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Ali Tait
12-05-2008, 18:56
Hi All,
Found this while nosing around.Might be of interest if you're stuck for space.

http://www.devilsound.com/DAC/

Regards,Ali.

jcbrum
13-05-2008, 11:07
Hi All,
Found this while nosing around.Might be of interest if you're stuck for space.

http://www.devilsound.com/DAC/

Regards,Ali.

I've tried one of those.

It's the same as this which costs 20

http://www.behringer.com/UCA202/index.cfm

JC

Filterlab
13-05-2008, 11:58
I can't even begin to imagine how bad that would sound. Just the side bus being used as a power supply would surely make it terrible.

devilsound
13-05-2008, 16:31
Hi guys,

I noticed there was some interest in our DAC, as well as some confusion (to say the least!) about what's inside. We'll be releasing a fair number of design details on the website in a week or so, including the chipset and architecture, for those interested in the guts.

Let me just say real quickly though that we started out to make a complete USB DAC, with a non-oversampled output stage (sounds way better that a normal DAC chip, but takes more to implement it), and just figured out how to make the thing on 3 square inches of circuit board. This isn't just a USB chip with a few nice cables - it's the same circuitry you would see in more expensive DACs, just shrunk.

Also, there seems to be massive internet confusion about the power in the DAC. Yes, powering audio (especially a DAC) with standard dirty USB power will sound terrible. Which is why we don't do that. Our DAC uses a megahertz DC-DC conversion circuit to regenerate the power, and then filters and down regulates that. It's a filtered switching converter, pretty much exactly what you would have with a wall power supply.

We get super clean positive and negative power rails, which allow us to use a real DAC chip, and DC couple the output. (A lot of the size reduction comes from not having the output coupling capacitors, which just hurt the sound, anyway.)

Anyway, skepticism is certainly understandable, but don't lump it in with the Walmart crowd - the chips in our circuit alone cost more than the DAC you mention above!

Here's a review (http://www.computeraudiophile.com/node/418) we got recently, (they compared it to a DAC 5 times the price!), which you might be interested in. Also, let me know if you have any questions, I'll try to answer them. (Or if your interested in more of the tech stuff, just check the website in a week or so.)

Hope this helps!

Jonathan
Devilsound Labs

Filterlab
13-05-2008, 20:18
Apologies for my sceptical reply as above, I guess it's the audiophile in me jumping to conclusions!

I will read the review. :)

devilsound
15-05-2008, 17:49
Apologies for my sceptical reply as above, I guess it's the audiophile in me jumping to conclusions!

I will read the review. :)

No problem! Actually, the web and forum feedback has been helpful, it just means we need to go ahead with releasing extra details about the innards. Granted, we are (quite literally) selling a black box, so it's no surprise that people don't know what's in it.

Ideally, we'd like to try to experiment with opening most or all of the design, not only so that people know what they're getting, but also just as a way of improving the product, and the state of computer audio in general.

There's a lot of intelligence and creative energy on the web, but it's hard to overcome the hurdle of polishing a design and becoming a manufacturer. So we'd like to pursue sort of blurring that line, and trying a cooperative effort to come up with the best possible circuitry (I think we have a really good start), which would be a benefit everyone ...

That's a direction for the future, though, it will have to happen over some period of time. Some initial design stuff should appear on our website in the next week or so ...

Jonathan
Devilsound Labs

leo
16-05-2008, 23:13
So this is more than just one of those stereo audio codecs with integrated USB interfaces like the PCM2906?

devilsound
19-05-2008, 04:01
So this is more than just one of those stereo audio codecs with integrated USB interfaces like the PCM2906?

Definitely! We just put up a whole lot of technical information about the guts, if anyone's interested in the architecture / chipset, you might want to check out the new design section (http://www.devilsound.com/DAC/design).

lurcher
19-05-2008, 06:40
(from the linked article)


The bit-shifting / channel-splitting circuitry is implemented using a Xilinx Coolrunner II CPLD. The devilsound DAC circuit board contains an JTAG header connected to the device, which allows the firmware is written to the chip after it has been assembled onto the board.

Cool devices those CPLDs aren't they, thats what I am using at the moment in my project to produce a differential i2s stream to drive a pair of 1541.

I should read up the link to the USB to i2s conversion links, not something I have looked at yet. Given that I listen to music at work on headphones using the PC as a source maybe its time I did

Filterlab
19-05-2008, 07:41
Interesting, I'll have to get my lugs round a set and see how they fair. :)

leo
20-05-2008, 00:23
Definitely! We just put up a whole lot of technical information about the guts, if anyone's interested in the architecture / chipset, you might want to check out the new design section (http://www.devilsound.com/DAC/design).

Well must admit I'm impressed that you've managed to cram all this in such a compact space.
Interesting dac choice

Filterlab
22-05-2008, 12:20
That is tight in there.

Has anyone heard one yet?

Prince of Darkness
22-05-2008, 16:43
JC, apparently:lol::lolsign::ner::eyebrows:

devilsound
01-06-2008, 06:46
(from the linked article)

Cool devices those CPLDs aren't they, thats what I am using at the moment in my project to produce a differential i2s stream to drive a pair of 1541.

I should read up the link to the USB to i2s conversion links, not something I have looked at yet. Given that I listen to music at work on headphones using the PC as a source maybe its time I did

Yeah, very cool. Actually, I'm not sure how else to do it, at least in that small of a space. I think some DIY types of projects use re-clockers like the CS8420 (http://www.cirrus.com/en/products/pro/detail/P53.html) or similar, but I'm not sure if this is a good solution, since it can add resampling artifacts (?), and it's sort of overkill (price, size, and power consumption) ...

There are some bit-shifting chips out there (shift registers), but you need quite a number of shifts, especially if you want to use one word clock for both channels ... not sure if anyone's had much luck with these, any suggestions? I think the CPLD stands, but I'm wondering what people do for breadboard / prototype types of project ...

Jonathan
devilsound labs

lurcher
01-06-2008, 10:48
I'm wondering what people do for breadboard / prototype types of project ...

At the momewnt I am using one of their Coolrunner II X boards, at $50 its hard to beat. The connections to and from the board are longer that I would hope, but it allows me to experiment with the vhdl. I plan to get a smaller board made wth just the clpd and a tentlabs clock source, enough IO and the JTAG pins, but that for later.

It certainly beats wirewrapping prototypes up (there thats me showing my age :-)).