I don't believe the TBP-1 is in any way SWR product. It is nothing like the typical SWR preamp nor does it have a similar tone. In terms of features, the TBP-1 is an almost-F-1X combined with half of an almost-SF-2 and a couple foot switchable features. If this thing were built by Alembic, it would be the perfect preamp, and I have asked Mica to consider an upgrade to the F-1X to modernize it with some of these useful features. I don't believe Alembic has any plans to do so, though.
I believe your search turned up my previous comments. In short, the TBP-1 is a useful preamp for live work with more convenience at a lower price than any of the premium boutique preamps. I can get it to sound like a flat F-1X by boosting the treble just a bit, and that's good enough for my gigging.
There are a handful of preamps that get great reviews, but some have different colors (colours for you, Graeme) that have people swapping between them as they search for tonal Nirvana. The important things are how you plan to use it and what tone you are looking for. In tone, the F-1X is pure. There are a handful of other boutique models that are reported to be about equal to it. There are other boutique models that inject tube warmth if that's more to your liking. The TBP-1 aspires to be like the F-1X, but sounds just a bit muted on the top end without really sounding warm.
The tube drive is the weakness as far as I can tell. Maybe someone with more tube savvy could figure out what to put in there, or what settings to make, to get a tone I would find more useful out of it, but I haven't been able to. If anyone has success, let me know how you did it! I haven't been able to get a buttery tube tone out of it, it just breaks up harshly. I admit not putting in too much serious time in trying to figure this out, though. It may be the hot output of the bass is just coming through too strong right from the start.
If you're really looking at mid-song tone changes for live use, I will stand by the Line 6 products. With a little bit of setup work, you can find a handful of of useful base tones. Set these to be the A channels of individual banks and then modify the settings for EQ or effects and save these in the B, C and D positions. Can't get any quicker and more repeatable tone changes than that. It has a built-in tuner and mute, though you can't check your tuning without muting. The XT model lets you send a separate clean signal out as well as the modeled/effected signal and can be had for a song on the used market. The newer X3 model will let you put out two separate modeled/effected tones at the same time if you want to send that drive tone to a guitar amp separately from your core bass signal.
-bob
