Baker69

Hi guys, I have an LD150 (which I use mainly for rehearsals) and an LD400 which is my main gigging amp. I was wondering if it possible to use both amps at the same time? The LD400 has a pre-out socket on the back, does anyone know if I can connect this into my LD150 at all? I would be interested in trying both amps together if it's possible. Cheers.