[00940]

Hi,
 
I've been discussing with another head-fi member what one could get as a very simple USB dac for 200-300€ these days.
 
Ease of soldering (pre-soldered expensive smd chips are good!) and implementation are important factors. Strong dislike of Chinese pcb with plenty of misused red wima caps is another. Avaibilty in Europe and reducing shipping/customs fees is a last factor.
 
 
Since the ES9023 is trendy, an easy choice would be an ODAC with an USB isolator powered from a linear supply. Either the doodlebug about to be introduced by Beezar or this one. Buying an ODAC from headnfi, the project would easily fit under 200€. Not very DIY, I know...
 
A first competing idea would be this:
 
- I2S input es9023 board with onboard PS (130€ shipped);
- I2S over USB board for USB input, with isolation (84€ shipped)
- 2X9V transformer (10€)
- small regulated ps for the USB input board (10€)
- box, cm filter, iec inlet, rca, etc (60€ shipped)
 
total: 294€
 
A second idea would be this:
 
- I2S input AK4396 board
- I2S over USB board for USB input, with isolation (127€ shipped, combined with the DAC board)
- 9Vdc wallwart (10€)
- small regulated ps for the USB input board and DAC (10€)
- edcor xsm10k-10k to replace the output stage (55€ shipped)
- box, cm filter, iec inlet, rca, etc (60€ shipped)
 
total: 262€
 
A third idea is quite close to the second:
 
- TP wm8741 opus board (63€ shipped)
- I2S over USB board for USB input, with isolation (84€ shipped, combined with the DAC board)
- 2X9V transformer (10€)
- 2Xsmall regulated ps for the USB input board and DAC (20€)
- edcor xsm10k-10k as output stage (55€ shipped)
- box, cm filter, iec inlet, rca, etc (60€ shipped)
 
total: 292€ (but there might additional customs fees on the opus board)
 
 
In all three cases, cost and complexity are contained by using decent voltage out DAC, not requiring I/V stage nor bipolar supplies. For 2 and 3, the use of transformers to go single-ended is thus required. The first idea offers an extra spdif input for cheap. The second has the advantage of being more easily powered by an external dc adapter, reducing size and complexity of build. I'm not too convinced the extra work on the wm8741 is really worth it.
 
What do you guys think ? Any hiddem gems we should consider ?

 

[Mullet]

Here is another idea... another trendy ES9023 DAC...
 
http://www.minidsp.com/products/minidspkits/curryman-i2s-dac
 
It requires two trafos though. One for 5v and the other for 15-0-15v. I built a beta version with an Amanero USB to i2s board. Also used 3 Sigma 25s for power supplies. I also added in an Acko reclocker/isolator and the build came out great. It can be build for less than €300. Plus, it has a really nice filter buffer on the DAC board.

 

[wakibaki]

You can get an AK4396 for ~€7 or less. You can get 5*100mm square PCBs for $20 + shipping from seeedstudio.com, so why not design your own, if you feel that strongly that the Chinese ones are crap, or you could buy the complete kit from China with the SMT parts fitted, and build it with any modifications you chose, you can get one for ~£25 (~€35) or you can just buy the board and SMT components fitted for ~£15: http://www.ebay.co.uk/itm/PCB-SMD-IC-NEW-Hi-end-DAC-24-BIT-192K-HZ-AK4396-sc-/200860051055?pt=UK_Sound_Vision_Amplifier_Parts&hash=item2ec431266f

w

 

[00940]

  Here is another idea... another trendy ES9023 DAC...
 
http://www.minidsp.com/products/minidspkits/curryman-i2s-dac
 
It requires two trafos though. One for 5v and the other for 15-0-15v. I built a beta version with an Amanero USB to i2s board. Also used 3 Sigma 25s for power supplies. I also added in an Acko reclocker/isolator and the build came out great. It can be build for less than €300. Plus, it has a really nice filter buffer on the DAC board.

 
Thanks for the hint. Looks good indeed and I wasn't aware of it. A filter/buffer can't hurt. It gets a bit pricey with shipping and customs fees (I'd guess 80€ all included) but not too much. A bit ironic considering the designer is German. Stocks are a bit erratic too it seems. Power supplies aren't a problem, I can etch some.
 

You can get an AK4396 for ~€7 or less. You can get 5*100mm square PCBs for $20 + shipping from seeedstudio.com, so why not design your own,

 
Thing is, the AK4396 board I linked to is only 42€, all parts soldered, when bought with the USB to I2S board, with no additional shipping cost. And it integrates nicely with the receiver board, that makes things easier and more compact. I agree with you that I could get exactly what I want by designing a board myself but the incentive is kinda low...
 
 
 
Another option that's been interesting me is the 99$ pcb from diyinhk for the es9018. Not the best pcb (I know) but it has been slowly upgraded following inputs on diyaudio.
 
That'd make about 160€ (shipped+customs fees) for the es9018 board and an isolated usb receiver. Obviously, PS will cost quite a bit more, even going for homemade pooge regs and we need to populate some parts on the board. Let's say 50€. Output stage could be edcor wsm10k-150 as used here, for 50€ shipped. We're at 260€, still missing case, jacks and so on. So about 300-320€ total.
 
 
 
There's really a whole lot of interesting stuff out there these days...

 

[00940]

You can get an AK4396 for ~€7 or less. You can get 5*100mm square PCBs for $20 + shipping from seeedstudio.com, so why not design your own,

Couldn't quite resist the temptation... still missing stitching with vias to link top and bottom groundplanes and some caps but it's indeed looking like a nice option. Fits a 5*5cm board easy.
 

 

[Mullet]

If you end up doing your own thing I might be interested in scooping up one from you. If that's cool with you of course...
 
Are you planning on .ext clock? The Amanero via diyaudio GB might be a really good option for USB to i2s. I think it's around €40. Also you could get one of Acko's isolator/reclocking boards from Acko. It contains the option for dual clocks and provides synchronous clocking. This would make one really nice DAC. Of course the price is driven up a little bit by the clock/isolator board.
 
http://www.diyaudio.com/forums/group-buys/227502-amanero-isolator-reclocker-gb-72.html#post3527710

 

[00940]

  If you end up doing your own thing I might be interested in scooping up one from you. If that's cool with you of course...
 
Are you planning on .ext clock? The Amanero via diyaudio GB might be a really good option for USB to i2s. I think it's around €40. Also you could get one of Acko's isolator/reclocking boards from Acko. It contains the option for dual clocks and provides synchronous clocking. This would make one really nice DAC. Of course the price is driven up a little bit by the clock/isolator board.
 
http://www.diyaudio.com/forums/group-buys/227502-amanero-isolator-reclocker-gb-72.html#post3527710

 
It's all rather hypothetical at this point. But sure, as Wakibaki said those pcb from China come by batch of 5, I could mail you one if it ever goes forward.
 
At this point, I'm trying to keep it all simple. So I was considering this usb receiver, based on the cm6631a. It has the advantage of being isolated and also in the 5*5cm format. Current plan is also to keep the ak4396 in hardware mode, which means pcm input only, no dsd.
 
Posted a thread on diyaudio about it, btw.

 

[00940]

Since I just got the news that the curryman should be soon carried by a French webshop, it seems like the evident choice (hoping they fixed their jfet matching problem). Same shop has a 2x12V+1X7V 15va transformer that will be perfect for it. I'll etch pooge regs for the analog side and follower emitters for the digital side. I'll set that ak4396 thingy aside

.
 
The diyinhk receiver I linked above seems a decent companion for it. Since the curryman works in asynchronous mode, we don't need the very best performance given by xmos solutions. This one is a bit cheaper but still has isolation after the receiver (which is better than the adum solutions since it puts less limits on accepted sample rates). And this with only one pcb to deal with. Pcb design is also a notch above the stuff we see from hifimediy and weilang.

 

[Mullet]

I'm glad to see you went with the Curryman. It was a very enriching project for me. And I like that it's such a flexible board. You have the choice to use an on-board or off-board XO, which is great. You can also put a switch between the buffer/filter and pre-filter to decide what sound you like best. I guess the isolation is key and it's great that the diyinhk board has it. Re-clocking is a whole nuther ball of wax. Enjoy the project.

 

[00940]

The board for rectification and regulation is done. I finally just went with lm317-337 for +/-11V, 5V and 3.3V (for the USB board). Schottky as rectifiers then a CLC filter with 470uF-10mh (14r dcr)- 1000uF. All caps are panasonic FR. It just fits in the 8*10cm the free Eagle version gives us.
 
I'm waiting for the rest of the parts to go ahead (next week probably).