I have acquired a Line6 bass POD pro, for several reasons that I won't go into and really are not germaine to my question. My main amp is a (pre-Fender) SWR 350X head and a SWR Workingmans 4 10 cabinet. It has been a solid, reliable and good sounding rig up until the addition of the POD pro. With the addition of the POD pro, my sound has lost fullness, sounds thin and sustain appears to have diminished. When I use the POD with a set of headphones it sounds great. I am running my bass that is equiped with a Sadowsky passive split P pickup directly into the front input on the POD, the modeled output on the rear of the POD into the active input on the front of the 350X. I have used both the passive and active inputs on the 350x and the active inputs sounds slightly better. Could it be because the 350X has a tube pre-amp that is mucking up the sound? The preamp and tone controls can be bypassed and it can be used just as a power amp. I tried this too. It sounded a little better but I lost some if not most of the SWR tone that I have come accustomed to as well as some of the functionality of the head. Anyone else encounter anything like this? And if so what did you do about it. I haven't spent a ton of time trying to dial this thing in but enough to be frustrated.