Question I am using the Line Driver output  of the RH450 to the PA. I was wondering if  the main volume knob control what comes out of the PA or only what is coming out of the speaker. Answer If you connect the DI output to the PA, the master volume of the amp has no incidence on the level in the PA - The master volume only controls the level in the bass cab speaker(s). You can still choose to have the DI output set to
  •  Pre- Preamp : in this case the signal from your bass only goes to the PA (Line Driver output).
  •  Post - Preamp : the signal passes through Spectracomp, Tubetone and Tone controls, and preset level before being sent to the DI output
In both cases the input gain has an incidence, so it should correctly be set from start. Also the Mute function will also mute the DI output in the PA.