I just got a Behringer micromon ma400 headphone amp, $24.00, as per someone's suggestion and it improves the tone when using headphones withe the mark V 25. I have audio technica ath m50x headphones. It cuts out the unwantef distortion fizzle ( was hearing it on clean channels too) because you can set the mark V 25 master volume low and turn up the headphone amp. Still experimenting...