Objective Reviews & Commentary - An Engineer's Perspective

November 8, 2011


fiio d5 packagingINTRO: This is another article in a series of inexpensive USB DAC reviews including the Turtle Beach Micro II and Syba C-Media CM119. Like both of those DACs, it uses yet a different version of an all-in-one C-Media chip (the CM108). So how does FiiO’s least expensive USB DAC measure up against it’s peers?

FiiO D5 USB DECODER: The D5 is a bit different than the other two C-Media DACs. It doesn’t plug directly into the USP port but instead has a short detachable USB cable using a mini USB plug allowing use of other cables. And, true to their tradition, FiiO manages to include several extra features not found elsewhere at this low price. The build quality is impressive using a full metal enclosure instead of plastic. FiiO also includes volume up/down buttons and mute buttons for the output and microphone. There’s an LED that shows it’s been acknowledged by the operating system and another for the Mic Mute. Plus you get two microphone jacks instead of one, a headphone out, a separate line out, and a coaxial digital output. When you consider the D5 has the same $25 street price as the Turtle Beach Micro II, FiiO gives you a lot more features.

FiiO D5 VOLUME CONTROL: The volume control isn’t a “local” volume control in the analog domain after the DAC (as in say the NuForce uDAC-2). Instead it’s really just a remote control for your PC’s volume control. Pressing the up and down buttons on the D5 changes the volume settings for the D5 in Windows (I didn’t test OS X or Linux). So it does not help preserve full 16 bit resolution at lower volume settings. Using the controls on the D5 is no different than using your PC’s volume control which causes a reduction of bit resolution at anything but full volume. Still the volume buttons could be useful, especially if you use a long USB cable and the D5 is located away from the PC or allowing volume adjustment without turning the screen on or logging onto a “locked” PC.

d5 modesWINDOWS INSTALLATION: The D5 installed smoothly in both XP and Windows 7 without needing any drivers. Windows reported it, interestingly, as a “C-Media USB Headphone Set”. The only sample rates and bit depths available are 16/44 and 16/48 as shown to the right in Windows 7 (click for larger).

SUBJECTIVE SOUND QUALITY: There was moderate hiss and noise with my Ultimate Ears IEMs and it was noticeably worse than the Turtle Beach Micro II and about the same as the Syba CM119. The sound quality seemed similar to the Micro II with its odd dynamic range control turned off but the D5 has more output and seemed to sound a bit better driving 16 ohm headphones than the Syba CM119. A blind test would be required to know for sure, but I’m fairly sure the D5, like the CM119 and Micro II, has some audible flaws.

fiio d5 dscopeMEASUREMENT SUMMARY: The overall results were not very impressive and generally similar to the Turtle beach Micro II and Syba CM119 which use two other chips from C-Media. This doesn’t speak well for C-Media based products when three different DACs, using three different C-Media chips, all have significant problems. There are some differences between the three. The D5 has the highest line and headphone output voltage and the lowest output impedance but the Micro II and CM119 have better frequency response into a line level load. The CM119 does especially poorly with lower impedance headphones. Here are the results compared to the $12 CM119, $25 Turtle Beach Micro II, and the $30 Behringer UCA202. The scores are “A” (excellent) through “F” (unacceptable):

Measurement FiiO D5 CM119 UCA202 TB Micro II
Freq. Resp. 10K +/- 1.5 dB C +/- 1.0 dB B +/- 0.1 dB A +/- 1.0 dB B
Freq. Resp. 33 ohms +/- 1.5 dB C +/- 6 dB F N/A +/- 1.8 dB C
HP Output Imp 0.72 Ohms A 5.9 Ohms C 47 Ohms F 0.95 ohms A
Max Output 10K 1.5 Vrms B 0.95 Vrms C 1.12 Vrms B 1.34 Vrms B
Max Output 33 Ohms 1.4 Vrms B 0.68 Vrms C N/A 1.26 V B
Max Power 32 Ohms 61 mW B 14 mW C N/A 50 mW B
THD+N 0 dBFS 10K 0.24% C 0.035% B 0.008% A 0.14% C
THD+N 100hz 10K 0.08% C 0.035% B 0.007% A 0.025% B
THD+N 1Khz 10K 0.08% C 0.035% B 0.007% A 0.02% B
THD+N 1Khz 33ohms 0.08% C 0.095% C N/A 0.12% D
THD+N 10Khz 10K 0.04% B 0.090% C 0.009% A 0.11% C
IMD CCIF 10K/33 011% D 0.028% D 0.005% A 0.028% D
IMD SMPTE 10K 0.80% D 0.012% B 0.002% A 0.02% B
Noise A-Wtd dBu -90.0 C -89.0 C -88.8 C -93.8 B
-90 dBFS Linearity 0.7 dB A 0.9 dB A 3.8 dB C 0.8 dB A
USB Jitter Jtest Poor D Poor D Very Good B Poor D


  • It’s cheap
  • Nice build quality
  • Volume & Mute controls
  • Coaxial digital output


  • Likely worse than many built-in (motherboard) sound outputs
  • Significant low frequency roll off from headphone and line outputs
  • High overall distortion, especially at low and high frequencies
  • Relatively noisy
  • Relatively high jitter

BOTTOM LINE: The extra features, especially the Mic Mute button, make the D5 especially well suited for things like Skype and web chat. But, otherwise, it’s external features and impressive build quality are only “skin deep”. What’s inside is yet another poorly performing C-Media chip. Of the three C-Media based USB DACs I’ve tested this one has the most features and highest output but is slightly less laptop friendly for portable use. Each of the C-Media DACs I’ve tested has a few unique relatively strengths and weaknesses. See the Measurement Summary above and Tech Section below for more details. As a secondary audio source for non-critical applications, or perhaps as a primary source for voice chat, Skype, etc, the D5 is a reasonable choice. For high quality audio, however, the Behringer UCA202’s line outputs perform far better for about the same price. And, as documented in my next two reviews, there are some better choices for portable USB “thumb DACs” for only slightly more money.



TECH STUFF: Based on information from the web, the D5 appears to use the C-Media CM108. Like the CM119 and CM102, used in the Syba and Micro-II respectively, it’s a fully integrated single chip that does everything necessary for a USB headphone DAC with a few extras thrown in. The volume control is simply another USB endpoint to allow remote control of the PC operating system volume and mute control. This is natively supported in Windows XP, Vista and Win 7 with no special drivers.

HEADPHONE TESTS: As with the other recent DAC tests, I used a 33 ohm load to represent typical portable headphones in the 16 – 80 ohm range. I also spot checked a few results into other impedances from 15 to 600 ohms. These tests were made from the headphone jack.

LINE OUT TESTS: I used 10K which is the typical input impedance of many headphone amps, such as the O2, and powered speakers. Performance into 22k or 50K loads will be very similar. I ran a few tests at 100K. I used the line out jack for these tests.

FREQUENCY RESPONSE: The other two C-Media based DAC’s had relatively flat low frequency response into 10K but not the D5. From either output it rolls off the bass so it’s down about 3 dB at 20 hz. This implies an undersized coupling capacitor that’s “upstream” of the line out buffer and headphone amp. Some might argue this amount of roll off is inaudible as the ear is less sensitive at very low frequencies, but it’s still disappointing. It means significant phase shift much higher in the audio spectrum and with headphones and recordings that go down to 20hz, you just might hear the loss of deep bass. The high frequency performance suffered the same poor filtering, ripple, and early roll off as the other two C-media DACs. Again, this will create significant phase shift in the audio range. Besides the line output roll off, the other big difference is the 33 ohm headphone load didn’t change the low frequency roll off. So apparently it’s a direct coupled headphone output. The second graph shows the Micro II for comparison. Note the Micro II is flat to below 10 hz into 10K and even does a bit better into 33 ohms:

FiiO D5 Freq Response 10K Line Out (yellow) & 33 Ohms (blue) -3 dBFS -3 dBu 16-44



THD+N vs OUTPUT: The D5 has slightly higher maximum levels than the Micro II but somewhat more distortion into 10K. The headphone jack into 33 ohms managed a relatively impressive (for this class of product) 1.4 Vrms. Into 15 ohms that dropped to 1 Vrms before hitting 1 % THD and into higher impedances it would hit 1.5Vrms. Power levels into 16, 32, 80, 150, 300 and 600 ohms are 63 mW, 61 mW, 28 mW, 7.0 mW and 3.7 mW respectively. While the headphone jack has more output than average, the distortion from both jacks is disappointingly high—generally around or well above the 0.05% goal. The second graph shows the Micro II for comparison (the trace colors are swapped and horizontal scales different):

FiiO D5 1 Khz THD N vs Output 10K (yellow) 33 ohms (blue) 16-44



100 hz 0 dBFS THD+N & OUTPUT IMPEDANCE: The first graph shows the line output can mange the same 1.5 Vrms as the headphone output into high impedance loads. At 0 dBFS the distortion was 0.24% which isn’t great but I’ve seen worse. At least the worst of it is the 2nd harmonic. In the second graph the D5 headphone output is over 1% THD at 1.04 Vrms. Removing the load increases the output to 1.09 Vrms for an output impedance of 0.72 ohms. This is fairly impressive and is another sign there are no output capacitors. The third graph shows the Micro II for comparison:

FiiO D5 Max Line Output 0 dBFS THD N 100 hz 10K BW=22 KhzFiiO D5 Max Headphone Output THD N 100 hz 100K & 15 Ohms (blue) BW=22 Khz



THD+N vs FREQUENCY: The D5 did especially poorly on this test at 0 dBu (775 mV). There’s little difference between the line out jack into 10K and the headphone output into 33 ohms. Both are around 0.06% to 0.10% over most of the audio spectrum and much worse below 100 hz and above 14 khz. This is not what I would call a “clean” DAC. As can be seen by the second graph of the Micro II, it’s significantly worse than even similar C-Media peers. The third graph shows the $30 Behringer UCA202 which has about twenty times less distortion (0.007%) from its line output jacks. An extra $5 buys much better performance despite the UCA202 being a much older design:

FiiO D5 1 Khz THD N vs Frequency ~0 dBu 10K (blue) 33 Ohms (yellow) 16-44

CM119 THD N vs Frequency ~0 dBu 10K (yellow) & 33 ohms (blue) 16-44

UCA202 THD vs Freq 10K (blue) Micro II (yellow) ~0 dBu 16-44


SMPTE IMD 33 OHMS: Even at only around 400 mV the dScope’s calculated SMPTE value of nearly 0.8% was pretty awful. Some of the IMD products clustered next to the 7 Khz signal are well above the desired –80 dB, as is the THD from the 60hz signal. The rest of the spectrum isn’t so bad. While the calculated value is higher, the spectrum is very similar to the Micro-II:

FiiO D5 IMD SMPTE 33 Ohms ~400mV


CCIF IMD MICRO II 44 Khz 33 Ohms: The D5 wasn’t quite as awful as the Micro II on this test but it was still fairly similar with lots of distortion products above –80 dB. This is rather poor performance:

FiiO D5 CCIF IMD -7 dBFS ~0 dBu 33 Ohm 16-44


CCIF IMD MICRO II 44 Khz 10K: Into 10K the CCIF IMD is only slightly better than into 33 ohms above. This is similarly bad to the CM119 and Micro II. The 48 Khz sampling rate was also similar to the Micro II. The second graph shows the Behringer UCA202 for comparison and more how it should look:

FiiO D5 CCIF IMD -7 dBFS ~0 dBu 10K Ohm 16-44

UCA202 CCIF IMD -7 dBFS ~0 dBu 10K Ohms 16-44


NOISE & LINEARITY: The weighted noise of the D5 was about 5 dB worse than the Micro II and very similar to the Syba CM119. This is marginal noise performance but is still acceptable for some applications and similar to the UCA202. The linearity was very similar to the Micro II and CM119 with less than 1 dB of error. The second graph shows the Micro II for comparison:

FiiO D5 -90 dB Noise Linearity ref 0 dBu 16-44



JITTER: Here’s the spectrum from the dScope’s J-Test for jitter. The result shows a lot of low frequency jitter (“spread” in the 11025 hz signal) almost identical to the Syba CM119. It’s much worse than average even compared to the $30 UCA202. At least the frequency accuracy (clock accuracy) is very good as shown by the frequency reading on the left. The second graph shows the UCA202 for comparison. Note how the “spread” is confined to below –118 dB on the UCA202 but reaches up beyond –70 dB with the D5:

FiiO D5 Jitter 11025 hz J-Test 10K Line Out ~400mV 16-44

UCA202 Jitter 11025 hz J-Test 10K ref ~0 dBu 16-44


TECH SUMMARY: Having reviewed the Turtle Beach Micro II, Syba CM119, and now the FiiO D5, it’s fairly obvious three different C-Media USB DAC chips all suffer some of the same major weaknesses. They include:

  • Poor High Frequency and IMD Distortion
  • Poor Jitter Performance
  • Poor High Frequency Response
  • Poor High Frequency Filtering (frequency response ripple in the audio band)
  • Excessive Phase Shift In The Audio Band
  • Excessive Low Frequency Roll Off Via Headphone Outputs (and line output for the D5)

To be honest, I would not choose any of these DACs for myself except for voice chat or a similar non-critical application. And for that use, the FiiO D5 is probably the winner because of its extra controls and features. Otherwise all three C-Media based DACs offer relatively poor audio performance. It’s likely most computers have better sound hardware built in—especially if it’s by Realtek, Intel, or Creative. The relatively poor performance of these three C-Media DACs also makes me wonder about C-Media in general. Some high end DACs, like the Schiit Audio Bifrost, use C-Media chips and I have to wonder if they too have excessive jitter, etc? Check back soon for two more DAC reviews that offer better performance.


  1. Thank you for the review, although I personally think that you shouldn't waste your time writing long articles for obvious underperformers. A short summary would have sufficed.

  2. "To be honest, I would use any of these DACs myself unless it was for voice chat or a similar non-critical application."

    Wouldn't that be a wouldn't?
    Looks like another detailed and good review :) - great work.

  3. Kudos for another good review. Disappointing results overall. Regarding motherboard audio, I'd place my bets on it being superior to both C-media solutions by a wide margin. Even well-executed AC'97 codec implementations back from 2004 (like the AD1888 that integrates everything into one IC minimizing the need for external components that the motherboard manufacturer can fail to imlement correctly. http://www.analog.com/en/audiovideo-products/audio-codecs/ad1888/products/product.html http://www.analog.com/static/imported-files/data_sheets/AD1888.pdf ) are probably superior.

  4. What about the cheap Muse Mini Dac TDA1543 X 4 NOS ? http://www.head-fi.org/t/512389/mini-dac-tda1543-x-4-nos

  5. Oh well, another one bites the dust... I am sure you meant "...wouldn't use..." in the first sentence of your last paragraph. I am waiting for the E10 review, so hopefully they got more right in that one.

    From a post made by Feiao in a H-F thread, he states (paraphrasing) "We just decide the final circuit structure:
    USB receiver: TE7022
    D/A converter: WM8740
    Volume control: ALPS potentiometer
    AMP section: AD8397
    OutputZ: <1Ω
    With gain control , bass boost , USB-COAXIAL output, line out and headphone out."

    If even they got the DAC part good enough, it may make a decent match to the O₂. On an interesting note, I purchased some time ago an E1 (USD12.00) and just got email confirmation from them that the output impedance is only .12Ω. My iTouch 3g gets plenty loud enough for my single BA UE Super.fi 3's but I did notice better sound quality through the E1 as opposed to the iTouch's 7Ω output. My IEM's say they are 13Ω and 115dB/mW.

    Are you planning to include optical or S/PDIF input in addition to USB for the ODA? It would come in handy, at least for me, as I would primarily use the coax or BNC input with my digital mixers S/PDIF output to bypass the built-in head amp. Additionally, all Mac's have Toslink® output inside the 3.5mm output jack.

    As always, your posts are a joy to read and I look forward to getting my O2 boards from JDS so I can build them up before Christmas. Cheers and keep up the good work!

  6. What are your thoughts on non-oversampling DAC's?

  7. Thanks to those who caught the missing "not" in the last paragraph. It's fixed.

    @inarc, I'm trying to keep these reviews concise while still trying to provide enough to compare each product to my other reviews. I've omitted several tests already. If I just came out and said don't buy any of the three DACs I'm sure some would start asking "why not?". The whole idea behind this blog is to back up my claims with detailed measurements.

    And the next two reviews should help put the three C-media DACs in perspective. The UCA202 also is an interesting comparison.

    @FlAudioGuy, I'm anxious to test the E10. It might be a good bargain in a USB DAC especially as it supports 24 bit operation via USB. The E1, OTOH, I'm not going to bother with. I've seen enough tests of the E1 to know it has some serious problems.

    If the O2 is for use with your SF3s you'll ideally want one of the gain options to be 1X.

  8. Thank you for the article.

    Maybe the price range for the last few DACs was set too tight. But I agree that having conclusive proof, that nothing this cheap is suitable for listening to music, is useful information.

    However what still suprises me is that you can have this big a difference in actual noise levels (orders of magnitude), and still see only little difference in the result for A-Weighted noise. Are our ears that biased? Or did I maybe misinterpret the table?

  9. Thanks for the heads up on the E1. I would be interested in reading some tests as I couldn't find any. I figured for $12 it wasn't a long-term keeper. I don't play loud through the SF3's, so if the problems lie with clipping perhaps I am just not hearing it. To my ears the bass does seem more prominent through the E1, though I will not rule out subjective bias. Or maybe the low .5V LOD output into the E1 doesn't power it properly and everything is distorted coming out! I will say I do not like the buttons at all, they are too sensitive and the clip is oriented backwards.

  10. Oh, and yes, 1X will be a gain setting for me as the SF3's are my primary monitors. I will make the 2nd gain setting probably 2.5X for future use.

  11. Those indeed are some disappointing numbers. Until I read this review, I thought the D5 was just D3 with USB connection rather than optical connection. The D3 has been gathering a good reputation, and it even supports 192KHz/24bit signal decoding. Is there a chance that the D3 might get reviewed?

    Anyways, D3 is just a matter of curiosity, and what I'm truly looking forward to is the E10 review, as I'm in the market for a cheap USB DAC/Amp with 96KHz/24bit support.

    Again, thanks for the review.

    1. There is some information and limited measurements of the D3 available here and here. It is apparently not as bad as the D5, but if the measurements are correct, the frequency response and (particularly high frequency) distortion are still worse than some newer generation onboard codec chips.

  12. @Anon, The D3 is likely not much better than the DAC built into network music players, etc. And not many PCs (especially laptops) have digital outputs. Using a USB -> S/PDIF box is just another source of potential jitter, another clock, etc. It's much better, and more elegant, to have everything in one box running from a single clock. So I just don't see many applications for a cheapo external non-USB DAC.

    @Guilty Spark, I'm not sure what you mean by an order of magnitude of noise difference? The TB Micro II has 34 uV of raw noise and the D5 has 47 uV--that's a 2.8 dB difference and far from an order of magnitude. There's a 4.8 dB difference in the A-weighted noise due to the different spectral distribution between the two DACs.

    Referenced to maximum output, 16 bits only yields a theoretical maximum range of 96 dB. For the Micro II that would be 1.26V/34uV or 91.4 dB. For the D5 it's 1.53V/47uV or 90.2 dB. So the unweighted dynamic range of each, due to the higher output of the D5, is only 1.2 dB apart.

  13. Thanks for the article! Quite stoked that you are trying to test the E10 out. Fiio did say on head-fi that the D3 and D5 series are really aimed for consumer use, whilst the E series is aimed for high-performance usage, so I am hoping that better performance can be observed from the E10, especially after the performance of the E7 on the bench. (Fiio claims to have improved upon the performance of the E7 by removing the OLED screen and the battery, and opting to refine the DAC and analog stage with the savings).

  14. The THD+N charts on all these C-Media DACs looks odd to me. Do you get the feeling that the chosen fabrication process is to blame? It looks like "thin" chip design... maybe too prone to voltage scatter. Is there any insight that you have about what makes these so bad?

  15. @akgk171 I'm not sure what's to blame for the high overall distortion and especially poor high frequency performance of all three C-Media chips, but it's hard to believe they don't know about the problems. And if that's true, they're obviously happy with such poor performance.

    If it was just one chip, and they fixed the problems in later revisions, that would be one thing. But it seems they believe distortion that's only 42 dB below the signal really is "good enough" for several of their mainstream parts. That's why I've lost a lot of respect for C-Media. Most of the motherboard chips, which are likely similarly priced, have far better performance, as do the relatively ancient low-end TI PCM2xxx chips.

  16. Thanks for this review. Didn't think Fiio would release something like this after their more than decent offerings in the past. But then again, this is more consumer oriented right?

    Maybe you can help me out. I have a LCD tv that I want to hook up to an old amp (NAD 3020e). I don't want to use the tv's headphone out so I'm stuck with optical/coaxial, since the tv doesn't have a regular analog out. The Fiio D3 seemed like a good option to fix this. Are there better options for me out there, around that budget/slightly higher? Thanks!

  17. @Erik, Assuming the TV will output regular 48 Khz PCM (vs Dolby Digital, etc.) the D3 should work just fine. Given the compressed nature of TV audio I don't think it's worth using a higher-end DAC. But make sure your TV has a menu setting for what kind of digital audio it will output. Otherwise on surround programming it will automatically switch to Dolby Digital and the D3 will either mute or freak out. The TV has to "downmix" surround to 2 channel PCM.

  18. 1. Are we going to see an analysis in the future about what kind of maladies the USB interface (the chip that feeds the DAC) can introduce or prevent?

    2. I've been reading a lot of TI's tech documents and they are showing me that there is no simple implementation of a DAC that can sound first class... or at least that's how they make me feel. Is that a good sales tactic on their end or are they right about needing a ton of pieces coming together just right?

  19. @akgk171, you bring up some good points. I do plan a USB article or two as it's a topic with a lot of confusion, myths, etc. And, to be honest, I don't yet know the answers to some of the questions myself. I need to make more measurements with different USB DAC hardware and I also hope to conduct some blind ABX tests.

    The USB DAC I'm hoping to pair with the upcoming ODA desktop headphone amp is a fairly simple solution. If it works well, it will at least partly prove TI's marketing wrong. :)

    There is surprisingly little solid published research quantifying the audibility of various kinds of jitter. And jitter is one of the more challenging things to get right--especially in more complex multi-chip (or worse multi-board or multi-box) D/A solutions.

    It's generally accepted that distortion products below -80 dB are inaudible. But, unlike amplifiers, DACs introduce things like low frequency jitter (which is heard more as "wow and flutter"), modulation noise, and often significant phase shift from the filtering. Those things are much harder to correlate with audible differences and/or establish a clear threshold.

    DACs also suffer from a certain amount of aliasing components that can end up in the audible spectrum. Some question if simple swept sine, chirp and/or impulse FFT testing is enough to fully reveal these components. One can say if the components below 20 Khz are under -80 dB they're likely not an audible problem. But do test signals fully reveal all such alias components? It's easy to use audio differencing with amplifiers to prove sine wave testing really does correlate with their performance playing real music. But that's more difficult to do with the time shifts related to digital devices like a DAC.

    We know that some DACs (and A/D's) can be entirely transparent from tests like Meyer & Moran. But they used professional grade hardware. The Matrix Audio blind test demonstrated the DAC in a cheap consumer Sony CD player could not be distinguished from a much more expensive Wadia high-end audiophle DAC. But what happens with USB computer audio with additional potential sources of jitter, etc?

    I'm hoping to use a mix of blind testing, bench testing, and possibly audio differencing, to try and shine at least a bit more light on where the point of diminishing returns is for DAC performance.

  20. Wow, that sounds exciting NwAvGuy! :D

    By orders of magnitude in my last comment I meant the THD+N ratings, that result in only one or two dBu difference of A-Weighted noise between the products.

  21. Hi NwAvGuy,

    I tried to use your contact form but kept getting an error message on send... We'd like to invite you up to our offices to give an objective review of some of our new items!

  22. @Brain, thanks for the invite. I'm not sure which office location you're thinking of, but I might be interested. The dScope works with a laptop and is portable. I've switched the contact page to use an external link and it seems to be working now. So please try again.

  23. D5 is designed to mass consumer market but not for audiophile. that is why it support MIC in which is total useless for audiophile.

  24. @NwAvGuy, concerning the out of band noise that ends up in the audible spectrum, there appears (to me, at least) that there's some difinitive proof found in Figure 10 of the AK4480 DAC's Eval Board manual (see page 14). http://www.akm.com/datasheets/akd4480-sb2-02e.pdf

    I don't know if that's technically audible, but it's definately measured and visible vs. Figure 9. The low frequency stair-stepping is odd but the entire noise floor is also elevated.

  25. @akg, Thanks for that link. Those are some nice measurements and more than usually found in DAC chip datasheets alone (vs reference designs). The AK4480 aces some of them.

    The stair stepping represents the FFT bins of the AP analyzer. They apparently had it set for a fairly small FFT size which gives coarse resolution at low frequencies. It has nothing to do with the DAC.

    The slight rise above 60K is typical of the noise shaping in many 1 bit DACs. The idea is to push as much noise above Fs/2 as possible (i.e. above 22 Khz).


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