As a guy who has spent more time behind a mixing console that behind a bass on stage, I always loved the DI sound of Aguilar amps. Dead quiet with appropriate levels. That low mid emphasis was pure magic out front.
Yep. When you remember that the TH amp is actually the TH DI with a power section things start to make a little more sense.
The "Drive" is actually a variable version of the AGS, which is like a cab sim - which kind of does the work of setting the EQ at a starting point that sits right in the mix with a kind of classic bass tone that just works.
As you turn the drive up it kind of starts off as a LPF, then starts getting into adding a HPF, then starts getting into pretty serious HP/LP-ing and adding a big upper mid focus, all while adding gain.
Once you have the AGS (or drive) going, it totally changes the nature of the gain control and EQ section due to the added gain and baked in EQ curve.
The gain control becomes like a distortion control, and that upper mid thing just makes it cut.
You kind of have to start using the treble knob to go after the upper mid once you get to that point.
The bass control is centered at 40hz - well, 40hz is seriously attenuated, and the nature of that control is changed.
It stays pretty flat from like 200 - 1K, so you can see how that mid control from 180-1k becomes your most powerful tone shaping tool.
It's a very cool design, but not if you don't know all that is happening or you think that the "drive" control controls the level of drive - which I think almost anyone would associate with some kind of dirt - as in "over drive."
Or you can keep the drive or AGS off, and just have a kind of regular old, pretty clean amp with a fairly classic design.
If you are looking for huge bottom end, and supper extended top end, this is not the amp for you - fair enough. But it's a great amp, and that AGS eq curve kind of works well in a mix with blues, rock, rock-n-roll country, roots, pop, etc... just a good classic bass tone.
@KJung used to describe it as the kind of the post mixed and mastered bass tone that you hear on thousands and thousands of classic albums. It's super familiar and works in the context of a mix. But ya, it doesn't do everything - that's why Aguilar has the AG700, and why it's a good thing there are a million different amps and tone shaping tools out there.