Hello!
At first, i think this is my first post in this forum.
So, i work as a backlinetech and have been using Kempers for a couple of years with different acts. I finally bought myself one last year (a kemper power rack) that i use as a "spare amp" for all acts i work with (profiling their amps) and usually give a linesignal to my FOH guy.
There is one important question i need to get an solution to. I havnt had to try this since it all works. BUT here is one livesetup im a bit concerned with...
One band im working with at the moment uses a great frickin sounding Fender Tonemaster 100W with a 2x12 cab running on 8ohm. Thing is, noone is alowed to maintain the amp or switch the valves (they have been running for 10years or so..) when it is working. There is a long explanation for this... And i just got in 1 year ago with this band so you can probably get that im a bit nervous here... i dont want to rely it works til the band splits up.
Here is the signalchain. Supersimple.
Guitar -> pedals -> splitter -> (A) Tonemaster (B) Kemper
Of course ive profiled the Kemper and this is mainly the signal my FOH guy uses but mixes in the original amp whenever feedback is beeing used with all the gnarly fuzztones beeing in the chain. (must say, im supprised how good the Kemper takes the pedals...)
Problem here is that the FOH is really happy with the linelevels from the kemper while the tonemaster is going wild and loud on stage.
My plan B if things go really bad, is to use speakercable from my kemper if the tonemaster amp dies during the show. However, the signal is not that loud and i cant turn up the volume since it will change the levels for the FOH guy. Why is this a problem..? The guitarist is oldschool and is by now halfdeaf. He didnt like the fact i have a "blinking devices" AND a rack on my station on my side but understands that i know what im doing. I (32 years old) will not be telling a 69 year old how to do a rockshow... im just the guy who fix problems if you know what i mean.
SO, how can i change the volumes so i can get a proper volume thorugh the cab (which would work more as a monitor if things blow up..) without blowing the cab?
Is there any way to have 2 different volumes out from the kemper making my linelevels L & R at one volume while the poweramp out is getting a louder one?
I dont want to hear any, its not possible beacuse you can just get another device or a splitter taking me to another device that will boost my volumelevels. It just has to work.
I just need to figure out what is working and how to do it in the most simpliest way.
Is an active speakermonitor the only "right" way with current setup?
FIY: No, we dont put in the guitars in his front monitors. Thats JUST for vocals... 
cheers!