I wanted to change the pickups and preamp in my BB735. I didn't know which pickups, but I was sure about the preamp. However, I ended up getting the pickups changed first. Then, the luthier who did the job told me to give the preamp a shot with the new pickups. And I like it. The preamp I think it's transparent and it just EQ. It doesn't add any magic (like the Aguilar or more coloured preamps) but it allows the bass to sound more transparent. I don't know if I will change it in the future, but for now, I just like it.