Audio-Technica hybrid tube headphone amplifier.

Audio-Technica AT-HA22TUBE

Rating:
4.5/5,
  • Audio-Technica hybrid tube headphone amplifier.

Recent Reviews

  1. earfonia
    Excellent hybrid tube headphone amplifier!
    Written by earfonia
    Published Nov 23, 2015
    4.5/5,
    Pros - Very good and musical sound quality, rollable tube, and earphone friendly -12 dB attenuation feature.
    Cons - Amplifier casing doesn't seem to be properly grounded & headphone output may get EMI noise when amplifier is close to EMI transmitting devices.
    This is only the summary part of an in-depth review of this headphone amplifier. Please visit this link for a more in-depth review (comparisons, features, measurement, and tube rolling) of AT-HA22TUBE:

    Audio-Technica AT-HA22TUBE In-Depth Review
     

     
     
    It was during last year (2014) Audio-Technica event in Singapore, that I had the opportunity to audition the AT-HA22TUBE headphone amplifier. Tested it with a few headphones, I was quite impressed with the sound signature. Few months later, I get a unit for myself. I've started drafting this review many months back, and it has been delayed due to unforeseen tight schedules. Glad that I finally manage to post the review of this wonderful small desktop tube amplifier.
     
    http://www.audio-technica.com.sg/products/amplifiers/at-ha22tube
     
     

     

     
    AT-HA22TUBE is a small desktop hybrid headphone amplifier. The gain stage is using modern tube, JJ E88CC, and solid state power transistors are used for the output stage. This configuration is aimed to combine the rich & smooth tube signature with the drive ability and transparency of solid state transistor, to get the best of both worlds. The tube is on socket, therefore can be easily replaced by other compatible E88CC / 6922 tube transistors.
     
    The following is a nice Audio-Technica advertisement video (in Japanese). The video shows the circuit board of the AT-HA22TUBE. All discrete components without any Op-Amp.
     
    https://www.youtube.com/watch?v=-XRdnHldMEs

     
     

     
    The case is solid and well made, made of aluminium alloy with die-cast front panel. On top, die cast tube cover is to protect the tubes, which can be removed for tube replacement. Overall build quality is solid and very good.
     
     

     
    Before getting into details here are some points of Pros, Cons, and some suggestions for improvement.
     
     
    Pros:
    Great sound quality. Neutral, lively & musical sounding.
    Rollable tube.
    Earphone friendly -12 dB attenuation feature.
     
     
    Cons:
    Amplifier casing doesn't seem to be properly grounded and headphone output may get EMI noise when the amplifier is placed in close proximity to EMI transmitting devices such as cordless DECT phone.
     
     
    Suggestions for improvements:
    Improve power supply with properly grounded power supply and casing to improve EMI immunity.
    Higher output power.
     
     
     
     
     

    Sound Quality

     
    The sound signature described here is based on the stock tube JJ E88CC. DACs that I used most for this review are ifi micro iDSD and LH Geek Pulse XFi. As for headphones, ATH-MSR7LTD, Beyerdynamic T1, and Sennheiser HD800 are my references for sound signature evaluation. I used other headphones and IEMs as well, but those three are the main headphones for evaluation.
     
     

     
    Neutral, smooth, and spacious is how I perceived the AT-HA22TUBE sound signature. AT-HA22TUBE is not the type of tube amplifier with very warm and mellow sound signature. It doesn't really sound tubish from tube amp perspective. In fact, AT-HA22TUBE is quite a transparent and neutral sounding tube amplifier, but not at the transparency level of an analytical sounding solid state amplifier. It has mild tube warmness and richness, effective enough to smoothen edgy treble without giving too much colouration or sacrificing details. It has the combination of smoothness of a tube amp and transparency of a solid state amp in a nice proportion. AT-HA22TUBE let me hear the characteristic of the various DAC output quite easily, which is a sign of a good headphone amplifier. While it does has tube flavour in its signature, but it does it in a transparent way, and still reveals the character of the source quite clearly.
     
     

     
    Bass sounds full with good weight and punch, but the speed is around average. Not very fast but not slow either. When the tube replaced to Genalex Gold Lion E88CC, bass tightness and speed improves slightly. Midrange is mildly warm and smooth with good tonal density. And the treble is smooth and transparent. Transient and dynamic are good. Though I don't consider the AT-HA22TUBE as super-fast and punchy, but I never felt the dynamic is lazy or lacking speed. It is quite lively sounding with good dynamic. Decay sounds quite natural, and a tad longer, less dry than my Violectric HPA V200 which sounds a little dry in comparison. Perceived level of detail is very good, realistic enough without being over emphasized. But it is clearly not an analytical sounding amplifier.
     
    What I like most is the level of holographic imaging and spaciousness that beats my Violectric HPA V200 desktop amplifier that cost a few times AT-HA22TUBE. And that alone speaks a lot of how good this little tube amp is. For those looking for a tube amp with strong tube flavour, AT-HA22TUBE might not be the right choice, at least with the stock tube. Though AT-HA22TUBE may have stronger tube flavour with different tube, the stock tube only gives mild tube flavour, which is actually just nice to make AT-HA22TUBE a good all-rounder amp, which goes well with wide variety of headphones and recording genres. AT-HA22TUBE sound signature matches quite well with my personal preference and after using it for almost a year; I honestly like it a lot. I do wish the bass could be tightened a little bit, I'm a fan of fast and tight bass, but for the price there is nothing to be complained of. The bass is fast and tight enough to make me toe tapping.
     
     

     
    I find AT-HA22TUBE matches easily with many headphones and IEMs, but especially good with neutral to bright sounding ones like ATH-MSR7/LTD, Beyerdynamic T1, and Sennheiser HD800. ATH-W1000Z was also sounded very good and enjoyable with AT-HA22TUBE when I reviewed it a while ago. As for IEMs, I really like how my DUNU DN-1000, DN-2000, DN-2000J and 1964 Ears V3 sound when paired with AT-HA22TUBE. I can hear a soft hiss noise on 1964 Ears V3, but hiss noise on IEM Is pretty low and at acceptable level. No audible hiss noise on dynamic drive IEMs that I tried. Especially for DN-2000J, so far I haven't found better amp or DAPs in my collection that matches DN-2000J better than AT-HA22TUBE. AT-HA22TUBE is simply a very musical and enjoyable little desktop tube amplifier.
     
     
     
     
    Personally I'm not a great fan of tube amplifiers with strong tube flavour, or those that sounding too warm and mellow. I prefer fast, detailed, and dynamic sounding amplifier with spacious holographic imaging, that doesn't sound harsh or analytical. AT-HA22TUBE being a hybrid amplifier is surprisingly has the sound signature that is pretty close to my personal preference. For the price, it is a steal! Kudos Audio-Technica!
     

     
     
     
     
    For more information about comparisons, features, measurement and tube rolling, please visit:

    Audio-Technica AT-HA22TUBE In-Depth Review

    1. View previous replies...
    2. dw1narso
      I mean RFI...
      dw1narso, Nov 25, 2015
    3. earfonia
      @dw1narso Wow that's very good info! Thank you! 
      In that case the tube cover holes need to be smaller.
      earfonia, Nov 26, 2015
    4. dw1narso
      One way to reduce RF to penetrate the tube, is to filter the RF before going in the tube. For example using low pass filter and or grid stopper.
      dw1narso, Nov 26, 2015

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