Hi guys. I'm in need of some help. I finished building my Amp15 today. I powered it up without the chip or the large caps, and everything looked OK. Rail voltages were in the right place and the 5V was OK. So, I put in the chip and the large caps and powered up again. I put the jumpers on JP2 and JP6. The red LED was on. As I put the jumper on JP1, the amp did not unmute.
I turned it off, let the caps discharge. I noticed D3 was a bit hot - too hot to touch for more than a second. Is this normal?
Next, I checked the solder joints on the chip and powered up again. This time as I was measuring I measured the rail voltage on Ch1 output!
Any help would be appreciated. What should I try next?