No, I am sure the left driver is the source of this noise, I checked it with the earpads removed as well and it is somewhere down, near the cable connection. Sometimes it goes away but sometimes in some tracks it reaches audible levels so it can become rather annonying. Other issue I recently found is channel imbalance but I need to check it with the E/90 as well to be 100% sure. Sometime in the future it will be sent to KOSS but as I recently learned, from the EU it can be tricky so I might organize a loan with somebody here who is interested in hearing it, hoping that in the end I will get a new set back