Hi, using the WASAPI setting, as it is the one that crackles the least.

Fine for a while then the audio slows down as if I stopped a turntable while it was spinning

Using a focusrite scarlett solo.

Any ideas on what settings to use, most seem to crackle

Fixed it by cranking up sample rate

Glad it's working now. The Focusrite cards are good devices, I use the Scarlett 2i4 with WDM-KS.