[Packgrog]

Originally Posted by nikongod /img/forum/go_quote.gif

The only mod I would like to see to the optical output (perhaps it extends to the whole player, and has been addressed since I last upgraded my rockbox) is the ability to output 24/96.

As per my tinkering with the code just a couple days ago, all files are converted to 16/44 prior to being output (unless it's already 16/44, in which case it bypasses the resampler).  I can confirm what the Rockbox developers have stated: it's probably more trouble than it's worth to try to alter it to allow higher bit depth and sample rate just for one platform that isn't among the most popular.  That said, it still sounds pretty damn good with the right DAC/amp combo.  I can't tell you how much I miss my Monica 2 DAC with this, though my D1 is pretty great with the right opamps.  

 

[ElEsido]

Check out this thread and the links therein and this discussion in the rockbox forum for more info on 24/96 on the iriver. Since to my knowledge the DAC chip in the ipods could handle 24/94 there might be interest for a high res rockbox version beyond the iriverH1xx comminuty.

 

[a_tumiwa]

i dont think ipod can support 24/96 , it is limited to 48khz

 

[Packgrog]

Check out this thread and the links therein and this discussion in the rockbox forum for more info on 24/96 on the iriver. Since to my knowledge the DAC chip in the ipods could handle 24/94 there might be interest for a high res rockbox version beyond the iriverH1xx comminuty.

iPods are limited to 16/48.  I've never seen documentation anywhere of the DACs used in those players being capable of 24/96.  I know for certain that the iRiver h1x0 Philips DAC is not capable of hi res either, and was only curious about how far we could push the spdif output, bypassing the DAC.
 
I tinkered with the Rockbox code to try to up the bit depth and sample rate (separate experiments).  Upping the sample rate requires tinkering with the calculations for playback speed and pitch, which is not terribly clear, and any audible benefit would likely be negligible.  Altering the bit depth seems to cause an integer overflow, as it seems to expect a 16-bit integer coming out of the DSP.  It's not entirely clear what the process flow is after this, and what depends on this 16-bit output.  Changing either of these is not trivial, especially when trying to make it user friendly for all platforms, needing to know their respective maximum resolutions, and having to make it dynamic based on the file's resolution and the iRiver's dual limits (ie: DAC vs. SPDIF, the latter of which can probably handle higher).
 
Of anyone, I probably have the best combination of incentive (I use the H120 as my primary source) and ability (I'm a professional software developer with experience in C) to make these changes.  I just lack the time, and this would take a LOT of time and care.  Given that 95% of my audio is in redbook, it's not really worth it.  It's easier to just transcode my hi res files to redbook first.

 

[ElEsido]

This is the most enlightening statement on 24/96 on rockbox I've read so far, thanks!
 
However the iPod's DAC are capable of 24/96, see:
tech info of the DAC used in 1st and 2nd gen pods
the datasheet of the DAC used in 3rd gen pods
I'm not sure about the current generation of ipods. 

 

[Packgrog]

Intriguing!  Not having either of these available makes experiments impossible.  I suspect the processor could be a limitation, though.  Could be worth investigating of the latter-day iPods have similar specs for their DACs

 

[plonter]

mmm..very interesting.  is the h120 bit perfect even with stock firmware?    this can be the perfect transport for me..not noisy and jittery as my desktop computer.
how does the headphone out sound?

 

[wolfen68]

Stock firmware is bit perfect.  The headphone out is OK but not the iriver's strongpoint.

 

[plonter]

Quote:

Stock firmware is bit perfect.  The headphone out is OK but not the iriver's strongpoint.

too bad they can't be found

  let me know if you have a used one for sale.

 

[theory_87]

where is the poll?
 
I'm using rb h140 optical out to ibasso d10 and analog out to ibasso Quest.Fi output to custom sf5eb/acs t1

 

[abyrvalg]

too bad they can't be found

  let me know if you have a used one for sale.

They can easily be found on Ebay, there is even a seller in Germany that sells refurbished irivers in excellent condition (don't know his name, a friend of mine bought from him and said that the player arrived in mint condition). It is really not a problem at all to buy one if you want it.

 

[plonter]

Quote:

They can easily be found on Ebay, there is even a seller in Germany that sells refurbished irivers in excellent condition (don't know his name, a friend of mine bought from him and said that the player arrived in mint condition). It is really not a problem at all to buy one if you want it.

thanks for the tip..I will search for one on ebay.

 

[High_Q]

Quote:

Originally Posted by plonter /img/forum/go_quote.gif
 
too bad they can't be found

  let me know if you have a used one for sale.

I have an H120 for sale if anybody is interested.  Check my sig.
 

 

[qusp]

actually the phillips UDA1380 dac is capable of hi rez 24/96, according to the datasheet. so there should not be too much standing in your way

 

[atsukita]

iHP metal S/PDIF mod
 
I succeeded to get metal S/PDIF out with iriver iHP-120 ,140.
(same as coax mod but I don't use coax jack and cable...

)
 
Use iHP's line-in mini-jack for S/PDIF metal out for easy modification.
S/PDIF out signal is "R" with this wiring.

 
I cut pattern of line-in Jack L&R, and connect S/PDIF.
following red line is cut part.

 
to access this side of board, needs to remove LCD display.
you need to remove solder for LCD back light.

 
So you can enjoy metal S/PDIF output with mini-jack.
May be mini BNC or RCA jack is better for signal quality but it will more difficult to install and fit to enclosure.
 
and...  other part of S/PDIF out is follows  if you need...