Introduction

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Fostex, known by many for their T50RP orthodynamic headphones recently released an innovative i-devices accessory. The HP-P1 unit allows for extraction of digital out from any modern Apple i-device. Unlike the analog line-out from the i-dock, the digital does not have to pass through the unit's internal DAC and therefore leaves the unit completely untouched. The HP-P1 can then via its own elaborate DAC setup convert the digital out to an analogue signal, and the trick here is that the HP-P1 uses a high quality DAC and amplification stage unlike anything ever incorporated into an i-device.

The HP-P1 can effectively turn any i-device into a high-performance headphone source or DAC. Fostex have graciously provided the HP-P1 with both analogue out and optical S/P-DIF.

Specifications

Digital connection from iPod iPhone to HP-P1 via 30-pin dock connector
High quality 32-bit DAC (AKM4480) and headphone amp for maximum sound quality
Lithium-Ion rechargeable battery (approx 7 hours)
USB powered operation also available
Hi/Mid/Low 3-step gain control on the headphone out drives all headphone types
Auxiliary analog Line Input for other MP3 players
S/PDIF Digital Out for professional recording
Analog Line Out for connection to an analog amplifier or a recorder
Unique Digital Filter - use regular filter or unique “minimum delay filter” without pre-echo
Housed in a rigid aluminum alloy chassis
Compatible with the following iPod/iPhones: iPod Touch (2nd, 3rd, 4th generation), iPod classic, iPod nano (4th, 5th, and 6th generation), iPhone 4, iPhone 3G, iPhone 3GS

The specifications look good except for when it comes to battery life.

Package

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The Fostex HP-P1 ships in a tightly packed cardboard box.

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The bundle is good, but it would have been nicer if it included a USB mini charger. You get the following with a HP-P1: Carrying system for the HP-P1 plus i-devices, one short dock cable, one USB to mini USB cable for charging, and of course a manual.

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Like the rest the carrying bag is well made. It fits the HP-P1 and an iPod or iPhone.

Closer Examination

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The HP-P1 is built like a tank but hardly weighs anything. At under 300 grams the HP-P1 is very light weight.

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The only issue is that the milled aluminium front plate has sharp edges. A few rubs with some emery cloth should do the trick. Finish wise the HP-P1 is extraordinary except for the way the volume pot is mounted. It does not feel as rock solid as the rest of the switches and housing.

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The aluminium casing is a thing of beauty. The craftsmanship is astonishingly high and it feels incredibly durable. Size wise it is 2 cm wider than the iPhone 4 and approximately three times as high.

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The front plate features two mini-jack sockets: one headphone out, and one analogue in. The digital USB is what makes this devices special since it allows for extraction of digital out from any i-device. The volume pot on the right doubles as an on/off switch. It only has a little imbalance at the start of the pot, but it did not pose a problem not even with the most efficient in-ears we tested with. The volume pot is totally smooth and allows for precise adjustments, add the three position gain switch on the back and pretty much all bases are covered.

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The HP-P1 is a feature packed portable monster. From the left you have a conventional 1/8" mini-jack analogue line-out, next is a S/P-DIF out. After that is where it gets really exciting for all the headphone aficionados. The unit offers three different gain settings for the headphone out along with manual filter selection for the DAC!

Filter one makes the DAC operate with a filter that is like that used on the majority of configurations available today it is what is usually referred to as a sharp roll-off filter. Filter option two is quite interesting. Fostex calls it minimum delay and basically eliminates pre-ringing. Without going into the details this type of filter should give a sound which is relatively similar to the old style integrated NOS DACs featured in a lot of newer Hi-Fi DACs or players like the Head-Direct HM-801/602/601. We will get back to the performance differences later on in the performance section of this review.

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The HP-P1 is a powerhouse of connectivity. It allows you to pass through a digital signal from an iPod or iPhone to a receiver through its integrated S/P-DIF or take advantage of its brilliant integrated DAC and hook up a system to its analogue out. For all the headphone people out there it has a very well performing headphone amplifier. The fact that everything except player is included in one unit makes it very versatile since it can be used as both a portable DAC and amplifier unit and as a digital transport for your home stereo.

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On top of the housing there is a small LED which glows red when the unit is on battery power. The HP-P1 claim seven hours of battery life which has proven to be realistic in our tests of the unit. With the internal amplifier on low gain and the DAC in use, the seven hours can be achieved. With the output on high gain and used with a set of power hungry cans, do not expect anything beyond five hours at normal listening volume.

Seven hours is a bit on the low side since even the iPhone will give you at least 12 hours of play time at normal listening volume out of its headphone out, but we suspect that the integrated DAC and high quality amplifier is more power hungry than the measly integrated stuff inside the iPhone.

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A lot can be said about the size of the HP-P1. If it were just a portable headphone amplifier it would be grotesque, but since it incorporates a wealth of features, some more unique than others, its size is forgiveable.

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The aluminium casing has a rubberised top coating on it which makes it a bit grippy. It is an elegant solution which stops the unit from sliding around on ones desk.

Performance

Testing the performance of such a versatile devices is always tricky. Therefore the test is broken down into three blocks: Portable user with i-device, i-devices transport, and headphone amplifier. Before any listening tests were conducted the unit was burned in for well over 100 hours in order to be sure it was performing its best. The Fostex HP-P1 was primarily tested with the following headphones: Head-Direct HE-500 and HE-300, Westone 4 and Westone ES5, JH-AUDIO JH|16Pro, Sennheiser PX 200-II.

Portable use with i-Device

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As a high-end portable sound system the Fostex HP-P1 works like a charm. Newer Apple iPods and iPhones can be hooked up digitally via a dock cable. This allows you to bypass the internal DAC and amplifier in the i-device completely allowing for a much improved sound quality. The difference between listening to the headphone out of the iPhone 4 and then via the HP-P1 is like night and day with both easy to drive in-ears and demanding fullsize headphones.

The HP-P1 proved its worth by being able to drive anything from the power demanding Head-Direct HiFiMAN HE-500s to the hyper sensitive Westone ES5 without breaking a sweat. The noise floor on the amplifier section is totally black, and there is zero static from the volume pot. With the HE-500 and the unit on high gain it actually sounded better than with the RSA Protector powering them in balanced mode. The midrange was very smooth and the bass extension and control was perfect, although slightly more prominent than on the Protector, with the HP-P1 used as source.

Compared to the headphone out of the iPhone 4 the HP-P1 delivers less background noise, better speed and control with full size headphones, and a smoother general sound.

Detail wise the HP-P1 performs well above that of the RSA Protector and is on par with the balanced module available for the HM-801, which in short means it completely annihilates the iPhone 4 headphone out. The sound stage is way better and much more coherent. That along with the fact that it has more micro details just makes it a fantastic companion for a set of resolving headphones or in-ears.

Paired with a set of demanding set of headphones like the HE-500s the HP-P1 performs admirably and it is definitely on level with that of the Head-Direct EF-1 stationary amplifier we usually test with. The sound signature is less colored, but the ability to power demanding headphones is there. Only the HE-6 headphones proved too much for the HP-P1, but again they are hardly made for use on the move.

Sound stage wise the balanced module for the HM-801 has the upper hand, but not by a lot. The RSA Protector is also pushes a slightly broader sound stage in balanced mode with the HE-500 and HE-300 headphones.

The two filter options sound almost identically, however, we noted a few differences over the course of our tests. Filter 1 has a slightly more grainy sound and gives a little more listening fatigue with in-ears like the ES5 and resolving headphones like the HE-500 and HE-300s. Filter option 2 is then on other hand a little smoother. The difference in treble intensity is very little and hardly noticeable except for on a few high focused numbers. The difference between the two filters is minimal at best and unnoticeable on most recordings.

i-devices transport

As a transport the Fostex HP-P1 works perfectly. Once you hook up the dock cable to the iPhone it immediately registers, and the same when you detach the i-device. The S/P-DIF out is conveniently located and is of solid quality. The unit can play while it is being charged from the USB port and therefore it is a viable source for any home entertainment system.

Headphone amplifier

The headphone amplifier section of the HP-P1 is very good as well. When used with the line-out from the HiFiMAN HM-801 the HP-P1 provides better sound with full sized headphones than the RSA Protector albeit missing balanced operation. The HP-P1 has a smooth sound signature with oodles of detail and just a hint of warmth compared to the RSA Protector which is quiet neutral. With the balanced module in the HM-801 the difference is negligible. Bass wise the balanced module for the HM-801 outperforms the HP-P1 and detail wise it is a toss up between the two.

Value and Conclusion

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The Fostex HP-P1 sells for $799.

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Sound quality
Amazing build quality
Three gain settings
S/P-DIF out!
Line-out
User selectable digital filter (although the difference between the two is very small)
Carrying bag included (although a bit bulky)
Ability to power all types of headphones

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High price
Relatively short battery life
No charger included

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Fostex managed to create a brilliant versatile device with the HP-P1. The HP-P1 excels by doing the job of several usually bulky units in a case which is roughly four times the volume of an iPhone 4. Considering the amount of features it packs and the performance level of both the DAC and headphone amplifier it is quite amazing that the unit does not cost more than it does.<br />
At $799 the unit is not exactly cheap, but to put it into perspective: the HP-P1 offers better sound quality out of its DAC than many $600 DACs we have come across and the integrated amplifier manages to beat a $400 headphone amplifier in our tests. That coupled with its small form factor makes it an outstanding unit even at its substantial cost. Of course the HP-P1 only makes sense if you own an Apple i-device, but even if you add a $249 160 GB iPod it is still a good bang for the buck high-end system.
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