This is normal, so be careful with this switch!

The "Volume" knob on the 896 has two settings controlled by the toggle switch next to it. The "up" position labeled "Main Out + Phones" allows the Volume knob to control both the Phones jack and the Main outs on the back of the 896. The "down" position labeled "Phones only" means that the volume knob will NOT control the Main Outs on the back.

A common misunderstanding is that "phones only" will turn the main outs OFF. That is not true.

When set to "Phones only", the Main Outs default to +4 dB outputs with no attenuation from the volume knob. So the main outs will essentially be running at "full blast".