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.
This is a natural phenomenon. You can spend the rest of your life trying to figure this out. Based on the writings of Stereophile and others, this hiss is originating from your components. The noise floor is poor and this hiss is symptomatic of poorly measuring components. if your amp has gain adjustments try lowering the gain. Stereophile has written about this before.
good luck.
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Hiss is random noise generated by active electronic components. It is not induced nor due to grounding issues like a 60Hz hum. Nor is it impacted by cables, AC power or external electrical components. Are you familiar with ’gain staging’? Basically, your amps are running at max gain and your preamp isn’t required to run at a level very far above its noise floor. Solution: Reduce the input sensitivity on your monoblocks and drive your preamp harder. As well if you are using a low-gain MC phono cart the signal to noise ratio of the MC preamp may be 10-20 dB noisier than a MM input. You can check this by switching to an unused line input, and if the hiss drops, that’s the contributor. The solution is the same - gain stage your preamp and monoblocks, and now your MC preamp as well, to raise the signal (variable) to noise (fixed) ratio. Gain staging is a basic survival skill in live sound and recording studios, (it was one of the first things I was taught, along with grounding theory) but is rarely mentioned in HiFi. Here’s are two good good tutorials: https://www.izotope.com/en/learn/gain-staging-what-it-is-and-how-to-do-it.html From Sweetwater Music: https://www.sweetwater.com/insync/gain-staging/ |
Ghosts in the machine…
Such an annoying problem to have. I read through above but could not tell if the problem persists with only a power cord being attached to the power amps, and the amps being connected to the speakers. From what I gathered, the RCA’s were disconnected at the preamp, but still connected to the amps? Does the hiss stay constant, or does it increase in volume as you turn it up?
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