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Really bad static/noise problems


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As the titles says i have really bad static/noise with my speakers.

I have a Chord Mojo connected to my Desktop PC which in turn is connected to my amp, which drives my speakers.

When set up this way though i get unbearable static that is a pretty damn loud buzz/hiss, it is unusable this way.

 

However when i connected my Chord Mojo to my phone or laptop it sounds great with no detectable noise/static from the speakers.

Just wondering how to fix it.

Also when the Chord Mojo is connected to my desktop but i have it powering my HD800 headphones instead of connected as a preamp to my poweramp i also get no noise/static

 

Could it be a ground loop or something between my amp and desktop? and if so would i need a isolation transformer?

I don't want to spend to much money if i can help it.

 

 

 

 

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I have tried plugging in my amp to a different powerpoint in the house to no effect, the chord mojo has a battery built in, I get really bad noise, from the system when it is connected to my pc and amp regardless of if i have it running off battery power or not.

 

 

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No I don't have an optical out. 

I have a matrix m stage that has a built in dac that I have used to preamp my amp and that was connected to my PC via optical I had pretty bad static with that though not as bad as my mojo. 

It most be some kind of problem between my PC and amp. Cause my chord mojo sounds great while powering my Sennheiser HD800 while it is connected to my PC.

My monitor has a USB hub in it. I have connected the chord mojo to that but it makes no difference to the amount of static than if I had it connected directly to my desktop

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1 hour ago, Ken98 said:

I have tried plugging in my amp to a different powerpoint in the house to no effect, the chord mojo has a battery built in, I get really bad noise, from the system when it is connected to my pc and amp regardless of if i have it running off battery power or not.

Was the answer to my question "yes"?

 

Do you have a different PC you can try really quickly and temporarily?

Does your current PC have a 3 pin power cord?

Edited by davewantsmoore
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Sorry, I misread that to say there was still a problem with headphones. That rules out USB noise from the PC . But noise with optical as well can't be ground loop as there is no electrical connection with optical.

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57 minutes ago, Ittaku said:

Is the PC output USB? Try something crazy, and add a USB hub between the PC and the DAC as a dirt cheap brain dead decrapifier.

EDIT: nevermind, I'm also  misreading/interpreting the posts.

Edited by davewantsmoore
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2 minutes ago, Addicted to music said:

His initial post says he’s used a laptop and that sounds fine.

Ah, so it does.

 

It seems like there is a problem with the grounding in the desktop PC.   Current that wasn't to flow to ground, is finding that the easier path to take it through the mojo, and into the ground of your amplifier  (and getting super imposed on your audio).

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Guest Eggcup The Daft

Where is the Mojo positioned when using the desktop, and are you using a screened cable to connect to the amp?

 

Did you move the Mojo when you tested with the laptop and phone?

 

Can you connect the Mojo to the laptop while it is in the same place as when you use it with the desktop, and test it with the desktop turned on?

 

This will rule in or out RFI from the desktop computer as the cause, which is the other possibility here.

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When using the chord mojo I have it position on my desk. I haven't moved it from that position when testing it using my phone and laptop.

When using the mojo with my phone and laptop I use a cheap Amazon's basic USB C to micro USB cable.

 

The amp I have I put together from a kit.

The guy who makes the kits Anthony Holton recommend me to get a isolation amplifier but that will cost me a few hundred bucks.

 

He said that the amp uses a mains Earth system and the mojo uses a floating ground system for grounding. Doesn't mean anything to me though.

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Guest Eggcup The Daft
3 minutes ago, Ken98 said:

When using the chord mojo I have it position on my desk. I haven't moved it from that position when testing it using my phone and laptop.

When using the mojo with my phone and laptop I use a cheap Amazon's basic USB C to micro USB cable.

 

The amp I have I put together from a kit.

The guy who makes the kits Anthony Holton recommend me to get a isolation amplifier but that will cost me a few hundred bucks.

 

He said that the amp uses a mains Earth system and the mojo uses a floating ground system for grounding. Doesn't mean anything to me though.

Was the desktop computer turned on when you tested from the laptop though? What I'm on about is the possibility that the Mojo is picking up noise from the desktop via RFI, which may be easier to deal with than a grounding issue (changing cables or the position of the Mojo). RFI with Mojos (and Hugos) have been reported elsewhere with desktop PCs, so this is worth following up quickly before trying to deal with the PC grounding if that is the cause.

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Guest Eggcup The Daft
17 minutes ago, Eggcup The Daft said:

He said that the amp uses a mains Earth system and the mojo uses a floating ground system for grounding. Doesn't mean anything to me though.

Essentially, because the Mojo is battery powered, it isn't connected to the mains earth. "Floating ground" means it isn't earthed. So any stray current in either the computer or the amplifier may run directly through the Mojo to the other, rather than to its own ground. There could also be a ground loop if the mains earth connections can complete a circuit between the two through the Mojo.

 

Headphones may work OK because they are only connected to the Mojo and not powered from the mains like the amplifier. The headphone amp may include an isolation transformer or similar for safety reasons as well to stop you becoming the ground when wearing the headphones. (I hope I've got that right, I'm no expert!)

 

 

 

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27 minutes ago, Eggcup The Daft said:

Was the desktop computer turned on when you tested from the laptop though? What I'm on about is the possibility that the Mojo is picking up noise from the desktop via RFI, which may be easier to deal with than a grounding issue (changing cables or the position of the Mojo). RFI with Mojos (and Hugos) have been reported elsewhere with desktop PCs, so this is worth following up quickly before trying to deal with the PC grounding if that is the cause.

I placed my laptop directly on top of my desktop while it was on. I connected my chord mojo to my laptop and then connected the amp to the mojo, no static or noise was detectable

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Guest Eggcup The Daft

OK.

Next...

 

Is the USB cable plugged into a USB2 or USB3 socket on the desktop? (this is a real long shot, but USB2 might be quieter)

Are you switching to line level output when using the Mojo with the desktop? (in case the noise is something being amplified in the Mojo)

As asked by others, does your desktop have a 3 pin cable connected, and is everything connected to the same plugboard or mains socket pair?  

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I have exactly the same problem with my desktop which is plugged into an amp and I've tried every amp that's passed through here(about 15) and the same problem, hdd noise and the mouse movements coming through the speakers.

@davewantsmoore  couple of years back I think I had a thread on this and you advised getting  a thing that I can't remember, off ebay and try it but it didn't change a thing.Was about 25-30 bucks and I just sold it before xmas to third drawer down.

Found it in my ebay purchases list.

 

Practical UCA222 U-Control Ultra-Low Latency 2 In/2 Out USB Audio Interface DA

 

image.png.9d9255481f9a2df3c5761c2f22094148.png

 

Certainly useless for my problem but maybe for the OP's one?

 

*The net and audio forums  around the globe and for years...always have a few threads with this exact problem; cable running to amp picking up the internal working of a PC. I've yet to see a solution to it.

 

 

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There was mention earlier of the same noise being there through optical. Can you confirm that's the case now? It's impossible for an electrical/earthing issue to get through an optical connection.

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My Desktop doesn't have any usb 2 sockets It has a bunch of usb 3.0 as well as a usb 3.1 type c which also produces awful static.

My amplifer is a poweramp, it has no volume controls, is using the mojo in line level mode wise?, dont want to wake the neighbors and blow my eardrums

My PC power cable is a 3 pin one.

 

I have the pc and monitor connected to a powerpoint surge protector which is then connected to a power board. I have tried plugging the amplifer into that as well as into another power point using an extension cable but it didnt help at all.

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4 minutes ago, Ittaku said:

There was mention earlier of the same noise being there through optical. Can you confirm that's the case now? It's impossible for an electrical/earthing issue to get through an optical connection.

I made a mistake earlier, my old preamp/dac combo unit was connected through usb type b not optical.

I unfortunately don't have an optical cable to test out.

 

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1 minute ago, Ken98 said:

I made a mistake earlier, my old preamp/dac combo unit was connected through usb type b not optical.

I unfortunately don't have an optical cable to test out.

Okay does the mojo have optical in?

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