MASS-Kobo Headphone Amp. model404

Discussion in 'Portable Headphone Amps' started by seeteeyou, Feb 8, 2015.
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  1. Overkill Red
    Just wondering if anyone has any impressions of the 404 with a set of modded/unmodded HD800s?
    I need a portable solution for the HD800s as I don't have enough fixed room on my desk, and the 404 is on my shortlist (trying to source a used one actually)
  2. mrmax

    Did you mean HD800 or HD800S? I have the latter and i think the 404 is the best portable/transportable amp for it. Very transparent and powerful. Of course a full on desktop amp is better but for the past 2--3 years (yes, i did try it using HD800 non-S) no portable solution has come close to it. Be sure your source is good though since IME, a poor source feeding the 404 will sound poorly with the HD800.
    Overkill Red likes this.
  3. Overkill Red
    Hey, sorry I meant the HD800.
    My current situation doesn't let me keep a full on desktop amplifier as I keep moving between residences, so I was looking for a really great transportable.
    I'll be using either a modded AK240SS or a Chord Hugo or both, so I should be alright on the source department!
    Currently trying to source one used, I've also emailed Mass Kobo but I'm not sure how good their English is..
  4. mrmax

    I think masuda san knows a bit of english as i saw some posts from his personal fb in english.

    Good luck.
  5. zachchen1996
    I'm selling my mass kobo 404 if anyone is interested! :)
    (sorry for the shameless plug lol)
  6. audionewbi
  7. Meowheng
  8. mrmax
    Saw this a couple of months ago.

    Nordost are expensive, honestly haven’t heard one yet. The opamp, i’ve always wanted to try as the stock is ne5532 i think.

    I’m really curious as well.
  9. audionewbi
    Time to contact the designer, if I do hear back I will post.

    Mass kobo 404 was always in my buy list however like the tera player missed out on the initial price deal.
  10. rq1111
    I had tried Mass Kobo 404 with HD800S but I prefer Hugo 1. Hugo is better than Mojo and 404. Mojo will sounds sibilance while Hugo smooth high treble and airy too.
  11. john1711
  12. audionewbi
    Mass Kobo 424 is due soon,anyone excited?
  13. lithiumnk
    Mass Kobo 424. This has added a new dimension to sp 1000. This japanese custom made amp has left me startled. Its like i am listening to a new player with a beefy amp. The 3.5mm grounding connection has improved the SQ to a great extent. I have set line out to 1v/1.25v on sp1k. It has adjustable output gain-changing switch for dynamic/planar hp & highly sensitive BA. Drives my lcd i4 with authority. The dynamics, bass slam & transparency are insane with pitch black background, fast transients and deep soundstage. Throw any type of music at it. It excels in all departments imho.
    The custom cable is made of 10 silver OFC wires; 8 for balanced(2.5mm) & 2 for earth(3.5mm) furutech plugs to pentaconn(4.4mm) connector. Running on 4 Panasonic Eneloop Pro rechargeable batteries (Japan Import).
    Highly recommended. Best portable solution imho.

    SP 1K CU + Mass Kobo 424 + Double Helix Cables ultrashort adapter male XLR to 2.5mm + Audeze Lcd i4 (balanced EA Horus). Output set to 0.7v in this pic. At 1.25v the volume pot remains from 7-8 o'clock.


    Adjustable output gain-changing switch



    <Specifications> (Batt. 6V or USB 5V)

    Model: Full-Balanced Portable Stereo headphone amplifier
    Input: φ4.4 TRRS x 1 (balanced or unbalanced)
    Output: model424 XLR-4Pin model428 4.4 TRRS (balanced) , φ3.5 TRS (unbalanced)
    Maximum Input Level: +16dBm (balanced), +10dBm (unbalanced)
    Maximum Output Level (P-P): 7 V (balanced), 3.5V (unbalanced) (with 32Ω loaded, 1kHz, THD+N 0.5%)
               (RMS): 2.3V (balanced) , 1.2 V (unbalanced) (with 32Ω loaded, 1kHz, THD+N 0.5%)
    Maximum Output without Distortion: 165mW (balanced), 45mW (unbalanced) (with 32Ω load, 1kHz, THD+N 0.5%)
    Frequency Characteristics: 20Hz - 20kHz (-1dB)
    Noise Level: Less than 40μV (in the minimum volume position, 32Ω loaded) Less than 150μV (in the maximum volume position, 32Ω loaded)
    Power Supply: AA Alkaline or rechargeable battery x 4
    External Power Supply: Micro USB +5v
    Consumption Current: 0.19A (battery 6V, No signal) 0.21A (rechargeable battery, 4.8V No signal) 0.21A (USB 5V, No signal)
               0.28A (battery 6V, 1/8 Output) 0.32 A(rechargeable battery, 4.8V, 1/8 output) 0.31A(USB 5V, 1/8 Output)
               0.49A (battery 6V, Maximum Output) 0.61A (rechargeable battery), 4.8V, Maximum Output) 0.58A (USB 5V, Maximum Output)
    Size: 97mmW x 132mmD x 40mmH (not include protrusions)
    Weight: model424 445g (with batteries), 387g (without batteries)
        model428 440g (with batteries), 382g (without batteries)
  14. zachchen1996
    Congratulations on your 424! I had the 404 and LOVED it but unfortunately sold it due to the gain being too high for the SE5 ultimate.
    If it's true that this new model works well with sensitive multi ba iems, I'll definitely have to put this on my buy list haha. :)
    lithiumnk likes this.
  15. lithiumnk
    Thank you.
    Quoting masskobo website " Both models are equipped with the same output gain-changing switch as the one used in model 406, our flagship model. Now you can listen to all types of headphones and earphones, with both dynamic and balanced-armature drivers properly with a single amplifier."
    I hope it helps.

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