Noise from USB DACs with desktop PC

[foxwelljsly]

I have a couple of USB DACs (Dragonfly and Topping E30). They both work fine on my Macbook Pro and Pi, but I get an audible buzz when I connect them to a USB socket on my Lenovo Thinkstation Desktop PC.

Any suggestions as to how I can address this?

I've tried one of these, but it does absolutely nothing and devices don't function when connected to it.

cheers

 

[davidsrsb]

Your desktop PC will be earthed, although it should have a Class II insulated power supply

 

[serendipitydawg]

Not an ideal solution, but you could try powering the E30 from a powerbank (battery). If that gets rid of the "earth buzz" the culprit is the Lenovo's power supply.

 

[AndyU]

I have a couple of USB DACs (Dragonfly and Topping E30). They both work fine on my Macbook Pro and Pi, but I get an audible buzz when I connect them to a USB socket on my Lenovo Thinkstation Desktop PC.

Any suggestions as to how I can address this?

I've tried one of these, but it does absolutely nothing and devices don't function when connected to it.

cheers

I had a similar thing years ago with an Arcam DAC; fine if my laptop was running of its battery, ghastly buzzy birdy noises when the laptop was plugged in to its charger. You could try a galvanic isolator like this https://www.olimex.com/Products/USB-Modules/USB-ISO/ but you might be throwing good money after bad. I just got a different DAC.

 

[foxwelljsly]

Thanks all. Tried the E30 powered from a battery pack - OK. Powered from a phone charger, also OK.

 

[davidsrsb]

What are you connecting your DACs to, headphones or an amplifier?

 

[tuga]

I have a couple of USB DACs (Dragonfly and Topping E30). They both work fine on my Macbook Pro and Pi, but I get an audible buzz when I connect them to a USB socket on my Lenovo Thinkstation Desktop PC.

Any suggestions as to how I can address this?

I've tried one of these, but it does absolutely nothing and devices don't function when connected to it.

cheers

Can you try another USB port on the desktop?

https://archimago.blogspot.com/2018/05/measurements-computer-usb-5v-power.html


And maybe try using a USB hub, some of these will filter/reduce noise:

https://archimago.blogspot.com/2015/05/measurements-usb-hubs-and-8khz-phy.html

 

[tuga]

Computer audio isn't as plug and play as it's claimed to be unfortunately... A computer is a source of acoustic and electric noise.

 

[foxwelljsly]

A bit of

What are you connecting your DACs to, headphones or an amplifier?

Quad 34 pre amp.

Noise drops to a negligible level when powered by a phone charger or battery, so will go with that.

Powered USB hub makes no difference, surprisingly. I can see myself popping a pi and/or a CCA in at some point.

 

[davidsrsb]

I think that this is an earth loop.
Try connecting the desktop PC case directly to the preamp rear panel with a short wire

 

[RJohan]

Ii had an even weirder experience some time ago. I connected two boxes with an optical cable. Huuuuum from the speakers. When I moved the power socket of one apparatus to the same spur as the other, it was gone. I get it if it had been coax.

 

[tuga]

Ii had an even weirder experience some time ago. I connected two boxes with an optical cable. Huuuuum from the speakers. When I moved the power socket of one apparatus to the same spur as the other, it was gone. I get it if it had been coax.

Maybe the Toslink interfaces were causing noise...?

 

[RJohan]

Maybe the Toslink interfaces were causing noise...?

Well, who knows...

 

[chartz]

I experienced the same thing in the past: perfectly silent Mac but noisy PC. I never figured out what the problem was. I gave up on PCs.

 

[colasblue]

Inexpensive PC audio is almost a complete dead loss if the PC runs a powerful graphics card. It's the graphics card that creates most of the chop on the earth line. Decent dacs with a properly implemented XMOS interface can usually overcome the issue but the cheaper ones don't. You get similar problems with the so called "audiophile" soundcards (both internal and external) made by Asus and Creative, absolute rubbish the lot of 'em.