Saturday, 23 February 2013


Since late 2012, I upgraded my computer workstation's DAC to the ASUS XONAR Essence One and this left my E-MU 0404USB free to be used as a dedicated ADC and measurement device.

For ease of use, I decided to "standardize" on the RightMark Audio Analyzer suite of measurements for these USB0404 measurements. At this time, the newest version is 6.2.5, available free from the website. In time, I might upgrade to the PRO version. What I can say so far is that RMAA is remarkably consistent with good inter-test reliability so long as one has the technique figured out with one's equipment. It's very easy to get things wrong during calibration for example. As usual, there are the caveats to keep in mind and the results I get here may not be comparable with others (good writeup here:

One nice feature about external DAC/ADC's like this one is the fact that it has LED's to indicate if signal is clipping. I've found this invaluable in measurements since it allows me to make sure I'm maximizing the measurable dynamic range.

To get a sense of what the E-MU 0404USB is capable of, here are a few numbers in RCA loopback mode - it looks like the 0404USB is not bad as a DAC itself! Internal DAC chip AKM AK4396 (same as Transporter).

Setup: AMD Phenom X4 Win 8 laptop on battery <---> USB2 <---> E-MU 0404USB (RCA loopback)
0404USB Driver: 1.40.00 Beta, L6.1.30.07 firmware.
USB cable used: generic high quality (<$20)
RCA cable: simple Radio Shack headphone phono to stereo RCA cable. As you can see in the image above, I have some generic RCA-to-XLR converters as well to plug into the analogue inputs up front.

Summary compared with Logitech Transporter (more detailed measurements of this device in a future blog post):
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Notice that the Transporter measures better here but it is using XLR cables. If I had some balanced TSR to XLR's for the E-MU, I suspect the it would be even better.

Nice and flat frequency response at 24/96:

Here's the THD graph (24/96 again):

The jitter is really good for the E-MU also (it uses an asynchronous USB2 interface). This was done with the Dunn J-Test at 24/48 playing and analyzed with WaveSpectra 1.40E running a 131,072 point Blackman-Harris FFT. Note that I have seen various comments made in the forums that the 0404USB has bad jitter issues - well, I don't see it, in fact if I were to estimate, we're looking at <250ps using both the DAC and ADC in this case:
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With digital silence playing, here's what the noise floor looks like:
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A few spikes noted, the tallest about -135dB down.

Noise floor zoomed into 0-100Hz range - notice essentially no 60Hz pollution:
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For such an inexpensive unit, I'm impressed! In the days ahead, I'll update this blog with the other DAC's and devices tested... I certainly do not claim that the 0404USB is near as good as dedicated measurement gear like the AP devices used by Stereophile. However, for the at home hobbyist, I suspect these kinds of tests will do nicely to help differentiate what's reasonably good from the bad.

From a subjective perspective, I've enjoyed using the 0404USB as my main DAC for about 3 years. The sound is precise and clean. Some would call it "analytical" but I honestly have no idea what that's supposed to mean since that sounds like a good thing to me :-). Basically, an honest portrayal of the digital audio with a good flat frequency response.

I do have a few gripes:
1. It's discontinued and the drivers were never great.  As noted above, I'm using the latest "beta" driver which is at least a couple years old. At least it's still compatible with Windows 8! On occasion, if I used the ASIO driver, it would mess up Windows mixer and I'd need to reset the sampling playback rate.

2. The headphone out is weak. It's fine with efficient headphones but my AKG Q701's were too much for the headphone amp.

3. Volume pot's got a bit noisy over the years.


  1. Hi, have you tested the latency using a VST? I'm planning to get this one, but I'm afraid about the lack of driver updates, although it have one of the best DAC in their price range.

    1. I actually have not tested this unit with VST, Renato. I see mixed reviews on the net and I suspect it's best to ask this on a place like GearSlutz for those with experience.

      The ADC is very good and I have done some home recordings with various mics, but nothing complex...

  2. I've read your review about Asus Xonar, and I've see the price is almost 3 times the value of EMU 0404.

    You wrote XONAR is your new DAC, raplacing the EMU. Analysing the numbers, both are pretty same (at least in result numbers).

    So, what makes Xonar better than EMU?


    1. Objectively in terms of sound quality, not much difference :-)

      Reasons for upgrade:
      1. Better headphone amp - can finally drive my AKG Q701 to good volumes.
      2. Better drivers - ASIO on the EMU was very spotty every time sampling rate got changed resulting in the occasional need to reset the unit or go into the audio controls in Windows.

      Worth the price? Well, that's completely subjective :-)

      One unit I probably would look at these days is the TEAC UD-501 for an even richer feature set though I don't know if the headphone portion would drive the Q701 well.

  3. Would you say, that E-MU 0404 USB is a good choice in 2017?
    Given, that there're no issues with drivers (there are no on linux, btw)

    1. Hi edio,
      No, I would not recommend the 0404USB these days. Still works great for recording of course but the drivers are dated in the world of Windows 10 and if you switch between different hi-res samplerates, sometimes you'll run into crashes and driver instabilities...


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  5. Not sure if anybody is still reading here. However I recently got an E-MU 0404USB which it seems it's still hard to beat without going up to the few hundreds $ range. I see you were using the XLR input with an RCA-to-XLR adapter. But to my understanding this way one gets the input mic that has 1.5kOhm impedance, isn't this too low to test line outputs? Using an RCA-to-TS, conversely, makes the ADC noise floor too high for unbalanced testing.

    1. Hi Interference,
      Good point about the use of the RCA-2-XLR adaptor and impedance.

      Yeah, depending on the analogue output impedance of the device, there could be some issue with 1.5kOhm. For most of the devices I checked out back when I was using the 0404USB, the output impedance of these were thankfully significantly lower. For example, my "reference" DAC for awhile was the TEAC UD-501 which has RCA output impedance of 22-ohms and XLR out was 88-ohms.

      This was improved when I upgraded the ADC to the Focusrite Forte in 2016 which has a line input level of 44kOhm.

      The RME ADI-2 Pro FS I'm using these days have XLR input impedance of 18kOhm and unbalanced 9kOhm.

      Agree, despite the age and new devices out there now, the 0404USB is still a remarkable piece of gear!

    2. Thanks for the answer! One can assume that whatever device is able to measure well on the E-MU XLR (mic) input will have no problem driving any kind of line-level input, still it may be a demanding impedance. I will try to experiment a bit with the devices in my possession :)

  6. FYI, I too am interested in the E-MU 0404 in 2020 for use with RMAA and as a preamp for a room measurement microphone. Several users at Gearslutz are successfully using the 0404 USB with Win 10 x64 version 1809 (OS Build 17763.316) as recent as March 1, 2020.

    So it may still work with the latest 1909 build of Win 10 x64.

  7. Correction: as recent as March 1, 2019. Sorry about that. :)

  8. It apparently also works on macOS Catalina.