I was listening a couple of weeks ago and the sound quality suddenly improved in the left channel. I am absolutely sure I could hear it clearly as I have been training my ears for nearly 60 years to listen critically. I got up and looked at the arm and cartridge and then noticed a fly had landed on the left-hand monobloc, probably wanting to keep warm or dry out.
I have caught some more flies since then and I'm going to be packaging them at $199.99 each. Those with monoblocs will require two.