Panel would be expensive. Try checking replacing the input bipolar lytic and the small 0.1uf cap somewhere midway between input and the panels. Sorry I forgot. Been too long. That fixed my 989.
Quad Esl 2905 reliability issues?
I have owned a pair of Quad 2905 for six years problem-free. These are my favorites amongst the high end speakers I have owned so far. But lately one of the panel start to buzz and pop 30 minutes into my listening session. Does it mean that I have panel failure? I am puzzled because I am sure I did not over-drive the speaker.