New Async XMOS 384K/32bit with PCM5102 DAC on ebay

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andynz

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Joined 2006
luxury54 said:
mine got lost and never received it so i finally got a refund
I'm happy because it was the first version without headphone output unlike this new version

so can you confirm that indeed the Windows driver doesn't have the periodical beeps as an evaluation driver from Thesycon?

also, have you tested it on it's headphone output? how does it behave with small loads like 32 ohm headphones? doest it have some sort of clipping?
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I have not tried the DAC with Windows, I use the Raspyfi instead. In case you have not heard of it it is a small credit card sized computer running a customised version of debian specifically for playing music on most USB DAC's. You can have the DAC and Raspyfi in a box with power supply and you can plau of any USB drive or network attached storage.

I have not tried the headphone output as I only feed the DAC into my preamp/amp/speakers.
 
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andynz

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Joined 2006
PreSapian said:
this one looks very tempting. with external power are we sure the dac will be fed from that source or will it still be usb powered? chinese designs sometimes have baffling flaws like that from my experience.

and i thought 5102 didn't need coupling caps? the pair of wimas next to the chip doesn't look welcomed.
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I can confirm that you can change from USB 5v power to your own external 5v power supply and the USB 5v is no longer used. I will post some pictures soon of what I did on board version 1.3 which is what I was sent.

The picture on ebay is not the version of board currently shipping. As i mentioned in my previous post you need to add a couple of solder bridges and ONLY use a regulated 5v external supply. DO NOT use the 6-9v the Ebay listing says as there is no on board regulator to drop the 6-9v to 5v.

vs 1.3 board has a some caps around the DAC but these look to be for the two extra DAC power regulators close to the DAC. Output decoupling would be electrolytics with HF bypass caps and these are not on the board around the DAC.

I will take a few pictures today to show the external supply mods and the dual board Raspyfi/DAC setup.
 
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valve5425

Member
Joined 2008
andynz said:
Good news guys. I pulled together an old linear high quality 5v power supply to power the DAC and kept the Raspyfi on the wall wart 5v supply.


With a good power supply this DAC is pretty darn good. Up there with the best.

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I've noticed this evaluation, ultra low noise, adjustable power supply from Texas Instruments, available from Farnell for around £18.00 ....... TPS7A4700EVM-094 .......... Would this be a quick and easy way of getting a clean, low noise supply. I haven't used this myself but will order one when I decide which DAC to go for.


I'm currently looking for a DAC project but can't decide if I need DSD. So many choices, too little time!! This board looks interesting for PCM and is certainly cheap. The upgrade looks like it may be worth a try as well.
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andynz

Member
Joined 2006
valve5425 said:
andynz said:
Good news guys. I pulled together an old linear high quality 5v power supply to power the DAC and kept the Raspyfi on the wall wart 5v supply.


With a good power supply this DAC is pretty darn good. Up there with the best.

_________________________________________

I've noticed this evaluation, ultra low noise, adjustable power supply from Texas Instruments, available from Farnell for around £18.00 ....... TPS7A4700EVM-094 .......... Would this be a quick and easy way of getting a clean, low noise supply. I haven't used this myself but will order one when I decide which DAC to go for.


I'm currently looking for a DAC project but can't decide if I need DSD. So many choices, too little time!! This board looks interesting for PCM and is certainly cheap. The upgrade looks like it may be worth a try as well.
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I know what you mean about choice and time. There are so many options out there now. I chose this board as it has a good chipset. The PCM5102A is direct output so no buffer stages to deteriorate the sound. It has 5 regulator sages I can find so does a good job of separating the power supply sections. It's a good "mid point" in the various options out there. It allows you to make some tweaks without you spending years getting it sounding just right. Whilst I am interested in the technology used I primarily want to be ble to sit down and listen to music and this DAC seems to be a good option for that.

We are the New Zealand ATC distributors and so are spoiled for great speakers and electronics to use. I purchased this DAC after a number of our clients wanted a front end capable of 384khz. I'm not really into the numbers games, there are some fantastic 44.1/16 recordings out there and whilst I can appreciate the quality of the tet 384khz tracks I have tried, it's primarily about listening to music. So far I have sat through tracks using this DAC and not flicked around. A good sign if ever there was of a great DAC.

Re the power supply form Farnell, that looks like a test board without rectifier and smoothing so possible not what you are after. My current power supply is using a bog standard LM317 but with 3 banks of 5,000uf smoothing after the rectifiers. Totally over the top but past experience suggests that most modern DAC's are good, it is the power supply that makes all the difference.

so my current thinking is buy a empty DAC box from Ebay, use my current toroidal, high speed rectifier and excessive smoothing caps then buy a couple of LM317 supply boards from Ebay. One for the DAC and one for the Raspyfi. I will post a few pictures shortly of the current experimental setup.

Just to reinforce my point, I wouldn't bother buying this DAC if your not going to run on a separate power supply. This is great sounding DAC so it needs to be given the chance to shine and give the sound quality that is far far beyond its price point.
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A

andynz

Member
Joined 2006
Here is a couple of pictures of the experimental setup. Please no comments on the state of the power supply and layout, this is just an experimental setup to make sure it all worked. The end result will look a bit nicer :)

Test rig with Raspyfi top right and DAC on the right.
An externally hosted image should be here but it was not working when we last tested it.


Closeup of current vs 1.3 DAC board.
An externally hosted image should be here but it was not working when we last tested it.


Note U13 missing which is the 6-9v down to 5v regulator. As the factory said I have shorted pin2&3 of U13 which then feeds the external 5v up to the "S1" "E" pad which is then horted to the centre pin of "S1" with a solder blob on the back of the board.
 
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press57

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Joined 2012
Here is a picture of the V1.4 board dated 9.9.2013.U13 is there plus some other differences.
 

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valve5425

Member
Joined 2008
andynz said:
valve5425 said:
Re the power supply form Farnell, that looks like a test board without rectifier and smoothing so possible not what you are after. My current power supply is using a bog standard LM317 but with 3 banks of 5,000uf smoothing after the rectifiers. Totally over the top but past experience suggests that most modern DAC's are good, it is the power supply that makes all the difference.
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Sorry Andy, I could have worded that better! You are correct to point out that this is not a stand alone PSU and will need a rectifier before it.

I was just mulling over the fact that this would be a vast improvement in noise levels over the LM317. 4.67 uvolts noise instead of 0.15 mvolts. Further advantage is that it's LDO, dropping only 307mv at 1A so potentially less heat. Granted it is not cheap but I can see that other DAC builders have got big gains in SQ with lowering the PSU noise floor.

I realise that you also put a big emphasis on your PSU's as do I. However my own building experience is with large, valve rectified, HT PSU's so, other than heater supplies, I haven't built many LT supplies and certainly not any precision ones which DAC's seem to do best with.

Look forward to seeing more results from you.
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andynz

Member
Joined 2006
Hi vavle5425. Yes your quite right the 317 is pretty noise for todays standards. The TPS7A4700 looks like an attractive option. Ebay has some setup on a 3 pin PCB for around $20US. Maybe this could be a secondary regulator after the 317 which can bring the voltage down so the TPS7A4700 only has a few volts to work with. I also have a bunch of older LT317AT regulators I used in a 1990's DAC upgrade for my much loved Marantz CD94 now long gone. Oh, just looked up the noise spec on the LT317AT and it is 50uV for 5v output so I think they will stay in the old parts bin. But I am rambling...

I wanted to buy a made up power supply so I can have a nice neat internal layout. Then I can have a perspex lid and see the sample rate LED's if I need to check occasionally.

From the Raspyfi website this looks like a good option for the power supply:

http://www.diyinhk.com/shop/home/13-17uv-ultralow-noise-dac-power-supply-regulator-33v55v-1ax4.html

17uv-ultralow-noise-dac-power-supply-regulator-33v55v-1ax4.jpg
 
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PreSapian

Member
Joined 2009
andynz said:
Re: "and i thought 5102 didn't need coupling caps? the pair of wimas next to the chip doesn't look welcomed."

I can confirm the PCM5102A output goes via a single series resistor straight to the output connectors.
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can i take the resistors out?

looking at the datasheet, 5102 requires 3 separate 3.3 regulars- please correct me if i'm wrong on this.
so which ones on this board would benefit the most by switching out to salas shunts?

i have gone ahead a placed a order for a board.
 
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andynz

Member
Joined 2006
PreSapian said:
How many regulators are there and would which ones be worth switching to salss shunt for?

And how did you select the de emphasis filter?
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I haven't changed the filter on the 5102, it sounds so good that I'm not sure it can get much better. I'm also ware that with the surface mount components it could be all to east to stuff up my working DAC.

There are 3 regulator stages bottom left and 2 more regulator stages round the 5102. There is the option to move all these off board but I'm in 2 minds about the value of that. Yes you could get lower noise using eternal regulators but I am inclined to think you are going to increase the chance of instability and oscillation by having longer connections between the the power supply and the 5102. On balance I think you are better using the best power supply possible onto the board and leave the rest alone. My goal here is to enjoy the music, not spend days and days modifying the board :)
 
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andynz

Member
Joined 2006
ghiglie said:
Hello,
I'm following you build, Andy, since it look like a real bedside setup.
I've got in order from Electronics-Salon a cheap LM317/377 dual power supply which I'll use in another testing project - but I saw this too based on LT1764, hope it helps.
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Ciao Ghiglie

Thanks for following the project! It's changing as it goes but I have pretty much decided on the following:

PCM5012A DAC Board (obviously!)
$T2eC16dHJHQFFhiC9KtVBSIei,m(yw~~60_3.JPG


Raspyfi
RaspyFi - Pi never sounded so good!

Regulator Board
4.17uV Ultralow noise DAC power supply regulator (3.3V/5V 1A)x2 (+-12V/15V 1A)x1 - DIYINHK
17uv-ultralow-noise-dac-power-supply-regulator-33v55v-1ax4.jpg


Toroidal 230v - 2 x 6v AC transformer
Toroidal 230V Mains Transformer 15VA 0 6V 0 6V | eBay
$(KGrHqV,!nsFCrWfq0ElBQ-UQUoE0!~~60_35.JPG


And an ebay aluminum box yet to be ordered based on what size all the boards come to when I connect it up.

I think that should do it and with the option of installing a 2.5" external drive in the box I can have my entire collection, DAC & power supply in one little box.

This box looks like a good option with IEC and power switch. You would need to modify the rear panel holes possible.
http://www.ebay.com/itm/2806-2-Aluminum-dac-Enclosure-DAC-BOX-case-suitable-DAC7-DAC9-ES9018DAC-1541-/121138708662?pt=US_Amplifier_Parts_Components&hash=item1c346e00b6
$(KGrHqZ,!rYFG1iISsbLBR1v4thjc!~~60_3.JPG
 
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A

andynz

Member
Joined 2006
PreSapian said:
can i take the resistors out?

looking at the datasheet, 5102 requires 3 separate 3.3 regulars- please correct me if i'm wrong on this.
so which ones on this board would benefit the most by switching out to salas shunts?

i have gone ahead a placed a order for a board.
Click to expand...

I wouldn't advise removing the series resistors in the output, they are there to limit damage to the DAC if you short the output and also help reduce instability.

As mentioned previously the DAC already has separate regulators round it. I don't think it is worth bypassing those but if you do, do so at your own risk and be prepared to order another DAC!
 
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