Tube Preamp with adjustable gain


I'm seeking suggestions for a good tube preamp that has adjustable gain for amps that vary in their sensitivity. I have 2 or 3 amplifiers that I like to switch for a different flavor and find my current pre is limited by only 1 setting.
frontier1
Th ARC LS5 MK I and II have a 30/12 db switch. It's only got balanced connections though.

The Audio Research LS25 and LS25 mk2 have an adjustable gain setting. There is a knob on the front panel to set the gain for low, medium or high. It is also an excellent sounding preamp.
Please correct me if I am wrong but I believe the Rogue Hera or Athena have stepped gain selections.