Noise Harvesters - Where to go from here?


#21

Do you have LED light fixtures or bulbs in the room? They can be a source of “Buzz.”
Paul had this issue when PS Audio moved into their new building. Thay had to replace some of the LEDs.
And, you may wish to check the Satellite ground outside.


#22

I do have LEDs in the room - LIFX color changing bulbs, but the “buzz” occurs whether or not they are on. For them to work, the switch must be on - is it enough to turn that off and test or do they need to be unplugged?


#23

Hum stays the same volume regardless of turning up the volume on the AVR.


#24

Paul, can you jump in here and tell your experience with the LEDs and the new Music room One–the one with the IRS?


#25

Flip the breakers for all ceiling lights and any wall outlets you don’t need for your system. The LEDs won’t make any noise unless ON (energized) but the switches can if they have dimming capabilities. Killing power at the breaker will ensure the circuit is dead.

If the ‘buzz’ goes away, begin turning each breaker on one at a time. You may have a bad switch or bulb, or not.


#26

In that case my guess that the source of the noise is the output sections of the AVR, this is anything starting with the DSP, output of digital volume control (maybe part of DSP) and analog gain section. If it is a low frequency mains kinda noise, then we all may guess what it is, but if it is some sort of higher frequency hissing sound as if air escaping from a bike tyre, it is rather a signal circuitry issue, interference, bad internal connection, etc. Just out if interest, is it possible to set your AVR to all effects, EQ and DSP off, some AVRs call this Direct mode, or Stereo mode… Does this reduce the noise? The noise could be a result of the DSP.

Some transformers can physically vibrate making a hissing noise or a buzz through a chassis into a table. Lifting or moving the device can alter it.


#27

A very interesting thread…


#28

Just for your interest. I had 2 speaker crossover inductors of 8.2mH, 1ohm (solid copper wires of 3mm! OD) that I placed inline feeding the PP and to my surprise, both channel speakers went buzzing at about mains frequency. With same setup bypassing PP, it is all quiet. Not sure what it means :slight_smile: Just sharing.


#29

Sorry for the delay - work has been busy and what little spare time I’ve had has been spent with the kids.

I got around to unplugging my DVR HDMI cable and the coax and that didn’t solve the issue, so I went through the process of unplugging all devices and then reintroducing them to see when the hum would pop in. It preliminarily appears it’s coming from my TV. I ran out of time to thoroughly test to see if any of the rest of the devices contributed to the problem, but could definitely toggle the hum by plugging and unplugging the TV.

The TV has its own outlet but I think it’s on the same circuit as much of the audio equipment (the 15 amp circuit).

How on earth does this get cured?


#30

Out of curiosity, does the TV cause hum only when powered on? Or also when powered off?


#31

You mentioned that you have a 20A circuit.
Is it dedicated for audio only?
Does the 20A circuit run to the main panel with no interruptions?
Is the TV on it or another circuit?
When I moved my 55" monitor from my 20A circuit to the 15A, I noticed no change in picture quality. So the monitor remains on the 15A circuit with all other non audio (which was my original intention).
Suggested test, if you have another TV switch them and see if the test TV produces hum.
Best
Chas


#32

Right now, the 20A circuit is not dedicated to audio only. It has a mix of devices and the electric fireplace.

I believe the 20A circuit runs directly to the panel with no interruptions.

I believe the TV is on the 15A circuit, which is shared with a mix of devices, including 2 subwoofers.

In addition to all the testing, I just think it would be prudent to move the audio equipment (Marantz, Parasound ) to the 20A circuit. That would separate it from the TV, which also has the two powered subs (4000W amp in each) on the same 15A circuit. What to do with the rest? PS4, Directv, Bluesound Node 2i - should that stuff try to go onto the 20A circuit, as well?


#33

Have you isolated the source of hum? Was it the TV? You mentioned that you could toggle the hum by plugging and unplugging the TV. Are you unplugging just the TV or the cable power box, or both?


#34

Unfortunately, still not isolated. I had everything stripped down and unplugged and was able to toggle the hum with the TV, but had to rush and put everything back together for an event, instead of incrementally adding components back in.

Now, if I plug/unplug the TV (just the power) the hum decreases too a much more tolerable level, but it is still there - so there must be something else contributing.

I did try unplugging the coax from my DVR and the HDMI cable running from the DVR to the Marantz - that did not help.

When I get more time, I will get everything unplugged again and start adding in a piece at a time to see what is contributing to the hum in addition to the TV.


#35

Also, to answer JeffofArabica - the hum remains the same level whether or not the TV is powered on or off.


#36

I think most of the new TV’s are in some sort of standby mode whether powered on or not. I think they have to be unplugged to be completely off.