Help! problems with my dac Topping

[TheBatsEar]

It would be cheaper to send the Topping DAC back and buy something with Toslink input.

However, i'm not yet fully convinced that noise enters the chain using USB is actually the problem.
Could be tested using a mobile phone as a source.

 

[MCH]

This is interesting, I was unaware of the existence of this device from Topping...

There is a thread on it.

It is pricey, but I find it one of these things that is good to know they exist, in case... If it works, of course

 

[antcollinet]

Would one of these work?

TOPPING HS01 USB Isolator 32bit 768kHz DSD512 - Audiophonics

The Topping HS01 is a small, high speed, low latency (0.29µs) USB 2.0 isolator. It is compatible with high resolution streams up to 32bit 768kHz PCM and native DSD512 for accurate sound reproduction.

www.audiophonics.fr

It might do. As long as it fully isolates the ground. From reading I think it does, but it is not clearly stated.

 

[antcollinet]

It would be cheaper to send the Topping DAC back and buy something with Toslink input.

However, i'm not yet fully convinced that noise enters the chain using USB is actually the problem.
Could be tested using a mobile phone as a source.

It isn't. It's a ground loop. The noise isn't from USB, it is from any magnetic field coupling into the loop. These devices break the loop and stop the noise that way.

Mobile phone as source couled be used to check - so could battery powered laptop as I suggested above.

 

[pma]

Topping D10s works perfectly with this. €18 product. No need to spend more money.

USB-ISO

Full speed USB isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

 

[threni]

You can use a cheap Behringer dongle, like a U-Control 202/222, to convert USB from the computer to optical to feed the DAC and achieve isolation.

I'm considering this myself. But if USB to dac has noise (random noises as well as 'i can hear you moving the mouse and dragging windows" noises, won't this get into the dongle via USB too?

 

[Sokel]

Topping D10s works perfectly with this. €18 product. No need to spend more money.

USB-ISO

Full speed USB isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

Good up to 24/96,it's a gamble for upsampling.

 

[raindance]

I'm considering this myself. But if USB to dac has noise (random noises as well as 'i can hear you moving the mouse and dragging windows" noises, won't this get into the dongle via USB too?

No, I have tried it, so long as the DAC is connected via optical it is fine.

 

[threni]

No, I have tried it, so long as the DAC is connected via optical it is fine.

So... How is the dongle getting the data without noise but my DAC (topping E30) is unusable via USB from the PC?

 

[antcollinet]

I'm considering this myself. But if USB to dac has noise (random noises as well as 'i can hear you moving the mouse and dragging windows" noises, won't this get into the dongle via USB too?

No, the noise is analogue noise in the earth loop. The dongle is digital to digital and won’t be effected.

 

[threni]

No, the noise is analogue noise in the earth loop. The dongle is digital to digital and won’t be effected.

But why can't the DAC do whatever the dongle is doing to extract the digital data without the noise?

 

[raindance]

So... How is the dongle getting the data without noise but my DAC (topping E30) is unusable via USB from the PC?

You're using it in a purely digital capacity and the noise is only in the analog stage of the dongle (which isn't being used). Providing audio bits to the DAC over fiber ensures that only actual audio gets decoded because the noise can't pass.

 

[half_dog]

Would one of these work?

TOPPING HS01 USB Isolator 32bit 768kHz DSD512 - Audiophonics

The Topping HS01 is a small, high speed, low latency (0.29µs) USB 2.0 isolator. It is compatible with high resolution streams up to 32bit 768kHz PCM and native DSD512 for accurate sound reproduction.

www.audiophonics.fr

I've bought one of these and later I can try it with my D10s and a DIY headphone amp which I had problems with ground loops - which was partially solved when the ground pin was "lifted".

 

[threni]

You're using it in a purely digital capacity and the noise is only in the analog stage of the dongle (which isn't being used). Providing audio bits to the DAC over fiber ensures that only actual audio gets decoded because the noise can't pass.

But aren't I using the PC, USB cable and DAC in a purely digital capacity (up until the output of the DAC) when I connect my PC to the DAC using a USB cable, and getting a load of noise?

 

[raindance]

But aren't I using the PC, USB cable and DAC in a purely digital capacity (up until the output of the DAC) when I connect my PC to the DAC using a USB cable, and getting a load of noise?

No, the analog stage that you are listening to is part of the DAC which is NOT optically isolated from the computer in your case.

 

[antcollinet]

But why can't the DAC do whatever the dongle is doing to extract the digital data without the noise?

The optical connecation to the dac is not electrical. With no electrical connection the ground loop is broken. No noise.

USB to DAC to AMP is all electrical - so when both the PC and Amp have ground connections there is a ground loop.

The noise is not in the extracted signal. It is added to the signal by the ground bouncing around due to the induced currents further down the chain (in the signal connection from Dac to amp - see my more detailed explanation upthread

 

[threni]

The optical connecation to the dac is not electrical. With no electrical connection the ground loop is broken. No noise.

USB to DAC to AMP is all electrical - so when both the PC and Amp have ground connections there is a ground loop.

The noise is not in the extracted signal. It is added to the signal by the ground bouncing around due to the induced currents further down the chain (in the signal connection from Dac to amp - see my more detailed explanation upthread

Yeah, I think I get it now thanks. The difference is there's no ground loop between the pc and the box producing the optical output. I guess I'm after balanced USB!

 

[antcollinet]

Yeah, I think I get it now thanks. The difference is there's no ground loop between the pc and the box producing the optical output. I guess I'm after balanced USB!

The USB isolators linked above should do the same job. Breaking the ground loop.

The loop goes from mains earth, through pc, through dac, through amp and back to mains (via the PC and Amps mains earth connections). The current in the loop is created by stray magnetic fields coupling to the loop (as though it was a short circuited single turn secondary on a transformer. The noise is added to the signal in the analgue connection in between the dac and amp by the loop noise currents causing a voltage difference from one end of the cable to the other.

Anywhere you can break that connection, breaks the loop and stops the loop currents flowing.

 

[threni]

The USB isolators linked above should do the same job. Breaking the ground loop.

The loop goes from mains earth, through pc, through dac, through amp and back to mains (via the PC and Amps mains earth connections). The current in the loop is created by stray magnetic fields coupling to the loop (as though it was a short circuited single turn secondary on a transformer. The noise is added to the signal in the analgue connection in between the dac and amp by the loop noise currents causing a voltage difference from one end of the cable to the other.

Anywhere you can break that connection, breaks the loop and stops the loop currents flowing.

The thing is I already have my main system working fine. I'm just after the ability to connect my desktop pc to my DAC. It's not something I'd use all that often (checking out flacs before I copy them to the main system; a little YouTube) so it's not worth much money to me. Certainly I'm not that bothered about quality as long as there's not a lot of hum/distortion etc. I've looked at soundcards and various boxes and it just ends up being quite ugly and expensive plus the uncertainty of not knowing if it'll work on Linux.

 

[antcollinet]

The thing is I already have my main system working fine. I'm just after the ability to connect my desktop pc to my DAC. It's not something I'd use all that often (checking out flacs before I copy them to the main system; a little YouTube) so it's not worth much money to me. Certainly I'm not that bothered about quality as long as there's not a lot of hum/distortion etc. I've looked at soundcards and various boxes and it just ends up being quite ugly and expensive plus the uncertainty of not knowing if it'll work on Linux.

Do you not already have an optical output on the motherboard of your PC? Many do.