power amp and guitar cab,

Yes it's really OFF.

If you want to turn the Cab Button on the front panel OFF again because you think it sounds better then go for it....choose whichever one sounds better to your ears.

Or, if you want a serious scientific discussion as to why the sound changes ever so slightly then prepare yourself for some serious scientific answers in this thread.

Monitor cab sim off and front panel cab sim off have the same function, except for one being global, the other one only for the monitor out.
No room for rocket science discussions or bat ears here.

Quote from Ingolf

Monitor cab sim off and front panel cab sim off have the same function, except for one being global, the other one only for the monitor out.
No room for rocket science discussions or bat ears here.

I wanted to say it just like ^this^, but my fingers typed something different.

Quote from plek

thanks for advice fella's, really helpful !!! its getting more like the axe fx forum on here every day

Sorry mate, didn't mean to offend you or make a fool of you.

Please, if you think it sounds different, let's keep this thread open and inquire/discuss further.
I will test this again later on, but having done this before I didn't sense any difference.

If you have monitor cab sim off and play with a guitar cab, front panel cab sim off button is useless, it makes no difference! So imho what happens is that you think that the sound changes, because if you press front panel cab sim off button it makes a pop sound!

Well, this should be rather easy to prove if true or not. Just reamp and record the same dry track with each method and then compare both clips with a frequency analyzer.

A recording would be very useful.
Also consider opening an official support ticket with your issue.
They're very helpful.