"Discontinued"....... LOL............
It was "discontinued" before Loud bought SLM...... Something on the order of 2003/2004 or thereabouts, IIRC.
The PB speakers originally went with the PB250 amp...... and made its 250W sound like about 60W. Those speakers are one huge reason why the PB250 and PB800 were not more popular, they probably get the "credit" for killing the original Ampeg "micro-amp" product line.
Eventually some more efficient drivers were used, but by that time it was too late, "everyone knew" that the amps were no good because they were so quiet.......... except it was the speakers that sucked. The powers that were listened waaaaay too much to the upright players who loved those things..... Too bad that all 20 of the electrified upright bass players in the US were not enough to form a "market" for those speakers....
Just another one of the SLM bone-headed mistakes that screwed up good ideas. We did make a number of those.