Thought this might be a good place to jump into the forum. I've been a proud Sunn owner since April '71, & made it my business to keep up with Sunn history ever since. When I bought my Sorado new (or, more precisely, my dad bought it for me
), it was a choice between that & the Sonaro; at that time Sonaro/Sorado were the same head, with 2-6550's rated @ 60w RMS, the difference was the Sonaro came with 2 115 cabs (dim. 24w x 24h x 9d ea.), my Sorado had 1 2-15 cab (dim. 24w x 42h x 15d). The schematic I have says it's for SONIC II, 200s, SORADO & SONIC 1-40. A year or two after my purchase, Sunn re-labeled them 190B for their mix & match system, & the power ratings were miraculously raised to 80w RMS! I read up about tubes from a link from tubesandmore.com & learned there that the higher rating was probably due to 6550-C's, rated 40w apiece.
Sledgeguitar, your rig looks to be the 412 cab from the Coliseum Lead set, which means it should handle way more than what the Sonaro head can ever dish out. Impressive stack you got there.