Amp: early 2000's Bad Cat Hot Cat 1x12 Combo Issue: A week ago I noticed an intermittent crackling, even without the guitar or effects plugged into amp. Turned amp off for 10 minutes; turned back on and didn't notice issue again over next 20 minutes of playing. A day or so later, after 40 min. or so of sounding perfect, there was immediate volume loss. You could still hear the guitar through the speaker, but without gain and at 10% of what it was, and it wasn't responding to the master volume knob. I put the amp in standby mode while I removed the guitar cable from the pedal board and plugged directly into the amp, thinking it could be an issue with my effects. Turned standby off, and the amp was back at full volume and gain, but the same crackling noise mentioned previously started, so I turned the amp off. The next day, the exact same scenario occurred. This time I timed it to exactly 45 minutes after starting to play, and again there was immediate volume loss after sounding perfect, so I hit the standby switch and heard a fading sizzle like bacon frying on a pan, then turned the standby off and the volume and gain were instantly back. I hit the tubes again with a pencil and heard no crackling or noise. Tubes: The power tubes are Ruby EL34s that are 14 months old with about 250-300 hours on them. They look fine, even at the 45 minute mark. No red platting or arcs when the standby is switched. No audible sounds when the speaker is on and I hit them with a pencil. Recent work: After 12 years of working flawlessly, in 2018 my amp sounded like **** and one of the tubes began red plating. I brought it to a fairly new tech who was under the supervision of a veteran tech and electronics engineer who found a shorted coupling capacitor feeding into the red-platting tube. He replaced the cap and the bias resistors it fried and it's corresponding capacitor on the other tube socket due to the stress from the original shorted coupling cap. He also put in the new power tubes. Worth noting: The tech noted that my power chord was very loose fitting on the AC output and could fail. I'm still using that chord, but as I said, their is a volume loss, not a volume cut-out like the amp is intermittently losing power. Another note: while this could just be in my head, lately I've felt that the tubes and the area around the tubes has been getting hotter than I remember, but I'm not 100% confident that's the case.