This implies that the amp voicing options are "active"?
In any case, the op can use his outboard preamp in the axe fx loop with the Tube Pre option.
worked great with my Egnater M4!
Eventually sold the Egnater M4 as I eventually saw the light that the Axe can do and exceed anything my M4 offered!
AND WITOUT THE ADDED BURDENSOME WEIGHT!! ��
No, the Vintage tone stack is a passive EQ model but it has a flat response when the controls are at noon. If you want "active" EQ you need to set the type to Active.
IMO tube preamps are obsolete but I don't fault someone for wanting to use one.