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Below expected peformance but very feature rich

A Review On: iFi Nano iDSD

iFi Nano iDSD

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Pros: Crams a lot of features in for the price: DSD, DXD, volume control, LED indicator of sampling rate, RCA output

Cons: Ultimately, the sound quality is substandard

I had high expectations of this based on so-called "professional reviews" listed on the iFi website & ones here. Particularly the one from the audiostream "Greatest bits" award: http://www.audiostream.com/content/ifi-nano-idsd-dacheadphone-amp. First listening impressions were not great. I let it run for a few days to be sure, tried the different filter settings, tried the line out vs the headphone out, tried different sampling rates. All to no avail. 


In Standard mode, contrary to what the manufacturer states, Standard Filter sounds better because the music has better pace, rythm and timing (PRAT). 


Overall though, it sounded somewhat off.


So I measured it... results were not very good. The ODAC easily outperformed it in 44k & 96k. The ODAC can't do higher sampling rates than that so no comparison there.


Vs the ODAC - you get a fancy box, nice short USB cable, RCA stereo leads, 2x straps and a rubbery protector to place between devices, DSD, DXD, >96kHz PCM, Sampling Rate indicator and internal battery. It is also better presented with a commercial appearance. But, after a few days, that doesn't matter anymore. The ODAC is simply better sounding for 95% of the music you throw at it. I'm not sure if I'll keep the iFi just for the higher sampling rates & DSD (which I have compiled quite a bit of). 


I tested this from a laptop, a PC, and a Samsung S3 using USB Audio Player Pro. Measurements were with RMAA 6.4 using an E-MU 0204 USB Audio Interface using ASIO drivers with identical loads (my custom amp / Audeze LCD-2) on another PC - ie. One PC or phone playing the test signal through the devices, and one PC recording via the E-MU.


The only change in the tests were the DAC, then levels were matched. So it is a direct comparison.


Click here to view the test results! 


The four big failings are: Frequency response, IMD, THD, and a noisy volume control.


PS- I did further measurements with a laptop as the source, running 96kHz/24-bit. Comparatively, the iFi was similarly worse measuring pretty much across the board


ADDITIONAL MEASUREMENTS FOR THE SKEPTICS: https://dl.dropboxusercontent.com/u/90236454/iFi%20iDSD%20Nano%20vs%20ODAC.pdf



I'm surprised you find iDSD not up to par. I like it and its DSD performance is great. My friend who owned a DAC which is 10X iDSD price commented that it's value-for-money. We tested it with LCD-3, HD650, Fidelio X1, AKG650, and many other HP, all sounded fine.
I bought an iDSD and had to return it. I have a very late-model computer running Windows 8.1 that only has USB 3.0 ports and no USB 2.0 ports. The driver for the iDSD did not work. It wouldn't play anything above 44.1 kHZ / 16 bit. I was disappointed that the iDSD simply didn't have a compatible driver for my Lenovo PC. For a product that is touted as having the latest features, it should have a driver that works with the latest PCs.
Thanks for an interesting review.
I can't comment on the sound as I don't have any of the two you compare. Also, I don't know from your review on what setup you made the comparison for sound evaluation.
However I am quite surprised by your measurements and your interpretation:
1) the frequency response you measure is clearly with the minimum phase filter, not the normal one (see CliOS measurements in the other review). With the normal filter, and using CliOS measurements, the frequency response is at least as good as that of the ODAC, and probably a bit better, not that it matters.
2) noise levels, dynamic range  are the same, quite clearly limited by your tools, THD is marginally worse with the ifi (still in the -90dB and probably due to your choice of filter BTW...)
3) Most importantly, the IMD is huge with the ODAC: -20dB at 8kHz!!! This is quite shocking.
Any idea where this atrocious IMD comes from?
fcaton - Your interpretation of the IMD graph is incorrect. This IMD test has two pulses, one @ 60Hz -5dB, other @ 7kHz -17dB. 
Also, with Standard Filter, ODAC still has superior Frequency Response. I've just added some measurements I did previously: https://dl.dropboxusercontent.com/u/90236454/iFi%20iDSD%20Nano%20vs%20ODAC.pdf
All measurements with iFi were worse including ones I didn't post. I posted results with Min Phase as that is the one most people listen to because they believe it to be 'natural'. The measurement legend specifies that I used Min Phase and Internal Battery Power for theoretically superior sound. 
Hi elmura,
Thanks for the measurements, but there is something wrong here.  This is the frequency response measured by ClieOS:
It's ruler flat down from 100Hz to less than 20Hz while your measurement shows a clear dip. The same is true for the high frequency response  above 15kHz.
Maybe you are measuring a sample that is not up to specs. But I also have to say that I can't help but find your swept measurements results very poor for both dacs.
It is true that different measuring systems and setups will produce differing absolute results. What's more important, is the relative difference within the same setup. All my comparisons whether from laptop as source, Samsung S3 as source or PC as source; With Min Phase or Standard Filter; unloaded or loaded; headphone out or RCA out... all showed the same relative difference.
ie. The iFi iDSD Nano measures somewhat worse than the ODAC pretty much across the board.
Hi Elmura,
First of all thanks again for you efforts, they're really appreciated: found for thought. I am not convinced by your "relative measurements" argument and least of all by the swept measurements. You should have found the proper frequency response, and I suspect that your sound card improves ODAC measurement as it should be -0.4 dB at 20kHz (http://nwavguy.blogspot.fr/2012/04/odac-released.html). 
That said, I've done a bit more research, and I have seen measurements similar to yours, worse and better. Interestingly, your original measurements are coherent with the one made by iFi:
Discarding your frequency response measurement which is clearly incorrect, you find the same THD+N spectrum with the first harmonic about -90dB. Its clearly not as good as the ODAC, but the ODAC is the best measuring DAC in this respect out there. Other measurements are identical for both dacs. So, qualifying the IDSD as sub-par because of that is a bit, how to say, too much? As is to say that the ODAC clearly outperformed the IDSD.
This is even more pertinent since there is one measurement (that you cannot perform) in which the iFi IDSD vastly outperforms the ODA: jitter.
ODAc measurement: http://nwavguy.blogspot.fr/2012/04/odac-released.html
IDSD measurement: http://ifi-audio.com/wp-content/uploads/2014/08/09-iDSD-nano-J-Test-44.1K-16Bit-1024x511.jpg
(from here: http://ifi-audio.com/audio_blog/does-the-nano-idsd-measure-good-bad-or-ugly/)
Note that the iFi vertical scale is from -70 to -150dB, while the ODAC is 0DB to 150dB therefore favoring the ODAC....
The true jitter of IDSD appears to be below the resolving power of the measurement instrument.
One last question: when you speak about sound evaluation, what headphones did you use?
Thanks again,
Fcaton - you seem to have an agenda. That or strong bias.
How is the iFi Jitter "vastly" better than ODAC and "below the resolving power of the measurement instrument"???
Firstly the ODAC was measured with 24-bit data hence showing a lower noise floor that uncovers ultra low level spuria under -130dB with peak Jitter of -117dB. The iFi was measured with 16-bit data with a noise floor masking up to -130dB and having a peak of -122dB. Better? Yes. At this ultra low level, almost insignifanct.
"Discarding your frequency response which is clearly incorrect" and "I suspect that your sound card improves ODAC measurement" -- An EMU 0204 USB was used to perform the comparative measurements. The ONLY change was the DAC. I ran multiple different measurement setups in a purely comparative manner. Indeed, one setup showed the ODAC being -0.36dB @ 20kHz. In that same test, at 20Hz, the iFi was 1dB lower, and 2dB lower at 10Hz.
The THD Swept -15dB graph shows the iFi being 11dB worse at 8kHz. The -6dB graph shows a massive 24dB worse distortion by the iFi.
I think you are trying to imply that grass is not green.
Sound evaluation was via an external buffer amp into a Audeze LCD-2 r2. Internal amp of iFi was worse.
Hi elmura,
Of course I have an agenda: I want to know what are the real differences between the ODAC, the iFi IDSD, the dragonfly and the HRT streamers as I don't want to buy all of them. So I wanted to understand your review of the iDSD which appears as one of the more informed, and the more negative. And I have also a strong bias: I do measurements for a living (not in audio, fortunately), so I tend to question measurements as much as subjective opinions, because measurements outcome depend as much on the operator and his philosphy or beliefs than on the thing measured. For a perfect demonstration in audio: 
BTW, your swept THD measurements should give striclty identical results to the standard method. Why it is not the case, I cannot tell.
As a final comment, I find it interesting that you discard the one measurement where the iDSD dac significantly betters the ODAC as "insignificant".
ODAC measurement show significant spikes above 120dB and very irregular. NwAvGuy arguments that "16 bits data would mask most of the spikes". Well that's highly debatable, but anyway, it will not mask the worst spikes!
Marginally out of topic, one may note that the dragonfly is objectively considerably better than the ODAC in this respect (24 bits data, this time):
So, we can agree that we disagree on the meaning of your measurements and on the measured quality of the two DACs. For me, both have their advantages and weeknesses.  ODAC: better THD+N; iDSD: better jitter.
I read your links. Some people who don't fully understand measurements publicly put a big question mark over them, infecting other readers with doubt.
The computerphile article / Geek / Sterephile situation you reference is a perfect example. The Geek & Dragonfly were tested by Geek at the usual test setup. Stereophile did so as well, but finding very high THD, reduced volume of the Dragonfly DAC until he could get a decent measurement. Thus the Geek test result is in fact an accurate test result. So, for average Joe who plugs in the Dragonfly into a set of powered speakers, or external amp with its own volume control, would normally set the volume of Windows to 100% to obtain bit perfect audio. In that scenario, the Dragonfly distorts like hell when producing a peak signal such as with most peaks in modern highly compressed pop / rock / dubstep etc music.
"ODAC measurement show significant spikes above 120dB and very irregular" Seriously? In what world does four spikes of up to -117dB Jitter (Only 3dB worse than 120dB)  equate to anything you said? The total difference between the two in Jitter is roughly 4.1% and below audibility.
In most other measurement, the iFi measures significantly worse (upto 25% worse in the audible range). Why is that so hard to comprehend?
You state "it's highly debatable" to the fact that 16-bit data masks lower level Jitter. With this comment, I realise now that you do not understand measurements. If you don't know or are unsure about something; ask, or research it. Don't go disputing it. You seem to have a library of references for articles that should either explain it or demonstrate it with graphs.
I find your take on the Geek/Stereophile debate actually amusing, in particular the "accurate" part. The dragonfly is sold as a combined DAC/headphone amp. So your average Joe will not plug a preamplifier to it, but plug a pair of headphones to it!  5 minutes on amazon will show you that most people use it with headphones where it is evidently not a problem (it is the amp that is clipping, in case you missed it...). For this vast majority of users the Geek test is not informative whatsoever of the quality (or lack of) of the dragonfly.
So, in this case, my opinion is considerably less arrogant than yours: indeed the original dragonfly had a clipping problem, that shows up in an unusual use of the dragonfly, and I thank stereophile for showing the problem and the easy remedy: a 0.5dB turn of a button. But we're digressing, aren't we...
I am a bit suprised that you don't see that jitter is very far from a standard distorsion test, and go lecturing me about doing my research.
FYI, your "audibility criterion" is based on E. Winner's article which is, putting it mildly, highly speculative. I'll let you do your own research as to why. I suggest the same concerning the 16 bits input data. Maybe you should crosscheck a bit the affirmations of  the ODAC designer...
Finally, since you claim to be so well versed in measurements, you should perhaps investigate as to why your swept THD data are so different form the standard measurement. If you had any idea of how it works and what it should do, you would have. That's considerably simpler than jitter but you obviously don't understand it.
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