My N800 sounds great through the headphones, but if I try plugging it into a line input on _any_ other device, it sounds like crap. I've tried the line-in on my truck, my home amp, an AV distribution amplifier and my 900 MHz wireless headphones transmitter. In addition to the noise during silence (but while the audio system is active), the same kind of noise also continues to a slightly lesser (but still completely intolerable) extent while sound is playing. The one exception is with a cassette adapter - the sound level is low, but the noise is gone. Apparently it has something to do with either the output levels or extreme sensitivity to impedance mismatch or both. I'm extremely disappointed, as I have two 8GB memory cards installed, and was looking forward to using it as a jukebox in my vehicles, but that's a no-go until I can find some way to work around this problem. I've upgraded the firmware twice, from 2007 to the first 2008 and now to the latest 2008, and there's no difference between any of them. I think this may be a hardware issue rather than software. Has anyone else noticed this problem, and if so, have you found a reasonable solution?
