I have 2. Both went to my tech after purchase. One was good but, he said there was some trouble with the driver stage and it was only putting out 130W. The power tubes were good, but he swapped the 12AT7 driver tube out with a 12BH7 and that solved it. Gave a clean 170W output, and since then I put a good set of GE6550A’s in and now it’s sounds awesome. With the OBC115 it’s a great match for this head. Yes, it’s simple, and usually I have the bass down to about 9 o’clock, and mid at 12, treble at around 3, the rest I do from my board.
The other AD200B I bought was a Euro model, only able to run 220/230. Took to my tech, he rewired the PT(?) to run 120 only, and again found the a 12BH7 in place of the 12AT7 was the ticket to get that one running at its best. It’s got Sylvania/Phillips 6550’s and RCA 12AX7’s and 12BH7.
I have not tried either of these with my only 810 (late 80’s Ampeg), but when I can I have run an OBC115 and OBC210 together, with a Thunderbird and I love that setup, so much so that I don’t see using anything else live for the foreseeable future. It’s great with the 115, and awesome with both 115 and 210.