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Hifiman he-400i Impressions and Discussion

Discussion in 'Headphones (full-size)' started by MattTCG, Jan 8, 2014.
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  1. DavidA
    @lurk, I think the new HE400i with the 2.5mm jacks are built to a lower QC standard since a friend who has one had to replace the ear pads after a year, they started to rip at the seams in a few places so they were replaced with Dekoni sheep skin ones which seem to have lasted a few years now and look great.
    forgot to add that my HE400i gets very little use these days, maybe used once a week at the most.
    Last edited: Dec 4, 2018
  2. lurk
    OK, I may hv gotten my dates wrong.
    My he400i is the smc version
  3. DavidA
    I'd say they are at lest 3 years old if they have the SMC jacks but I'm still a bit concerned that my HE400i will look like yours in a few years.
  4. lurk
    I live in the tropics, with the headphones getting sun on a daily basis

    Hot and humid all year long,
    Maybe thts why the p/leather deteriorates fast
  5. DavidA
    You might be right about the environmental conditions playing a part in the deterioration of the leather/pleather. While I do live in Hawaii about 200 yards from Ala Moana beach I usually have the AC on 24/7
  6. lurk
    I posted similar photo of my hd800s earpads earlier 20181128_122153_HDR.jpg
    DavidA likes this.
  7. CoFire
    Wow, that 400i has some battle damage! Looks to me like MANY hours of enjoyment. My 400i are 3 years old, the headband looks good but the earpads are cashed! I bought Focus A replacements and ZMF Universe Preforated Lambskin, not sure I'll ever put the Focus A back on them. I ordered some ZMF Eikon to see what all the clamor is about but either way, I think both pads are winners with the 400i (having not confirmed the Eikon pads).
  8. E1DA
    Just finished test of the new PowerDAC version #2 which is a bit smaller and less noisy(-102dbA). 72 LVC gates power stage(the first one had 64) provides 1.3ohm output impedance and 0.432A output current per channel. In case USB3 with 0.9A rated current, PowerDAC can work safely at >=11.5ohm drivers and provide up to 1W/channel. I think, -102db(A) for an open loop system(no any feedback) is a very good result and it is close to ordinary headphone DAC+amp combos S/N.
  9. E1DA
    PowerDAC_v2_square_1kHz.png PowerDAC_v2_square_1kHz.png PowerDAC_v2_square_20Hz.png Today I had tested an impulse response 1kHz and 20Hz square wave, looks not bad.
  10. E1DA
    Haaaah! I got -106dbA Signal/Noise finally )) Hmm, it becomes closer and closer to an ideal solution for a person who spends a lot of time afront of laptop/desktop and who need high-resolution audio from USB with output power numbers typical rather for AC powered headphone-amps than for USB cable dongle DAC :wink:
    HungryPanda likes this.
  11. AJZ0
    No correction needed. Rather than waste your time just telling you that I can sometime remember things, I took some measurements. The equipment used was
    Ambient noise.

    High gain, maximum volume, no bass boost.

    Low gain, maximum volume, no bass boost.

    High gain, maximum volume, bass boost.

    Low gain, maximum volume, bass boost.

    Audio output to Q1.

    I am well aware of many, if not all, of the limitations of this test and discourage any generalisation based on the measurements shown and any exclusive discussion in this thread. Notwithstanding these limitations, this does demonstrate that the Q1 can drive the HE400i hard enough to make some loud noise, especially on high gain which was easily audible many meters from the measurement rig.
  12. E1DA
    As I already mentioned, the simplest and the same time most effective mod of he400i frequency response is a placing on the magnet some phase alignment element. In the best case, it's could be 3D printed phase alignment body, in the simplest case sticky paper(BTW, my 400i has some tracks of applied sticky paper, seems it is factory attempt to adjust freq.resp. but finally, they took stickers off. And after that we should be surprised so different sound of he400i?). I got two freq.resp. with calibrated mic installed in the flat rubber and pressed to he400i, so it is not an absolute value of real response but relative one, sorry I've no artificial ear yet. I adjusted both driver this way to match freq.responses as close as I can, and will keep it a week or two to see my feeling. As you can see, that mode affects mostly 10kHz peak and 14kHz dip. If add some air gap between magnet and paper the effect could be less sharp and around 10mm becomes almost not noticeable. Also I believe effect could be reduced if use less density paper like tissue. The sound with such mod makes more body feeling for a voices, significantly less sibiliants(probably too much), and much more and thinner hi-hats(doesn't looks too much) etc. Overall, I tend to call a new sound of modified he400i as "more expensive" but a bit dark(I feel that 5-10kHz range reduced too much) and probably less loud WeChat Image_20181225140455.jpg 2018-12-25_13-21-03.png :wink:
    Last edited: Dec 25, 2018
  13. ls13coco
    I haven't looked into this at all yet, but is there any known "backplate mod" for 400i's that do not have a backplate?
  14. E1DA
    not sure if I understand but if a "backplate" means grill then I have to say I tried he400i without the grill and found no big difference with the original frequency response. I even did put there 2 layers of 5mm felt to get less ambient noise propagation, and if I remember correctly it is just slightly affected 10-20Hz. I.e. grill-mods essentially have homeopathic-placebo relief.
  15. E1DA
    as I remember, a home cinema theater specs require at least 105db max SPL so 87db is far below that(1/63 power difference). Probably you'll get better result at music signal instead of pink noise.
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