A 50 watt tube amp is gonna be loud as hell. Not sure why there's much worry for a 115 combo amp. Especially if they make an extension speaker for it….
I'm looking forward to checking one out for sure.
If I remember correctly, a TBer with professional knowledge about amps said in some thread that a Watt is a Watt regardless how it is being produced. So I understand that as meaning that a 50 Watt RMS tube amp is as loud as a 50 Watt RMS solid state or hybrid amp.