DDC - Digital USB interfaces - Xmos or Amanero Combo384 based - Raspberry Pi - HifiBerry DAC+ Pro - reviews, comparison, modifications and USB-Audio in general

[hgpsemaj]

   
Cool stuff. Sounds like the future to me
Also, I'm trying to figure out if such an rpi stack would fit into my current Minimax Plus Dac.  Do you know approx how tall is that case? And/or how tall is that rpi stack assembly inside it?

 
The height of the enclosure is 3.5", the width and depth is 7" x 7".
 
The Raspberry PI is not next to me at this moment, so I shall let you know the actual dimension of the RPI stack later.
 
 
 
 
Regards,

 

[hgpsemaj]

   
Does your brother have the Naim Audio NDS? It's about $13.000 

 
Looks like a mixture of modern and vintage gears:
 

 
The one that I like most is the SME phono (i.e.100V/60Hz input.). 

 

[abartels]

 

Yes, I will need a case which has a greater height, 9CM instead of 7CM, then I can put different R-Core in the enclosure, mount them on their side,
this will give me room enough to place all the pcb's.

I suppose rpi+DAC+ alone will be very very good, without fifo-isolator-dualdacboard, so that is maybe the way you should go.
The pcb's are not that big, but they won't fit in your dac 

Yap, was afraid of that. Not that much space inside my minimax. Your current rpi+berrydac stack might fit though.

 Yes it probably will 

 

[abartels]

Looks like a mixture of modern and vintage gears:
 

 
The one that I like most is the SME phono (i.e.100V/60Hz input.). 

 
Nice stuff 

 

[wakka992]

Hi guys,
I'm looking for a USB to spdif interface, I'll be using it with Hudson CV2+.
For now I was considering Breeze U8 with Taema transformer.
Is it wise to buy that or there's a new xmos chip around?
Thanks

 

[hgpsemaj]

   
Nice stuff 

 
 
In acoustic wise, when Raspberry PI3 / R2R Soekris DAC out perform Naim NDS by a huge margin, I would say this Naim NDS 'it is nice from far, but far from nice'.
I've been picking up HiFi as a hobby for many years, I got a feeling invest load of money on those audio gears would not guarantee a positive and proportionate return.
I'm glad to see this Raspberry PI3 is equipped with spdif /AES digital output, you know........................there are lot of DAC in our market are only equipped with spdif/AES input. I think this is the right time for those users give their beloved USB Interface a break, and try something new.

 

[hgpsemaj]

Hi guys,
I'm looking for a USB to spdif interface, I'll be using it with Hudson CV2+.
For now I was considering Breeze U8 with Taema transformer.
Is it wise to buy that or there's a new xmos chip around?
Thanks

 
In costing wise, Breeze Audio DU-U8 RMB618 is a pretty good choice, but now there is a F1/Xmos PCB cost RMB999, mind you, need to add PS.

 

[abartels]

Ians stuff is expandable with spdif / AES output, just have to connect it =)

 

[prot]

 Yes it probably will :bigsmile_face:

I might call you on that

 

[wakka992]

In costing wise, Breeze Audio DU-U8 RMB618 is a pretty good choice, but now there is a F1/Xmos PCB cost RMB999, mind you, need to add PS.

A ready made one with the new Xmos? I'm not that much into DIY, just some basic soldering... maybe if it's not that complicated I'll try it

 

[Caper]

A ready made one with the new Xmos? I'm not that much into DIY, just some basic soldering... maybe if it's not that complicated I'll try it

It´s ready to use "as is"
Complete board that only needs a case.
Powered by USB.
 
http://www.ebay.com/itm/111961717820?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[prot]

The height of the enclosure is 3.5", the width and depth is 7" x 7".

The Raspberry PI is not next to me at this moment, so I shall let you know the actual dimension of the RPI stack later.
Regards,

Thx for the info.
3.5" isnt that tall .. and that rpi stack looks like it can take some slimming .. might fit into my minimax after all.

 

[prot]

Hi guys,
I'm looking for a USB to spdif interface, I'll be using it with Hudson CV2+.
For now I was considering Breeze U8 with Taema transformer.
Is it wise to buy that or there's a new xmos chip around?
Thanks

Guess you meant Burson cv2.
Anyway, Breeze is still the cheapest and by far the best in terms of p/q. Also, it could very well be that a ddc wont make any audible diffs in your setup.. better start with something small/cheap and see if it really helps.

 

[b0bb]

  Friend of mine is an audio diyer, he build this Raspberry PI3 recently, and pairs it with a diy R2R DAC. The acoustic playback is astonishing, it outperforms my brother's Naim flagship system entirely. I shall upload more images later on.
 
I upload all these images via my mobile phone, so it was a bit clumsy. . 

The RPi can send the data directly to the Soekris via I2S. It has a built in FIFO reclocker and galvanic isolator, this takes care of the jitter issues on the RPi I2S outputs.
This is how I use the RPi with the Soekris, I have got 4 of them,
 
This considerably simplifies the setup and reduces RF noise overall.
 
Your friend might see some benefit here, PM me if there is further interest.

 

[rb2013]

 
The RPi can send the data directly to the Soekris via I2S. It has a built in FIFO reclocker and galvanic isolator, this takes care of the jitter issues on the RPi I2S outputs.
This is how I use the RPi with the Soekris, I have got 4 of them,
 
This considerably simplifies the setup and reduces RF noise overall.
 
Your friend might see some benefit here, PM me if there is further interest.

Interesting thread on the Raspberry Pi for high end audio:
 
http://www.dimdim.gr/2014/12/the-rasberry-pi-audio-out-through-i2s/
 

The Raspberry Pi: Audio out through I2S

Posted on December 8, 2014
There are currently four ways to get audio out of the RPi:

• Use the audio out 3.5mm jack. It’s very easy to get it to work, but the sound quality is pretty bad, since it uses PWM to generate the sound. Due to that, its real resolution is in the neighbourhood of 11 bits. We have no use for that.
• Use the HDMI port. It works OK, but is useless to us audiophiles.
• Use a USB to I2S adapter, such as an Amanero or an XMOS-based device. Now we’re talking. They work quite well, and the quality of the I2S signal is dependent largely on the technology used (CPLD vs. XMOS, etc) as well as the quality of the on-board clocks. The problem is that they add another link to the audio chain, as well as increase the cost. Remember, the RPi is supposed to be a low cost solution.
• Use the GPIO pins of the RPi to get direct I2S output. This sounds way more interesting, right? Let’s try that!

Now we have to configure the software for I2S output. For my distribution of choice,Archphile, it’s a piece of cake: http://archphile.org/howto/i2s-dacs-and-the-raspberry-pi/
Audio playback works just fine!
Well, almost fine..
You see, in theory the RPi has a bit of a problem with its I2S output. Since the only clock onboard the RPi is a 19.2MHz crystal, it should have trouble generating proper clocks for its I2S output. For example, for 44.1KHz audio, the LR Clock must be running at precisely 44.1KHz. That is not possible, since the frequency is not a multiple of 19.2MHz. Thus, the frequency can be either 19.200.000 / 435 = 44.138KHz or 19.200.000 / 436 = 44.0366KHz. This is a limitation of the Broadcom BCM2835 in conjunction with the 19.2MHz crystal and there is nothing that can be done.
In order to confirm the theory, I decided to run a few tests. I hooked up my logic analyzer to my RPi, set it up for I2S output, and fed it some 44.1KHz music.

I took 1 sec worth of samples with my logic analyzer, configuring it for I2S signal. I got this:

The PCM Clock is already appearing a little dodgy. Let’s zoom in:


As you can see, the pulses do not have the same duration. They appear to alternate between two values. So it is obvious that the signal has jitter. A lot of jitter. Since we’re here, let’s have a look at the LR Clock signal as well:


The duration of the pulses appears to alternate between 11.33μS and 11.38μS, giving respectively 44.12KHz and 44.04KHz, values very close to the ones I calculated previously.
So, the theory is sound and the RPi’s clock is not up to snuff by strict standards. What this means is that the RPi’s I2S output is not capable of “Hi End” audio transmission. It is essentially not bit perfect (edit: this is not correct, strictly speaking. It is in fact bit perfect, it is just not “proper”.).
In the real world, chances are that this problematic clocking will not be particularly audible under normal circumstances, say with a normal-specc’ed sound system. But an audiophile should definitely steer clear of the RPi’s I2S output, instead opting for a USB to I2S interface.