Sound issues because of amplifier?

Hello, 

I'm using Traktor & the S4 for a while now, but recently invested in a new amp (Nuprime IDA 8) & speakers (Triangle - Elara ln 01) and face some sound issues that I can't resolve, and that I didn't face in the past (previously connected to my home cinema amplifier + speaker). 

In fact, it seems that traktor suddenly suffer from some 'lags' and the sound pops & cracks (a bit like a very old vinyl) often (4 times per song, even when just playing the song, not doing anything else). I checked if an increase the USB buffer or the latency would help, but no improvements. It's not the cable either, and it still works perfectly with my old amplifier. 

On this amplifier, I don't have any option (like "direct sound") that would allow me to minise the audio processing. Any idea what I could explore as potential solutions?

Thank you in advance for your help

#Others_Dec_2018