There a many questions on this forum about the irritating noise with Code 25 and Code 50.  However, it happens via the speaker only, not via the headphone connection. The presets sounds very nice in that situation. Can you explain?

Because of the noise issue I just use the Natural sound and add FX pedal effects. No noise at all. But that is not the way I want to use the Code 25. I want to use the presets.