Korean Pocket Rocket: The Audinst Amp-Hp

audinst_amp_hp_02

Most of the portable headphone amplifiers available on the market fall either to the sub $100 or the over $300 range, but with the Audinst AMP-HP, we finally have a solid recommendation in the $100+ range. The AMP-HP is available for $159.00 from Audinst’s eBay store, and though it may not offer fancy specifications on paper nor tiny minute dimensions, Audinst has succeeded in bringing another well-designed product in the market. Let’s take a look at what this amp is all about.

INTRODUCTION TO THE AMP-HP

The AMP-HP comes from the same company that has brought us the much loved Audinst HUD-MX1 desktop DAC/Amp box, almost two years ago. The HUD-MX1 may not be the groundbreaking, technical giant of a DAC. But the combination of features, usability, reliability, all packaged into a fairly affordable price has made the HUD-MX1 into one of the favorite DAC/Amp box in the market. The recipe for the AMP-HP seems to be the same as that of the HUD-MX1: a solid performing product that does the specific job it’s intended to do and offer it at a good price. At $159, the AMP-HP outclasses all of the sub $100 portable amps that we’ve reviewed. It may not offer the slim and tiny build of the $300 amps, vacuum tube  amplification like on the ALO Continental amp (a review coming up), or balanced drive as in the Ibasso or RSA balanced amps. But at $159, it’s an amp that will deliver the needs of most of the portable audio users out there: a powerful, punchy sounding amp with a solid build quality. Build quality is very mature, evident from the quality of the enclosure, knobs and switches. It is better built than all of the sub $100 amps I’ve reviewed, and it even offers a better build quality than a lot of the $300+ portable amplifiers I reviewed in the Usual Suspects.

GAIN SETTINGS

I was slightly puzzled and disappointed when I first received the AMP-HP as I couldn’t find any gain selector switch. I immediately thought that Audinst had missed such an important detail on this otherwise excellent looking amp. But as I spend time with the amp, I found out that the AMP-HP doesn’t seem to need any gain switch. I can be listening to the JH5Pro IEM, which is one of the most sensitive sounding IEM around at around 9-10 O’clock on the volume level, and that gives me plenty of control for even low volume listening. The Hifiman RE-272 IEM was slightly higher at 10+, the Sennheiser HD25-1 at 12+, and yet I can be listening to the big Hifiman HE-500 or the Audez’e LCD-2 at 3-4 O’clock. Somehow, the AMP-HP managed to accommodate a very wide range of headphones within one gain setting, very nice indeed.

Front panel is very basic and spartan. Power switch, 3.5mm out, and volume knob are all of very high quality.

 

On the back is where you charge the Lithium Ion battery using the supplied charger.

 

Size comparisons with an iPod Classic 120GB.

 

Size comparisons with an iPod Classic 120GB.

 

GENERAL SOUND IMPRESSIONS

This is one of the few amps that I find need a light burn in for the sound to open up. Brand new, my impression of the amp was quite flat– where is the detail? where is the soundstage? Bass was good, but it didn’t have enough detail in the bass. I ran it for some 24-48 hours of continuous play (with the charger plugged in) and now I find the sound to be far more favorable. The soundstage has opened up, the details now present, and the tonal balance gives me a full bass down to the low lows, with okay mids and plenty of treble. It’s not a bassy sounding amp, but what stands out is how the low bass performance is very good among portable amps. It has a very good PRaT with the solid state speed and the bass performance combined. Very likable, if you happen to like low bass like me, but perhaps not the best amp for midrange or treble lovers.

COMPARISON TO THE JDSLABS CMOY

Among the sub $100 amps, the JDSLabs Cmoy is clearly my favorite and so I decided to compare the Audinst AMP-HP. The JDSLabs has always been a very strong performer in soundstage and in this case I find the JDSLabs to give a wider and spacious soundstage than the Audinst. The JDSLabs also had a smoother and more midrange centric sound which naturally leads to a fuller midrange on the JDSLabs. The Audinst was more of a different amp — the soundstage not as wide but deeper than the JDSLabs. The Bass was definitely better on the Audinst — as the JDSLabs have problem giving a full performance on the low bass frequencies. The Audinst also had better PRaT, through the punchier bass and overall faster pace and transients. I have to admit, despite the JDSLabs being smoother and more spacious in the sound (the JDSLabs is actually smoother sounding than many $300 amps), I find the bass performance and the overall PRaT of the AMP-HP constantly winning my preference over the JDSLabs. Not to mention the higher current output of the AMP-HP which enables it to drive the big orthodynamic headphones — something that’s way out of the JDSLab’s capability.

OTHER DETAILS

The AMP-HP only comes with one switch: the power on switch. There is no bass boost switch or anything like what you may find in the Fiio E11 or the JDSLabs Cmoy. However, bass performance is very solid and much better than either the E11 or the JDSLabs. In comparison with the Fiio E11, which I think has one of the best bass in the sub $100 range, the Fiio definitely feels loose and boomy in the bass compared to the AMP-HP. This is not a particularly dark amp either (unlike say RSA amps), as treble presence are quite plenty. The amount of top treble is slightly higher than what I would’ve liked, and though it is not in-your-face annoying, I would’ve liked it to be 1-2dB lower at 8kHz to kill sibilance. The voicing is definitely very good for Rock, simply in virtue of the bass — and none of the amps in the sub-$100 range can quite compete with the PRaT of the AMP-HP. Pair this with the Sennheiser HD25-1 and you got yourself one of the best portable set up for Rock. Pair this with the JH5Pro IEM and it’s even better. Pair it with the Audez’e LCD-2 and you’ll be pretty amazed at how well the little Audinst amp drives the big LCD-2 headphone. I also tried the AMP-HP with the Hifiman HE-500 headphone, and though it can drive it good, the synergy was not as good as with the LCD-2 headphone.

The MUSES 8820 Op-Amp

Although the AMP-HP comes with a socketed DIP op-amp, the stock MUSES 8820 op-amp is something I don’t see very often, and it turns out to be a very good quality op-amp. I tried swapping the MUSES with my current favorite: the OPA2227 from the JDSLabs which I found to be better than the OPA627, and the MUSES 8820 simply outclasses the OPA2227. For more details of the MUSES 8820 you can visit the Muses website here or click here to download the data sheet.

In addition to the MUSES 8820, the AMP-HP also uses the popular AD8397 op-amp on SMD form.

The MUSES 8820 op-amp on a socket.

 

Very clean SMD-soldering on the back side, just like on the Audinst HUD-MX1. Also seen here is the AD8397 op-amp.

 

Overall internal layout.

 

ALPS is perhaps the biggest manufacturer of volume control for audio amplifiers. Here we have a very good quality ALPS potentiometer with very low level of channel imbalance.

 

END WORDS

The AMP-HP sells for $159.00 direct from Audinst’s eBay store, which makes it quite an interesting product for the price. It’s true that you don’t get the JDSLabs’ smooth and spacious sound, but at the same time you are definitely getting better detail levels, articulation and control. The most addictive part is truly the bass section as the AMP-HP delivers one of the most solid, tightest, and lowest punching bass section I’ve heard from portable amps. Previously we haven’t had a good amp to bridge the gap between the sub $100 amps and the premium $300++ portable amps, but now I think the AMP-HP really fills the gap very well.

Availability

The AMP-HP can be bought directly from Audinst’s Ebay store for $159.00 with free shipping.

Gears used for the review:

iPod Classic 120GB, JH5Pro, Hifiman RE272, Sennheiser HD25-1, Beyerdynamic DT1350, Audez’e LCD-2, Hifiman HE-500, Sennheiser HD800.

 

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  • jacko

    Hi
    Where can I buy the MUSES 8820?
    Thanks

    • Anonymous

      Not that easy apparently. Both Mouser and Farnell don’t carry it. Digikey lists it in their database, but they have none in stock. 

      http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MUSES8820D-ND

      • http://www.facebook.com/scmonterog Susana Montero

        hi mike
        I’m looking for an amp that works well with my Hifiman re262 and a Cowon c2. Could you plz help me? I listen classic, electronic and rock music. Cheers

        • http://www.headfonia.com Mike

          Susana,
          What is your budget?

          • http://www.facebook.com/scmonterog Susana Montero

            My budget is around 300 usd. Im sorry for my delay. Thank u again. :)

  • http://pulse.yahoo.com/_LCK7YSFPMB2HRLSBXFRY4VF75Y Peter S.

    Would this be a good compliment to the HUD-MX1?

    • Anonymous

      You can link it to the HUD-MX1’s analog out, but I probably wouldn’t bother. The onboard amp on the HUD-MX1 is good enough. The AMP-HP is designed as a portable amp, after all. 

  • Mr. Freeze

    I recall you did a review of the Audiotrak Imamp a while ago.
    How does the Imamp compares to the Amp-HP in terms of sound signature?
    Which amp as the most gain (when run on batteries)?

    • Anonymous

      Hi,
      I don’t have the Imamp any longer, but the Imamp had a slight more emphasis on midrange and less so on bass.

  • Shaw

    What is the synergy like with the AMP-HP and the HRT Music Streamer II?

    • Anonymous

      I think it should be okay, but I haven’t tried it personally.

  • jinj

    with so many good sub$200-100 amps coming out like the audinst and JDScmoy, I am curious to know how they compare with their expensive rivals like the slim and arrow in terms of sq. Will the cheaper amp be a better bet if purchase something blindly? or are they the best only in their respective price range?

  • Dookie182

    he mike,

    Great review as always. How does the amp-hp compares to the pa2V2?
    They  both seems to share a good prat factor and tight bass. is the Amp-hp better than the pa2V2 in this regards? what could be the other differences?
    does the +90$ price ticket from the pa2V2 and amp-hp worth it?

    how does the amp compares to the alo rx2 at it seems to also have an incredible bass?

    I’m looking for a nice portable amp to pair with my hd25-1 II. 
    hoping you will also grab a unit of the ZO personnal subwoofer V2
    kindest regards

    • Anonymous

      The bass on the AMP-HP is much better than the PA2V2. Weightier and more punchy.

      The ALO Rx2 bass is more of a powerful bass slam, the AMP-HP is more of a deep punch. Though the ALO Rx2 still wins on other technicalities count such as cleaner bass, more spacious sound and so on.

      Yes, the ZO personal subwoofer.. I’ll write them another email.

      • Dookie182

        as always mike, thanks a lot for your advises.
        looking forward to the ZO personnal subwoofer.  they are going to release the V2 of the ZO during september ;-)
        kindest regards

        • Anonymous

          Okay that’s good to know, thanks for the information.

  • Random

    How easy is it to turn the volume knob? Having a single gain setting seems like an easy way to destroy your hearing if your hand accidentally brush against while it’s in your pocket. 

    • Anonymous

      Good question, and sorry for missing it on the review.

      The knobs are good and have a good amount of resistance and I think such accidental turning would be a very rare case.

  • Barun432

    Is the Audinst AMP-HP competent enough to drive the HE 300 headphones ?

    • Anonymous

      Yes. Definitely so.

  • Barun432

    How does the Audinst AMP-HP compare to the AMB Labs Mini 3 in overall performance, mainly imaging and frequency ranges?

    • Anonymous

      I think the Mini3 is still better in terms of technicalities. It’s cleaner, more articulate, et cetera. But I wasn’t so big on how it presented music overall.

  • Daniel

    Would this be a good amp for an ATH-M50? Do you have any suggestions for an iPod/iPhone LOD? Do you have any plans to do reviews on iPod LOD? Can’t seem to find many reviews on them.

    • Anonymous

      Hi Daniel,
      I think it will be a good amp for the M-50, but I think the Ibasso PB-1 will be an even better match, sound wise: http://www.headfonia.com/ibasso-pb1-toucan-unboxing/

      As for LODs, ALO audio makes an extremely good LODs if you want to go for the premium stuff, but it may be more expensive than your M-50. Otherwise you can get stuff that Fiio is selling, they do the job well. http://amzn.to/n5YqAx

      • Daniel

        There is always something better… Would you have any idea how the Ibasso T3/E11 would compare to the AMP-HP for the M50?

        I might go with a T3/E11 not sure which would be a better much or how much I should pay for a used T3.

        • Anonymous

          The T3 is very bad, I really wouldn’t recommend it. The E11 is better. The AMP-HP is even better.

        • Anonymous

          The T3 is very bad, I really wouldn’t recommend it. The E11 is better. The AMP-HP is even better.

          • Daniel

            So based on the T3 being very bad. I assume you would recommend the E11 over D-zero? D-zero is suppose to be very similar to D2+.

            • Anonymous

              Now the D2+ is an entirely different amp than the T3, and I also am not sure if it would sound similar to the D-zero. Just looking at the size of the amp, they would use smaller SMD parts than what the D2 would use, and small SMD parts always degrade sound quality.

            • Anonymous

              I still think the PB-1 is one of the best amp you can get for the M-50, even better than the Audinst AMP-HP.

          • Daniel

            So based on the T3 being very bad. I assume you would recommend the E11 over D-zero? D-zero is suppose to be very similar to D2+.

  • B3dz

    I know it’s a bit off-topic LOL, Do you think ALO audio “The Continental” has a synergy with IEM like Westone ES 5 or JH 16 since i heard that it was made purposely to drive big headphones?

    • Anonymous

      I don’t have the Continental with me at the moment since a friend borrowed it, but if you don’t mind waiting till roughly next week when I’ll publish the review, I’ll try it with the JH customs and report it on the review. 

      • B3dz

        Gradolicious!! I’m looking forward to your review then. :)

        • Anonymous

          Getting the Continental back today.

        • Anonymous

          Getting the Continental back today.

  • Anonymous

    Here is another take on the Audinst AMP-HP by Austin from Audio Excursions

    http://audioexcursions.com/files/audinst-amp-hp-portable-…

  • Anonymous

    Here is another take on the Audinst AMP-HP by Austin from Audio Excursions

    http://audioexcursions.com/files/audinst-amp-hp-portable-headphone-amplifier-review.html

  • Thomasbourbon

    Audinst+HD25-1 seams great for rock, but what about electro ?
    Thanks !

    • Anonymous

      Hi Thomas,
      I think it would be good for electronic too.

    • Anonymous

      What matters I think is that the Audinst + HD25-1 combination will give a very good tight punchy bass hence it should work for Electronic.

  • Minhtranweb

    Hi Mike, I’m a newbie here and looking for a portable amp for my HD650 (using iPhone as the source). After reading you reviews, I guess this AMP-HP will be suitable for my cans. I really like the bass sound with pop, R&P and rock. Could you give me any advice, I really appreciate it.
    Thanks

    • Anonymous

      Yes, by all means it should be good for Pop, R&B and Rock.

  • Sears

    Considering its technical specs, do you think the amp-hp drives headphones with really low impedance well, such as V-MODA’s M-80(28.5 ohms)? Or should I look for something with a lower gain setting for such use?

    • http://www.headfonia.com Mike

      I haven’t really tried it with the M-80. Perhaps give the JDSLabs C421 a try? It comes with a gain setting and the price range is pretty close to the AMP-HP. https://www.facebook.com/headfonia/posts/211639922252107

      • Sears

        I contacted Audinst and they said the AMP-HP was designed to match quite well with low impedance headphones below 30 ohms as well. Speaking of which, how do you think the AMP-HP compares against the C421? The good news is that I can purchase the AMP-HP at a special offer of around $120 (delivery fee inclulded), but I wonder if I should just get my hands on something better. Although I don’t intend to spend over $300 for a portable amp, for the time being…

        Oh, and from your review, I assume you’re saying that the AMP-HP outperforms all sub-$100 amps you’ve previously reviewed, from an overall perspective?

        • http://www.headfonia.com Mike

          Sears,
          I think the AMP-HP definitely has enough current for your M-80. I’m just not sure if you’ll get a good volume control range with it, since the gain is not selectable.
          As for the AMP-HP and sub $100 amps comparison, I wouldn’t say that. Some of the sub $100 amps still wins on some aspect.

  • Sylvesterlin

    Do you think the AMP-HP will work well with PK1?

    • http://www.headfonia.com Mike

      Yes I think so. I would probably recommend something more spacious sounding though like the new C421 amplifier.

  • Sam

    currently, I listen to my JH5 right out of an iPhone 4S. how much mprovement in the sound can I expect when the JH5 is amped with the Audinst? thanks.

    • http://www.headfonia.com Mike

      I would just go direct with the JH5 Sam. It’s good straight from an iPhone and doesn’t really require an amplifier. 

  • Ken Tjin

    Do you think the AMP-HP would benefit SE535 Ltd Ed or Sony EX1000 from iphone 4 as the source? 320kbps MP3/ALACs

    • http://www.headfonia.com Mike

      Maybe not so much.. try the RSA Shadow for those IEMs.

  • http://www.facebook.com/stephen.loke.7 Stephen Loke

    What DAC would go well with the AMP-HP. I use the Sennheiser HD25-1 II

  • http://www.headfonia.com Mike

    Orko,
    Not that I can think of at the moment. Perhaps the Fiio E17 can still be considered the better deal with its built in DAC.

  • Atriya

    Do you think the AMP-HP would be good with my HE-400 + DACport LX rig? Debating over whether to get this, or E11, or cMoy. Thanks! Classical music is a priority.

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