Performance Testing

Given the similarity of these upgraded cables and the stock IKKO upgrade cable with the OH1s, I had to combine everything accordingly! Seen above is the IKKO ITM01 portable DAC/amp and ITM-IKKOFFL upgraded cables, used with my phone (Type-C cable), and the general setup you would use with a more stationary source, such as a desktop PC or laptop with the longer USB Type-A cable. What this now also allows is for an accessible 3.5 mm jack closer to your keyboard in the latter case, and the magnetic connectors also have the portable nature of the ITM01 shine further by having the cable plugged and using the magnets to quickly align and complete the connection, which is great for use on the go.

At this point, I would be talking about the actual DAC, but IKKO has worked with ESS Technology to get a 2-channel stereo DAC, the ESS9298, somewhat custom-made for IKKO. It makes comparisons to other portable DACs harder, and the absence of an audio analyzer makes testing the quality of said DAC even harder. All I can say is that you have support for PCM 32-bit at 384 kHz playback, which is plenty enough for me. Noting that the specifications don't go overboard may indicate that this is a more budget-friendly DAC, but the absence of any MQA on-device rendering is something I personally could not care less about. Likewise, the rated SNR of 118 dB, -118 dB, in fact, is slightly lower than contemporaries, but the output power of 125 mW at 32 Ω over the 3.5 mm single-ended connector is plenty for this segment. In fact, it's higher than that offered by the battery-operated options from FiiO and Qudelix, and does this at the same 2 Vrms to where the current output is where it goes higher. This is plenty of power and voltage for most headphones on the market, but do due diligence before committing to a new headphone or earphone purchase, of course!


Remember that button in the middle? In addition to having just a DAC inside, IKKO decided to clearly target the mainstream consumer who may be looking for something slightly more than a stock adapter dongle from the likes of Apple and Samsung. Those things are remarkable value for money and often included with phones to where most people will not need more than that as a DAC with mobile devices. They also tend to be transparent sounding, in that there is no influence on the tuning of the headphones or earphones connected to the dongle. IKKO is not going after that market, and there in fact is no single transparent mode as much as three modes to toggle between. By default, the ITM01 powers on in Music mode and has a yellow LED light up on either side to indicate as much. Press and hold down the button for a few seconds and you are in their purple Game mode. Do this again and it's blue for movies.


Since there is little information available about the DAC, I decided to use the IKKO OH1s and my sound card as a control set to compare the three modes. The actual frequency measurements were taken similar to other IEMs, so refer to any recent IEM review to know more. IKKO says that Music mode takes advantage of the "professional-grade DAC chip" to provide "a strong driving force, restores high-fidelity sound quality, and gives full play to the strength of the headphones." What I can tell you is that this mode effectively made the OH1s sound more in line with my own hearing in that the treble response wasn't as elevated, even at the resonance peak of the coupler at 8 kHz. There are subtle differences here, and Music mode being the default makes sense.


Game mode does a couple of things, one of which is unfortunately console-restricted to where I could not test it. IKKO says this will "automatically recognize the transmission rate of the game device and directly control the sound of the game console system," and the on-board adaptive driver with adaptive impedance helps here. When using this mode for PC gaming, you will notice some bass elevation coupled with recessed upper mids and treble. The aim is a flatter profile to provide more range for the mids, which can comparatively boost footsteps, gunshots, etc. Playing an FPS game does show the difference well, and the more forward-facing vocals now also indirectly help with voice chatting. There is a DSP-based 5.1 channel virtualization, which looks to get you almost the same experience as Dolby 7.1 Surround Sound without paying for the certification and implementation. Now you have a virtually larger soundstage that also images sound directions slightly better than before.


Movie mode is basically Game mode without the EQ changes. You retain the sound signature but get the 5.1 channel virtualization and boosted soundstage with the aim of added holography to the listening experience. It's no Super X-Fi, and I didn't think it was truly worth it for movies with open-back headphones. Closed-back headphones and IEMs sounded worse to me in this mode because you are just trying to enjoy the audiovisual experience here, not concentrate on them as in the Game mode.