iBasso AMP2 module for DX200

Update your DX200 listening experience!

PROS: adds a smoother flavor to the original DX200 reference sound, 4 channel architecture with 3.5mm TRS connector.

CONS: no balanced output.

The product was provided to me free of charge for the review purpose in exchange for my honest opinion.

Manufacturer website: iBasso, for Sale on iBasso site and Penon Audio.


Intro.

As I mentioned in my DX200 review, the modular design of this DAP allows users to update its sound signature by replacing the amp module. I’m intentionally using “update” instead of “upgrade” because it’s a matter of a personal subjective opinion that will depend on your sound preference as well as pair up synergy with various headphones. Considering how many today’s audiophiles buy multiple DAPs and various portable amps, the modular design is a cost effective and a space saving solution where you don’t have to worry about a bulky stack up with interconnect cables or spending more money to buy a standalone portable amp.

Also, with a choice of different modular amps that integrate seamlessly with DX200, you can pick and choose the one which is going to pair up better with your set of headphones, to give you more or less power depending on your headphone requirements, and to provide a different coloring of the sound tonality. The key here is flexibility and convenience, and now you have a choice which one to use with your DX200, either stock AMP1 or the newly released AMP2, plus iBasso promises more amp modules to be introduced soon. In this short review, I would like to share with you what iBasso AMP2 brings to the table and how does it compares to AMP1.

Unboxing & Accessories.

Even though we are talking about a relatively small amp module, iBasso still had a sturdy compact cardboard packaging box with a soft foam insert and a cutout to secure AMP2 inside. While in some cases I found packaging irrelevant after unboxing, here it becomes very useful for storage of stock AMP1 after the replacement. So, make sure you don’t throw it away because it’ll come in handy later.

You will also find a warranty card and an instruction card, along with a small flat-head screwdriver required to remove/replace the amp module. Definitely keep it handy because such narrow head screwdriver is not very common. Also, it fits well inside of the packaging box along with a replaced amp module.

Design.

Because we are dealing with an interchangeable modular design, AMP2 dimensions and the fit with a DAP is identical to a stock AMP1. Just like with AMP1, AMP2 module slides in at the bottom of DX200 and stays behind the display, hidden from the front where the joint seam is only visible from the back and the sides. With two latches and a pair of screws on each side going into these latches, the module attachment is very secure. As a suggestion, when loosening up the screws, don’t remove them all the way, just far enough to slide the module out. The screws are very small, these are set screws without heads, and easy to lose. Thus, try not to remove them completely.

Also, you will notice right away that while AMP1 has 3.5mm HO, 2.5mm BAL output, and LO, the new AMP2 module only has 3.5mm HO and LO ports. There are more differences under the hood of this module, and just because BAL output is missing it doesn’t mean iBasso decided to cut corners in their design. Instead, they implemented something different, called a four channel architecture with a virtual ground. When iBasso posted the official product description of AMP2 module, I got a lot of questions with my readers asking if 3.5mm HO port is TRRS balanced due to mentioning of 4 channels. While I confirmed that it’s a standard 3.5mm TRS jack, I was curious to do my own research, to understand what this is all about.

For those familiar with a balanced TRRS connection, you have Left and Right channels with a positive and a negative signals each, where the “hot” signal is referenced to a separate negative instead of a common shared ground. Based on my understanding, iBasso implemented a design with a “virtual ground”, referring to the negative feedback in an op amp where you have a node that is kept as a steady reference potential without being directly connected to the ground. Thus, instead of referencing the “hot” signal to a common ground, it’s referenced to this virtual ground node which in theory should improve sound quality.

Though it’s not a true balanced topology, AMP2 design allows to buffer, to isolate, and to eliminate a ground current interference between L/R channels. As part of its four-channel architecture, Left and Right channels use a dual op amp and two buffers while the Output ground uses a separate op amp and a buffer – all together 5 high speed op amps to provide around 320 mW into 32 ohm load (based on ideal calculation of 3.2Vrms HO output). Plus, they made sure to use a brand name high quality components, such as Nichicon FW series audio aluminum electrolytic caps for power filtering which iBasso selected after testing and comparison with other caps.

Sound analysis.

Considering AMP2 HO output is rated at 3.2Vrms while corresponding 3.5mm HO output of AMP1 is also 3Vrms, I expected both to have the same volume level in comparison. While testing and comparing it with many different IEMs and full size headphones, I confirmed this to be true. Btw, even so it’s not the best practice, I was able to hot-swap AMP1 and AMP2 without powering down DX200 which made comparison easier because I didn’t have to wait for a full shut down and power up of the DAP.

So, how does AMP2 sounds in comparison to AMP1? I find AMP2 to have more sub-bass rumble with the bass going a little deeper and the sound being a little fuller. Mids have more body, especially lower mids, while upper mids and treble are just a little smoother and more organic in comparison. As a result, the overall signature shifts from a neutral-revealing (AMP1) to a neutral natural (AMP2). But at the same time, the retrieval of details and the layering of the instruments and vocals remains the same. Soundstage width between 3.5mm ports of AMP1 and AMP2 is close, though I find AMP2 just a little bit wider, but not as wide as AMP1 balanced 2.5mm output which also has more power. Furthermore, AMP2 yields the same level of hissing as AMP1 with very sensitive IEMs, and hardly a noticeable hissing with low impedance iems.

ibasso_amp2_cb13-20

Conclusion.

For those who found DX200 w/AMP1 to sound too revealing or to lack some bass, AMP2 adds just enough coloring to fix that without compromising retrieval of details. AMP2 retains the resolution and the detail retrieval of AMP1, but looses some transparency due to a subtle coloring of the tonality which adds more body to the sound, adds more weight to the sub-bass, and makes bass and lower mids sound fuller. I’m not talking about a drastic night-and-day change, for that you still have LO to bypass internal head amp in order to drive external AMP of your choice. AMP2 gives you just enough change to fine-tune the sound when pairing with IEMs and full size headphones that benefit more from a neutral natural signature with a smoother tonality. And if you want to go back to the neutral-revealing signature, just switch back to the original AMP1 module.

 

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