Buy a new servo controlled Rythmik subwoofer. I have owned Velodynes in the past.
Velodyne DD15 - worth repairing the plate amp?
The amp in my 2008 Velodyne DD15 is dead as a door nail.
How good is this old marvel compared to today's offerings?
Worth investing another $500 (to have amp repaired, incl roundtrip shipping, tax, etc)? Or just use as passive sub?
How does it compete to modern subs, for example SBS SB-2000 or SB-3000 (both under $1k pre owned)?