Most preamps give you that option already, so we didn't think it was totally necessary to add one.
Adding that option would require a hardware change, so we're not exploring it at this time.
Dave
TWA
A few of my guitars have K&K pickups and I don't use the preamps.
With the appropriate Master Gain and Notch filter settings, I'm able to EQ the signal into the TWA.
Dave
TWA
Robert Epprecht