blown by naïve tone chasers back in the day...Same thing I had always heard. I think Pagey has confirmed this himself, unless he's been pulling a Rev. Willie G and purposely sending people off in the wrong direction.

Very Cool Amp:
DSL40C with 7025-WA's and a WGS Veteran 30 - Better tone than the 90 watt Creamback!
Vet 30's kick all kinds of butt.
Dude! I was shocked!
Every WGS speaker I have used has been amazing. My favorite speakers are the Mesa-branded, British-made Celestions (C-90 and V-30) but the WGS' are right behind them, even before the "regular" Celestions, in my book.
Wonder how there bass speakers are ..................
What about EV bass speakers, 67?
OUTRAGE!They don't make bass speakers