iFi iDSD GR 2 Review: A DAC/Amp That Rewards Experimentation

Portable DAC/amps occupy an interesting place in personal audio. They are considerably larger than the tiny USB dongles that can already make a good pair of IEMs sound excellent, yet they are still supposed to offer enough convenience that you would choose one over a full desktop headphone system.

The iFi iDSD GR 2 sits toward the serious end of that category. It combines a Burr-Brown PCM1795 DAC with a fully balanced amplification stage, up to 1,513mW of output power, a battery, Bluetooth and enough sound adjustment options that simply finding the setting you like can become part of the listening experience.

That last part ended up defining the GR 2 more than I expected. I started testing it as I would almost any DAC/amp, looking for its basic sound signature and trying to determine how well it could drive different headphones, but I increasingly found myself changing the GR 2 around the headphone rather than judging every headphone from the same setting.

Some combinations worked beautifully, particularly the Sennheiser IE 200 and Grado GS1000, while my Sennheiser HD 660S never quite clicked in the same way. Even switching from a conventional connection to the more powerful 4.4mm balanced output did not necessarily improve what I heard.

So with a $529 asking price, a footprint approaching that of a dedicated digital audio player and more sound controls than most portable DAC/amps offer, what exactly makes the GR 2 worth carrying around?

iFi iDSD GR 2: Key Specifications

• Price: $529
• DAC: Burr-Brown PCM1795
• Maximum PCM support: 768kHz
• DSD support: DSD512
• Balanced headphone output: 4.4mm
• Single-ended headphone output: 3.5mm S-Balanced
• Maximum balanced output: 1,513mW RMS at 32 ohms
• Maximum single-ended output: 567mW RMS at 32 ohms
• Digital inputs: USB-C, optical/coaxial S/PDIF, Bluetooth 5.4
• Analogue inputs: 4.4mm balanced, 3.5mm single-ended
• Bluetooth codecs: aptX Lossless, aptX Adaptive, aptX, LDAC, LHDC/HWA, AAC and SBC
• Battery: 4,900mAh
• Rated battery life: Approximately seven hours
• Charging time: Approximately 3.5 hours
• Dimensions: 141 x 75 x 19mm
• Weight: 268g

These specifications come directly from iFi, including the 1,513mW balanced output, seven-hour battery rating and 268g weight.

Pros

• Warm, full-bodied sound without needing additional processing
• Excellent XBass implementation
• Extensive sound adjustment without relying on conventional EQ
• Clear imaging
• Strong pairing with the Sennheiser IE 200
• Enough power to make the Grado GS1000 come alive
• Useful range of wired and wireless connections
• Excellent as a transportable desktop DAC/amp

Cons

• Headphone pairing matters considerably
• Too large for the kind of everyday portable use I would want
• XSpace is much less useful to me than XBass
• Balanced output does not automatically sound better
• Gets noticeably warm while operating and charging
• The number of sound options requires some experimentation

The GR 2 Has A Warm Sound Signature Straight Out Of The Box

Even with XBass, XSpace, K2 and K2HD switched off, the GR 2 already has a distinct character of its own. In Bit-Perfect mode, it sounds warmer and more full-bodied than the cleaner, more clinical presentation I hear from the FiiO M15S.

"Warm" is the obvious description, but I think thickness gets closer to what I hear. Notes carry more body, drums sound more substantial and the overall presentation feels denser without simply becoming bass-heavy.

That character is important because the GR 2's sound-processing options build on an already recognizable foundation rather than creating its personality from scratch. The rest of the review is really about how well those different settings can shape that foundation around the headphone you're using.

The IE 200 Is Where The GR 2 Really Started Making Sense

The Sennheiser IE 200 was the pairing that initially made me understand what the GR 2 could do particularly well. The IE 200 begins with a relatively detailed and delicate presentation, while the GR 2 adds weight and bite underneath it without taking away the qualities that make the Sennheiser enjoyable.

The soundstage moves slightly more forward, but the IE 200 already has enough room that I never felt the presentation became cramped. Instead, instruments gained more physical presence, and the whole presentation sounded considerably more substantial.

XBass made the pairing better again. The IE 200 has a fairly neutral approach to low frequencies, so giving it additional bass weight fills out an area where I sometimes want more impact without fighting against a headphone that already has an exaggerated low end.

The result was one of my favorite combinations throughout the review. I did not have a Sennheiser IE 900 on hand at the same time, but after hearing how well the GR 2 complemented the IE 200, that is a pairing I would particularly like to try.

Balanced Didn't Automatically Sound Better

Naturally, after getting such a good result from the IE 200, I wanted to see whether moving it to the GR 2's 4.4mm balanced output would improve things further. It didn't.

If anything, I felt that some of the prettiness of the original pairing disappeared when I changed cables. Returning to the IE 200's stock cable gave me the sweeter and more convincing presentation, so that is ultimately how I preferred listening to it.

That doesn't mean balanced is worse, just as it doesn't mean the stock connection will always be better. The result depends on the headphone, amplifier topology, gain and listening level, but it reinforced something I kept encountering with the GR 2: more power is not automatically the same thing as better sound.

The right pairing matters more.

The HD 660S Didn't Give Me The Result I Expected

The Sennheiser HD 660S was one of the pairings that initially made me question the GR 2's ability to handle more demanding headphones. Even through the 4.4mm output, I never felt that the GR 2 brought out the HD 660S's signature sound as convincingly as some of the other amplifiers I have used with it.

I had a similar experience with several balanced-armature IEMs, including the Contour XO, UE 11 and UE 350. None sounded bad, but I did not hear the same kind of synergy that I experienced with the dynamic-driver IE 200.

I wouldn't turn a few pairings into a rule that the GR 2 doesn't work well with balanced-armature earphones, because there are far too many different implementations to make that claim. What I can say is that among the IEMs I had available, the dynamic-driver IE 200 was easily the pairing that impressed me most.

The HD 660S result initially seemed easier to explain as a question of amplification. Then I finally connected the Grado GS1000.

The GS1000 Changed My Mind About The GR 2's Power

I had been waiting for an adapter that would let me properly connect the GS1000 to the GR 2, and the result changed my interpretation of the earlier HD 660S test. With the +6dB gain setting and XBass engaged, the GR 2 was able to make the Grado come alive in a way I had sometimes struggled to achieve with this headphone.

One of the tracks that made the difference obvious was "24" from Switchfoot's 2023 re-release of The Beautiful Letdown. When the toms entered, there was a punch and physical body behind them that immediately caught my attention.

As a drummer, toms are something I tend to listen to particularly closely because I don't only want to hear the initial attack of the stick. I want the body of the drum to follow it, with enough weight and resonance to communicate that this is an actual drum rather than simply a low-frequency impact in the mix.

The GR 2 and GS1000 delivered that body. The toms had impact, but there was also enough substance behind that impact to make them sound convincing.

That is why I no longer think my HD 660S experience can simply be blamed on a lack of power. If the GR 2 can get this kind of result from the GS1000, then headphone matching and the settings being used clearly matter at least as much as whether the amplifier can produce enough volume.

XBass Is The Setting I Kept Coming Back To

Sound-enhancement controls on audiophile equipment can easily become features I test once and then leave switched off. XBass was almost the opposite, because the longer I used the GR 2, the more often I found situations where I actually wanted it.

The IE 200 is probably the clearest example. Its relatively neutral bass response leaves room for additional weight, and XBass gives it considerably more low-end authority without making the bass feel loose or disconnected from the rest of the presentation.

It was similarly useful with the GS1000, where additional bass weight contributed to the physical body I heard from drums. In both cases, the effect felt much more useful than opening a conventional equalizer and manually creating a bass shelf.

That doesn't mean I would leave XBass on permanently. A headphone that already has enough low-frequency energy may not need it, but the implementation is clean enough that the switch became something I genuinely used according to the headphone and recording.

XSpace Isn't Nearly As Useful To Me

XSpace never became the equivalent feature for soundstage. I appreciate having the option and tested it repeatedly with different equipment, but I rarely found myself leaving it engaged.

To me, imaging and soundstage are still much more convincingly defined by the headphone itself, the recording and the player. XSpace alters the presentation, but I don't find the effect as naturally integrated or as useful as what XBass does for the low end.

If I want a large acoustic space, I would rather begin with a headphone that naturally creates one. The GS1000, for example, already does far more for the perception of space than I could achieve by applying a spatial effect to a headphone that does not naturally present music that way.

For me, XBass is a tool. XSpace is an option.

K2 And The Digital Filters Made Me Want To Experiment

The GR 2 becomes considerably more complicated once you move beyond XBass and XSpace. There are K2 and K2HD modes along with four selectable digital filters, giving you considerably more control over the presentation than I normally expect from a portable DAC/amp.

iFi describes K2HD as a harmonic-restoration process, while K2 provides a lighter version without the same upsampling stage. The GR 2 also provides four selectable digital filters, meaning these adjustments can be combined with its analogue sound-shaping options rather than functioning as a single preset system.

Normally, the purist side of me would probably find the most neutral combination and leave it there. With the GR 2, I increasingly found myself moving away from the standard configuration simply because the processing was implemented well enough that experimenting became enjoyable.

I would be careful about describing K2 or K2HD as simply adding "more resolution," because apparent detail and actual DAC resolution are not the same thing. What matters more is that different settings can change how textures, transients and fine information are presented enough that I wanted to keep trying them.

That is an important distinction between the GR 2 and simply having an EQ on a music player. The M15S has EQ and plenty of software-based sound controls of its own, but adjusting the GR 2 feels much more like changing the behavior of an audio component than editing a frequency curve.

How The iFi iDSD GR 2 Compares With The FiiO M15S

This is also why the direct comparison with the M15S became one of the most useful tests I performed. With the processing disabled, the M15S gives me the cleaner and more clinical presentation, while the GR 2 gives me more warmth and body without sacrificing the clear imaging I want from the IE 200.

Neither is automatically better. If I want the crystalline character of the M15S, I can use its own output, while the GR 2 becomes appealing when I want the presentation to sound fuller and less clinical.

The difference is that this is only the beginning with the GR 2. I can then turn on XBass for bass-heavy music, experiment with K2 or K2HD, change digital filters or adjust the gain according to the headphone.

That flexibility became the more meaningful advantage than any individual processing mode. The GR 2 doesn't force me to accept one sound signature and then search for headphones that happen to match it.

I Would Call This Transportable Rather Than Portable

iFi positions the GR 2 as a portable DAC/amp, and at 141 x 75 x 19mm it is certainly small enough to carry around. At 268g, however, its size and weight are much closer to the kind of device I want in a bag than something I want connected to me while walking around Manhattan.

Once I add a phone or music player, the GR 2, a cable and a good pair of wired IEMs or headphones, the package becomes substantial. For normal commuting I would rather use good TWS earbuds, particularly because a noisy train or city street is hardly the environment where I am going to appreciate what the GR 2 does best.

Where this form factor makes considerably more sense is travel. If I am going on a business trip, putting the GR 2 and a good pair of IEMs into my laptop bag gives me a genuinely high-quality listening system once I reach the hotel.

That is where I think the GR 2 is particularly compelling. It provides something approaching a serious desktop listening experience without requiring me to transport a desktop system.

The Battery Matters More For Travel Than My Desk

iFi rates the 4,900mAh battery for approximately seven hours, with a quoted charging time of around 3.5 hours.

For the way I use the GR 2 in an office, battery life isn't something I think about very often because power is normally available. The more interesting benefit is being able to use the same setup on an airplane or somewhere else where I don't necessarily want to depend on an outlet.

Seven hours may not sound enormous compared with a phone or dedicated music player, but that isn't really how I would use this device. It is enough to give me several hours of serious listening away from a desk, and that is the portability I actually value here.

Bluetooth Is Good To Have, But I Would Still Use A Cable

The GR 2 also supports Bluetooth 5.4 with aptX Lossless, aptX Adaptive, LDAC and several other codecs, giving it considerably more wireless flexibility than a conventional desktop DAC.

I still don't think Bluetooth is a key reason to buy one. If I am going to use a device like the GR 2 with high-quality wired headphones, then for serious listening I would generally connect the source through USB as well.

Bluetooth can still be useful in the right setup. If my laptop is connected to a television and I want to sit across the room on a sofa with the GR 2 beside me, wireless input lets the source stay where it is while I continue using my wired headphones.

That is a useful feature to have. It just isn't how I would do most of my critical listening.

It Gets Warm, But Not Hot Enough To Concern Me

The GR 2 does become noticeably warm during longer sessions. While it was connected to my M15S and charging its internal battery at the same time, I measured the exterior at approximately 38.5°C using the thermometer on a Pixel 10 Pro.

That is warmer than my M15S normally feels, but I wouldn't describe the temperature as concerning. The chassis feels warm in the hand rather than uncomfortably hot, and the measurement was taken under the relatively demanding condition of simultaneous playback and charging.

Final Verdict

The iFi iDSD GR 2 surprised me because the longer I used it, the less interested I became in finding its one "correct" sound.

At its most neutral, there is already a recognizable character. Compared directly with my FiiO M15S, the GR 2 sounds warmer and more full-bodied, while the M15S gives me the more clinical and crystalline presentation.

What makes the GR 2 different is how much further I can take things from there. XBass became a feature I genuinely used, K2 and K2HD made me willing to experiment with processing I might normally leave disabled, and the different gain and filter options let me approach each headphone somewhat differently.

That flexibility does not mean every pairing works. The HD 660S never sounded as convincing to me as I expected, and the balanced-armature IEMs I tested didn't produce the same kind of synergy as the IE 200.

The GS1000 demonstrated the other side of that equation. Once I found the right combination of gain and XBass, a headphone that I have sometimes struggled to make sing suddenly delivered drums with the impact and physical body I had been looking for.

Even the IE 200 challenged another assumption. Moving to a 4.4mm balanced cable did not improve the pairing, and I actually preferred the sweeter presentation from the stock cable.

Those experiences are why I don't think the GR 2 should be judged simply by asking whether it is powerful, neutral or technically capable. It is all of those things to varying degrees, but its more interesting quality is how much control it gives the listener over the relationship between the DAC/amp and the headphone.

I also wouldn't personally carry it around every day. It is transportable rather than truly pocketable in my use, and I would much rather put it in a laptop bag for a hotel room, office or flight than walk around Manhattan with an additional 268g box connected to my source.

For that kind of listening, however, the GR 2 makes a strong case for itself. It gives me a warm and substantial foundation when I want it, plenty of clean power, and enough useful ways to alter the presentation that I can adapt the source to the headphone rather than constantly searching for a headphone that happens to match the source.

The best thing about the GR 2 isn't that it has one sound that works with everything. It's that it doesn't have to.

Frequently Asked Questions

How Much Does The iFi iDSD GR 2 Cost?

The iFi iDSD GR 2 is priced at $529 in the US. It combines a Burr-Brown PCM1795 DAC, balanced headphone amplification, Bluetooth and battery operation in a single device.

Is The iFi iDSD GR 2 Really Portable?

Technically yes, but I would describe it as transportable rather than something I would want in my pocket. At 268g, it makes considerably more sense to me in a laptop bag for travel, hotel-room listening or moving between desks.

Can The GR 2 Drive Full-Size Headphones?

It can deliver up to 1,513mW RMS into 32 ohms through the balanced output, but my testing showed that matching matters as much as outright power. The HD 660S was not one of my favorite pairings, while the Grado GS1000 sounded excellent once I found the right gain and XBass settings.

Does 4.4mm Balanced Sound Better On The GR 2?

Not automatically. With the Sennheiser IE 200, I actually preferred the stock cable to the 4.4mm balanced cable I tested, which reinforced that amplifier topology, gain and headphone matching matter more than simply choosing the connection with the higher output specification.

Is XBass Worth Using?

For me, yes. XBass was one of the GR 2's most useful features, particularly with the Sennheiser IE 200, where it added weight to the neutral low-frequency presentation without making the bass sound loose or disconnected.