Ampeg SVP-BSP
The Billy Sheehan preamp. I love Sheehan. I love his tone. He even signed mine (before I got it).
This is the worst sounding preamp I have ever used. The distortion is unusable, and sounds nothing like Sheehan in any possible way. The compressor is terrible and an afterthought. The clean channel is just absolute pure horsecrap. The bass is centered super, super, super low so all you get is sub-bass hollow-ness. The midrange is non-existent. The highs are set so high it makes it sound like you have a tweeter even if you are running an old school full-range 215 cabinet.
This thing just had noooooo tone. Empty empty empty. Built-in smiley-face tone, all subs and high offensive glassiness even when supposedly set flat, not possible to get a thick warm usable clean tone at all, and the distortion was just nauseating.
I remember seeing Sheehan back in the early 2000s and he had one in his rack, but it wasn't connected or turned on. I asked him once back then (on AOL IM of all things) if it was still in production, and he had no idea about anything involved with it.
Strange he put his name on such a POS. I guess they paid him well, because he did actually use Ampeg amps for years and years. But there is no way in hell (or whatever he believes in) that he could have used that horrid, horrid, preamp. In nearly 40 years, that's the worst piece of equipment I've ever heard for bass. I played through a 60's transistor hand-held radio once through a Mr. Microphone FM modulator that had a better tone and actually sounded great overdriven! It's like they purposely designed the BSP to suck. BSP should stand for "Billy's Sucky Preamp."
But yeah-the Ampeg SVP-BSP is the worst piece of bass equipment I've ever heard.