Hi there, i just changed my factory BOSE stereo and replaced it with an Alpine HU. The speakers all work fine as i fitted an BOSE amplfier adaptor thing. But when i switch the HU on/off, or change equalizer,put MX on/off. It makes a loud sound like the HU has just blown or the amp has switched off. Ive been told that the sound is coming from the cars built in amplifier but some ppl have also said it is a common occurence in alpine HU when replacing a BOSE stereo in Audi cars with the Alpine one. Anyone had the same problem, or have any solutions for this? will be much appreciated!!