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This is a review of Trasam HA-2 portable amplifier. http://penonaudio.com/TRASAM-HA2plus

I have been noticing lately a lot of people using portable headphone amplifiers, and often for a wrong reason. Without a doubt, a portable amplifier looks cool strapped to your DAP or a smartphone with a rubber band, but you obviously would want to get one for its functionality, not just looks. Driving high impedance headphones is always a challenge where a typical smartphone or an average power DAP won’t be able to do it efficiently, unless you push the volume output high where you are operating in saturation region. Or perhaps you are not happy with HO output or sound sig of your DAP and want to bypass internal amp by using external one from LO. Another good reason is while using your audio source at a lower volume to preserve a battery while amplifying signal externally and taking advantage of portable amp's built-in battery.

Whatever your reason is, you might want to take a look at the latest HA-2 from Trasam which I just got a chance to play around with. I wasn’t even looking to test more amps/dacs, but Trasam statement about challenging sound quality of FiiO E12 really caught my attention. I don't have original E12, but do have their IEM edition of E12A, and decided it will be a nice test to put HA-2 against E12A along with E11k and C5 amps, and also see how it pairs up with some of my DAPs. Here is what I found.

There is nothing special about the packaging it arrived in. It was just a basic brown carton box with a foam cutout inside for the amp and a bag with accessories. Not sure if Trasam is going for “environmentally” safe packaging, though foam would defeat this purpose, or maybe they just decided to save on coast. Either way, inside of the box you will find a small portable amp with dimensions of about 95mm x 60mm x 15mm and somewhat resembling footprint of Topping NX1. In addition to HA-2 amp, accessories included usb to micro-usb charging cable, a rubber band, and 3M stick-on silicone “feet”. I was happy to see micro-usb cable, meaning I don’t have to deal with mini usb to charge the amp, and was pleased with its quality considering micro-usb connector had extended plug. Such connector is very rare to come across and great to use with your smartphone inside of heavy duty cases. I would have liked to see a basic 3.5mm LO cable; perhaps Trasam can consider it in the future.

Unboxing and Accessories.

In terms of a build quality, HA-2 has a sturdy aluminum shell which is always a good choice for heat dissipation. Design and features of HA-2 are rather minimalistic. At the top you have a power on/off switch (actually ALPS quality switch), 2x 3.5mm ports for HO and Line In, and rotary volume knob with a numbered dial. At the bottom you have micro-usb charging port and led right next to it. There are no High/Low gain switch or Bass boost we come to expect from other portable amp designs. Though bass boost is not a deal breaker for me, having a gain switch would have been a good idea in HA-2 considering its high output power. My only concern here is that having an independent power switch means that you have to be always aware of your volume level when you switch HA-2 on so you don’t blow your drivers and your ears. While switching between different headphones, I made sure to turn down the volume before turning this portable amp on. On contrary, E12A and C5 volume knob has twist to turn power so you never have to worry about high output level at power on.

Design.

In case if some of you are thinking that review has been not too complimentary so far, you will be in for a nice surprise since I’m getting to the best part of it - a sound test! This is where HA-2 was able to redeem itself and made me forget about the packaging and power switch. Taking full advantage of 3 socketed OPA2604 top performance OpAmps, looks like Trasam designed a portable amplifier with a clearly neutral and a very transparent sound signature. With an above average soundstage width and relatively dark background, I was very pleased with its sound.

From a limited available spec, I read about 16 ohm to 150 ohm output impedance, while I was able to drive ATH-R70x (470 ohm) with an authority of a full power and volume dial on HA-2 at only 50%. The HO output is definitely very powerful, and I would go as far as suggesting that it's more suitable for full size high impedance cans rather than efficient low impedance IEMs. Don't get me wrong, I tested it with a number of my IEMs, but couldn't go pass 25%-30% with most of them. Perhaps that's where a low/high gain switch would have been appropriate. Also, even at such high power and with some of my sensitive IEMs, I still heard the same level of hiss as I get with N6, X3ii, or AK120ii DAPs - it wasn't any harsher or louder. Of course, high power comes at a cost of battery endurance. According to the spec, HA-2 implemented a dual power supply with +/- 8.3V 1A output, indeed, very impressive. But even with its 2000 mAh battery, you will get approximately only 8 hours of playback time.

Furthermore, I found it to be an excellent pair up with my smartphone (Galaxy Note 4) and experienced no EMI interference. Sound was clean, transparent (literally just like a scaled up HO output of my Note 4), and with enough power to drive even demanding cans.

Next, I tried to see how HA-2 stacks up against its competition.

Keeping in mind pricing E11k ($60), HA-2 ($79), E12A ($159), and C5 ($160), I found the following when comparing these four:

E11k - a little warmer/smoother and a bit less detailed, average soundstage.

HA-2 - neutral and very transparent, above average soundstage.

E12A - neutral and transparent, a touch more sparkle at the top, and a touch wider than HA-2.

C5 - balanced neutral with a bit of coloration, wider/deeper soundstage.

This comparison results stayed true while also testing w/different DAPs (N6, X3ii, and AK120ii) including E11k, E12A, and HA-2 amps.

- with N6

HA-2 - relatively neutral, transparent, with a sound being a touch smoother and a bit narrower.

vs HA-2, E11k is a little smoother and less detailed.

vs HA-2, E12A has a nearly identical sound sig, FiiO is a touch wider.

- with X3ii

HA-2 is brighter, more detailed and wider than X3ii built-in amp.

vs HA-2, E11k is a little smoother and less detailed.

vs HA-2, E12A has a nearly identical sound sig, FiiO is a touch wider.

- with AK120ii

HA-2 brightens up a sound, a little more detailed, crispier.

vs HA-2, E11k is a little smoother and less detailed.

vs HA-2, E12A has a nearly identical sound sig, FiiO is a touch wider.

In conclusion, when it comes to sound quality I can definitely confirm that HA-2 could go head-to-head with E12A at half the price. Of course, if you factor in E12A having a gain switch and bass boost, and better battery life - the price difference will be more justifiable. But if you need to drive a pair of demanding full size or IEM headphones and looking for something cheap and portable - Trasam HA-2 will do an excellent job!