[akosinskiy]

Hello,

Not sure if someone already raised such topic. I have an issue with my setup since I moved to new house. There is some noise coming out of my loudspeakers when I listen them in stereo. The noise becomes much stronger when I start using my projector. If I use class D power amps with SMPS the noise would be gone but as soon as I switch to class A/B amp (I tired a few) it is back. All my devices are on the same dedicated 20AMP line. Any idea what could be done? Thanks!

[Mag]

  Static noise you are hearing might be from setting your input/output levels to max. Try backing the levels off to like 80% see if that works. When set too high or max you can get distortion, but when it happened to me, I describe the sound as a tearing static sound. Anyway if that is what it is, it can damage your speakers.

[Speedskater]

Often an interconnect cable pick-up problem.
for RCA interconnects use a coax cable with a heavy braided shield.
for XLR interconnects use a Shielded Twisted Pair (STP) cable.

[rollo]

  Is it a new dedicated line ? Check ground connection. Make sure it IS a true dedicated line.


charles

[akosinskiy]

Yes, it is a dedicated line, I run it myself from electrical panel.

[Letitroll98]

Yes, it is a dedicated line, I run it myself from electrical panel.

I think we found the problem Houston.

Sorry to be so mean, I couldn't resist, forgive me please.  But... This is where I'd look first.

[akosinskiy]

I think we found the problem Houston.

Sorry to be so mean, I couldn't resist, forgive me please.  But... This is where I'd look first.

Not a problem at all what could I do wrong? It's a short run from electrical panel to two 20A outlets, all 3 wires are installed properly, tested with a tester just in case. Any ideas?

[BCRich1]

You have a Cable Box in the system? If so try disconnecting the Coaxial Feed to the box. See if it goes away. Is the Projector on the same circuit as well?
Cheers…Mike

[TomS]

The class D amp likely has a low pass output filter around 20 khz whereas the A/B does not. Are noisy light dimmers a possibility?

[oldhvymec]

It is usually a slight voltage difference between a component's PS and another component's ability to filter properly. Modems are notorious for it. 80% of all my buddies listen to one thing from me.

The routing king!!! I have gotten rid of more noise issues by routing than any other single repair, other than having
components on both L1 and L2 circuits. I fixed a few with step downs from 220/240 to 120vac and isolation transformers too.

Can you get the noise to Yo Yo? By lifting and lowering cables does the sound change?
That will tell you if it's routing. Routing includes component location too. Transformers
in the wrong location. A/B amps? Reclock the amp 90 degrees.

A BAD cable connection or broken shielding from the move.

I wish you well.

[akosinskiy]

You have a Cable Box in the system? If so try disconnecting the Coaxial Feed to the box. See if it goes away. Is the Projector on the same circuit as well?
Cheers…Mike

No cable box. The projector is the only one which is NOT on the same 20A circuit, as I said, I have noise without it but hooking up HDMI to projector makes it much worse. When I hook up projector to the same circuit it does not become worse. I did make sure though that projector is on the same leg as 20A circuit.

[akosinskiy]

The class D amp likely has a low pass output filter around 20 khz whereas the A/B does not. Are noisy light dimmers a possibility?

There are light dimmers on a the same circuit as projector but in a different room. Not sure if it matters but the issue exists when the light are off in that room.

[WGH]

I had a computer monitor that was causing static and low hum in my stereo, it took forever to track that down because the noise would come and go.

The culprit will eventually be found. I would unplug everything including RCA cables and start all over, one component at a time. Eventually plug everything into different outlets watching the polarity.

A source like a smart phone can be plugged directly into the A/B amp, this eliminates everything upstream. Starting with the volume low, is there static?

Listen to the preamp with headphones with the amp totally unplugged, is there static?

Try different interconnects. I've been playing with stereos since 1968 and have a big bag-o-wires. I dive into the bag when I need to cobble components together and find that some interconnects don't work anymore. Interconnects do go bad, solder joints degrade and small wires break.

Try different power cords, I'm a fan of shielded power cords because I have 15 things plugged into a 4-outlet receptacle. Not all my power cords are shielded. Does it make a difference? I dunno, but the shielded power cords are a larger gauge and used on the amps, preamp and sub. I switched out cords while trying to find the source of the low hum. They don't hurt the sound and in the case of the Viborg 1501 it improved the sound.

"Then on a whim one day, I tried a Viborg MBU1501 power cable I found on Amazon of all places.(at the time priced between $100-$150 depending on length) Bottom line, the best power cable I've found for any of my three amplifiers. Since I first discovered this cable, two other friends and myself have bought a total of 12."
https://www.audiocircle.com/index.php?topic=180338.msg1895594#msg1895594
Viborg makes a lot of cool stuff, many AC members use their stuff including connectors, plugs and outlets. Click Search and type in Viborg.
http://www.viborgaudio.com/en/

[akosinskiy]

So here is the latest update. I disconnected everything from the amp (it is integrated now, the issue is still there). I disconnected all other electronics from that 20A circuit. I disconnected all other circuits in the main panel. Basically only the amp is plugged in the whole house. It is sitting a feet away from electrical panel. The static is still there, same level as far as myself and my wife can hear. Any other thoughts? Try a different leg on the mains? Kill your neighbour/hydro company?

[WGH]

I disconnected all other electronics from that 20A circuit. I disconnected all other circuits in the main panel. Basically only the amp is plugged in the whole house.
The static is still there...
Try a different leg on the mains?

Maybe. Have you tried another circuit and not use the dedicated 20A? All you need is a long heavy duty extension cord.

[akosinskiy]

Maybe. Have you tried another circuit and not use the dedicated 20A? All you need is a long heavy duty extension cord.

It was much easier - I just plugged the amp into a dedicated 15A outlet next to electrical panel which according to my calculations is on another leg. Same results Anything else I can try to do?

[Tyson]

Try a cheater plug.

[WGH]

You will probably have to find someone who has heard this static before. One thought is to record the static on your phone and upload the audio to a free online storage service like Google Drive, check the box to enable everyone to download.

So far you have tried all the easy diagnosis options. The noise doesn't appear to come from a source or interconnects, it happens with multiple amps so it can't be dirty tube pins. Is there a 5G transmitter close by? Lots of facts mixed with fiction regarding 5G so if your avatar starts wearing a tin foil hat we will know you went down that rabbit hole. Does your noise sound like this?
https://biome-living.com/sound-of-5g/

I suppose the next step (after the cheater plug) is to check for noise on the main line either at the panel or on the pole. I have no experience with this type of noise but other AC members have.

Mains noise suppression - seeking for advice
https://www.audiocircle.com/index.php?topic=162241.msg1727433#msg1727433

"Search" for "dirty" in AC, check "The Lab", "The Path of Least Resistance", and "Power Conditioning"

What electronics have you tried? All we know is they are Class A/B and Class D. I recently heard a Buchardt I150 Class D integrated driving a pair of Fritz Carbon 7 Speakers at Fritz's house and it was very nice, it didn't sound like class D at all, I would have never guessed. You wrote Class D was silent, might be the way to go. Give Fritz a call, his speakers and the Buchardt is a killer combination.

[Tyson]

Stuff like this is why I eventually bought a PS Audio P10 for my upstairs system and a couple of P5's for my downstairs system. 

[WGH]

The noise becomes much stronger when I start using my projector.

This is an important clue.

I use a Tripp-Lite Isobar Ultra Surge Protector, the isolated filter banks really work.
https://tripplite.eaton.com/isobar-6-outlet-surge-protector-6-ft-cord-3300-joules-diagnostic-leds~ISOBAR6ULTRA


Isolated Filter Banks Provide Extra Protection

    Outlets arranged in 3 exclusive isolated filter banks to limit noise interaction among connected equipment
    Blocks disruptive EMI/RFI line noise up to 80 dB that can cause equipment damage or data loss
    Combine large toroidal chokes, ferrite rod-core inductors, HF/VHF capacitors and metal oxide varistors to block interference