There IS a problem with the NP-30 line, and this problem WAS confirmed by Yamaha USA. It's clearly another quality control issue with Yamaha. Some units have not been affected, but MANY have. I've had countless emails from other NP-30 owners here in the USA, and the UK who are having the same problem. One owner in the UK got confirmation from Yamaha UK that Yamaha Japan has known about the problem and are currently shipping parts to fix it, again showing it's a hardware problem.

A few lucky ones out there don't have this issue, but those of us who DO have the problem can tell you it's very annoying. Nothing more frustrating than a high pitch frequency noise coming from the internal speakers and output jacks. It's bad enough on the internal speakers, but when you run it through a 30W stereo amp system it's pretty much slapping you in the face.