[quote name='dood' timestamp='1487765614' post='3242536']
The BxK and Vintage models are two different types of drive and there are a number of 'updates' shall we say for each model. For example
Vintage Microtubes - Vintage Deluxe - Vintage Deluxe II - Vintage Ultra. Each in turn have an enhanced feature set, but essentially start with a similar voice. It's similar for the BxK range too. The B3K doesn't have the full EQ section that the B7K does and the Ultra version is the latest update of the B7K, if that makes sense.
Like the MXR M80, if you turn off the drive section, the EQ (preamp) sections of the B7K, Deluxe and Ultra versions are all still running. You'll only switch that off if you disengage the pedal completely. Having a B7KU and a VM would probably be a really nice mix, though I'd be tempted to put a B3K in front of the Vintage Ultra, simply because I would kinda set the VMU to be my 'amp on the edge of break up' all of the time, then use the B3K or similar to push it over the edge.
Ultimately, I've not tried both ways round and the only way for knowing what works for you is to try it out. I know that's not going to be easy unless you can get to somewhere like Bass Direct and try out all four!
[/quote]
Maybe I have entirely mis-interpreted what you have said here but can you engage and disengage the drive section of the B7K whilst leaving the EQ running via the single foot switch?