Noise spikes at lower frequencies, possibly caused by power supply mains Rising noise level "skirt" around our main 12 kHz tone, indicating random clock jitter Lower output level by nearly 3 dB. This means its dynamic range is actually worse than what is shown in the graph

This is a detailed review and measurements of the popular Schiit Modi 2 Uber DAC and comparison to Topping D30. I own both units. The Modi 2 Uber edition is one of the three versions of this DAC and retails for $149 plus shipping. The Topping D30 is available on Amazon Prime for $119 and includes shipping so good bit cheaper.The two are similar in features in that both have three inputs: USB, S/PDIF coax and Toslink optical inputs. Both have external power bricks. The Topping has its power switch on the front which I prefer to the back switch of Modi 2 Uber. I also like the English labels on Topping as opposed to alien symbols used in Schiit Modi 2 Uber.A while back I reviewed the plain Modi 2 and unfortunately it did not perform well. This prompted people to ask me to measure the Uber edition since it has an external power supply and as such, should not be affected by the USB power as Modi 2 was.The Topping D30 was also reviewed earlier but this is an extended set of measurements than I used to perform then.So let's get into the data. As usual, if you are not familiar with what these graphs mean, refer to my tutorial on understanding audio measurements: https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-measurements.2351/ Let's start with the test of Jitter and Noise using the USB input. The test signal which is essentially a 12 kHz tone is played by Roon in exclusive mode and the output of each DAC is measured by my analyzer. Anything other than the 12 kHz tone is unwanted:The Topping D30 has a nice flat noise floor with a couple of tiny spikes here and there. The Schiit Modi 2 Uber on the other hand suffers from three maladies:Fortunately the levels in #1 and #2 from audibility point of view are pretty low so not a major concern. Just lack of good engineering at play.Let's look at the distortion and noise from a 1 kHz tone that itself is filtered (i.e. everything shown is unwanted):We see that the Modi 2 Uber has much higher noise at lower frequencies (< 6 kHz) where our hearing is most sensitive. It also has higher harmonic distortion spikes than Topping D30 with the exception of 5th harmonic.We can put this in the form of classical THD+N measurement by having my analyzer add up the noise and distortion contributions:We see that the Modi 2 Uber underperforms Topping D30 by 7 dB. But wait, there is more!As I was running this test the bar graph kept jumping from time to time when analyzing Modi 2 Uber. I was puzzled by this so tested the Topping D30 again and it was rock solid. As you see, Modi 2 Uber min THD+N is -96 dB but then increases way up to -59 dB (smaller numbers are worse). The D30 on the other hand only varies between -103 and -102 dB.To see what was going on I ran the previous spectrum measurement of 1 kHz in repeat mode on Modi 2 Uber and got this:Bottom group of graphs shows the lower distortion level. But once in a while, the distortion and noise jump up as shown in green and yellow. So clearly something is wrong. Way wrong.I then hooked up the Modi 2 to my Stax headphone amp and listened. The problem became super obvious: the DAC would play the 1 kHz tone cleanly for some 8 to 10 seconds and then there would be a soft glitch/static. Sometimes it would do this once. Other times it would do it twice and once it did it three times in a row!I then tested the S/PDIF input using my generator as the source and there was no glitch at all.This is completely repeatable on my system.Before any owners say they have this unit and don't have this problem, I played a bunch of music with the DAC and I could NOT detect the glitch there. Whether it was masked by music or is a problem that occurs at 0 dBFS, I don't know. What I do know is that in identical situation with dozens of DACs including the Topping D30, this problem does not occur.Let's move on and test DAC linearity over S/PDIF. Here we send a digital sample to the DAC and keep changing its value linearity and see if the analog voltage coming out of the DAC does the same. An ideal DAC would produce a flat line at zero with no deviation:The Schiit Modi 2 Uber turns in pretty poor performance. Using my self-imposed 0.1 dB error limit, it is only able to output a signal that is less than this error at 72 dB and higher. This translates into 12 bits of clean output. The Topping D30 on the other hand marches on to -90 dB which is equivalent to 15 bits. This is significantly better performance than Schiit Modi 2 Uber.The picture is even worse than that. At -120 dB, the error from Schiit Modi 2 Uber is 15 dB. At the same level, the Topping D30 error is just 2.5 dB.Feeding both DACs a very low level -90 dB sine wave generates this:While the Modi 2 Uber sine wave is pretty clean, its level has dropped by a fair bit which reflects poorly in linearity tests (noise dominates over the signal).I could run more tests but I think the picture here is quite consistent in each measurement. Schiit Modi 2 trails the Topping D30 by a significant margin.I connected both DACs to the inputs of my Stax SRM-007t driving the Omega pro headset. Using its AB switch I could instantly go between the two DACs while Roon played the same music to both.There was no comparison here: the Topping D30 had far more authority, detail, bass impact, air, etc. In every way it was superior to the Schiit Modi 2 Uber. A child could tell the difference.What is that you say? You thought DACs don't sound very different? Well, that is the case if you match their levels. The Topping has nearly 3 dB higher output than the Schiit Modi 2. So if this is not compensated for, the extra level absolutely translates into better fidelity.Why did I run the test knowing what I know about the levels? This was to dispute the subjective tests online where people say Topping D30 doesn't sound as good as Schiit Modi 2 Uber.If they can't hear the louder DAC, i.e. Topping D30 sounding better, they need to turn in their audiophile card. It is simple as that.To match levels, I used the Roon DSP volume control and notched down the Topping D30. Unfortunately the resolution was too coarse. I could either have it be a bit louder than Modi 2 Uber or a bit less loud. Regardless, almost all of the above differences I heard when I didn't level match went out the window. Both DACs sounded pretty good. Trying hard I thought the Schiit Modi 2 Uber sounded a tiny bit brighter. This is not a very reliable observation so please don't hold me to it.The measurements show that the Schiit Modi 2 Uber DAC is simply not competitive in performance. It has lower output, higher noise and jitter and much worse linearity than Topping D30.Worst yet, its USB implementation appears to be faulty causing glitches in the output.Time and time again when I test Schiit products they demonstrate lack of design verification and targets. The basics are not done. Just aren't. The company needs a reboot in its development process and must establish competitive targets and strive to achieve them in new products. Just because a product produces music, it doesn't mean it is working correctly.Fortunately our hearing is nowhere as sensitive as our instrumentation. So if you own a Modi 2 Uber, I am not telling you to run out and buy something else. But if you are in the market for a new DAC, I am compelled to recommend buying a different product whether that is Topping D30 or other DACs in this price range. They have all gone though proper engineering and design verification to produce performance that at least meet the CD specification in noise and resolution.As always, questions, comments, corrections, etc. are all welcome.----If you like this review,for these types of hardware purchase using Patreon ( https://www.patreon.com/audiosciencereview ), or upgrading your membership here though Paypal ( https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054 ).