RCA interconnects range from 3 meters to 1 meter. Speaker cables are 2.5 meters.
high frequency intermittent noise
I have a noise issue that is intermittent. Here is what the noise sounds like:
https://clyp.it/4b233bmm
Here is what I know so far:
https://clyp.it/4b233bmm
Here is what I know so far:
- The sound affects all components and is compounded if all components are turned on. I have turned off my preamp, phono preamp, leaving just my mono blocks on, and the noise still appears.
- I have turned off everything and unplugged everything in the house including my dimmer switch, and the noise still appears.
- I have a pair of pro-audio monitors, self powered with class AB amps, and when I plug those into the same outlet, I hear the same noise coming through the pro-audio monitor. So this rules out my big system.
- The noise is primarily during the day and goes into the evenings, weekends too, early mornings it does not appear.
- I live in a pre-war mid-rise building. I have no ground, I'm using a Nordost QKore grounding system. This did reduce the noise floor quite a bit, but has no affect on this intermittent noise.
- I have a cell phone tower directly across the street from my building in Manhattan.
- Looking at a real time analyzer, I see peak at 2kHz when the noise appears.
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- 157 posts total
@james1969 Any chance you have a radio that is AC 120V powered? If you do try the same test Al, (almarg) asked you to do in an earlier post. (Page one) One other test you might try. You will need buy a pair of RCA shorting plugs. Disconnect the interconnects from the back of the power amp/s and plug in the shorting plugs. Check for the RF signal noise. |
I put the PS Audio Noise Harvesters on the Furman P-2400 IT to see if they would stop blinking, they did not. And when I turned on my light on a dimmer in the kitchen (different circuit), the PSNHs went crazy. So does the Furman even do anything to filter noise? The noise floor in the music has been lowered. There is benefit sonically in the music though. |
james1969 OP @james1969 My idea to try the radio was to see if the noise was on the AC mains lines. From your post it appears the noise is not on the AC mains power lines. I am not quite sure though why you didn’t pick up the noise on the battery powered radio though. I suppose the static sound of the radio off station might have drowned out, masked, the signal noise you were listening for. If the noise is being radiated through the air it could be near impossible to totally filter it out. If at all. There are line filters, ferrite beads, and filter capacitors, that are designed to block unwanted signals. Problem is one size does not fit all. You have to know the frequencies you are dealing with to filter them out. I am not sure who you would need to hire for that. Al, (almarg), might know. Part of your problem could be the long 3 meter RCA interconnects you are using. You may have to try some that are 100% shielded. That can have a down side on the SQ of system. And even though the Furman P-2400 IT didn’t solve the problem and the signal noise is being radiated in the air, the power cords that feed your audio equipment will act as receiving antennas and pick up the signal and feed it into the audio equipment. As you probably already know a heavily shielded power cord can suck the air right out of the sound of an audio system. My experience with ferrite beads on a power cord can/does the same thing. Even the speaker cables can work as an antenna and send the noise to the speaker drivers. Just curious, by chance does you preamp have a headphone jack? If you have a pair of head phones it would be interesting to know if you can hear the noise through them. If you do have the jack and the phones and you still hear the signal noise though the phones disconnect the RCA interconnects from the preamp that feed the amp/s. Are these interconnects the 3 meter long ones? Jim |
- 157 posts total