Plug the right channel cable output from the preamp into the left channel input of the amp and vice versa. This is just switching the channels. If the left channel output from the preamp is faulty, the noise will shift to the right speaker. If the left channel of the amp is bad, the noise will stay in the left speaker.
ARC Ref 3 and ARC Ref 110 tubes
I have a ARC Ref 3 and Ref 110. I am getting a crackling sound out of the left speaker. I am assuming I got a bad tube somewhere. I tried replacing the Power tube (6550C) in the Ref 3 but I still get the crackling sound out of the left speaker. I got 1500 hours on the other tubes in the Ref 3 and 1000 hours on the tubes in the Ref 110. Is there a way to narrow down which tube might be bad without playing a chess game of swithing tubes all around? It seems to me my system has also some slam loss.