Last November, I had a B500DR for almost a week before I took it back to the store for a refund. It had lots of great 'gimmick' features, (watching the lights move was fun) but it was SERIOUSLY lacking in output. Compared to my old Portabass 250 the B500DR sounded more like a weak 50 watts (used with the same Ampeg PBH210 4ohm cab). I used the B500DR for one set before putting my PB250 back into service. To play with the band the B500DR was clipping and distorting well below our normal stage volume. The settings on the B500DR: gain was between 7-9 and the master 8 - 9, eq's at bout 6 - 7. The PB250 at stage volume runs at about: Gain 4, Master 3 to 5, similar Eq and no clipping or distortion. I think there is a valid reason the B500DR amp is being discontinued, it just doesn’t produce the sound levels equal to its quoted power ratings and hefty price.
Unless you really have a need for multiple foot switch able EQ settings, you can find better bang for the buck with other heads.
Now, I’m the first to admit I may have just gotten a bad unit, but I’ve tried other B500DRs at different store with similar results. I’m totally unimpressed with the sound and value for the money the B500Dr offers.