Hello, I'm new to this forum, but I have been knowing this forum for a few months. I have researched a lot on this forum and I gotta say that this forum is absolutely amazing. Anyway, I have a brand new GK-Mb115 combo amp. Bought it from MF, received it on January 5th, 2012. When I first received it, I noticed a very high pitch dat-dat-dat sound from the amp and soon I figured out that the amp was catching my iPhone's signals and turning into the annoying dat-dat-dat sound. As I expected, if I turn my iPhone into airplane mode or put my iPhone far away from the amp, then the high pitch sound goes away. Check this article: Why your clock radio is all abuzz about your iPhone - O'Reilly Broadcast I sent an email to GK, MF, and went to the nearest GC so far. MF said if there's any problem with the amp, then they will happily to exchange or refund it. GC said it might be the shielding problem or just this specific model's problem. GK said "I'm at NAMM so don't bother my happy time" (just kidding. GK said "I will be out of the office until 01/25/12 due to the NAMM show. I will be checking emails on a limited basis and will respond to you as soon as possible.") Well, apparently I'm waiting for GK to give me an answer. So, does anyone have the same issue as I have? or does anyone know how to get rid of this annoying high pitch dat-dat-dat sound? Thank you for reading and have a nice day.