[jkeny]

Thanks for the answer guys, I get it now. I presume you can use a memory stick for this local storage? What disk space is needed?

[JDUBS]

Thanks for the answer guys, I get it now. I presume you can use a memory stick for this local storage? What disk space is needed?

You need something that will operate in fixed disk mode, like an SSD or certain compact flash cards.   I have a 2gb CF card and am no where near filling it with applications.

-Jim

[mgalusha]

There is a thread on using a memory stick on the networkedmeadiatank.com site but it's not really made to work this way. I don't know just how much disk I'm using currently, can't be much. I'll have to log in and check.

Looks like Jim posted at almost the same time I did.

[jkeny]

While waiting to hear about the PS mods & sonic benefit, I haven't seen much discussion in the thread about the sound quality out of the box of these NMTs compared to CD transports or other music streamers such as the Squeezebox. Can anybody give a benchmark?
Has there been a jitter test run on them anywhere?

[ashok]

While waiting to hear about the PS mods & sonic benefit, I haven't seen much discussion in the thread about the sound quality out of the box of these NMTs compared to CD transports or other music streamers such as the Squeezebox. Can anybody give a benchmark?

My previous experience with similar players has been with a Roku Soundbridge, and the Audio Engine W1 wireless adapter.

I had Roku set up to retrieve FLAC files wirelessly from my NSLU2 file server. I had installed uNSLUng on it, and then the mt-daapd (or Firefly) music server. The connection suffered from drop-outs every now and then, but apart from that, the sound was reasonable. The S/PDIF output from the Roku was fed into a NOS DAC.

This system was pretty good, except for the drop-outs. But the NOS DAC was a little too laid back for me. Plus, I did not care much for the two-line display of the Roku. Wanted something more, so I gave that up.

The Audio Engine W1 adapter also works well, and is a pretty nifty device. The transmitter portion plugs into a USB port on my laptop. The receiver plugs into a power outlet near the stereo. It includes a DAC in it, and a  1/8" to RCA cable allows connection to a line-level input in the preamp.

The W1 supports sampling rates up to 48kHz (bit depth 16). Sound quality is fine, maybe just a little bright for my tastes. But it is convenient. My laptop was still connecting wirelessly to the NSLU2 to fetch the music, so I would have occasional drop outs. I still have the W1, but do not use it at all.

With the ioBox, I use a Keces 131.1 DAC. It is an oversampling DAC, and sounds really nice, and took out the laid-back effect that I was getting with the NOS DAC. The ioBox with Keces is definitely better than the Roku + NOS DAC, and easily beats the W1.

At the moment, both my CDP (Sony SCD 2000ES) and the ioBox connect to the Keces. CDP via optical connection and the ioBox via a co-ax. My preference is for the ioBox. The CDP sound just seems a little bit recessed or hidden compared to that of the ioBox. The assumption here is that the cable should not be making a difference. One of these days I will get around to swapping them around.

Of course the convenience with the NMT is unbeatable.

[jkeny]

Thanks Ashok,
That review is good - I'm still trying to justify buying one just for audio though! Now if a couple of tweaks, such as Mike is planning, raise it's game then I'm getting there!

[JDUBS]

Thanks Ashok,
That review is good - I'm still trying to justify buying one just for audio though! Now if a couple of tweaks, such as Mike is planning, raise it's game then I'm getting there!

jkeny, what do you see as the NMT's competition?  The Logitech Transporter will do 24/96 over the network but its retail price is (I think) around $2000, or like 8x-9x an iobox or Popcorn Hour.  Plus, with reports that NMT's can do 24/192, I think they may stand alone in their network transport capabilities.  I believe its worth a shot to try out.  I had a Transporter and don't miss is at all with the ioBox here.

I had a Popcorn Hour but sold it on eBay (for 80% of what I paid for it), just so I could get the coax output the ioBox offers.

-Jim

[jkeny]

Yes Jim, you're correct in that it represents best value for money around at the moment & I love the MPD interface to it. I'm just waiting to hear the results of the mods - mods I would be looking at - clean PS (as Mike is doing) & possibly tapping off I2S from the Sigmatel chip to feed a DAC housed in the box (possibly a Sabre). If this can be done, I'm not interested in coax or optical . Would the Popcorn be a better NMT, in this case?

[JDUBS]

Yes Jim, you're correct in that it represents best value for money around at the moment & I love the MPD interface to it. I'm just waiting to hear the results of the mods - mods I would be looking at - clean PS (as Mike is doing) & possibly tapping off I2S from the Sigmatel chip to feed a DAC housed in the box (possibly a Sabre). So I'm not interested in coax or optical if this can be done. Would the Popcorn be a better NMT, in this case?

I agree, I would love to see I2S successfully tapped on these NMTs!!  I think that all NMTs are largely the same with some slight functional and cosmetic differences.  This is what I noted when moving from the Popcorn Hour to the ioBox.  One thing that is nice about the Popcorn Hour is that it is always first with the firmware releases.  It also has the most active user community.  However, software is developed for the NMT platform so is usable across the different makes / models.

-Jim

[jkeny]

Has anybody looked into the I2S yet? What chips are in the box apart from the Sigma chip? I'm thinking that whatever chip outputs SPDIF signal then I2S probably feeds into this chip. Or is SPDIF direct from the Sigma chip?

Edit - the input into the HDMI chip will also be I2S

[jkeny]

I've seen a report on WhatHiFi (I know - don't shoot me for referencing this mag) saying that the sound quality of the Popcorn Hour A110 was

Only the sonic performance is a bit of a letdown. Although there?s much detail to surround soundtracks, we found music playback to be rather lacklustre.

Actually it said this about the HD Digitech HDX-1000 but their review of the PCH says the audio quality is the same http://www.whathifi.com/Review/Popcorn-Hour-A-110-1TB/

This is a slight worry as that's my main interest

[ashok]

The review does not say how they did the audio test. I suspect they may have used the on-board D/A converters and taken the analog outputs out of the NMT.

I think the key to making these devices work for stereo audio is to use a good quality external DAC.

[jkeny]

Qgreed - anybody wish to open up theirs and nominate the SPDIF or HDMI chips?

[jkeny]

I posted this over at http://www.networkedmediatank.com/showthread.php?tid=20910&page=2 but thought I should post here too as this is where I started my journey:

OK I've done some digging and here's what I found : http://www.networkedmediatank.com/showth...p?tid=9051
Hardware HDX 1000
* Processor : Sigma Designs SMP8635 Rev. C
* DDR DRAM : 64-bit 512Mb
* External NOR Flash : 16-bit 256Mbit
* LANCHIP: REATEK RTL8201CP
* Audio D/A CHIP: AKM AK4420ET
* HDMI 1.3 CHIP: SILICON IMAGE SIL9134CTU
* SATA TO USB: JMICRON JM20330
* USB SLAVE : CY7C68300C-58 LFXG07

So if we look at the datasheet for the AK4420 DAC chip - the input pins that we can tap I2S off are:
Pin 4 = MCLK (The Master Clock) goes to our DAC input pin named BCK
Pin 6 = SDTI (The Data Stream) goes to our DAC input pin named DATA
Pin 7 = LRCLK (The Word Clock) goes to our DAC input pin named WS

For the sake of simplicity, if we were using a TDA1543 DAC (16/44KHz) - just substitute your own 24/192 DAC
pin 1 is BCK
pin 2 is WS
pin 3 is DATA.

So by keeping the leads short we could feed I2S signal to our DAC avoiding SPDIF which is supposed to give better sonics!

[jkeny]

Another cross-post but this is the last:
Multi channel I2S tapping is a bit more difficult - the SIL9134CTU (HDMI chip) was difficult to find a datasheet for but I eventually found this: http://receiverfaq.ru/1/yamaha/RXV663.pdf
A schematic for

On Page 5 you will find the SIL chip and the I2S inputs are
pin 5 = MCLK (the Master Clock)
pin 6 = SD3
pin 7 = SD2
pin 8 = SD1
pin 9 = SD0 - all these are the I2S Data pins
pin 10 = WS (The Word clock)

So, with a bit of work & 4 DACs one could tap into the I2S for multi-channel output!

Or, indeed, these 4 I2S data streams could be fed to a SABRE32 DAC for superlative audio output!

[JDUBS]

Nice work, jkeny!  Very interesting.  With only a CF card inside, there is some (enough?) room to maybe add a decent dac?  That could be cool...tap the i2s and send the signal right to the dac.  Or you could tap the i2s signal and route it to the back of the unit.  Probably replace one of the analog RCAs with an i2s connector.  Mmmm.... 24/192 via ioBox -> Twisted Pear Buffalo dac.  aa

-Jim

[jkeny]

Jim,
be careful about the length of these I2S lines, they carry a high speed clock signal which is easily contaminated. Ideally as short a lead as possible!

[JDUBS]

Jim,
be careful about the length of these I2S lines, they carry a high speed clock signal which is easily contaminated. Ideally as short a lead as possible!

Believe me, I won't be attempting this sort of soldering! 

I think a hand full of inches inside the ioBox plus a hand full outside to a dac should be ok, right?

-Jim

[jkeny]

10" is about the max using Cat 5 twisted pair LAN cable

[jkeny]

Jim,
Let us know your progress!

Mike,
Any news on your updates?