That's exactly what the VLE is for... a kind of 'on the front panel of the amp' tweeter control. I believe this control comes directly from the MusicMan amp line that Markbass manufactured. If I remember correctly, the MM cabs did not have tweeter attenuators. I virtually never use the VPF (maybe up to 8 o'clock max to just soften the mid response a touch in some rooms with some basses), but I regularly use the VLE at low levels to take the edge off the top end. That control is very good to take the edge off the top end in a very natural subtle way... more changing the nature to the upper treble response than totally quashing it (just like an onboard passive tone control on a bass). Very nice.
Just like an onboard pre with an active treble control and a passive tone control, the interaction between the VLE, the active treble control, and the tweeter attenuator can be very powerful in sculpting just the right 'nature' of treble response you want. This is very cool with a cab like the Bergantino HT or AE series, where there seems to be quite a bit of upper mids coming out of the horn. Turning the tweeter attenuater down can suck a lot of definition out of your tone (i.e., the treble and upper mids are attenuated). Cranking the tweeter up a touch, and then softening the top end with the VLE can result in a nice amount of upper mid grind without the upper treble slicing your ears off.
Interestingly, I've moved to using the F1 almost exclusively, especially with the newer Series II Epi cabs. It's just slightly tighter on the low end, and slightly more upper mid articulate than the LMII (which results in a touch more perceived volume on the gig), which really works nicely with my instruments. The LMII is still the best deal out there if you are looking for clean, transparent SS tone, but the F1 really is something special, and that head pretty much blew away the guys at the recent GTG.
All good stuff!!!!
