HiFiMan HE400S Measurements and Impressions I don't normally do unboxing photos, but see attached. This a nice touch from HFM and a huge improvement from the packaging of the prior generation HFM headphones. BTW, the HE400S is light at 12.5 oz. Before I forget, the HE400S is actually more efficient than the Sennheiser HD650. I didn't need to have the volume knob as high as the HD650 to get the same volume. HE400S Impressions with Cheap Amps: Vali or Magni 2 (Answered Question for Member) My concern with Vali is its slightly higher output impedance, which could be an issue with orthos (softer sound). I suspect it wouldn't be an issue since the HE400S is so darn efficient. Ultimately, it's more a matter of delivered power (of which output impedance does have a lot to do with). But in the end efficiency matters more. Higher efficiency is essentially free power. A lot of free power - given that you need x10 more power to get x2 volume. The HE400S measure a flat ~22 ohms impedance. The output impedance of the Vali is 6.5 ohms. The damping factor is 3.3. Good enough. Coming from the tube world, we like to see ~3.0. I know some folks like to see 5. Others like to see 40,000. Take guidelines with a grain of salt. Bottom line is that it's worth it to give the Vali a shot. I happen to have Vali and Magni 2 on my desk. The DAC used is a Modi 2 since I figured it would be kind of lame if I threw a Yggdrasil in the mix. I figure you guys would be interested in much better amps and headphones if Yggdrasil was already your DAC. So what's the verdict? Hard to say. This is a classic tube(hybrid) vs. solid-state argument. Bass quality on the Magni 2 is better. Lower extension, better sustain, more precision. The Vali's bass doesn't extend as low. It's more murky. Less clear. But not annoying so where I want to say "yuck". Vali does the job on the bass OK and Magni 2 while better, still doesn't win awards for being able to reproduce the most accurate Moffat Bass (i.e., clean precise well articulated low bass with impact.) It wouldn't necessarily say Vali is more resolving with this setup either (a better DAC may change things, but this is out of the scope of this comparison - we are talking budget everything here). However, there's a really nice bloom and engaging quality in the mids. Call it the Donald North Audio effect - something about soapy suds and Sofia Vergara rubbing her boobies on you. I'd have to give the Vali a slight nod, despite inferior bass quality. Both amps are more tonally similar than not (after the Vali warms up). If you listen to a lot of techno or electronic with low bass start-stop stuff, the Magni 2 might the better choice. HE400S Measurements Three notable things: Gradual bass rolloff. Not a showstopper and not really all that noticeable with most music. The slight mid/high bass bump helps alleviate this. Compared to other headphones with flat bass extension all the way down to 20Hz, the HE400 does sound "less full" in the bass. I wouldn't call the HE400S bass light at all. PADS WITH BETTER SEAL: http://www.superbestaudiofriends.or...fiman-he400s-with-focus-pad-measurements.189/ 8kHz peak, but surprisingly not that annoying. Some sibilance, maybe accentuates some grain and adds some harshness. The effects of this peak are less noticeable with resistor ladder/string DACs or vinyl as a source. Tube amps also take a little bit of the edge off. I haven't done CSDs yet, but I don't think we will see significant ringing in the form of long lived ridges at 8kHz. In any event, the good ol' TP mod will do wonders to flatten this peak. Very good low distortion characteristics. Figure 1: HE400S Frequency Response and Distortions Figure 2: HE400S CSD Note the "ortho" walls, the long thin low amplitude extended ringing. I am not sure they are very audible or audible at all. Although we are nitpicking and doing quite a bit of critical analysis, For $299, the HE400S is quite an impressive headphone. As you said, quite neutral... but with a few minor warts understandable at its price point. I can see people who had difficulty with the HE-560 (upper mid peaks) having an easier time with this headphone. Despite the sensitivity (it does work well out of portables), it does like power. Running the HE400S from the Rag and Studio provides a difference experience with more bass heft, slam, and control. Lesser sources result in a softer sound. I agree. The HD600/650 from a top shelf tube amp and top shelf DAC is easily more resolving. Also more air and extended up top. However, the bass quality of the HE400S is superior to the HD600/650. HE400 bass is cleaner and less murky. The murky bass has always been a weakness of the HD600/650. Those with less uber amps and DACs would be well or possibly better served by the HE400S, depending upon sonic priorities. Personally, I do feel that the HE400S does deserve to go on the Leaderboard. It's darn inexpensive, super efficient, and you get pretty ortho sound. I imagine tweaks would do wonders to this headphone.