DIYHiFi.org

Since there is a bit more life again here, I'll try to post this here.
First a little introduction about how I came to open this thread.

Most music I have is CD 44.1/16.
I'm planning to build a R2R DAC without digital filter, AND playing 176.4 or 192kHz files over it.
I'm thinking to do the digital filtering offline, eg with SoX, or another software which will be able to perform this task. Here are some sw comparisons (though for "downsampling"): http://src.infinitewave.ca/
The DAC will have a FIFO reclocking before the converter chips.

To be able to play these files, instead of having a PC in the living room, I was looking for a streaming client which can play these files, preferably from a NAS, so I (and the family) do not have to start a PC first.

Squeezebox comes to mind, but no higher than 96kHz, and needs a high performance NAS (rather a real server i think). Then there are LINN's and other expensive pieces, with already built in high or not so high performance DAC's and analog stages.

Eventually, I came across this piece:
http://box-designs.com/main.php?prod=st ... ce&lang=en

It is in a price range which is acceptable, has a very simple DAC (chip is CS4344) and S/PDIF output up to 192/24.

There are two possibilities now, either use the S/PDIF output or to tap directly the I2S lines.
Here are some pictures of the internals (text in German though): http://www.stereoplay.de/testbericht/di ... 1,925.html

The Streambox is based on the StreamUnlimited Stream700 platform, which is also used by Naim, Cyrus, Musical Fidelity, ...
Here is a description of this platform:
http://www.streamunlimited.com/v3/en/St ... 20V2.1.pdf
It uses a BridgeCo DM860 chip.

Does any of you know more about this streaming client platform?
Streaming over Ethernet, is it always asynchronous?
It has also an USB input, no idea if it is async too or not.

I would enjoy a discussion of all of the above aspects anyway.

This streamer doesn't have audio frequency xtals on the board. There should be at least 2 xtals for such duty - i only see one.

Therefore you'll have to rely on PLL+FIFO on DAC's side - and still - you won't get the performance of basic XTAL... As in the "xtal Vs PLL" the xtal always wins...

Squeezeboxes do have xtals for 44/48 frequencies, so you can both use them for reclocking of your DAC, and by clocking the streamer from your DAC just like regular CD player.

That's correct, i assume the right frequency is created by a SW PLL. Hence we see quite a bit of jitter in the measurements of Stereoplay.

I'm not really scared away by this, as the FIFO i'm planning to use has a memory depth of around 32'000 samples when half full.
After the FIFO any good quality clocking scheme (with two clocks, for both 44.1 and 48 kHz fs family) can be used.

Squeezebox is, as I stated, not ideal for my use, as I want to play 4x SW oversampled 44.1/16 music.
AFAIK Squeezebox doesn't seem to be able to do this, it goes only up to 96kHz.
And I have the impression that Squeezebox cannot play from a "cheap" Linux based UpnP / DLNA NAS as eg from Iomega.

Hi,



IF you have to deal with cleaning up jitter anyway, then I would just use SPDIF. It has the benefit of easy full galvanic insulation and takes away other compatibility headaches. For a FIFO with fixed clocks 32K Samples seems small (only 60 Minutes capacity at 100ppm clock speed difference for CD, less than that at higher sample rates and/or greater clock speed differences) yet the added delay seems excessive...

I had the chance to evaluate the Streamium Solution (others too) and personally I will stick with a PC instead, I have gotten used to a level of usability and interface sophistication the stand alone players I have tested so far cannot match. The sound quality with a correct jitter removal solutions does not seem to differ.

If using Linux and XBMC (for example) you can get by with very low power hardware. I am currently using an Atom 330 (passive cooling) in an OrigenAE S16T case and with an ATI Radeon 4350 Card, this is ridiculously overpowered for Audio under Windows 7 (I can play 1080P Video on this setup). For music only I originally used a 1GHz VIA Board...

Ciao T

Hi Thorsten, thanks for the suggestions.
Yes SPDIF is good for galvanic isolation, just a bit more hassle as I'd need to build the DAC with a SPDIF receiver. As far as for the WM8804/05 and using it at 176.4, i'm at a loss, no way for me figuring out how to program it.
OTOH....it would make also for a much more flexible DAC, as SPDIF is still very popular.
I have to look again into other receivers which are 192/24 capable...

I thought about using this part to galvanically isolate the I2S line:
http://www.analog.com/en/interface/digi ... oduct.html
Of course placing it on the "jittery side" of the FIFO.

You are right, the FIFO seems small, but it has a certain logic which will use silence between tracks to correct the "fill" level. Don't know much more about how it is done exactly.

Oh this case looks cool indeed. So you can operate it over touch screen without monitor? I'd need it almost only for music, and it has to be easy to operate also for other family members (i.e. easy browsing though music / playlists etc.)

Hi,



I and family members generally use the MCE Remote and the screen. It is a trifle fiddely with touch, the screen is small, but large enough to browse from a few feet away.



This is primarily a function of the software. There are now several options that allow you to simply "browse" in coverflow mode and use the MCE Remote numerical keys as T9 text input for searching (like mobile phone). Just avoid CMP^2... ;-)

Ciao T

Hi,



As addendum, I can recommend iTunes/Audionirvana Pro for any who must have Apple Products at all costs, Win 7 with J-River and J-Play are excellent, personally I continue to use Mediaportal with the ASIO Music Player plugin. My DAC/Preamp is now AMR DP-777, connected via USB...

Ciao T

My buddies, who use Mac, say Pure Music.

Jackal barf!

If you want unembellished digital audio from a Mac, use Decibel. (To be fair, there's a couple other more obscure applications, too.)

Pure Music, along with the programs that use iZotope, sound far too enhanced to me. If you like to watch your TV with the color level set close to max, these are the applications for you. Lots of guys love that, though.

Besides... The effect of software (that doesn't add subtle dithering and so on) is really to a large degree an EMI/RFI problem. At least that is my experience.

Life of a repo man is always intense.

Jocko,



Based on testing at my other day-job, Audio Nirvana. Pure Music and Decibel are pretty good as well. You may find little difference between them, depending how well the DAC attached rejects Jitter and avoids coupling RF Noise...

Ciao T

T,

Ever check out the, ahh, vulnerability of most amps to noise on the AC mains that might be in the, say, 50 KHz to 1 MHz range? As in where most switching supplies operate?

Especially amps and preamps with very efficient toroidal power transformers, simple big single cap power supplies, bipolar transistors, and lots of feedback?

Tense situations.

Hi,



Funny you should mention it. There is an upcoming third part to an article series that covers Computer Audio which will raise this very Point, i will be in HiFi+ but should be posted on the AVGuide site once published.

I do have to say that I generally do not use or design amplifier (or other) power supplies the way you describe, simply because you never know how much SMPS crud will pollute the mains at a given location. You can have a look here at one of the ways how I approach this in the "Sir Pottymouth" Amplifier thread. This Amplifier will also have a very large NEC-Tokin Mains Filter fitted that is effective above around 30KHz...

http://www.diyhifi.org/forums/viewtopic.php?f=5&t=2144&start=75#p45600

If you are worried about the PC's Supply only (not about those your neighbours have plus all the others, including in TV's, LED or CCFL Lights or electronic transformers for halogen lighting everywhere) it is not that difficult to design a filter to deal with that noise...

Ciao T

My buddies tried Audio Nirvana (or whatever it is called). They didn't like it.