This is spot on for what is causing the problem:
"The tweed-man, ac15, plexi, supra, vari-plexi, and new tweed all have this."
"POD HD Amp Models, which can also be a source of disruption. To minimize this disruption, limit the cases where you switch between one of these Amp Models and one of the other POD Amp Models."
RTFM - Read The Freaking Manual
To bad it happens on the DT50, does not happen on the DT25 which is why I made an assumption, however assumption means make an a$$ out of......
Thanks for all the replies!!
I really like those amp models but cannot afford during gigs for a loud pop even if between songs just to be able to use a handful of amps. I have worked around them with others......
BTW part of what gives these amps their "character" is the cabinets they use, so assigning the Supro Cab to say a GibTone will produce similar but not exact results. Same with the new 8xTeed in the new vintage models pack, it can impart some of the sonic sound but does not total replicate the tweed amp model........
I know people say use the preamp with a DT50, my take is use what sounds good, sometimes the preamp does sometimes the fully modeled does...