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.