Nifty device for isolation between your DAC and PC

pete_mac

Super Member
About a month ago I ventured into the world of USB DACs with a HotAudio DAC WOW which I am mightily impressed with. However, when recently listening to some music that has some periods of silence in it, I noticed some background digital ‘hash’ noise coming from the PC via the USB. There’s an audible digital background noise which occurs concurrently with cursor movement, webpage activity, hard drive use etc. In addition, there’s a minor ground loop too. It seems to be fairly common with low-end USB DACs (and even some not-so-low end DACs!).

After doing all of the usual (and not so usual!) ground loop isolation testing and not being able to rectify the problem, I started looking for solutions. Some people suggested using a ground loop isolator that sits in the analogue signal path and achieves galvanic isolation via the use of transformers. This is a very ‘lossy’ way of dealing with the problem, causing distortion, loss of bass and treble information, and a general attenuation of the signal. You can buy high quality units from Jensen Transformers that aren’t too bad, but they are $200+. Regardless, I wasn’t happy with the idea of this kind of device sitting in the line-level analogue signal path.

After digging around a bit, I found some references to the ADUM4160 chip which is designed to provide galvanic isolation for USB devices. Lo and behold, a few people are making DIY or ready-made units which utilise this chip. I was immediately interested as the galvanic isolation is provided on the digital side, and the data passes through perfectly to allow the DAC to undertake the conversion process unaffected.


The device that I’ve ordered is the USB2ISO from electronicsshop.dk:

http://electronicsshop.dk/usb_isolation.htm?currency=USD

One downside to this device is that some 24bit/192khz USB DACs have problems eg. the Hiface doesn’t work, but the Musiland does.


The USB2ISO arrived yesterday. Nicely packed with an anti-static package for the unit, and in instruction leaflet.

USB2ISOsmall.jpg


Most importantly of all... it does what it says on the tin!! Ground loop gone, no more digitial 'hash' noise, quiet as a mouse. BRILLIANT!

If it makes sense, the quiet parts of the music are now 'blacker' and there is more resolution in the sound. Switching to the DAC WOW lowered the noise floor compared to the onboard PC sound, even with the digital hash noise. The noise floor has now dropped even further.

VERY happy with the outcome, and I highly recommend this little device to anybody using a USB DAC via their PC or laptop and is experiencing power-supply-related noise etc.
 
Nice

i Just ordered a hot audio Wow DAC 15 minutes a go..coincidently here is a post. Looking forward to trying it thanks for this tip if run to some noise.
 
A quick update... I'm still massively impressed with what this little device does.

I've recently upgraded my speakers to a nice pair of Sound Dynamics 300ti with the titanium tweeter. These speakers are very detailed and sparkly in the top end, but there absolutely no trace of the digital hash and background power supply noise that was evident prior to to fitting the USB2ISO.

My system now sounds incredible!

i Just ordered a hot audio Wow DAC 15 minutes a go..coincidently here is a post. Looking forward to trying it thanks for this tip if run to some noise.

Nice work. I really like the sound offered by the DAC WOW.
 
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