Got an used Lyr just 2 days ago. It has noticeable background noise. I'm using HD650 and AKG Kxx. AKG has louder noise than HD650. When I turn volume up the noise increased accordingly. I tried to swap the tubes(JJ E88CC), change the power cable, change the power outlet, move around and change the RCA cable, but nothing worked. The noise even exists after I disconnect the RCA cable. I searched online, looks like many people also has noise problem for Lyr. Is it possible that the tube is dying? Any suggestion to fix it will be appreciated.
first, is the distortion worse on one side or another? Swap your tube positions and see if the more audible distortion switches positions. If so, you have defective tubes, contact Schiit CS.
If not, it may be a ground loop issue. try individual swapping out all the componets in your chain to isolate the cause.
1) Check all your cable connections & make sure your tubes are seated properly. dont forget to check your headphone cables and power plug.
2) Remove your dac from your chain, test again. Leave the dac out of your chain for the remainder of testing
3) Try with a different source player & different media players on computer & different tracks
4) Try your setup on a different wall plug without any extension cables/surge protectors.
5) If a computer try a different AC cord/adapter (that was what was causing my issue)
6) Try a different amp or try without the amp.
7) Try with different headphones or try swapping the wires for L/R inputs if the noise is louder on one side.
If nothing else is the culprit, then contact Schiit CS & tell them exactly what you already did for troubleshooting