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Fostex HP-P1 Portable Amplifier and DAC for iPod/iPhone (Short REVIEW and Impressions Thread) - Page 2

post #16 of 1275
Quote:
Originally Posted by Vitor Teixeira View Post




Hi qusp,

 

Does that mean that we can actually output 24/96 from an iPod/iPad?

So this is a dream came true! An iDevice and the HP-P1 is all we need to carry an outstanding music library!

But the downside it's that we cant sync those files with iTunes, right?

And for the iPad it's only possible with the camera conection kit?

I'm a bit confused..
 

 


ipad can output audio complying to the usb audio spec, some devices allow 24/96 and higher under the latest specification. the ipad firmware was recently upgraded to allow 24/96 playback currently this means only some movies and FLAC will play at this resolution. afaik the other idevices do not yet allow this, only ipad, but it will probably change soon enough. it works with some other devices too, some home docks will allow it, but CLAS doesnt, i dont yet know if the HP-P1 does, someone else will have to check. so as far as portable goes, only ipad and only with the cck both v1 and v2 ipad allow it; but it only works with dacs that will play it 

 

post #17 of 1275
Thread Starter 
Quote:
Originally Posted by qusp View Post

about the internal battery, i think there is very little chance it will be anything but a custom specced battery pack, hopefully they will buy stock and sell replacements themselves, but i dont like your chances of finding one the same. that being said, its probably either lithoium polymer,or lithium ion/nanophosphate/lifepo4. each cell in these packs has a specific nominal voltage, so probably when the time comes, you would be able to find a replacement that is higher capacity (but should be the same voltage) although, with a properly set up charge management system the chances of the device outlasting the battery are slim, these things (especially lifepo4) take thousands of charge cycles before they even start to go off meaning they should last for decades, in fact they only have simulated estimates of how long lifepo4 lasts, i guess it hasnt happened yet haha


You're one knowledgeable guy... thanks!  So you are saying that if (big if) I do find the need to replace batteries, instead of replacing the 'pack' which would have things like voltage regulators and maybe intelligent charging circuitry, I would replace the actual cells that deliver the juice- and this might be possible?  You are probably right though- that while the life between charges may decrease, I'll probably be onto the next amp/DAC long before this thing completely dies off.  I guess it's similar to the design philosophy of the unibody Macbooks and iPods.
 

Quote:
Originally Posted by kiertijai View Post

Where can you order that?   How much it is?

What gen of ipod can it be used with the greatest result?  Can we use with the imod or whipmod?


I purchased mine here for $649. USD:

http://www.performanceaudio.com/buy/Fostex/HP_P1/25154

You may have to inquire about overseas shipment though.

 

According to ALO's website, you can use the iMod with the Wadia dock.  I'm speculating here; but I would think that means you can also use it with the Fostex (and the CLAS?).  Fostex does list the 'classic' as being compatible with the HP-P1, but it doesn't specify what generation.  I wonder if they only meant the 6th generation, which is when they first started calling it 'classic'?

 


Edited by Mkubota1 - 8/8/11 at 1:45pm
post #18 of 1275

hey hey, you havent quite got it. yes lipoly and lifepo4 packs often come with charging circuitry to limit the input charge and make sure that they arent over discharged as well. aplies more to lipoly, not so much to lifepo4 because lipoly can literally explode in slow motion and cause fires, whereas you have to be pretty 'absentminded' to cause such a problem with quality lifepo4; its much more forgiving, but not immune. this is mainly for batteries that are sold to the public for use in a variety of devices, just as a backup. but i would say that the fostex has its own charging circuit to take care of this and the battery, being that it was sold to an oem producer, it is not required by law to have the circuit, as they now are for the packs sold to the public. 

 

no what i was saying, is that which ever chemistry it is, it will be a certain voltage and a certain capacity for example 13.2v (4 x 3.3 cells) and 2300mah (capacity) this will have been specified by fostex to get the best runtime in their specific amount of space. the energy density of batteries increases as time marches on, but in general each battery chemistry sticks to a nominal voltage per cell in the pack. for lifepo4 the nominal voltage is 3.3vdc per cell and from memory lithium polymer is 4.2v, this means that over its charge when fully charged it (lifepo4) will be closer to 3.6vdc per cell and near the end of its useful life more like 3vdc, but it spends most of the cycle between 3.4-3.3 dropping from 3.6 pretty quick and dropping from 3.3-3 pretty quickly also.

 

so the charger and charge manager/fuel gauge in the fostex, will be designed to charge based on the nominal, max and min thresholds of the chemistry its designed for. if you go and change that voltage or battery type, the charger will act on the wrong info, thinking the battery is full when its not, thinking its empty when its not etc and damage, or make the battery go al explody in your pocket. battery capacity is ok to increase, generally anyway, as the charger will be based on the voltage thresholds, not the capacity, it judges its actions on that and has no idea of the capacity, which is what gives you longer life anyway.

 

with me? sorry for the longwinded explanation; its what i do hehe. so all i'm saying is, as long as it will fit, its the right chemistry and the right number of cells that are wired in the correct way (series or parallel), it may well work even if its not the same custom made pack, but you absolutely must make sure thats all correct by checking with the manufacturer, dont take my word for it.

 

its all elementary anyway as i doubt very much it will be an issue you ever have to deal with.

post #19 of 1275
Thread Starter 
Quote:
Originally Posted by qusp View Post
with me? sorry for the longwinded explanation; its what i do hehe.


Awesome information.  I think I'll print this out and stick it in the box so I'll know where to find it 15 years from now- assuming I'll even care at that point. 

 

Quote:
... its all elementary anyway as i doubt very much it will be an issue you ever have to deal with.

 

I hope and think so!  redface.gif  Thanks again!

post #20 of 1275

Just put in my order for one of these with Performance Audio; thanks for locating that dealer.  Price is better than other places I've checked.  Did call in however to find out their first allotment has already sold out, so I guess we'll see when they'll get another batch and when they'll send me my order.  Looking forward to comparing this against my current setup!

 

-Ed

post #21 of 1275
Hey Mkubota, do you know if it will work with an iPod 5G, I mean is the 5G (video 60 GB) considered a Classic?
Been looking to the compatible models and I've a doubt now.
post #22 of 1275
Thread Starter 
Quote:
Originally Posted by Edward Ng View Post

Just put in my order for one of these with Performance Audio; thanks for locating that dealer.  Price is better than other places I've checked.  Did call in however to find out their first allotment has already sold out, so I guess we'll see when they'll get another batch and when they'll send me my order.  Looking forward to comparing this against my current setup!

 

-Ed


When I placed my order, their site had not indicated that they were sold out.  But then I got a reply saying that it was on back order for about a week at that time, and they asked if I still wanted it.  After I told them to ship it to me as soon as they got them, they charged my credit card which was a bit of a turn off.  But I gave them until the date that they said they would arrive, and sure enough they shipped it the next day!

 

Quote:
Originally Posted by Vitor Teixeira View Post

Hey Mkubota, do you know if it will work with an iPod 5G, I mean is the 5G (video 60 GB) considered a Classic?
Been looking to the compatible models and I've a doubt now.


I'm not sure.  If you look at the iPod history, it is considered part of the Classic line:  http://en.wikipedia.org/wiki/List_of_iPod_models  However, before the 6G Classic it was just called the iPod.  So technically it was never called a Classic.  Wadia states compatibility of their dock with 5th gen iPod (video) and later.  http://wadia.com/products/transports/170i/craftsmanship.php  Of course, that would be speculation to assume that compatibility is the same as the Fostex (or the CLAS).

post #23 of 1275
Quote:

Originally Posted by qusp View Post


ipad can output audio complying to the usb audio spec, some devices allow 24/96 and higher under the latest specification. the ipad firmware was recently upgraded to allow 24/96 playback currently this means only some movies and FLAC will play at this resolution. afaik the other idevices do not yet allow this, only ipad, but it will probably change soon enough. it works with some other devices too, some home docks will allow it, but CLAS doesnt, i dont yet know if the HP-P1 does, someone else will have to check. so as far as portable goes, only ipad and only with the cck both v1 and v2 ipad allow it; but it only works with dacs that will play it 

 


Jeremy, what is the source of this information please? (It's news to me. According to Vinnie, nothing in the design of CLAS limits high res. The issue is on the Apple side)

 

Ah, I see the issue now. High res may curently only be available through the iPad camera kit and therefore only to standard USB DACs. So this is a limitation in the current iPad firmware that may impact on the CLAS, Fostex, Wadia, Pure-i20 etc. Still it is early days as to how this will unfold.


Edited by cooperpwc - 8/8/11 at 9:38pm
post #24 of 1275

How powerful is the amplifier?  Can it drive modern day can : LCD2, HE5, HD800

post #25 of 1275

flac player doesnt have any limitation on ipad as least its confirmed to work at 24/96, pretty sure i read it regarding clas in there the other day, but it doesnt make any sense that it would work, as the ipad only does it via the usb audio spec, which clas does not comply to (being that you cannot use it with a pc). as it has its own proprietary way of transfering the data which is more likely to be causing problems if you are having any, the chances of the ipad supporting that protocol are very slim, but not impossible. the info was first posted on here by Benchmark, who discovered it would work with their dacs

 

I said noting about the CLAS doing the limiting, but its not the ipad, cck, or usb audio codec thats doing it, clas may do hires internally, but until they rewrite the software to allow hires with ipod/ipad natively, it will not happen, because that IS where the limitation is, the ipad was just catching up with the usb standard with that firmware update, which allows much higher than that now without a driver (32bit 384khz and multichannel)


Edited by qusp - 8/8/11 at 9:51pm
post #26 of 1275

The authentication chip coomunicatiun protocols are different. Within that, I don't know if the CLAS is different again from Fostex, Wadia and Pure i-20. This is an issue that I think we are going to hear a lot about. It is absurd if these high end units are denied high res. (Personally I don't care; I'm a dinosaur with my CDS, but a lot of people do.)


Edited by cooperpwc - 8/8/11 at 9:52pm
post #27 of 1275

i dont think its a matter of being denied it, apple arent great for being open, but in this case i dont think it has to do with that. THEY have to rewrite their DSP software for it if they use proprietary software to transfer data (especially if they do it asynchronously of slave the idevice as clas does), , its them thats doing the limiting now. i dont know, but wadia will be using their own software, not sure about the others. the cck does not make this possible, it just happens to be the only device at the moment that handles the transfer within the standard i think. bit of conjecture there so i'm not stating a fact, but the pieces all fit.

post #28 of 1275
Quote:
Originally Posted by kiertijai View Post

How powerful is the amplifier?  Can it drive modern day can : LCD2, HE5, HD800



No, it have quite weak output. I have problem to even get enough volumefrom it  with Sennheiser HD600, so it cant drive them to ideal SQ.

post #29 of 1275

No, it have quite weak output. I have problem to even get enough volumefrom it  with Sennheiser HD600, so it cant drive them to ideal SQ

    Thanks,

    So I think we have to use it with the Grado's, Ultrasone, Sennheiser below 600,  JVC DX1000 , Sony MDR Z1000  and other IEM, CIEM.

That should be enough.

post #30 of 1275
Thread Starter 
Quote:
Originally Posted by kiertijai View Post

    Thanks,

    So I think we have to use it with the Grado's, Ultrasone, Sennheiser below 600,  JVC DX1000 , Sony MDR Z1000  and other IEM, CIEM.

That should be enough.


I think so.  I wouldn't really want to use it as a primary amp for my HD580s.  Any IEM, custom or universal, should be fine.  Perhaps sensitive headphones like the ones you mentioned should be fine too.  As far as sheer power output, there is nothing really special about this amp.

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