Fostex HP-P1 Portable Amplifier and DAC for iPod/iPhone (Short REVIEW and Impressions Thread) - Page 21

Quote:

Originally Posted by jax 

I've not been able to find a list in any of the Fostex literature of which file-types might be supported by the HP-P1.  For those who own it, can you confirm that it supports all formats that are native to iTunes/iPod support (AIFF, WAV, AAC, MP3...etc.)?  I was very disappointed to see that the new iBasso DAP does not support AIFF, but understand that it is an Android based system.  A good part of my library is in AIFF and the thought of converting some 1000+ albums is not an appealing one. 

 

 

I'm pretty sure that the signal going to the Fostex is the digital output of the OS audio system in the iPod or iPhone and that is independent of what software is doing the playback.

Quote:

Originally Posted by Currawong 

I'm pretty sure that the signal going to the Fostex is the digital output of the OS audio system in the iPod or iPhone and that is independent of what software is doing the playback.

So are you implying that the Fostex can decode anything the OS audio system is able to put out?  Then is it the operating system that determines whether any DAC can decode WAV or AIFF or FLAC, and not the DAC?

Quote:

Originally Posted by jax 

I've not been able to find a list in any of the Fostex literature of which file-types might be supported by the HP-P1.  For those who own it, can you confirm that it supports all formats that are native to iTunes/iPod support (AIFF, WAV, AAC, MP3...etc.)?  I was very disappointed to see that the new iBasso DAP does not support AIFF, but understand that it is an Android based system.  A good part of my library is in AIFF and the thought of converting some 1000+ albums is not an appealing one. 

 

 

You can play AIFF files through the HP P1. I've put about 50 CDs worth on my Touch & they play back through the HP P1. I believe if the file type is native to what the "player" will recognize it's already been converted to the digital xs &os by the time the signal is leaving the player  through the 30pin LOD to  usb cable to the Fostex. I don't believe any dac can recognize anything other than a raw digital signal, that has to be resolved by the firmware that makes up the OS of the player. Think of the HP P1 as a CLAS with a different dac & (unlike a CLAS) an included onboard amp. You won't find any information from Fostex on this for the simple fact this is not a player.
 

Quote:

Originally Posted by Currawong 

I'm pretty sure that the signal going to the Fostex is the digital output of the OS audio system in the iPod or iPhone and that is independent of what software is doing the playback.

If you're using the LOD to usb cable it is . If you're not using this output option, which would boggle my imagination why you would'nt, you could have saved yourself a good bit of expense on a portable amp sans dac. (Did any of think that your iPod or iPhone was sounding that much better due to better amplification alone when using the HP P1(& this cable) ?)
 

DACs take data in PCM format. The application does the conversion from the file format to PCM (frequently using OS provided software libraries, but not always). Since the iPhone "Music" app does not support FLAC, some folks use a third-party app to play thier FLAC files on the iPhone. No DAC decodes WAV/AIFF/etc files unless it also acts as a source device (e.g. AirPlay, DNLP, USB memory sticks, etc).

Well, I also just added Flac player to my Touch , but the screen on my Touch does'nt display the file size it is playing(maybe my version of Flac player is different). One of the Flac Albums I loaded on to the Touch is a 24/96 Brahms album I had sitting in a folder from a HDTracks download. I have no way of telling what has happened to the file before it enters the Fostex. As the files were dropped into a document folder sitting in iTunes I think there may be a strong possibility that they may be being downconverted to 48k before being passed on to the Touch as when you choose custom AiFF encoding you are given the option of 16bit/48k rather than 44k. I don't think Apple was considering the fact that the music files were going to be passed through a dac that did'nt have a ceiling limit of 48k before being played. So the limiting factor is what the player is outputting I guess. However, I think that the 32bit dac chip might do a little upsampling to whatever is fed to it. so some of that 96k signal is appoximated once again.(& this a a big guess on my part)

I don't think the HP-P1 up samples the digital out, but you could check the manual. If it does not, you could hook the digital out of your HP-P1 to a DAC that shows sample rate and confirm that your 24/96 files are staying 24/96. 

Quote:

Originally Posted by knowhatimean 

Quote:

Originally Posted by Currawong 

I'm pretty sure that the signal going to the Fostex is the digital output of the OS audio system in the iPod or iPhone and that is independent of what software is doing the playback.

If you're using the LOD to usb cable it is . If you're not using this output option, which would boggle my imagination why you would'nt, you could have saved yourself a good bit of expense on a portable amp sans dac. (Did any of think that your iPod or iPhone was sounding that much better due to better amplification alone when using the HP P1(& this cable) ?)

That's a very good point. I should compare using the analogue line out into the HP-P1 to using the DAC as well. It's one of those things so obvious that I never thought to compare it. Mind you, at least one of my amps has such a well-designed input stage that it will make even the output of an iPod sound good, if not so detailed as a good DAC.

Quote:

Originally Posted by VandyMan 

 

Quote:

So are you implying that the Fostex can decode anything the OS audio system is able to put out?  Then is it the operating system that determines whether any DAC can decode WAV or AIFF or FLAC, and not the DAC?

 

DACs take data in PCM format. The application does the conversion from the file format to PCM (frequently using OS provided software libraries, but not always). Since the iPhone "Music" app does not support FLAC, some folks use a third-party app to play thier FLAC files on the iPhone. No DAC decodes WAV/AIFF/etc files unless it also acts as a source device (e.g. AirPlay, DNLP, USB memory sticks, etc).

Jax: What VandyMan wrote. A computer (which the iDevices are) sends out PCM data. It's the same if you plug the USB adaptor for the iPad's camera connection kit and plug in a DAC. However, Apple keeps information about how to get digital output directly from the dock connector a closely guarded secret. A company has to get approval from them to make an officially compatible device. OT, but the reason for this is mostly likely to stop customer complaints that their iDevice crashes or doesn't work with a 3rd party device, which people would start complaining about if everyone and their dog could build devices to use the digital out. Whatever the secret sauce is, it's also built into the Linux kernel-based OS used on the iPod Classic.

FYI, I have been using my HP-P1's optical out into a iBasso DB2 balacned dac the last two days and very much enjoying my two portable balanced headphones out of the RSA SR-71B.  Yes, I can tell a difference in the sound from the singled end amp of the HP-P1. Oh, I see I have already made this point before...sorry.

Quote:

Originally Posted by VandyMan 

I don't think the HP-P1 up samples the digital out, but you could check the manual. If it does not, you could hook the digital out of your HP-P1 to a DAC that shows sample rate and confirm that your 24/96 files are staying 24/96. 

 

Nope, Fostex dropped the ball on including any information on the dac that is used in the HP P1 as far as it being in the user's manual. It's really not that big of a deal to me finding out if 24/96 stays 24/96 as it turns out that using flac player is a bit of a pita to use for me(as I don't really get most of the music I put on my players from downloads). I'm pretty happy using Wav files. If I need a fix of Hi Rez music when I'm home I'll turn on my SACD player w/ my full home system. If I'm feeling a little lazy (at home), the HP P1 & Pods can still get me pretty close
 

I tried the flacplayer app with large files in store today with the fostex hp_p1, and got the same screen reading  `File:96000 Hz/ 24bit,  HW 48000Hz`

Quote:

Originally Posted by ExpatinJapan 

 `File:96000 Hz/ 24bit,  HW 48000Hz`

So explain please, what does it mean? File is 96000 Hz/24Hz but what does HW 48000Hz mean? Downsampled?

Well, seeing as how this thread has been relatively inactive for about a week now, I'll make a few more comments. First, I'm not quite sure if it's because of some new changes to what I'm now using with my HP P1 (Whiplash Audio LOD to USB cable & Senn HD 25-1-11 headpones) but the AKM Dac inside the P1 is sounding quite a bit more detailed & extremely less "colored" sounding than most of what I've heard from equipment I have (or had) using Wolfson dacs or the Phillips(I think) based dac that was in my Hifiman HM 602. To be honest, though I'm not quite sure if this is due to the actual implementation of the chip used the design of this dac or the series of recordings I have loaded on my iPod Classic(the Antholog of RCO live, vol.6, 1990-2000)(I had no idea Hindemith, was such great music! Actually there is even some very well recorded Mozart in this set; I've come across very little well recorded Mozart (or do I just hate HIP?) I will go as far to say that tube amplification might be a "coloration" I wouldn't care for with the HP P1(& of course my choice of music that I listen to) For,"exceptionally well recorded" acoustic music the HP P1 by itself may be all you need. It works for me! (Alright, "96000hz/24bit HW 48000hz" is "probably" what the flacplayer app is reading as the playing file is being read as, & what the file would be output as if it is being played through the iPod or iPhone's dac. What is actually being output is in question because the output is "not" passing through the iPlayer's dacs. I don't see this app being sophisticated enough to see the signal is not making it through the dac (& I'm honestly not that interested in what is happening as I love the sound from HP P1 & I'm not really using flac, I don't need it)(I tried it on my Touch, it's alright "but nothing to write home about" for me) Oh, one more thing , I think I disagree with Jude's comparison of the Beyerdynamics DT 1350s being the preferable cans for classical music as opposed to the HD 25-1-11s. I don't know if it was the recordings or the associated source components used, but I'm finding the Senns to have a bit more layering to their sound then the Beyer's do (whereas the Beyer's may have some advantage in the potrayal of the frequency extension, I'm finding the more "mid-centric" sound of the Senns to be closer to what I like when listening to "live" recordings)

knowwhatimean: Of the non R2R chip-based DACs I've heard, I've most often liked the AK-based ones, one of which is in the Fostex and another in my ULN-2. 

I did compare using my iPhone 4S's built-in DAC to the Fostex DAC. I connected the iPod through the Fostex's Line In so that the different output impedance of each device wouldn't be responsible for the differences. The amp was the L3. There's definitely a significant improvement with the Fostex, if not a dramatic one, with an improvement in instrument detail and separation. With the iPhone, the sound was more "in my head" but with the Fostex, everything was more spread out. It was much the same improvement as I got going from using the HP-P1's inbuilt amp to using the L3.

I've been listening to the HE-500's with the HP-P1 for the past couple of days and I'm really enjoying what I'm hearing.  Not sure if it's brain burn-in or that it's able to actually drive it well enough to get really good sound but it's been great.  I've always contemplated on getting a desktop amp because everyone, and I mean everyone has told me that I need a desktop amp for the HE-500.  I am positive a desktop amp will make them sing better but I am perfectly content at what the HP-P1 is already doing with these headphones.