Audiotrak ImAmp

According to the manual, the ImAmp supports op-amp rolling, and so I set out to play around with some different op-amps. Opening the case is relatively easy, simply unscrewing two screws on the top and two on the front panel side, and the cover can be removed. Inside, I find the layout to be very clean. Most of the parts are an SMD type, with brand name capacitors such as Wima and Os-Con and the Korean brand Sam Young. You will also find a Burr Brown OPA2134 op-amp placed on a socket.

The stock opamp is the OPA2134, and is actually pretty good, but I also tried some different opamps with the ImAmp:

  • OPA2134 (Stock): Generally laid back, nice big soundstage.
  • AD825 (single channel SOIC package, with an adaptor): Generally laid back, bigger soundstage than OPA2134, nice open sound, a little grainy.
  • LT1364 (DIP Package): Forward sound. Very smooth. Not as spacious as the AD825, but smoother and cleaner at the top frequencies.
  • OPA2107 (DIP Package): Slightly lush, full midrange.
  • LME49720 (Metal TO-99 Package): Very tubey, thick midrange.

Other than those, I also tried the ImAmp with the AD8066 and AD797 op-amps, but for some reason they don’t work on the ImAmp.




On battery power, the amplifier runs at a lower ±6~±8V, while it runs on a higher ±10V on external power. I really don’t notice any performance differences with the walwart on, except when I needed to run the amplifier while battery level is low. The external power supply that’s supplied with the ImAmp supports a worldwide voltage from 100V to 240V, so you can take it for international travelling and have a decent amplifier for listening at the hotel room.

I briefly compared the ImAmp on the stock OPA2134 with the built in amplifiers of the Audinst HUD-MX1, the Nuforce uDAC, and the Dr. DAC DX2, the Ibasso D10, and found the ImAmp to fare better with a smoother and more musical sound than the rest.

Overall, the ImAmp has slightly warm sound with a pleasing midrange, with a slightly relaxed treble that results in a likeable sound that’s not fatiguing for long term listening. At this price range, the ImAmp is actually very fun sounding, and the sound is tuned to work well with a wide range of music genres. Some amplifiers like the D10 emphasizes the treble, and may sound more lively, but it’s actually less refined in the treble area. The uDAC also has some coloration in the treble and bass, although it is a little more punchy than the ImAmp. When compared to the built in amplifiers of the HUD-MX1 or the Dr. DACs, I find the ImAmp to deliver a more solid power and overall smoother sound. I have been listening with the ImAmp with a ton of headphones, and I never found a glaring coloration.

For the price that it’s selling for, it does make a fun and good sounding little amplifier. Think of an amplifier that you can take to the campus, office, travelling, and with enough gain to cover just about most headphones. The sound signature is generally pleasing, without any dryness, harshness, or any other nasty thing often heard on cheaper amplifiers.

My ImAmp is purchased from AudioBasic in Singapore. You can also get it at the Audiotrak eBay store.


Equipment used for review:
Headphones: Beyerdynamic T1, Sennheiser HD800, Etymotics ER4S, JH16Pro
Source: Ipod Classic 120GB
Amplifiers: Audiotrak ImAmp


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34 Comments

  • Reply June 27, 2010

    Earfonia

    Did you try to change the OPA2134 opamp with AD8066? Would be interesting to know the changes in the sound signature 🙂 Tx!

    • Reply June 28, 2010

      Mike

      Bram,

      Somehow the AD8066 doesn't work on the ImAmp, as well as the AD797. Perhaps you can explain why?

      • Reply June 28, 2010

        Earfonia

        That's strange, as long as the op-amp power supply voltage is not higher than +/- 12 VDC, AD8066 should be compatible with OPA2134.

        AD797 is single channel op-amp, so not compatible with OPA2134 which is dual channel.

        • Reply June 28, 2010

          Mike

          Ah! I didn't check the spec sheet on the AD797. It is single channel.

          • Reply January 29, 2011

            jrko

            Hi Mike. Which version of the Burson discreet opamp did you use?

            • Reply January 29, 2011

              Anonymous

              Last time I check, there was only one version. Did they make a new one?

              • Reply January 31, 2011

                jrko

                My bad. I saw the list of opamps theirs can replace and assumed it was a different model for each replacement!!

                • Reply February 1, 2011

                  Anonymous

                  No probs!

                  • Reply January 31, 2016

                    AndroidVageta

                    I have NO IDEA if you will get this but can you tell me exactly what “AD825 (single channel SOIC package, with an adaptor)” is? I want to replace the opamp in this but don’t know what you’re talking about with that. Have a link that I can purchase at or something? Thanks!

  • Reply August 15, 2010

    deion

    Hai , Mike . Can I connect the gears in this way ?

    Laptop >> Audinst MX1 >> ImAmp >> PRO900

    if yes , which option is best way to go ?

    1)Laptop >> Audinst MX1 >> ImAmp >> PRO900

    2)Laptop >> Dr.Dac2 DX >> PRO900

    Currently , my budget is quite tight and I'm only able to get either Dr.Dac2 DX or Audinst + ImAmp . And I wont looking for an upgrade for next 2 3 years . So I need need to get best options . Can you do me the favor ? Thanks

    • Reply August 16, 2010

      Mike

      I would go with the Dr. DAC2 DX. Having the superior DAC would benefit you more in this case.

      • Reply August 17, 2010

        deion

        thanks for the reply =D

  • Reply August 15, 2010

    deion

    please do let me know if you have better suggestion than MX1+ImAmp and Dr.dac2 … thanks

    • Reply August 16, 2010

      Mike

      Nothing at the moment Deion…

      • Reply August 21, 2010

        Ozone3

        How about HRT MS2 with Imamp? This combo is in the same price range and it also works off the grid. From the reviews I read, it seems that the HRT MS2 would best the HUD-MX1 DAC portion. The slightly warm presentation of the Imamp should pair well with the HRT MS2 and smooth away some of its "harshness".

        • Reply August 21, 2010

          Mike

          Yes, the MS2 with the ImAmp should be a good combination.

  • Reply October 14, 2010

    Pat M

    I picked up an Imamp a couple months ago and I have to say it's pretty darn good when using the external power source and merely OK using the internal battery with HD600s. This is why I primarily use it as a stationary desktop rather than portable. The external power boost presents what I perceive as a stronger, clearer sound than with the battery pack. A big difference was also had when I went from a standard LOD iPod out to 3.5 to an iPod out to RCA (silver wiring). Very nice. I like to call it semi-portable as I can use the external power with extension cord and walk around my garage with it, ha.

    • Reply October 13, 2010

      Mike

      I know. I love the fact that you can use it with a battery and with a wall adapter for instant power boost!

  • Reply October 24, 2010

    Waterloo

    Hi currently I'm deciding between getting the ImAmp or the Audinst as my first amplifier.. will be using with a pair of AD700s. Which would you say is a better choice? What about pairing either with DT770s? Will the ImAmp be sufficient to power them

    • Reply October 25, 2010

      Mike

      I've used the Imamp with the HE5 Orthodynamic, so it's probably enough for the DT770 or the AD700. Cheers.

  • Reply October 26, 2010

    Waterloo

    okay thanks, will the audinst or imamp be more suited for dt770s? if I want a greater improvement on bass?

    • Reply October 26, 2010

      Mike

      Mmmmm… both units really won't give you that much improvements in bass.

  • Reply October 26, 2010

    Waterloo

    alrite thanks…

  • Reply November 21, 2010

    Mattering

    Nice review! Tempted to buy an imAmp but I'm currently saving for JH16 Pros 😀

    • Reply November 22, 2010

      Mike

      Lol you should be eyeing the Pico Slim with your JH16Pros. 😀 I find it to be my favorite amp with the JHs, especially the 16s, as it is the only portable with enough bass control for the JH16s. 🙂

  • Reply June 16, 2011

    Jldiablo

    Hi mike,

    I am currently looking for an amp to pair with my HD600 and Shure SE535.. stuck on getting fiio E11, fiio E7, JDSLabs Cmoy or this Audiotrak ImAmp.. in one of your review you said that E11 is preferable than E7 if DAC function is not needed, and JDSLabs Cmoy has better sounding than the E11. However you did not compare the ImAmp with any of the other three amps above directly.. would like to see your option on these three amps (E11, the Cmoy and the Audiotrak)..

    thanks!

    • Reply June 17, 2011

      Anonymous

      Yes, I didn’t compare them to the ImAmp because I no longer have the
      ImAmp. 🙂

  • Reply July 14, 2011

    Randius

    I have the opportunity of getting the ImAmp or the Fiio E7 + E9 pretty good price. Which one will you recommend? I will be pairing them with either the iPhone 4 or laptop as source and the 1964-Q. Thanks.

  • Reply February 24, 2012

    Albert

    Hi Mike,
    May I know where to buy Burson Op-amp in Jakarta?
    Thanks for any info.

    • Reply February 24, 2012

      Mike

      Albert,
      You have to go direct to Burson.

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