So I finished installing my Amp 6 Basic a month or so ago. Everything was fine for a while. Now when I turn on the amp, it makes this horrible, loud screeching sound, similar to nails on a chalk board, but much louder. It used to make the thumping sound, when turned on, but that didnt seem like much of a problem.
It will only make this sound if it is plugged into an MP3 player/source. So say the amp is OFF, then plugged into an iPod, and then turned on, it will make the sound. Also, if the amp is not plugged into a source, like an ipod, it wont make a sound while it is turned on, but if I then plug it into a source while it is still on, it will make the sound while the plug is being inserted to the iPod.
Some facts about it that may help narrow down the reason why, although I cannot figure it out myself.
--The amp has been charged with an insufficient AC-DC adaptor, it is rated at only 200 mA MAX.
--The amp is used to power a boombox, so the amp is permanently installed to a 12V, 5 Amp hour SLA battery.
--The amp has an on/off power switch wired to it, but it does not go to the mute function (there is no mute function, the way it is wired), instead the switch cuts the power directly, so the switch is in between the battery and the positive terminal on the amp. It is worth noting that the amp used to make the thumping sound when turned on, since there was no mute function, but now it is just a very loud screeching sound, with no thump.
The only thing that I can think of is maybe the battery is not charging fully? Also, when I run the amp now, it cannot play at full volume without the sound going in and out of play, every few seconds.
Also, is there any chance that by not having the mute function working, that the surge of power directly to the amp may have screwed something up?
Any help would be very much appreciated, this is my second amp that I have had problems with, I am hoping that I don't have to buy another....