Denon Amp Thunder Noise Diagnosis

My Denon AVR drives a home theater system, and the moment the amplifier powers up the speakers erupt with a rolling, thunder-like rumble. The noise stops only when the unit is switched off. All speaker wires, RCA leads, HDMI runs, and power connections have been double-checked and seated firmly, so loose cabling does not appear to be the culprit. I’m looking for an experienced audio-electronics technician who can come on-site, trace the fault, and advise on the fix—whether that turns out to be a failing power-supply capacitor, a grounding issue, or something deeper on the amplifier’s main board. If parts need ordering, I’m happy to approve them once the underlying cause is confirmed. Please let me know: • Your house-call availability in the next week or two • Any diagnostic tools you typically bring (scope, multimeter, ESR tester, etc.) • An estimated timeframe for pinpointing the issue The end goal is simple: silence the storm and restore clean, balanced sound to the theater.

Project ID: 40294385

Location: Doreen, Australia