HIFIMAN EF400 Desktop Balanced Headphone DAC& Amplifier with Himalaya R2R DAC, 3.5/4.4/6.35mm Output for Home Audio

After doing a lot of research online, I was told there would be little reason to buy more expensive dac amps over the K5 Pro that I already own, but surprise surprise, the EF400 made my Planar's sound way better in terms of bass and fullness. I didn't think it would be drastic but A-B testing between both units made it clear enough that it was worth the upgrade. It's also pretty simple to setup and use, I didn't even bother with drivers since it was plug and play. When it came to gaming and watching stuff, as expected it performs exceptionally well. I used High Gain Over Sampling on the Left Knob for Planars and it sounds perfect. Make sure your windows volume is set to 100% and then adjust the Right Knob for volume carefully because this thing can get dangerously loud. Overall very satisfied and I will update this review if this thing dies randomly.

Been using this DAC/AMP for over a year now. I use this with Empyrean II, which still performs very well without any DAC/AMP. However the reason I use this over FiiO7 (the other DAC/AMP I have) is because it emphasizes the good sound design in the bass range. If you want a slight warm touch that could make songs sound "fun", this is a go-to DAC/AMP.Portability: No. Very heavy.Usability: Easy to useComfort: Could be too big to fit on desk. I use it under the desk.Modes: NOS/ OS. High gain / Low gain. I use Low gain OS.

This unit must be used with a PC source. When connected to my iPad Pro as a source, NOS mode produces crackling noises throughout any CD-quality tracks. Engaging OS mode makes the crackling go away, but NOS is the preferred mode for myself and most other EF400 owners. After contacting Hifiman, they say there is no fix for this nor any firmware update in the works. The device does not appear to be firmware updatable at all. That being said, it does have a great sound and is a great performer despite this annoying issue. I prefer using my iPad Pro as a source over my gaming PC as it is cleaner and quieter source, and it works perfectly with all my other DACs and DAC/Amps. There is a quirk with this device with its NOS mode for 44.1 sample rate tracks when connected to lower powered source devices such as iPads, so be aware of this and only purchase if you're planning to use with a PC/Mac source.UPDATE: I figured out how to fix the NOS mode buzzing issues, which seem to only happen on CD quality tracks when using an iPad or iOS device as source. The way to fix it is to use Roon and turn on Sample Conversion and set it to Max. I went back and forth turning it on and off and it really does work, made the buzzing go away, and the buzzing comes back when you turn it off. Glad I finally found a workaround. Still was not convenient and cost me extra to purchase Roon.

Would be well worth it if it lasted past 50 hours of use. I bought a unit and it drove my planars really well and sounded really good until about 50 hours into my burn-in period, then static/ distortion presented in the right channel. Power cycled, disconnected, reconnected, turned Roon off and on etc. problem persists. Will be returning. This was connected via USB C to MacBook Pro using Roon, listening with Arya v2. I am going to chalk this up to low quality caps which I have read were used in the build. I will look for a different R2R solution to compliment my X16/ A90 stack.

The media could not be loaded. It’s a dumb DAC/AMP that sounds fantastic and is very powerful that has no remote or Bluetooth capabilities and doesn’t compete with others in this range but if you don’t care about those features then this is still a solid high end choice. It’s super powerful and I don’t even need to push my headphones past 25% volume. It’s mean to be used with a computer but a phone or iPad will work fine as well. I am using it as part of my meditation setup and running Moondrop Para planars. For convenience I added a WiFi tp link Kasa power adapter that I control through my phone when I want it to turn on / off daily.

It is an incredible value to get a balanced R-2R DAC and a balanced headphone amplifier with this kind of power for this price. Especially one that sounds this good.The sound is better than the Monoprice THX 887 (which I think sounds decent but not fantastic). And, I am a firm believer that specs don't tell the whole story when it comes to sound quality- how a device responds and measures in terms of THD, noise, and response with a static test signal into a static load is a poor predictor of sound quality. For example, the Topping A90 measures extremely well but sounds lousy IMO.This is a very good sounding device. It has the warm, natural R-2R character. It sounds better in NOS mode, unlike my Musician Pegasus R-2R DAC which I prefer with oversampling on. There is less detail and separation compared to the Pegasus, especially in the lower mids on stacked vocal harmonies. But still very good. To me, OS mode has a bit of the glassy, constrained sound of a lesser dac. All oversampling digital filters are not created equal, and I'm not terribly fond of this one. The good news is, with oversampling off, I don't perceive much of a loss in high frequency as a result of filter slope affecting the audible band as I do on the Pegasus.I like my music loud, and this powers hard to drive headphones quite well, including my HEDD Heddphone, and my HE-6SE, although the HE6 could benefit from more power if you like your music loud and with slam. But don't get me wrong, it is really good, and phenomenal for the $There is a slight metallic nature to the timbre of upper treble, like hats and cymbals, but it is minimal and it is the only detracting sonic coloration i can perceive in this unit.Now here is the problem- there seems to be some kind of minor design flaw in the DAC.When I play lossless FLAC files I ripped directly from the original CD, verified bit-perfect rips, I can hear static in both ears, similar to a dirty vinyl record, on quiet passages when in NOS mode. Switch to OS mode and the problem instantly goes away. Play an M4A/AAC compressed version of the same file and there is no problem in either OS or NOS mode (i ripped all my CDs into both FLAC and M4A files).I am using USB Audio Player Pro for Android in Bit-perfect mode on a Samsung Galaxy Note 20 Ultra as my source, via USB-C.I don't have this problem on ANY of my other USB DACs, including R-2R DACs in Non-oversampling mode such as the Musician Pegasus.I figured I may have a defective unit, so I ordered a replacement, and the replacement device does the exact same thing.And, I just noticed another reviewer complaining about the exact same problem. That review is spot on.I've knocked the unit 1 star for this, otherwise it would be a slam dunk 5 stars at this price.