Goldpoint attenuators are good quality. The B1, I haven't heard, but I'm certain it's good. I'm not a fan of potentiometers....even though Alps are good quality. You should really consider Tortuga, unless you think you might need a preamp that'll definitely play nice in any setup regardless of amp or source. Passives can be tricky in that way, though Tortuga is perhaps the best / most flexible / and least electrically "fussy" full passive around. Another option, and these don't come up often, is the Wyred 4 Sound STP-SE. It is a fantastic preamp. Had one for a few years. I only sold it to fund the build of a custom preamp. The Wyred is buffered (like the B1), but uses a very high quality stepped ladder attenuator (somewhat like Goldpoint, but different layout). Plus it is fully balanced (if you ever want to go that route) and remote controlled. Might be more than you want to spend, but it's one of those preamps that sits in that area where you'd need to spend $$$ to significantly better. Same goes for Tortuga if your system is passive friendly (it most likely is now, but might not be in the future if you tend to swap gear a lot). Anyway, hope this helps. I think your mind is in the right place, for sure.

Sorry, didn't mean to turn your post into a thread. Just sharing other possible options if you don't come across a B1.
