The box on the mid-pot determines the boost/cut frequency. The typical ones are 250, 375, 500 and sometimes, 800 Hz. My Classic has 250, which adds a lot of low thickness. The older mid-boost modules are wrapped in copper foil and can have a capacitor and/or resistors hanging off them, to modify the mid or "added" high-frequency a bit more. On the TCT, the very top range of the mid boost has a treble boost as well, you should be able to hear it, if you leave the normal treble boost flat. According to the spec sheet, the new TCT and mid-boost modules have this as well, not just the original ones.
Cheers,
EG[/QUOTE
Yes that's what my two Tobias's had the mid break out box wrapped in copper soldered to the control cavity centered at 250hz.