There has been an abundance of relatively small sized desktop headphone amplifiers, mainly from China, but the ImAmp caught my eye due to the Audiotrak name behind it. Audiotrak is becoming quite a common name in this industry, with their line of audiophile soundcards and desktop DACs, and so the Audiotrak brand does lend some credibility to this otherwise unknown amplifier. Having reviewed the Audiotrak Dr. DAC Nano Dr. DAC DX2, and the Dr. DAC Prime, the Audiotrak name has left a positive impression as a relatively affordable yet high quality Korean products. Also, while the entry level amplifiers from China often come with a rough build quality and questionable reliability, the ImAmp has a very good design and build quality.
I was even more interested when I was told that the ImAmp can run on batteries. I don’t know of too many desktop amplifiers that can do this. So I bought one, took it home, and started trying out the amp.
The ImAmp is relatively small in size, as you can see in the photograph, next to the RSA Protector and the Audiotrak Dr. DAC2. With the ImAmp, you have two power supply choices. It can run on either a 12V-15V external DC supply, or purely on its internal rechargeable batteries. There are two available inputs, a pair of RCAs in the back and a 1/8″ jack in the front. Very practical, as it accomodates both the common RCA found in desktop sources as well as Ipod LODs that often are terminated in 1/8″. Make sure that you don’t plug both inputs at once because they are in parallel.
The dimensions are fairly small, certainly much smaller than the last transportable amplifier I own: the Triad Audio Lisa III. The width is not so ideal though, as it’s quite wider than an Ipod Classic, hence it doesn’t stack so well with the Ipod. But still the dimension is small enough to fit in a pocket (think a jacket with big pockets, not jeans pockets). With the internal battery, the ImAmp weighs about 200g, just about the same as an iQube amplifier.
What a surprise. The ImAmp is able to drive big and power hungry full size cans like the HD800, the HE-5, and the Beyer T1. All of these on battery power. This is quite shocking, considering that even the Triad Audio Lisa III couldn’t drive the HE5 to any decent volume without heavy distortions. With the HE5LE plugged in, the ImAmp does have a very small distortion on loud passages, but only on around maximum volume level. Not bad for such a tiny amp!
Does this mean that the ImAmp is too sensitive for IEMs? Without a gain selector switch, or any gain adjusting jumpers inside, that would normally mean so. But not so with the ImAmp. This is one of the reason that I find the ImAmp to be properly designed with practicality in mind. The clever people at Audiotrak designed the ImAmp to have two different headphone outs: 1/8″ and 1/4″. The 1/8″ has a lower gain than the 1/4″ out, making it perfect for small headphones and IEMs. With the JH16Pro IEM on the 1/8″ out, I’m listening comfortably at 8-9 O’clock volume, which gives me a decent volume control range from the minimum position at 7 O’clock. A lower gain on the 1/8″ output would have been more ideal, so I can have a bigger adjustment range with IEMs, but even now I don’t find it a problem, as the potentiometer has no channel imbalances at low volume level. Hiss level is very low with the JH16 IEM until about 3 O’clock, which is way out of its listening range.
Earfonia
Did you try to change the OPA2134 opamp with AD8066? Would be interesting to know the changes in the sound signature 🙂 Tx!
Mike
Bram,
Somehow the AD8066 doesn't work on the ImAmp, as well as the AD797. Perhaps you can explain why?
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.
Mike
Ah! I didn't check the spec sheet on the AD797. It is single channel.
jrko
Hi Mike. Which version of the Burson discreet opamp did you use?
Anonymous
Last time I check, there was only one version. Did they make a new one?
jrko
My bad. I saw the list of opamps theirs can replace and assumed it was a different model for each replacement!!
Anonymous
No probs!
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!
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
Mike
I would go with the Dr. DAC2 DX. Having the superior DAC would benefit you more in this case.
deion
thanks for the reply =D
deion
please do let me know if you have better suggestion than MX1+ImAmp and Dr.dac2 … thanks
Mike
Nothing at the moment Deion…
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".
Mike
Yes, the MS2 with the ImAmp should be a good combination.
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.
Mike
I know. I love the fact that you can use it with a battery and with a wall adapter for instant power boost!
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
Mike
I've used the Imamp with the HE5 Orthodynamic, so it's probably enough for the DT770 or the AD700. Cheers.
Waterloo
okay thanks, will the audinst or imamp be more suited for dt770s? if I want a greater improvement on bass?
Mike
Mmmmm… both units really won't give you that much improvements in bass.
Waterloo
alrite thanks…
Mattering
Nice review! Tempted to buy an imAmp but I'm currently saving for JH16 Pros 😀
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. 🙂
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!
Anonymous
Yes, I didn’t compare them to the ImAmp because I no longer have the
ImAmp. 🙂
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.
Albert
Hi Mike,
May I know where to buy Burson Op-amp in Jakarta?
Thanks for any info.
Mike
Albert,
You have to go direct to Burson.