hi guys. what exactly is the difference between the Vox AD15VT and the Vox AD30VT? besides that the 30 is more powerful
The 30 has a 10" speaker compared to the 15's 8" one, and the 30 has a switch on the back that controls how much power is going to the amp, which can make it quieter than the 15 if you want it to be (the 15 doesn't have this).

I think it's worth an extra 50 bucks for a 10" speaker

I think that's it