Very bad and low volume over mini-jack

While waiting for my DAC to arrive I connected my RPi2 to the Amp with the mini-jack.
This has worked fine for some weeks. But now, for unrelated reasons, I had to reinstall the system fresh.

And now the volume of the mini-jack is suddenly extremely low. I have to put the Amp volume up to 70% to hear that there is indeed some kind of music playing. Where normally 20-30% is enough. Also what I then hear is appalling; lots of noise and cracks.

I played a little with the playback settings; but to no avail.
Also I tested the cable and the amp with another device, and they seem to be just fine.

Any tips anyone?

Did you flash the same version? Maybe some volume optimalisations took place in the meantime, and since many only use DACs, noone has noticed it just yet.

Probably not the same version; I installed the first one some weeks ago, and the one I am using now is the latest from the website.
Seems like there has been an update in the meantime.

Hopefully my DAC arrives soon…