Actually we could both be right. The first version of this cab was the 1810 The revision added Scorpion 10's and called it the 1820.That's an 1820. I had one.
Then Peavey built a 1508 and 1820. All variations ran at least 600 watts biamped and used Black Widows, and in the newer models, Scorpions, except the 1508 which was probably Eminence.
EDIT: By my own description I'm wrong and you're right! This pic is an 1820, not the 1810.
