I wish I knew...it's a rather neat lookin' amp.
My dad bought a pair of Bell bookshelf loudspeakers back in the early '60s while stationed in Chartres, France (before being shipped off for Nam). I believe they have a 2" cone tweeter and an 8" woofer in a ported enclosure...they're kinda crude sounding, thin, and lacking body, which is unfortunant seeing that they're built as solid as a rock, and the cane grill is sharp as hell! That doesn't mean that the integrated amp is lifeless, though. His Bell speakers were driven by a 45 watt Kenwood receiver of the same vintage, and when my mom used the Bells, they were driven by a cheap 15 watt RadioShack receiver. Who knows...those Bells may sound sweet under tube amplification!