I recently bought a little dot I+ tube with Sylvania 408A tube. I first listened with it connected to K702 and really enjoyed it. It is dead quiet when music is not playing or when the volume is turned all the way down. A few days later, I borrowed some Beyer DT1350 to listen with Little dot and started to hear some noises. I heard these noises when the headphone is plugged into the amp, even if the amp is not connected to any source. The noise sounds like small hiss or buzz and is very very subtle, but audible. The DT1350 is dead quiet with my ibasso D6 or IPOD directly so I know it is not the headphone. I swapped some WE 408A tubes and the noise sounds the same. I wonder if these noise is pretty normal or is the amp faulty? Like I said, the noise level is very low, but it is there when DT1350 is plugged in. Anyone can help me on this? Thanks.
Edited by andychen - 1/24/12 at 11:24am