I had problems with intermittent noise with my Line 1. Turned out to be a bad tube. I would definitely check that out first before sending it in for service. Good Luck.
Sonic Frontier Line 2 Preamp Noise
I have been using a Sonic Frontier Line 2 Preamp for almost a year (bought new from Upscale Audio) and it sounded great until recently. Currently, there are noise coming out of the left chanel and I have narrow the problems down to the preamp. Does any body know what causes this problem? I did replaced the stock tubes with NOS recommended by Kevin of Upscale Audio. Could it be a bad tube? Any help is greatly appreciated. Thanks.