PerformanceTesting 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
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.