This was in working condition about 5 years ago and one channel would drastically decrease in volume until a medium slap on the side would fix it. I then purchased another M400 on Ebay to replace it. After that, I noticed that one phono connector on the back of this one was very loose and the plastic housing was cracked. I had put off looking at it for the past 5 years. Recently I replaced the phono connectors thinking that would fix it. Now it hums loudly when plugged in—even without any input. I’m not up for trying to repair further. So I’m selling it as is.