2. amps-preamps
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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
perkri
892 posts
 

Here’s another thing to try. 
 

when amp in, connected to speakers with nothing else connected, try holing into the rca connectors and see if the noise subsides 

 

other thing to check, is the DC on the speaker outputs if you have a multi meter.  

boxcarman
333 posts
 

Assuming you have backup equipment, take the amp and preamp out and try your backup amp setup.  One other thing, I had a tube phono pre amp that after 30 min. or so, began to hum until it was unplugged.  And yes, it was well grounded.

ditusa's avatar
ditusa
1,766 posts
 

@forestg Wrote:

I’ve owned this system in its current iteration for a few years now. This hiss started maybe 2 or 3 months ago, but I lose track.

How old are the two amps?

Mike

audphile1's avatar
audphile1
4,363 posts
 

Speakers do not hiss. Amps, preamps and source components do. Especially tubed ones. Disconnect your preamp from your amp and turn the amp on. If you still hear hiss thru your speakers. your amp is the culprit.

If the hiss stops, power it all down, connect your preamp to amp but don’t connect sources to preamp. Turn on the preamp, then amp. If it hisses now, it’s your preamp. Repeat this for each link in the signal chain. 

audphile1's avatar
audphile1
4,363 posts
 

Also, you stated the hiss is constant no change in hiss loudness with volume variations, that says it’s the amp. If the source for the hiss was upstream, the amplifier would amplify it, as it does with any incoming signal. So your amplifier is most likely the culprit unless your speakers work like antennas and pick up static from some unknown source which is extremely unlikely.

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