I have had one for years. I had swapped out the Bag End 8"s years ago for Celestions because of some overzealous funk with a Guild Ashbory. If you know that bass it put's out tremendous fundamental and took out one of the 8"s. This time I swapped out the speakers for the Low Down Sound 8"s. These go down to 55hz. Turns out the buzz I was hearing was not the Celestions wearing out but a loose speaker wire lug. Am I returning the LDSs? No way. Huge low end. The BBII used to have such great tone that I would play it even when on a 5 the boom of the B would just drop away. Not now folks! The second upgrade was the replacement of the GT 12ax7. Some folks say that some of the hybrid amps don't utilize the tube and it's more of a marketing gimic. There is a noticeable sonic difference between 12ax7s in this Baby. Pun intended. The GT while not noisy was sounding flat and lifeless. I tried a NOS Tesla. It sounded like syrup. I kept playing it because it was so luscious and thick. I tried the reissue Tung-Sol. Now that baby is clear and articulate in a way the Tesla wasn't. I prefer the Tung-Sol because the mids and highs on the BBII are so good and smooth. At least I can change back and forth. These amps are true sleepers with their great DI and "more me" function when recording. I have played some monstrous distorted tones through it direct on one of the "State of the Groove" releases. As an amp for backing up singer songwriters it is the richest thing I've heard for it's size. I originally bought it for acoustic bass guitar work but it sounds equally good and I use it mostly with passive Fenders and active Boutiques.