Getting left channel blobs from Accuphase C220 phono preamp

Hi! Recently connected an Accuphase C220 phono pre to my system. Connected to it are Denon AU 300LC (RCA, main out), Adcom GFP750 (XLR, main out) and (McIntosh C22 (RCA, fixed out). Cartridges connected are Micro Benz Gold (MC, to Technics SL1200 GLD)) and Audiotechinca AT150 MLX (MM, to Clearaudio Concept), Powered on, both cartridges play flawlessly on systems as connected (self Head Amp and McItosh/Adcom), but after some time, starts giving mild to strong, intermittent or at times persistent, blobs in left channel (speaker), right channel playing perfectly as should. Eventually, left channel drops to silent on audio, and sending blobs to the speaker. Switching to CD or deck, both channels work fine. Previously I had the same experience earlier, too with an Accuphase gear (C200, now connected with a Luxman TT), which now seems to have fully subsided and playing in absolute quietness. I don't know how it remedied itself, as I did not do any servicing on that. Will appreciate if anyone has any solution to suggest. Thanks.