Used Nordstand 2b+ bass pre 4b, I believe it's Volume(pull passive), Blend, Bass and Treble, all pots work as they should, just pulled from my 86 Fender Jazz Special and replaced with the 3b+4b! Sounds crazy good!
Unfortunately, I have found that the volume pot is statically in and out, I am willing to drop $125 on this, since I thought it was just dirty, but it's rather going in an out after a good amount to spray. Once its turned up past 3db it stays very clear...