Disklavier

I'm sure I'm missing something here, but in silent mode with my headphones only one side works. In other words, there is a 'balance' problem. However, I can't find any way of adjusting this.

The puzzling thing is that if I select 'voice' and choose any of the other voices, both sides of the headphones work perfectly.

There are only two controls on the headphone input on the piano - volume and reverb.

Thanks in advance

Kevin