Review of Objective2 Headphone Amp (Assembled) by JDS Labs

Discussion in 'Headphone Reviews' started by dalethorn, Jan 27, 2012.

  1. dalethorn

    dalethorn Active Member

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    The Objective2 is a small (4-1/4 x 3-1/4 x 1-1/8 inches excluding projections) headphone amp, normally sold as a kit I presume, by JDS Labs (designed by 'NwAvGuy'). It's a beautiful piece of gear and sounds very good. I tried it with a German Maestro 8.35D headphone which is fairly efficient and 35 ohms, and with my strongest material it didn't distort even a little as far as I could hear. My ultimate test for dynamics, despite it not being the very best original recorded quality, is Jimmy Smith's Basin Street Blues (HDTracks FLAC format) where mass horn crescendos at 10 and 14 seconds into the track will stress-test any headphone and amp. I also have a Chesky FLAC track, Wonjung Kim - Girl From Guatemala, which has some major dynamics. That one played well. My stress-test tracks for bass are Afro Celt Sound System - Inion Daughter, Donald Fagen - Morph The Cat, and Pink Floyd - Speak To Me. The bass was as good as I've ever heard.

    With this amp everything is on the front panel. AC input (see below), power switch, miniplug headphone output, LED power indicator, volume control, high/low gain switch, and miniplug line input. I'm using a genuine FiiO right-angle LOD cable to connect to Apple i-devices, and based on my experience using the Apple composite A/V cable with another headphone amp, I'd say the short (2-1/2 inch) FiiO cable does not compromise the sound quality.

    One thing I haven't done is try to get to the batteries. I assumed I would be able to easily swap them and charge them externally, but it appears that the only way to do that is to remove the 4 screws on the back panel and then replace the batteries and the panel after the swap. Not very convenient. And there is a danger factor with this amp. All of the AC adapters I've ever had (and that's a lot!) are AC to DC, but this amp requires an AC to AC adapter to charge the internal batteries if you don't want to swap them as described.

    Running tests with the Sennheiser HD-800, I almost forgot how good the HD-800 sounds. A headphone this good shouldn't live in the closet. The following are a few tracks I used for testing that will reveal various problems in headphones and amplifiers:

    David Chesky/Wonjung Kim - Girl From Guatemala - 96k FLAC:
    The bass of the 800 often gets less than enthusiastic response from users. Listening with this amp - Mmmmm, good. It still won't satisfy most bass mavens, but if you're not a basshead, it works. The extreme highs here with very loud xylophone(?) impacts on the high notes are not only clean and clear, but the tonal colors are vibrant and detailed and you hear things that just get smeared or distorted etc. with less than a decent headphone amp, or most run-of-the-mill headphones. Note: This a a very low-volume track even accounting for the huge dynamics, so I had to use maximum volume on low gain for a decent and fairly loud play. No problems at all. No background noise. So I took the kit into a central room in the house where I could close the door and shut out 99 percent of the daytime noise. Then I put the amp on high gain and ran the volume to maximum and still no amp noise. For just a second I hit 'play' to a music track and BLAST! - turned that one down really fast! There is no noise apparently.

    Cat Stevens - Morning Has Broken - CD rip to 320k CBR MP3:
    This is my main test for "How does it sound in general?", and everything was right. Balance, tone, everything.

    Clark Terry - Sugar Blues - 96k FLAC:
    Another low-volume track played at maximum volume on low gain. The horn blasts here in the last parts of the track have a real edge to them. With this amp and the HD-800, the edges had a certain tonal quality. Does that seem like a peculiar thing to say? With the other headphone the edges were just edgy.

    Scarlatti/Kipnis - Sonata in E - 96k FLAC:
    A very low-volume track played at maximum volume, on high gain this time. Lots of transient detail with the harpsichord's plucked strings - sounds really good.

    Tony Bennett - I Left My Heart In San Francisco - CD rip to 320k MP3:
    This track's sibilants have sibilants, if you get what I mean. The sibilants have a life of their own, like echo effects that reverberate off into space somewhere. You probably can't say "Sssssssssssssss..." as strongly as the sibilants on this track. Yet they're not irritating played fairly loud, even if somewhat unmusical.
     
    Last edited: Jan 28, 2012
  2. dalethorn

    dalethorn Active Member

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    Additional notes on O2 amp

    I don't know if this amp (which is normally a kit) is available in Britain or Europe as yet, but since it's my very first amp review, I figured I should post it anyway. I received it in a small box delivered by the Post Office, so it can probably be mailed anywhere.
     
  3. saturn9

    saturn9 New Member

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  4. dalethorn

    dalethorn Active Member

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    O2 Amp

    I sure hope if anyone orders this that the quality control is consistent and it meets spec. I hear so many comments about low-cost amps and their colorations that I wonder how it could be. A decent headphone amp should be flat from 20 to 20 khz, or flat to very near that range.
     
  5. saturn9

    saturn9 New Member

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    Sorry I've no personal experience of this amp. Be interesting to hear from someone who has!
     
  6. dalethorn

    dalethorn Active Member

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    O2 amp

    After 4 long days of listening, I have a better understanding of why people don't always get the improvement they seek with a particular headphone and amp combo. Here's my experience so far:

    Sennheiser HD-800: Spectacular, no other words to describe it.
    Shure SRH-940: Slightly grainy, not recommended.
    Beyerdynamic DT-48A (oval pads): Same as Shure 940.
    Grado PS-500: Amazing, just amazing.
    German Maestro 8.35D: Excellent in every way.

    All 5 of the above are highly detailed headphones, so the amp is not forcing tighter detail on the SRH-940 and DT-48A to make them sound grainy or whatever. Both sound better on my desktop sound card or even an iPod, believe it or not. I have a feeling (which I can't prove) that the difference is, a headphone which is lighter in the bass and/or lower midrange than the HD-800, PS-500, or GMP 8.35D is not going to fare well with this amp. Something with tubes or which acts similarly to tubes might work better with the DT-48A or SRH-940.
     
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