[TenTec] Jupiter tx bandwidth question

[Piper925]

Hello all. After deciding to jump on the dsp bandwagon, my choice will be
the Jupiter.
After looking around I think it will be my
best bang for the buck.
 Question is, I've heard tell that the tx bandwidth
is only adjustable on ssb. Can anyone give me a
little insight on this? And what would that fixed
width be on other modes? I realize that on a
crowded ssb portion of a band, 3900Hz is a bit
much. While in the am windows this is a
comfortable setting.
Thanks in advance,
Tom   n1ogc