Al I can say is that my 561M does have a cooling fan fitted - M fitted it when I was having problems with the main composite out when warm. That fault was since fixed.

Interestingly, with MConfig set to only switch the fan on when warm, it has so far *never* come on. With it on though, I do find the noise intrusive.

Afraid I am not going to volunteer to take my 561 apart to see how connected, but a friendly email to M might get an answer.

HH1 Photo 34. 598DP, 504, 518, 561(M), DSP5000, DSP33C, DSP33
2nd Room: 541, 555