I've got a BWG 250b, that a friend here in town bought new in the 70's. I got it in a trade for a nano reverb and 100 bucks. Its almost as loud as my K12 full range monitor and I'm still experimenting with it as a power option for my FX Ultra, pushing my 2 JBL's. It definitely turns my Ultra in a "real amp" in terms of feel and sound. The K12 sounds more hifi and less like an amp - its sounds "right there" if that makes any sense and the power amp cab sounds...well it sounds like my 73 fender twin.
I'd love to hear it with a SMS Classic. I'm lusting after the SMS now that I've discovered Brad's website and started reading about his products. That would be the ultimate back-up to the Ultra.
Little written about these things because they are so ancient - so if anybody has any info good or bad I'd love to hear.
Talking about simplicity. No knobs! Just an on/off switch. Its heavy, but still a 2RU so its easy to move around.
From the net....
100 Watts per channel at 4 ohms. 39lbs. manufactured in LA from 1975- 1980.