Table of Contents
(Before I even begin with the introduction, I wanted to say that the above table of contents is for your convenience. I’ll also include a tl;dr summary at the beginning of each major section.)
Introduction
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
This review is specifically about the AM5 amp module designed for the FiiO X7 DAP. For a review of that particular player, you may want to click here for my review or take a look at the many other reviews of the X7.
I would like to thank FiiO for letting me demo all of the X7 amp modules in exchange for my honest opinion!
Specs
Before we go onto the rest of the review, it might be handy to have a specifications table on hand.
Build Quality
Tl;dr: Great build quality. Perhaps the only con is that the color doesn’t exactly match the rest of the X7.
The AM5 amp module, like the rest of the X7, exhibits some great build quality. The metal feels smooth and polished, with no rough edges. AM5 also snaps in easily, where it is flush, tight and secure to the rest of the X7’s body once you put in the included screws.
It pretty much looks like it belongs with the rest of the player, if it weren’t for the fact that it’s a much darker shade of grey compared to the rest of the X7’s brighter silver color. Honestly, this isn’t such a big deal for me since I’m not looking at the player for much of the time. There’s also the fact that you won’t notice this at all if you buy a cover for the X7.
Not much for me to complain about here.
Battery Life
Tl;dr: You take a pretty substantial hit to battery life compared to AM1, but that’s the price of having that much power on tap.
Unfortunately, more power on tap means that the battery life will inevitably suffer. In AM5’s case, the hit to battery life is notable.
I conducted my battery life testing under the following conditions: the X7 powering the Etymotic ER4S at low gain at a volume level of 38, using the FiiO Music app in Android mode, and with the screen, pulsar light, Wi-Fi, and Bluetooth off. The music the X7 cycled through was mixture of CD-quality and high-res FLAC, as well as some DSD tracks. CD-quality FLAC tracks made up the vast majority of the music.
Under those constraints, as seen in the screenshot below I managed to get about 6 hours and 30 minutes of playtime. In comparison, with the AM1 amp module volume-matched and under the same conditions, I got 8 hours and 22 minutes of playtime. With the AM2 amp module under the same conditions and volume-matched, the X7 could play for 7 hours and 41 minutes. With AM3 SE powering the same headphones volume-matched and playing under the same conditions, the X7 could squeeze out 7 hours and 14 minutes out of its battery.
This is my major complaint with the AM5 – battery life on the X7, which was only acceptable to begin with on the AM1, now takes a pretty big hit. Hopefully you aren’t going anywhere without a charger for long (or even moderate) periods of time if you plan to pair up your X7/AM5 combo with your full-sized headphone.
However, at the same time, I also understand that FiiO really can’t do much about this situation, short of maybe adding an extra battery to the amp module which would probably add lots of challenges (as well as probably increasing the price). This is the price of trying to driving big headphones with a little player.
Sound Quality
Tl;dr: The AM5 does well with a wide variety of headphones, from IEMs (surprisingly) to many (but not all) full-size headphones. Better than AM1 and AM3 SE, and IMO slightly better than AM2, though the latter is debatable. However, I did end up liking AM3 balanced over AM5.
Headphones primarily tested with: FiiO EX1/Dunu Titan 1, Etymotic ER4S, Hifiman HE-400i, and Sennheiser HD700.
Now is probably the most important part. How does it sound?
Overall, I would say that the AM5 has a neutral tone. It’s not very slightly warm, as some may perceive with the AM2, nor is it slightly bright, as some may say with the AM1. Really, it’s in between those two.
AM5 sounds plenty detailed and has great separation. While the soundstage is only moderately large (but by no means small), it boasts pretty good depth. Altogether, this makes for a very 3D soundstage with good imaging and layering (it’s easy to pick out sounds in terms of left/right and near/far).
AM5 also has the finesse to drive IEMs despite having way more than enough power for them. I could not detect any hiss or noise when I paired the AM5 to the Etymotic ER4S and the FiiO EX1, even with the music paused and the volume cranked up to max on high gain. Combined with the low output impedance, the AM5 is actually well-suited for driving in-ear monitors.
AM5 also did well with full-sized headphones, as it was designed to do. It never made my Hifiman HE-400i and Sennheiser HD700 sound underpowered with strained notes or uncontrolled bass or with any of the tell-tale signs that a headphones is not receiving enough power.
Volume-Matched Comparisons
All comparisons here were conducted under volume-matching with a C-weighted SPL meter.
Vs. AM1
The AM1 in comparison to the AM5 sounds “brighter” and a little more “metallic” and “brittle.” The AM5, in contrast, sounds somewhat “warmer” but also more natural in that notes are still as detailed without sounding like the detail is forced like AM1 can at times. For example, cymbals come across more cleanly on AM5 than on AM1 because on the latter, cymbals are too strong. This also means that stuff like vocals are given more “depth” and nuance on AM5. AM5’s soundstage is about the same width as AM1 but is slightly deeper, making for a more 3D soundstage in which it is easier to perceive depth and layering of notes. All of this can be noticed even when using easy-to-drive IEMs like the FiiO EX1.
AM1 also sounds somewhat underpowered in driving full-size headphones in comparison to AM5. Not only do we get less grainy and strained notes, more-controlled and deeper and textured bass with AM5, but separation also seems to be somewhat better.
All in all, I definitely prefer the AM5 over the AM1 purely in terms of sound quality no matter what headphones are used. However, one has to consider the significant advantage in battery life the AM1 holds over the AM5 (in this case, perhaps the AM2 is better).
Vs. AM2
AM5 and AM2 for the most part sound very, very similar. However, notes seemed to be a bit clearer, perhaps sharpened up a bit (but not overdone) on AM5. This can, for example, make wind instruments seem a tiny bit airier and vocals a bit “breathier.” AM5 also perhaps has a slightly wider soundstage, but depth of the soundstage is comparable between the two. I must emphasize that all of these differences are not that big, and that the two sound very close to each other.
To be honest, there’s not much improvement (if at all) in going to AM5 over AM2 for IEMs, even for harder-to-drive ones such as the ER4S. However, there seems to be an audible, if not major, improvement in using AM5 over AM2 to drive full-size headphones – for the HD700 and HE-400i, I thought I heard on AM5 that notes were slightly less grainy, slightly more open-sounding, that there was slightly more hard-hitting bass, and with slightly more separation.
So AM5 or AM2? Honestly, I think the biggest difference between the two is really how much power each can provide, and so this really depends on what type of headphones you listen to. If you mostly listen to IEMs with perhaps the occasional moderately power-hungry full-size headphone, go for AM2 because it has better battery life. If you frequently listen to hard-to-drive full size headphones, go with AM5.
Vs. AM3
First off, overall AM5 sounds very similar to AM3 in terms of soundstage size, detail retrieval, separation, imaging, etc. AM3 even sounds similar to AM5 in that they both seem to present notes that are a bit “sharper” than on AM2.
For IEM’s, you’d be hard pressed to tell any differences between AM5 and AM3 SE. However, for full-size headphones, AM5 as expected comes out ahead. AM5, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
But what about AM5 vs. AM3 Balanced? Here, I actually prefer AM3 balanced by a bit. AM3 balanced presents a slightly wider soundstage with slightly airier notes (perhaps due to the blacker background given by balanced operation). Separation is noticeably better (more separated) on AM3 balanced than on AM5. This also means that imaging and especially layering are better on AM3 balanced than on AM5.
However, both AM5 and AM3 balanced powered my HE-400i and HD700 just as well as each other. I really couldn’t hear a difference in this respect.
Overall, I wouldn’t say you are missing out on much if you choose to take AM5 over AM3 in balanced mode. The real noticeable difference between the two is the better separation of AM3 balanced (which also leads to better layering, etc.) but otherwise they both sound as good as each other when powering larger headphones. Battery life is also similar between the two amp modules. I would say go for AM3 if you have balanced headphones that you want to get the best out of, otherwise you will do just fine with AM5.
Conclusion
Tl;dr: The first and last sentence of the next paragraph.
The AM5, at only $99, is a relatively affordable way to really give your X7 the power it needs to drive a wide variety of headphones, as well as giving better sound quality than the included AM1 amp module. My only major complaint with the AM5 is the worse battery life, which is unfortunate but unavoidable due to physics. Perhaps more people would be better served by the AM2 if they don’t have so power-hungry headphones, due to its similar overall sound quality but with better battery life. And there’s also the AM3 balanced module, which IMO is the best for full-sized headphones but obviously requires investment in balanced cables. Overall, get the AM5 if you want something that can really drive larger headphones well but without having to spend more to get into a balanced setup.
Thanks for reading my (somewhat) long review of the AM5 amp module!
- Introduction
- Specs
- Build Quality
- Battery Life
- Sound quality
- Volume-matched Comparisons with other amp modules
- Conclusion
(Before I even begin with the introduction, I wanted to say that the above table of contents is for your convenience. I’ll also include a tl;dr summary at the beginning of each major section.)
Introduction
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
[size=11.0pt]A little bit about me: I consider myself to be a relatively inexperienced audiophile, having only taken this hobby seriously for the past 2 or 3 years. Funnily enough, I actually began to take an interest in my headphone system with the purchase of a FiiO E7. The next logical upgrade from there was the FiiO E17, which I appreciated but soon found it a bit lacking in sound quality after I was exposed to other audio equipment. Now, after having been away from FiiO for a while I am now back with their X7 DAP.[/size]
[size=11.0pt]I tend to like a neutral sound signature, perhaps with a bit of warmth. But if one were to ask me to pick between a very warm or a very bright sound signature, I’d go towards the brighter one. I like a large variety of music including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.[/size]
[size=11.0pt]I tend to like a neutral sound signature, perhaps with a bit of warmth. But if one were to ask me to pick between a very warm or a very bright sound signature, I’d go towards the brighter one. I like a large variety of music including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.[/size]
This review is specifically about the AM5 amp module designed for the FiiO X7 DAP. For a review of that particular player, you may want to click here for my review or take a look at the many other reviews of the X7.
I would like to thank FiiO for letting me demo all of the X7 amp modules in exchange for my honest opinion!
Specs
Before we go onto the rest of the review, it might be handy to have a specifications table on hand.
Amp Module | AM1 | AM2 | AM5 | AM3 Balanced | AM3 SE |
Voltage Amplification | OPA1612 | MUSES02 | MUSES02 | OPA1622 | OPA1622 |
Current Buffer | AD8397 | BUF634 | TPA6120A2 | OPA1622 | OPA1622 |
Output into 16 ohms | >200 mW (16Ω/1 kHz) | >350 mW (16Ω/1 kHz) | >800 mW (16Ω/1 kHz) | >420mW (16Ω/1kHz) | >250mW (16Ω/1kHz) |
Output into 32 ohms | >100 mW (32Ω/1 kHz) | >300 mW (32Ω/1 kHz) | >500 mW (32Ω/1 kHz) | >540mW (32Ω/1kHz) | >190mW (32Ω/1kHz) |
Output into 300 ohms | >10 mW (300Ω/1 kHz) | >30 mW (300Ω/1 kHz) | >55mW (300Ω/1 kHz) | >70mW (300Ω/1kHz) | >25mW (300Ω/1kHz) |
Output Impedance | <0.5 Ω (32Ω load) | <0.5Ω (32Ω load) | <0.5Ω (32Ω load) | <0.3 Ω (32Ω load) | <0.3 Ω (32Ω load) |
S/N Ratio | ≥115 dB (A-weighted) | ≥118 dB (A-weighted) | ≥120 dB (A-weighted) | ≥115dB (A-weighted) | ≥115dB (A-weighted) |
THD + N | <0.0008% (32Ω/1 kHz) | <0.001% (32Ω/1 kHz) | <0.001% (32Ω/1 kHz) | <0.0008% (32Ω/1 kHz) | <0.001% (32Ω/1 kHz) |
Channel Separation | >73 dB (32Ω/1 kHz) | >72 dB (32Ω/1 kHz) | >72 dB (32Ω/1 kHz) | >110 dB (32Ω/1 kHz) | ≥72dB (32Ω/1 kHz) |
Peak Output Voltage | >5.2 Vp-p | >8.8 Vp-p | >11 Vp-p | >11 Vp-p | >7 Vp-p |
Max Current Output | >250 mA | >250 mA | >250 mA | >160 mA | >80 mA |
Battery Life | 9+ hours | 8+ hours | 6+ hours | >6 hours | >6 hours |
Build Quality
Tl;dr: Great build quality. Perhaps the only con is that the color doesn’t exactly match the rest of the X7.
The AM5 amp module, like the rest of the X7, exhibits some great build quality. The metal feels smooth and polished, with no rough edges. AM5 also snaps in easily, where it is flush, tight and secure to the rest of the X7’s body once you put in the included screws.
It pretty much looks like it belongs with the rest of the player, if it weren’t for the fact that it’s a much darker shade of grey compared to the rest of the X7’s brighter silver color. Honestly, this isn’t such a big deal for me since I’m not looking at the player for much of the time. There’s also the fact that you won’t notice this at all if you buy a cover for the X7.
Not much for me to complain about here.
Battery Life
Tl;dr: You take a pretty substantial hit to battery life compared to AM1, but that’s the price of having that much power on tap.
Unfortunately, more power on tap means that the battery life will inevitably suffer. In AM5’s case, the hit to battery life is notable.
I conducted my battery life testing under the following conditions: the X7 powering the Etymotic ER4S at low gain at a volume level of 38, using the FiiO Music app in Android mode, and with the screen, pulsar light, Wi-Fi, and Bluetooth off. The music the X7 cycled through was mixture of CD-quality and high-res FLAC, as well as some DSD tracks. CD-quality FLAC tracks made up the vast majority of the music.
Under those constraints, as seen in the screenshot below I managed to get about 6 hours and 30 minutes of playtime. In comparison, with the AM1 amp module volume-matched and under the same conditions, I got 8 hours and 22 minutes of playtime. With the AM2 amp module under the same conditions and volume-matched, the X7 could play for 7 hours and 41 minutes. With AM3 SE powering the same headphones volume-matched and playing under the same conditions, the X7 could squeeze out 7 hours and 14 minutes out of its battery.
This is my major complaint with the AM5 – battery life on the X7, which was only acceptable to begin with on the AM1, now takes a pretty big hit. Hopefully you aren’t going anywhere without a charger for long (or even moderate) periods of time if you plan to pair up your X7/AM5 combo with your full-sized headphone.
However, at the same time, I also understand that FiiO really can’t do much about this situation, short of maybe adding an extra battery to the amp module which would probably add lots of challenges (as well as probably increasing the price). This is the price of trying to driving big headphones with a little player.
Sound Quality
Tl;dr: The AM5 does well with a wide variety of headphones, from IEMs (surprisingly) to many (but not all) full-size headphones. Better than AM1 and AM3 SE, and IMO slightly better than AM2, though the latter is debatable. However, I did end up liking AM3 balanced over AM5.
Headphones primarily tested with: FiiO EX1/Dunu Titan 1, Etymotic ER4S, Hifiman HE-400i, and Sennheiser HD700.
Now is probably the most important part. How does it sound?
Overall, I would say that the AM5 has a neutral tone. It’s not very slightly warm, as some may perceive with the AM2, nor is it slightly bright, as some may say with the AM1. Really, it’s in between those two.
AM5 sounds plenty detailed and has great separation. While the soundstage is only moderately large (but by no means small), it boasts pretty good depth. Altogether, this makes for a very 3D soundstage with good imaging and layering (it’s easy to pick out sounds in terms of left/right and near/far).
AM5 also has the finesse to drive IEMs despite having way more than enough power for them. I could not detect any hiss or noise when I paired the AM5 to the Etymotic ER4S and the FiiO EX1, even with the music paused and the volume cranked up to max on high gain. Combined with the low output impedance, the AM5 is actually well-suited for driving in-ear monitors.
AM5 also did well with full-sized headphones, as it was designed to do. It never made my Hifiman HE-400i and Sennheiser HD700 sound underpowered with strained notes or uncontrolled bass or with any of the tell-tale signs that a headphones is not receiving enough power.
Volume-Matched Comparisons
All comparisons here were conducted under volume-matching with a C-weighted SPL meter.
Vs. AM1
The AM1 in comparison to the AM5 sounds “brighter” and a little more “metallic” and “brittle.” The AM5, in contrast, sounds somewhat “warmer” but also more natural in that notes are still as detailed without sounding like the detail is forced like AM1 can at times. For example, cymbals come across more cleanly on AM5 than on AM1 because on the latter, cymbals are too strong. This also means that stuff like vocals are given more “depth” and nuance on AM5. AM5’s soundstage is about the same width as AM1 but is slightly deeper, making for a more 3D soundstage in which it is easier to perceive depth and layering of notes. All of this can be noticed even when using easy-to-drive IEMs like the FiiO EX1.
AM1 also sounds somewhat underpowered in driving full-size headphones in comparison to AM5. Not only do we get less grainy and strained notes, more-controlled and deeper and textured bass with AM5, but separation also seems to be somewhat better.
All in all, I definitely prefer the AM5 over the AM1 purely in terms of sound quality no matter what headphones are used. However, one has to consider the significant advantage in battery life the AM1 holds over the AM5 (in this case, perhaps the AM2 is better).
Vs. AM2
AM5 and AM2 for the most part sound very, very similar. However, notes seemed to be a bit clearer, perhaps sharpened up a bit (but not overdone) on AM5. This can, for example, make wind instruments seem a tiny bit airier and vocals a bit “breathier.” AM5 also perhaps has a slightly wider soundstage, but depth of the soundstage is comparable between the two. I must emphasize that all of these differences are not that big, and that the two sound very close to each other.
To be honest, there’s not much improvement (if at all) in going to AM5 over AM2 for IEMs, even for harder-to-drive ones such as the ER4S. However, there seems to be an audible, if not major, improvement in using AM5 over AM2 to drive full-size headphones – for the HD700 and HE-400i, I thought I heard on AM5 that notes were slightly less grainy, slightly more open-sounding, that there was slightly more hard-hitting bass, and with slightly more separation.
So AM5 or AM2? Honestly, I think the biggest difference between the two is really how much power each can provide, and so this really depends on what type of headphones you listen to. If you mostly listen to IEMs with perhaps the occasional moderately power-hungry full-size headphone, go for AM2 because it has better battery life. If you frequently listen to hard-to-drive full size headphones, go with AM5.
Vs. AM3
First off, overall AM5 sounds very similar to AM3 in terms of soundstage size, detail retrieval, separation, imaging, etc. AM3 even sounds similar to AM5 in that they both seem to present notes that are a bit “sharper” than on AM2.
For IEM’s, you’d be hard pressed to tell any differences between AM5 and AM3 SE. However, for full-size headphones, AM5 as expected comes out ahead. AM5, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
But what about AM5 vs. AM3 Balanced? Here, I actually prefer AM3 balanced by a bit. AM3 balanced presents a slightly wider soundstage with slightly airier notes (perhaps due to the blacker background given by balanced operation). Separation is noticeably better (more separated) on AM3 balanced than on AM5. This also means that imaging and especially layering are better on AM3 balanced than on AM5.
However, both AM5 and AM3 balanced powered my HE-400i and HD700 just as well as each other. I really couldn’t hear a difference in this respect.
Overall, I wouldn’t say you are missing out on much if you choose to take AM5 over AM3 in balanced mode. The real noticeable difference between the two is the better separation of AM3 balanced (which also leads to better layering, etc.) but otherwise they both sound as good as each other when powering larger headphones. Battery life is also similar between the two amp modules. I would say go for AM3 if you have balanced headphones that you want to get the best out of, otherwise you will do just fine with AM5.
Conclusion
Tl;dr: The first and last sentence of the next paragraph.
The AM5, at only $99, is a relatively affordable way to really give your X7 the power it needs to drive a wide variety of headphones, as well as giving better sound quality than the included AM1 amp module. My only major complaint with the AM5 is the worse battery life, which is unfortunate but unavoidable due to physics. Perhaps more people would be better served by the AM2 if they don’t have so power-hungry headphones, due to its similar overall sound quality but with better battery life. And there’s also the AM3 balanced module, which IMO is the best for full-sized headphones but obviously requires investment in balanced cables. Overall, get the AM5 if you want something that can really drive larger headphones well but without having to spend more to get into a balanced setup.
Thanks for reading my (somewhat) long review of the AM5 amp module!