Took me a long time to circle back to this and get it resolved but it's done now. Thanks to your help, I went with the Panny FC caps and got the installed a few days ago. I finally had time to test things today and was at first dismayed. When hooked up, the audio coming out of the speakers was terribly distorted and buzzy. Thinking the repair had been botched somehow, I called my friend the electrical engineer and asked him what other problem might have existed. He asked if it sounded distorted to me or if it sounded like half the waveform were missing. Upon thinking about that question, it did sound very much like half the waveform was missing. I poked around inside the chassis, trying to find something that would give me an audible crackle. I couldn't find anything.
Now, a small digression into some necessary backstory. When I first bought this power amp back in the early 2000s, it was for use with a Foreplay II. The FPII had, into this overly-sensitive amp, too much gain and too much noise. So, in addition to building the Sweet Whispers in the -20 to -50dB configuration, I hacked up the small cable inside the power amp that ran from the RCA input PCB to the main amp PCB and added 10dB L-pads at the inputs to the main PCB. After doing so, I contacted Cambridge Audio and asked if I could obtain another unmolested cable in case I ever wanted to go back. Fast forwards to last month and, in the midst of acquiring and rearranging components of my stereo, I had this power amp hooked up to a solid state preamp. Since I no longer needed the 10dB of padding, I swapped to the virgin cable Cambridge had provided me. When the amp suddenly sounded terrible, I re-opened the case and noticed all the bulging and leaned over caps and figured that was the problem.
So today, after failing the test playing, I opened the chassis back up and looked for possibilities. Looking at the PCB, I quickly realized that the fact that I could hear the distortion in both channels meant that there were VERY few possibilities for the failure point as the only pieces the channels share in common are the cable that carries the audio signal from the RCA jacks to the board and the toroidal transformer on the AC mains. Everything after that was a dual mono configuration. I couldn't think of any possible way the tranny could fail that would result in buzzing. As far as I know, the things either conduct or don't. So, impossible as it seemed to me, it had to be the small cable Cambridge had provided. Swapping it more out of pedanticness than actual expectation it'd do anything, I buttoned the chassis back up, tested again, and was rewarded with completely proper function and possibly even a little better performance than I had a month ago (not surprising considering the 8 failed caps).
I still don't understand what you could be wrong with the little internal interconnect cable that would lead to it sounding like half the waveform was missing, but it's obviously the problem.
