Although not specifically a bass amplifier, the model #666 was advertised as being suitable for bass instruments.  However, it's design, which consisted of four 8" speakers with 30 watts output, probably was a little thin for bass reproduction.  Still, the 4 speaker design was innovative for the time.  Controls were the same as the #1212A; that is, two channels, with volume control for each, and a master tone and vibrato controls.  The model #666 sold for $139.90.