Help with hiss


Hello Friends,

My speakers have developed an audible hiss that I am trying to chase down. The hiss can be heard from across the room and while music is being played. Sometimes, the hiss is pulsating and sometimes constant. It occurs at all hours, perhaps less so in the early morning. Sometimes there is no hiss at all and everything is silent. It is an intermittent issue that is unpredictable.

My speakers are powered by mono block amplifiers. Both speakers exhibit the exact same behavior. The monos are plugged directly into the wall outlet. I also plugged them into a PS Audio AV Power Center with no relief. I changed power cords with no relief. No other piece of gear is on, although all are plugged in and some are in standby. I turned one mono off of course stopping the hiss in that speaker. The other continued to hiss. In reverse, same result.

This is not a “hum” (like from a ground loop). It is the same hiss that you can hear with your ear next to the tweeter but much louder.

I’m happy to answer any questions at all to help me resolve this. Thank you in advance.

 

forestg

Assuming the hiss comes from both speakers, then it is not your speakers or your amplifiers.  It comes from further upstream, a component that processes both channels. 

I would guess your preamp.  

@soix Thank you so much. This is definitely a drag. It does happen at night, but my listening may start before the hiss starts. Once the hiss starts, it’s pretty obvious. Even my wife noticed it. I had feared that it might be something in the grid. My neighbor had recently built a wood shop. When I heard the hiss, I asked him if he was using any of his shop tools (sometimes the hiss sounds like a saw starting up). He denied using anything in the shop. It also occurs when he’s not even home.

@ditusa  Since you ask, I’ll assume it matters….Odyssey Audio Kismet Reference monos and Odyssey Audio Kismet monitors. Flawless performance for years. Thank you!

You said that your amps are plugged directly into the wall outlet.  What else is on that circuit? Have you tried unplugging everything else that's on that circuit.

I installed two dedicated circuits for my gear. One is used for the power amps and the other for the rest of the gear. Noise was reduced to virtually zero.

Good luck.

@carlsbad2  I had given that some thought, and I agree that it is likely upstream from the amps/speakers. Question: my preamp is a tube pre that is not on or in standby mode. It is plugged in, but fully “off”. Could it still create a problem? Thank you!

@nd1der  All the rest of my gear is plugged in to a Brick Wall, which is plugged into the same circuit. This includes the Mac laptop that I use for steaming. Knowing that computers can cause issues, I unplugged that from the Brick Wall with no relief. I’m not sure if it’s on the same circuit, but my internet modem is in the same room. Concern that might be an issue, I turned off and unplugged the modem with no relief. Thank you! Keep it coming!!