I'm helping a friend of mine putting together the AMP6-BASIC, and I've come across a few issues and have questions.
1. In bag no. 2 the resistors R5 and R6 are suppose to be 56 Kohm, but looking at the color code, the ones provided seem to be 82 Kohm (grey-red-black-red-brown). I don't have any equipment for measuring resistance available so I cant say for sure, but this can't be good right? Bag no. 1 includes two extra 22.1 Kohm resistors which can be used for setting the gain to -1 V/V, but I think the amp will be used with an IPod so the -2.5 V/V gain would be desirable.
2. How do I tell the polarity of the diode D1 (the one that provides polarity protection for the power supply connection)? In other words, which end of the diode is plus and which is minus?
3. Looking at the PCB, the end of D1 which is connected to the fuse holder should be plus. Is that correct?
4. According to the instructions the sleep/mute jumper or whatever it is, has two pins. But it actually has four. I've searched the forums and it appears that this is a question of different revisions of the board. But I'm confused. Can someone explain exactly what these jumpers do and if they should be in place or not when the amp is in use?
5. The two jumper connection pins closest to the edge of the board seem to be connected to ground so I'm guessing the jumpers, if in place, should be placed perpendicular to the closest edge of the board. Is that correct?