I have a Rogue Magnum 99 also. It’s suffering the same issues that you have But only on the left channel. I do not have an amplifier as I use amplified speakers. I live in the Colorado foothills. We get a lot of Lightning, even in the winter. (2nd only to Florida). Our grid system when struck by lightning, turns off for a split second and then immediately back on. Guessing that’s not good for sensitive electronics. I sent it to my local shop, who are quite good. They could not hear popping. They charged me $60 for diagnostics, but could not even hear it. So I send it to Rogue and had it “Supered” while it was there as the repair cost is $250. ($600 for the upgrade which included the repair) ALL good! Fantastic!
I ran it for a week. And was awakened at 2 AM to very LOUD popping and no signal. (Oops-maybe lightning? see my other recent post on the same topic-LOUD popping on Rogue. (Thank you all again that offered advice). I had that repaired by my local Audio repair shop. It’s still suffers, again, from fizzing and tapping-sounds like Fred Astaire with canastas.
My repair person said he can’t fix it because he can’t hear it. I’ll bring in my Focal speakers, maybe that will make a difference at his shop.
BTW I really noticed the changes with the upgrade. Worth the $. It will probably have to go back to Rogue again. $200 shipping plus the repair. Ugh!