What Step-up transformers are best value?

Having directly compared the two, the Lundahl LL1931 is considerably better than the S&B TX-103/Bent Audio Mu SUTs. They do, however, require several hundred hours of break-in to sound their best. Merely my opinion (and my system) and the usual disclaimers apply.

Check out the Hagerman Piccolo, especially if you aren't afraid of using a soldering iron. It is very good stock, but really shines with some very small improvements, like a better cap in one key location and some "boutique" resistors in 2 locations. All 3 of these "mods" are directly in the signal path so they should be easy to identify from the provided schematic.

It also provides variable loading on the fly with the flick of a knob and 3 different gain levels.

I also recommend the Hagerman Piccolo. You can buy it already made from Hagerman.

http://www.hagtech.com/piccolo.html

Dear Lutenist: That VDH cartridge is very good one and IMHO to shows at its best it needs to be " surrounded " by the right/best analog audio links you can achieve/find.

IMHO that Croft you own to process the BB very low and critical cartridge signal made more " damage " that good to preserve the cartridge signal integrity.
Maybe could be better in favor to achieve a more real/true cartridge quality performance make a change of that item for a better unit that can honor and make justice to that top BB cartridge.

Add a SUT to that cartridge signal processor IMHO could be a big mistake. Of course that what I'm posting here depend of what are your targets on quality level perfomance level and if you want to herar the BB like a real/true BB or just simple hear it with a lesser lot lesser quality performance that what the BB can/could offer.

Regards and enjoy the music,
Raul.

I can vouch for Fidelity Research FRT-3G as excellent and very musical transformer for its price. Very versatile.