It sounds like a coupling cap has gone bad perhaps. If this is in a chain with a tube pre, that would make even more sense. If that's true, consider having the tube pre looked at as well, or measure DC on the outputs with a basic multimeter.
Schiit Loki equalizer causing POPPING SOUND
I cannot figure this one out. It occurs in my (R) speaker only, upon turning on the equalizer’s adjustment settings, and then again, when I shut off or turn on the Loki. Annoying and startling on my Klipsch Cornwall Heritage pair.
Any suggestion would be appreciated and thanks!
Dave