The key to the TH is IMHO the Drive control, which is really badly mis-named. Go back to like page 92 of this thread for an excellent discussion on how the Drive control works. At low levels it adds a touch of tubey-ness. Then as you turn it up it rolls off the very low end and starts to roll off the very high end. So it is both an High Pass Filter (rolling off the extreme lows) and a Low Pass Filter (rolling off the highs). It also adds a upper mid bump as a part of this process. Think of it as eliminating the rumbly low noises (and you can then boost the actual low frequencies that you want) and also eliminating any undue harshness from unwanted highs. It is really a strange but useful control. Not a typical "Drive".
I normally start by adjusting the Drive first, keeping the Gain off or very low so I am very clean, then adding Bass, and adjusting the Mids and Treble as needed. The Bass seems to be centered on a very low frequency, which I like.