Review and Measurements of Intona USB Isolator for Audio DACs

[gvl]

There is an elegant solution to the intersample peak problem, it is called a filterless NOS DAC.

 

[Dialectic]

There is an elegant solution to the intersample peak problem, it is called a filterless NOS DAC.

A solution so elegant that it causes lots of other problems.

 

[gvl]

A solution so elegant that it causes lots of other problems.

I didn't say it was perfect

 

[bennetng]

Here is John Siau's comment before the actual release of DAC2:
https://hydrogenaud.io/index.php/topic,98753.msg820027.html#msg820027

So you can see there is a trade-off in terms of SNR, also you can see how it works. It is just a digital attenuation working at higher bit-depth before the audio data reaching the DAC chip. You can do the same even with a Realtek. Of course it won't make a Realtek become a Benchmark but in the sense of dealing with intersample peaks they are basically the same.

Archimago was kind enough to use my test signal on some of his DACs:
http://archimago.blogspot.com/2018/...howComment=1514806847604#c6918600883178190233

Another test:
https://audiosciencereview.com/foru...ation-audible-intersample-clipping-test.2231/

Notice the test signal I used in the first and second link are different. The one posted in ASR can be used to evaluate intersample overs by listening (at safe volume). Also in the HA thread I posted in Archimago's blog you can see a developer addressed the issues he faced when dealing with floating point and fixed point data. Those who don't have any programming backgrounds can read the thread below and know their differences.

https://hydrogenaud.io/index.php/topic,110802.msg912765.html#msg912765

 

[dallasjustice]

@amirm Does the intona cause RME totalmix to drop its connection? When I used the intona with the Lynx Hilo, Hilo remote would disconnect the DAC. The intona interferes with 2 way communication on the Lynx Hilo some how.

 

[amirm]

Let me test.....

 

[March Audio]

Dallas, early intonas had issues with certain xmos usb chips but was fixed with updated firmware, something I gather you cant do yourself and it needs to go back to intona. This may have no relation to your issue

 

[Final]

I’ve had similar experience with my Intona. Lost handshake if I Powered off the DAC first. Had to remote it from the chain. Establish handshake without Intona and then put it back again. Same issue with Ifi IUSB 3.0 by the way.

 

[Music1969]

The Intona adds a bit of noise to low frequencies. Not sure what it is about but it is extremely small.

Hi armir and all,

Do we now have any idea what this introduced noise was?

While I can understand the Intona not improving the RME performance (because it's great DAC) it's a little worrying that the Intona can measurably make things worse, given the price of the Intona - it's not exactly cheap... even if the difference it makes is small.

Cheers!

 

[amirm]

The extra noise seems to be at mains frequencies. Somehow that is worsened through Intona. Such things may be situation/system dependent.

 

[Music1969]

The extra noise seems to be at mains frequencies. Somehow that is worsened through Intona. Such things may be situation/system dependent.

Noted, thanks armir. The "somehow" part is what I was wondering.

Any specific theories (or even guesses), even with your own system that was used for these measurements?

 

[Final]

Ground loops are almost universally characterized by being a low frequency hum, sometimes remarkably pure power line frequency which is either 50 or 60 Hz in most parts of the world.

Hiss would usually be some kind of EMI whether from local gear or nearby broadcast including cell towers.

In general if being battery powered fixes the problem, you just take advantage of the fact that most higher quality battery powered gear has internal batteries and rthey can be recharged via a USB port. You can even find USB cables that provide separate USB plugs for signal and power for negligable money. You then hook a low-buck USB power supply up to keep the battery perpetually charged. Worked for me many times. Take the $100's you saved and invest it in what really makes having a great system worth it - more prerecorded media. Or chase something that really matters like room acoustics or start saving up for a good subwoofer if you don't have one!

Well the Intona is what worked for me. After my initial post I also ordered a new power supply for my Asus laptop. The noise was gone. The power supply was the culprit. Consequently the Intona is not strictly needed anymore.

However as galvanic isolation is a good thing,the Intona stays in the chain.

 

[Veri]

Well the Intona is what worked for me. After my initial post I also ordered a new power supply for my Asus laptop. The noise was gone. The power supply was the culprit. Consequently the Intona is not strictly needed anymore.

However as galvanic isolation is a good thing,the Intona stays in the chain.

 

[tvrgeek]

Just ordered a LTM 2884 demo board from AMD. I will give it a comparison to a $12 E-Bay special. I think the first conclusion made here is the better DACs can, if they want, do a decent job. I have noticed more talking about it. The AMD 40160 seems a common chip too. If not on my server, I want it on my bench for a USB scope.