This Jess Oliver designed Oliver Sound B120 tube bass amp is in great working and looking condition. 35W. These are pretty rare, and it has gobs of tone. Great little amp. $400 Shipped CONUS Complementing and eventually supplanting the Powerflex Series, the Uniflex (combos) and Duoflex (separate components) lines featured a reworked control panel and offered the musician a second choice in power output. A smaller 35W amplifier powered the single-channel, single 12″ G120R guitar (a.k.a. Little David) and single 15″ B120 bass Uniflex models. Solidstate rectifiers, 6L6 power tubes, 6EU7 phase inverters, and smaller transformers were just a few of the major electrical differences between the old and the new. A two-channel version of the 35W amp with reverb and tremolo powered the single 15″ G150R and the twin 12″ G200R.