Audiolab 8000Q pre-amp,

I have a 8000Q pre-amp that occasionally mutes itself for very short periods, (a second or two). I feel the problem stems from the source switch as carefully positioning of the switch does cut down the frequency of the fault.
Has anyone else come across this and, how did you manage to rectify it..
Regards to all,
Also check if the amp has a muting relay (like my 8000C). Malfunctioning of this relay could also be the cause.
On my 8000C the relay that mutes the output also switches the output to the headphone socket (I think), so you could check to see if the headphones are switched on when the amp mutes itself ... this would tend to indicate a relay fault.

Just a suggestion ... I don't own an 8000Q.