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View Full Version : Dac Destroyer - USB Isolation Question?



RichB
11-02-2012, 11:53
Hi All,

As a bit of a daft experiment i went and got one of those Dac Destroyer things on ebay from Dave at Hot Audio. Didnt expect it to compare to my other dacs but at the price £40 (delivered) I needed to satisfy my curiosity.

Took about 10 days to arrive from the Canadian seller and the item was well packaged for its long journey across the pond. At first sight the construction appears solid and was supplied with a somewhat short usb a to b lead. Couldnt wait to plug it in and go.

So first test is in my second system from desktop PC to Pioneer A400 amp, drivers are instantly recognised and the dac appears ready for use in seconds. Instantly notice loads of background noise, seems as if the DAC is picking up all of the internal noise of the PC such as hard drive clicks and a sort of static buzz when moving the mouse around the screen and scrolling internet pages. This noise comes through the speakers whether the amp is turned up or down and even when the aux input is swiched to another channel. I've tried the DAC from both front and rear USB sockets on the PC and the noise remains the same. I've used other mains powered DACs in this system and never had this problem, nor have i noticed any bad noise when using the PC onboard sound to the amp.

So last night I popped around a friends house and we used the DAC between his dektop PC to a NAD amp and Kef Codas, no noise whatsoever. In fact we enjoyed the way it gave it gave better depth to bass and more open sounding vocals. I've also tried the DAC between my laptop and Arcam - Rega setup and no noise is noticable from this set up either.

I contacted the seller who replied almost immediately:

'There are a few people with noise issues, but it is a very small number like about 2 per 1000 units.
It seems to be a ground problem within the PC or perhaps the amplifier / preamplifier.

It can be any number of things.

I have suggested in the past that the user use a "USB ISOLATOR" those apparently work wonders and isolate the PC from ground completely.

Other then then you could send it back to me.

Sometimes you can try moving plugs around and that sometimes works.
Ground loops are often difficult to track down.
They make passive isolators as well for the RCA side of the DAC but I have never tried them.

The galvanic isolators are the best solution from what I've read.'

It is clear the noise problem is obviously coming from my PC and the DAC is not defective. The only USB isolators I have seen are around the £40 mark which seems a bit daft given the value of the DAC.

In fairness to the seller he has been entirely reasonable and i believe his product to be good quality at the price point. I was therefore wondering if any AoS members had experienced similar problems with USB Dacs/Soundcards and how you got around them?

If i cant overcome the ground problem i have I'd rather keep the DAC or swap/sell on this forum than return to the seller given the cost of postage to canada.

All help and advice welcome.

Rich

Stratmangler
11-02-2012, 12:42
Try connecting a wire from the screen of one of the interconnect cables to the chassis (casework - not the RCA female connection) of the amp.

http://media.techtarget.com/whatismedia/images/rca-connector.gif

Werner Berghofer
11-02-2012, 12:58
Richard,


I was therefore wondering if any AoS members had experienced similar problems with USB Dacs/Soundcards and how you got around them?

I think I made a very similar experience: see → this thread (http://theartofsound.net/forum/showthread.php?t=15149&page=7) for more details. Also adding a galvanic isolator didn’t help in my case. Fortunately my workaround was very simple: I switched to S/PDIF via optical Toslink to connect the DAC, but this option may not be available in your setup.

Werner.

bobbasrah
11-02-2012, 13:39
Perhaps it might be worth trying a PCI usb card, as they are quite cheap usually under a tenner. This puts a separate usb hub on your machine so it should not be affected by other usb devices.
If however your PSUs are polluting the PCI line the same thing may happen.
Maybe worth a try....

RichB
11-02-2012, 17:32
Thanks for the suggestions guys, I've been trying a few out this afternoon:

Chris - Tried a bit of wire between the interconnect screen and the amp chasis, unfortunately this had no effect on the noise.

Then dug out an old powered usb hub and tried the DAC via that, this turned the hisses and rumbles into a high pitched sort of whine noise which just got worse with volume, it was quieter than the original noise but would still annoy when not playing music.

Werner - Interesting thread, i read through. Unfortunately the DAC is USB input (power and audio) only so i appear to be stuck with this as an input.

Bob - I'll pop down the local computer shop tomorrow to get a PCI USB hub and see if this fettles it.

One of these days I'll perhaps stop fidgeting and actually listen to some music eh?:cool:

bobbasrah
11-02-2012, 18:22
Thanks for the suggestions guys, I've been trying a few out this afternoon:

Chris - Tried a bit of wire between the interconnect screen and the amp chasis, unfortunately this had no effect on the noise.

Then dug out an old powered usb hub and tried the DAC via that, this turned the hisses and rumbles into a high pitched sort of whine noise which just got worse with volume, it was quieter than the original noise but would still annoy when not playing music.

Werner - Interesting thread, i read through. Unfortunately the DAC is USB input (power and audio) only so i appear to be stuck with this as an input.

Bob - I'll pop down the local computer shop tomorrow to get a PCI USB hub and see if this fettles it.

One of these days I'll perhaps stop fidgeting and actually listen to some music eh?:cool:

Fair enough Richard,
My only reason for suggesting a card is that I have 2 usb hubs on the motherboard, one dedicated for the dac, which displays no noise whatever. :cool:Having said that it is also independently powered.:D
For the price it is worth a shot....

pete_mac
12-02-2012, 23:45
I had this EXACT issue with a HotAudio DAC WOW which I use with my PC audio setup. It was very frustrating at the time!

I bought a USB2ISO isolator and this completely rectified any problems. I have a 100% 'black' background with no hash or other noises now.

I do not know whether the issue is due to my PC or simply due to the power supply design on the DAC WOW.

As a side note, I found the sound quality of the DAC WOW to be very good overall, but not on par with the better compact USB-only DACs out there. For example, the HRT Streamer II+ has noticeably better detail retrieval and accuracy, but is much more expensive. The bang for buck quotient of the HotAudio stuff is pretty good.

RichB
13-02-2012, 09:14
Just ordered a USB2ISO so heres hoping, thanks for the heads up!

pete_mac
14-02-2012, 00:42
Nice one! Good luck. Report back once you've tried the isolator.

RichB
16-02-2012, 20:17
Nice one! Good luck. Report back once you've tried the isolator.

Hi Pete, The USB2ISO arrived today from electronics-shop.dk, took 2 days to get here. Plugged it in and it works a treat... all noises are eliminated from the usb output, background is completely silent. So i'm now enjoying Seth Lakeman's Freedom Fields through the Dac Destroyer... First impressions are better bass and acoustic guitars are considerably sharper. Definately a step up from the PCs onboard sound. Having said that I still prefer my TC-7520 but the Dac Destroyer's portability makes it ideal for when i want to use a laptop with any of my other systems.

Thanks for the tip on this one. All in all I'd recommend both Hot Audio and electronics-shop as a recent convert to the advantages of galvanic isolation!

bobbasrah
16-02-2012, 20:59
Glad that the problem is resolved Richard. Enjoy...

Pete, I read your original post on this device and you made an observation that puzzled me. You said that this USB2 HiSpeed device failed to pass 24/192 to the Hiface but would do so to the Musiland....
Which Musiland were you referring to out of curiosity, and did your WOW Dac work with it?

pete_mac
17-02-2012, 00:12
Excellent result!!


Glad that the problem is resolved Richard. Enjoy...

Pete, I read your original post on this device and you made an observation that puzzled me. You said that this USB2 HiSpeed device failed to pass 24/192 to the Hiface but would do so to the Musiland....
Which Musiland were you referring to out of curiosity, and did your WOW Dac work with it?

Hi,

that information came straight from the USB2ISO website which was based upon first-hand user feedback. I, however, have had no direct experience with the USB2ISO and the Musiland or Hiface.

bobbasrah
17-02-2012, 07:06
Fair enough Pete, with so many disparate claims to what optical v coax v usb can/will do, the relative advantages of each method, and the throughput limits of galvanic isolators for usb, the note that this isolator successfully passed 24/192 was a puzzle in context. What was different with the receiving equipment and signal methodology where one did and one did not work?
That was a puzzle, nothing more.

At least Richard's problem is resolved, which was the objective.....