Up until the iPhone 4s Apple gave us direct, easy access to the analogue output of their portable's DAC via the 30-pin connector, bypassing the amplification stage. This made it a great option for upgrading headphone audio quality by simply adding an external amp. Portable amps became a very popular upgrade path for audiophiles with i-devices. Although the 'Lightning' connector of the iPhone 5 has damaged that trend by removing the analogue output, the digital output remains unchanged and this leaves the best option for improving sound quality open. This option is to have both the DAC and the amplification done externally. The only problem is that the iPhone supports a proprietary standard of digital audio and Apple charge a premium for companies to unlock it.
The Fostex HP-P1 claims to be the world's first portable DAC for iPod / iPhone, but I'm a little late to this party so the competition is growing. It's still a very elegant portable solution for improving i-device audio quality, but at £500 the aim seems to be to absorb the Apple tax as much as possible by using more expensive components. Since it requires a digital signal from an i-device it hasn't been badly affected by the new Lightning connector, all you'll need for the iPhone 5 (or any new model with the 'Lightning' connector) is a new cable.
The HP-P1 is a neat box measuring 75x25x130mm and weighing 260g. It contains a 32bit AKM4480 DAC, a high quality headphone amplifier and batteries to last around 7 hours. There's a digital output, as well as an analogue line input / output and two switches. One to select one of two digital filters and the other to select three levels of gain. Despite not even owning an Apple device myself I've been very curious about the HP-P1 for a while. Now thanks to SCV London, and the wife's iPhone 4, I have the opportunity to put this machine through it's paces...
SOUND
The presentation of the P1 is quite close to the iPhone 4 I used to test it with. I'm not saying that the P1 doesn't make improvements to the sound because it does, but it doesn't push the tonality in a drastically different direction. This presentation is also close to Fostex's desktop DAC & headphone amplifiers (the HP-A3 & HP-A8) so perhaps this partnership with Apple was a match made in heaven.
I find the iPhone 4 pretty well balanced. The bass is quite lean, sidestepping the typical unrefined punch you get with most of the competition. There is a nice emphasis on midrange which has some detail, but it does show a little congestion. The treble is decent and not too offensive, probably the best you can hope for at this level. I am really impressed by the iPhone 4's sound for a portable device (in general), it's probably the best sounding smart phone for popular music and it's friendly with most headphones. I don't have any other Apple products to hand so I don't know how consistent this sound quality if through the range.
The first thing that I noticed when listening to the HP-P1 (after the iPhone 4) was a deeper and wider feeling in the bass, it gave a more enveloping experience without colouration. Kicks have much greater definition without adding weight, this is impressive bass as it should be, without bloat and this is a big accomplishment. Soundstage was the next thing to hit me, nowhere near as closed in or as dry as the default iPhone4 sound, it was considerably more exciting. Perhaps most interestingly for vocals was the lift of midrange dynamics. Everything felt more forward, clear and open, with little sense of fatigue or sibilance. Overall the HP-P1 gave an infinitely more engaging and enjoyable experience, it can be subtle at times but the more you go back to listening to the iPhone directly the more you'll want to keep using it. It just doesn't put a foot wrong. These sound quality improvements are quite typical for Fostex, perhaps only really lacking in the smoothness arena.
There are two digital filters on the HP-P1. Switching between them seems to alter bass and soundstage presentations slightly, needless to say the effect is very small, but I have this experience with most of the filters on the Audiolab M-DAC too.
The HP-P1 is better suited for portable headphones and the small 3.5mm headphone jack solidifies this ethos for me. If you think that a small connection is normal on a portable device this size take a look at these similarly priced portable players: Colorfly C4, Hifiman HM-801 and iBasso DX100.
I tested the HP-P1 with a variety of headphones and my favourites were the VModa M-80 and the Sennheiser Momentum, they got the biggest boost from the amplification, or you could say they were the worst straight out of the iPhone. Both of these seemed to really thrive from the balanced nature of the Fostex's sound. If you're more interested in an analytical presentation from the likes of the AKG 701, the Beyerdynamic DT880/600 or the Sennheiser HD800, then the HP-P1 could be a great way of showing that off. If you prefer the bass body of such headphones to be boosted by amplification, as I do, then maybe the HP-P1 (or Fostex in general) is not quite what you're looking for.
Of course everything sounds better through the HP-P1 compared to the iPhone 4's standard headphone output, even if it's a little bit, but the Beyerdynamic DT770/32 Ohm was a bit of a let-down. Not because it was bad on the HP-P1, but because it was way better than it should be straight out of the iPhone 4. It seems that this headphone is tuned to sound great despite unrefined amplification. The AKG K550 did this to me as well, although I felt it was similarly weak on everything rather than similarly great like this DT770.
As well as delivering a much more refined sound the HP-P1 produces heaps of clean volume too and that's before you go near the gain adjustment. Even on the lowest gain setting I found enough volume for the 600 Ohm Beyerdynamic DT880. As I mentioned in the HP-A3 review I like neutral / balanced amplification to refine the bass-happy nature of headphones like the Sennheiser Momentum and Denon AH-D7000 and that worked pretty well here too.
MUSIC
Here are some individual music tracks and how I felt the Fostex HP-P1 coped with them on a few different headphones. These were listened to in Apple lossless format and MP3 - 320kbps compressed (Spotify).
- Norah Jones: "Seven Years" - [GermanMAESTRO GMP 8.35D] - This great headphone already performs well directly from the iPhone 4, the details are all there but Norah's voice and the guitars just seem a bit more real through the HP-P1. The differences are subtle but it's more like you're in the room with them.
- Henry Jackman (Wreck-It Ralph): "Jumping Ship" - [Sennheiser Momentum] - Usually this headphone beats you in the head with some very fun bass, but not through the iPhone or Fostex. It can feel a little bit restrained in the midrange with the iPhone direct, claustrophobic even, but this goes away nicely when switching to the HP-P1. Bass becomes more dynamic and spacious without plumping up the performance.
- Portishead: "Glory Box" - [Beyerdynamic DT880/600] - I was surprised how much bass these headphones managed to retain through the iPhone 4. I should also point out that it's pretty impressive for the iPhone to be able to drive 600 Ohm headphones to reasonable levels, but it does. This album's low frequencies verge on the ridiculous, for such an analytical headphone driven from well balanced amplification, that's being slaughtered, I expected the sound to feel weird or lacking, but that just didn't happen. Apart from volume the differences between the iPhone and HP-P1 were rather minimal on these headphones, although there was a touch more of an open feeling and a coherence to the midrange and soundstage on the latter.
- Gresby R. Nash: "The Life You Love" - [VModa M-80] - The iPhone 4 experience was enjoyable, but there was a decent boost when listening through the HP-P1. Bass texture and soundstage seemed to come together for good resuts.
- Radical Face: "Welcome Home, Son" - [Mad Dog/T50RP mod] - There is something about these headphone's presentation that's hard to get used to. At first it feels lacking somewhere, but with a little time I start to really like them (I'll be analysing this headphone in full very soon). At low to normal volumes there was little difference between the iPhone 4 and HP-P1's sound. After cranking up the volume the differences became more clear. With the volume pushed on the iPhone the sound got splashy, sibilant and pretty disgusting - this didn't happen with the HP-P1. These headphones take some driving, actually making the 600 Ohm Beyerdynamic seem pretty friendly, mostly with quality but also volume.
- Metallica: "Broken, Beat & Scarred" - [Beyerdynamic DT770/32] - Perhaps there was a small increase in bass quality and soundstage moving up to the HP-P1, but the difference was very minimal. I wish the Fostex made these awesome headphones sound even better, but they're just so forgiving of amplification. This is another headphone that I am looking forward to reviewing soon.
COMPARISONS
Competition for the HP-P1 is still pretty light. There are other i-device DACs, perhaps the most famous is the Cypher Labs AlgoRhythm Solo, which is a similar price to the HP-P1, but is purely a DAC (does not include a headphone amplifier). This makes a big difference to portability because you then need at least 3 devices stacked for your headphones and that's starting to get pretty serious! There are other combined DAC and headphone amplifiers like the V-Moda VAMP (which is based on the Venturecraft GoDap 4). These might look more neat than the HP-P1 but they only fit one shape of iPhone, rendering them useless on upgrading. More recently there have been models from Sony and CEntrance (PHA-1 and Hifi M8 respectively). Rather interestingly both of these work with a computer as well, to support this dual functionality they have two USB inputs. This is because Apple's digital audio output for the iPhone and iPod is a proprietary type of USB audio and is not compatible with anyone else's.
Unfortunately I haven't heard any of the portable Apple DAC & amps listed in the above paragraph, so I can't offer any insight as to how the HP-P1 compares with them. What I can tell you is that the HP-P1 is bettered by it's own desktop brother model (HP-A3), which is £200 cheaper. This might seem rather disappointing, but you have to remember where the money is going with such a device. Some is eaten up on Apple tax, another chunk has gone on build quality, materials and design (so it doesn't look or feel horrible next to an Apple device). Limitations of squeezing a DAC, headphone amplifier and battery into such a small space take the rest of the blame. I should also point out that the HP-A3 is a very good sounding unit, the fact that the HP-P1 can't quite keep up isn't to say that it's bad. You just have to ask yourself if the portability is really necessary.
Competition for the HP-P1 is still pretty light. There are other i-device DACs, perhaps the most famous is the Cypher Labs AlgoRhythm Solo, which is a similar price to the HP-P1, but is purely a DAC (does not include a headphone amplifier). This makes a big difference to portability because you then need at least 3 devices stacked for your headphones and that's starting to get pretty serious! There are other combined DAC and headphone amplifiers like the V-Moda VAMP (which is based on the Venturecraft GoDap 4). These might look more neat than the HP-P1 but they only fit one shape of iPhone, rendering them useless on upgrading. More recently there have been models from Sony and CEntrance (PHA-1 and Hifi M8 respectively). Rather interestingly both of these work with a computer as well, to support this dual functionality they have two USB inputs. This is because Apple's digital audio output for the iPhone and iPod is a proprietary type of USB audio and is not compatible with anyone else's.
Unfortunately I haven't heard any of the portable Apple DAC & amps listed in the above paragraph, so I can't offer any insight as to how the HP-P1 compares with them. What I can tell you is that the HP-P1 is bettered by it's own desktop brother model (HP-A3), which is £200 cheaper. This might seem rather disappointing, but you have to remember where the money is going with such a device. Some is eaten up on Apple tax, another chunk has gone on build quality, materials and design (so it doesn't look or feel horrible next to an Apple device). Limitations of squeezing a DAC, headphone amplifier and battery into such a small space take the rest of the blame. I should also point out that the HP-A3 is a very good sounding unit, the fact that the HP-P1 can't quite keep up isn't to say that it's bad. You just have to ask yourself if the portability is really necessary.
The construction of the HP-P1 feels top class, there is no hint of flex to the outer frame. The front and back of the device are nicely finished by solidly fitting aluminium plates, these contain all the ports and switches, the rest of the chassis is covered in rubber. As you can see from the first image this rubber has a nice texture to it. Apart from looking cool and keeping it free from surface scratches itself this also helps it to not damage your iPod/iPhone while it's sat on top. A slightly tapered design helps you to orientate the unit and small ridges on either side of the top help keep your iPod-iPhone from sliding off. Despite being a fairly simple looking device the careful thought that's gone into these little design flourishes make it nice to use and a pleasure to own.
The line input is nice if you have a non-i-device portable as well (for using amplification only), but just to clarify - if you don't have an i-device at all you shouldn't be looking at the HP-P1, it should go without saying that there are far better amps for £500. There is also a line-output in case you only want to use the HP-P1's DAC (to output that to an external amp). An optical digital output will cater for those who want to use their i-device as a digital transport when they get home, for connection to a better DAC. All these things could be nice touches for a few, but I can't help thinking that it's not what you buy the HP-P1 for. I wonder how much smaller and cheaper the HP-P1 could be if there were only two connections (and the volume dial) - USB & headphones, perhaps a third connection to charge the batteries, but this could be combined with USB. No gain switches, no digital filters, no superfluous digital / analogue inputs and outputs. The only feature that I would be tempted to add would be the ability to connect the DAC to a computer as well. I see such a specialist device and I want to take that to it's logical purity. If I want to output digital from an i-device I would get a separate doc and leave it next to the hifi. I wouldn't buy a portable device to output most of it's functions to large external systems. This is just my opinion of course, but I do wonder how many potential customers share this thought.
The non-stepped metal volume dial feels very nice, smooth to turn, with no wobble and it has a satisfying click to turn the unit on and off. I would prefer a bit more grip on the dial surface, I never had an issue turning it, just personal preference. I noticed no channel imbalance at even the lowest volumes that I could hear so all-in-all very impressive. I just wish it was on the top of the chassis instead of the bottom, so the USB cable didn't get in the way when the i-device is sat on top.
The space for the i-device on top of the HP-P1 measures 112mm. The iPhone 3 was 116mm tall, but since it's sides were tapered it would fit fine. Although the iPhone 4 is slightly smaller at 115mm the flat sided design becomes slightly problematic, the slightly inset glass bottom almost let it get away with fitting, but it still feels like it could do with another half millimetre or so. Of course this means that the considerably taller iPhone5 or 5th generation iPod Touch (124mm) are definitely too big to sit inside this space. OK it's not exactly end of the world stuff, but if you are very precious about scratches on the back of your precious i-device you might want to cover the aluminium ends of the HP-P1 with something. The previous generation (4th) iPod Touch, with it's 111mm height and a slightly tapered design, would fit here quite nicely.
FINAL THOUGHTS
It' a shame that the HP-P1's DAC cannot connect to a computer. With cheaper desktop models performing better it's clear that the focus here is on the portability of audio quality rather than it's ultimate value. If improving your iPod or iPhone's sound quality on the move is your goal then the HP-P1 becomes an enticing option.
The list of portable i-device DAC & headphone amplifiers is slowly growing, but I'm willing to bet this ageing Fostex unit will put up a good fight. It doesn't look out of place next to the best looking Apple devices either - with similarly high quality build, materials and a well considered design.
EQUIPMENT USED
iPhone 4, Fostex HP-A3, Desktop PC, Dell Vosto Laptop, Denon AH-D7000, Sennheiser Momentum, Beyerdynamic DT770 Pro Limited Edition 32 Ohm, Beyerdynamic DT880 Pro 600 Ohm, GermanMAESTRO GMP 8.35D, V-Moda M-80, SoundMAGIC HP100, Mad Dog (T50rp mod)
