I recently bought an old NAD C300 off ebay. All was fine at decent levels using my crappy onboard soundcard on my PC until i put in an old Sound Blaster Audigy eX, now everytime i turn it up it swtiches to standby and i have to turn it off and wait a few minutes before i can turn it back on again. Switching back to my old soundcard is better but that now switches the amp off at certain levels. it never did before. Can anyone help?! Thanks