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.
coolsound

Showing 1 response by rslifka007

Dear Coolsound, Suggestion: Interchange the tubes. If th problem is then in the right channel.... you've found the cause !!! tube...or tubes. Let us know. cordially, Richard