Problem with Supratek Chardonnay


I have owned my Chardonnary since early in 2003. Recently I have noticed that the sound breaks up in one channel when there is significant emphasis on high notes. This problem switches channels when I switch my preamp output cables but not when I switch input cables to the preamp.
I have tried switching tubes but this does not cause the problem to switch channels. I have cleaned my input and output connections. So now I am wondering if I have bad capacitor or some other part going bad. I would appreciate any input you smart folks can provide.
jimyork
Thank you - that is probably the best approach. I was just curious what I might learn from others.
I had a different problem with my Supratek and thru exchanging emails with Mick at Supratek and a voltmeter he was able to walk me thru the repair process.