Hello. When playing through my Amplifi TT with headphones (Beyerdynamic DT 770 PRO 250 ohms), I have started noticing a low buzzing sound from the low A and E strings. At first I thought I had fret buzz going on with my guitar until I switched to another pair of headphones (Sennheiser Amperior) and the buzzing went away. I have the latest firmware update installed in my AmplifiTT. Maybe it's a problem with the headphones? I don't hear this buzzing when just listening to music with them though. Is there a particular pair of headphones in the range of $50 to $150 someone would recommend for using with the AmplifiTT?