do I need a di box or a new pa?

[antispatula]

I have a cheap 100w pa system. I plug my digital piano into it, and I put the keyboards fader at 75%, the channels input in the mixer at 75%, and the master volume is at 75%. At this level, if I'm not careful epecially with the low notes and super high notes, it distorts like crazy. Is this because it's a cheap pa system ($179 new....) or because I should run the keyboard into a di box or something before I go into the pa's head?

 

[mixsit]

You may or may not have metering on both the input/channel and master out, but the first thing would be to test for input overload first.
One way is to turn the master way down so it can not distort there. Play the offending hard notes. If it's clean you still have some input headroom to play with. But it might also mean that you were maxing out the power stage (or the speakers).
Wayne

 

[Cazzbar]

You shouldn't need a DI box to connect an electric piano to a mixer (as that's only a guitar thing)

Instead of setting everything at 75%, usual procedure is to turn the main ouput faders on the mixer right down and turn your keyboard output right up to about 90%... then on the mixer, turn the PFL switch on for the channel(s) you've plug your keyboard into... start playing a few notes, and adjust the channel gain so that the meter reading peaks just below 0dBVU. Then bash the keys as hard as you would whilst playing to check you're still not going above 0dBVU, as anything above this point and you're risking distortion. (you don't have to actually hear anything during this process, which really scares anybody else in the band as they think nothing is working ). Then switch off the PFL switch. Set the keyboard channel fader(s) and the amps to 0dBVU (unity position). Start playing a few notes and slowly turn up the main output faders on the mixer to the desired level.