[comabereni]

4/1/05 Update:

I now have the schematic and PCB in hand. If you are interested in this project, shoot me a PM. Even if you don't plan to build this but want to join the discussion, shoot me a PM with your postal address and I'll send you printed photocopies--I don't have a scanner and am not sure the small printing on the schematic, which is is slightly faded in a few areas, would translate all that clearly into a JPG anyway, so I'll just do it the old fashioned way and send you pages in the mail.

While there are a lot of components on this board, it doesn't appear all that difficult. All the components are clearly marked, the screenprinting is good, and the PCB itself is nice.

Thanks.


_______________________________________________

Original 3/22/05 Post:

I bought doobooloo's Lite DAC-38T PCB and parts yesterday and will hopefully be able to start building this DAC in a few weeks. I thought I'd see if any of you here had any interest in building this DAC for yourself so we could make a group project out of it. My not-so-hidden agenda is that this is my first DIY audio project and I'm anticipating having questions, combined with the fact that I've only found one other English speaking forum where this DAC has been built... ONCE.

Lite Audio's DAC-38T page
diyclub.biz sells complete kits for $420 (including case), or the PCB alone for $21.

Now for the good stuff:

1) The sound of the completed project as described by the builder I found on diyAudio.com: "The DAC sounds very good. I can only compare to CI Audio VDA1 and optional VAC1 power supply. It sounds better, soundstage much wider and accurate, qualities that CI Audio had in the top range now are present in midrange and at lower freq (dynamics, etc)."

2) In the words of doobooloo: "This DAC kit utilizes the ultra high-end 24bit/96KHz PCM1704 that is capable of 8x upsampling at an amazing 768KHz." I did some searching and found that LessLoss makes a DAC utilizing the same chipset that starts at around $2,500, as well as TEAC with their $6,000 Esoteric D-70, so it ought to be a worthy project.

__________________________________________

I would be willing to let any of you who help me with this project audition the completed DAC. Something along the lines of I ship it to you at my cost and you ship it back at yours, or to the next person on the list. I'm neither greedy nor impatient when it comes to hobbies and projects, so wouldn't mind having this float around for awhile before coming back home to my system. It would also be interesting to know how it stacks up against better known DACs.

Thanks,

-coma

Click for the on-line schematic (small)

 

[individual6891]

How much is the PCB?

Is there a schematic floating around anywhere?

 

[comabereni]

The PCB is US$21.00 from diyclub.biz. I'm not aware (yet) where you can find a detailed schematic online, but will try to make this available as soon as I get it from doobooloo.

-coma

 

[Magsy]

I saw this in forsale, read the whole thing and thought woo, I'll buy it. Of course, when I scrolled down I realised someone had already bought it!

I need to read up a bit but Individual, if you want a board maybe we can split the postage or something (unless its dirt cheap anyway?)

Back to the cooking...

 

[chillysalsa]

You just beat me to buying it from him!

Does the kit come with '-K' versions of the DF and PCM chips?

I'm trying to figure out what would be cheaper: get just the PCB and source the parts myself, or get the full kit $420. If the full kit comes with pricey "premium" version of the parts, it may be worth it.

Are the R-core transformers 220 or 110V primaries?

 

[philodox]

That is pretty advanced for a first DIY project is it not?

 

[motherone]

I'd be down for doing this DAC as a project. I just finished modding a superdac, so now I'd like to build a big, bad*** one from just the PCB.

I wonder if a group-buy could be done for the critical parts? (I.e. transformers, chips and carrier boards). It looks like DIY club is charging at least $5-10 more per part than what it would cost to get 'em off of digikey (with the appropriate converters).

R-core transformers are hard to get here in the states, so that would be the really difficult part, if you wan to stay true to the design.

 

[comabereni]

Quote:

Originally Posted by philodox That is pretty advanced for a first DIY project is it not?

Probably

. I'm sure I could figure it out eventually on my own, or by recruiting my EE brother-in-law's help at family gatherings (lucky him), but I'd rather get some of you going on it since it's your passion already. You were going to build one anyway--why not this one?

The one English-speaking person I've found that has attempted this kit completed his almost a year ago--I don't know if he's still around or interested in talking about it.

I understand actual polarity of a few parts might be reversed from what's silkscreened on the PCB, but it is supposedly easy to figure out. What doobooloo said, paraphrasing, is that it should be pretty easy once you identify and source the parts (might be the hardest part). He mentioned that the heatsinks are difficult to locate. Maybe he'll chime in a little here and there to tell us things like where to buy stuff, but I don't want to give him the impression he's doing tech support for a kit he sold.

Finally, I haven't done the exact math on the materials, but it looks like the kit is pretty well priced compared with sourcing things on your own (plus it comes with a case IIRC), but I can't guess the quality of what's included. I know that my doo-assembled kit comes with the highest-quality PCM1704U-K and that PCM1704-K is printed on the PCB, so it appears it was designed around that chip and that the kit perhaps ships with it as well.

From LessLoss.com's site: "Many people do not know that the PCM1704 is classified into different categories of perfection. There is the PCM1704U, which is the least expensive and worst lot. Then there are better ones, which are marked PCM1704U-J and PCM1704U-K at the factory. We would like to stress that the LessLoss DAC 2004 uses only the best and most expensive PCM1704’s. We have chosen the best converter and then use only the best lot of these converters."

-coma

 

[guzzler]

I'd be in for a PCB, not for a kit though as I don't have time or reason to build it for ages, but it's nice to have the PCB available

(same as the DynaHi

)

g

 

[individual6891]

Quote:

Originally Posted by Magsy I need to read up a bit but Individual, if you want a board maybe we can split the postage or something (unless its dirt cheap anyway?)

Well i'd consider this or the DDDAC1543

Will need schematic of this one before I put it as a strong choice

 

[DaKi][er]

I'm in the process of building my own dac using the df & pcm1704 chips, and I am awaiting parts and the PCB to come back from being made and then I can post results and impressions of it

Schematic
Board
3D Render

I have all this, inc transformers, to (hopefully) fit in a Hammond 1455N1601
(So does that make mine ultra lite?)

I haven’t gone for the K version of the chip myself, I got the mid range one to use but you can use any of the 3 from the economy version to the expensive, going for $20, $25 and $35 from digikey and I even think it is possible to stack these chips like they did with the old tda15** or whatever they used

One thing I notice is there is no smd at all on that board, the pcm1704 is only available in SOIC20, so do they expect to use adapters to dip package? Why not just put the smd direct on the board, it’s not like they're hard to solder
And if a df1704 has to go on there as well, that's only in SSOP28 as well

 

[comabereni]

Quote:

Originally Posted by DaKi][er One thing I notice is there is no smd at all on that board, the pcm1704 is only available in SOIC20, so do they expect to use adapters to dip package? Why not just put the smd direct on the board, it’s not like they're hard to solder And if a df1704 has to go on there as well, that's only in SSOP28 as well

Correct. I believe doobooloo was saying it requires adapters.

 

[00940]

Hijacking your thread...

DaKi][er : didn't you forget to set SEL1 and SEL0 of the pcm2902 to high ?

 

[DaKi][er]

Quote:

Originally Posted by 00940 Hijacking your thread... DaKi][er : didn't you forget to set SEL1 and SEL0 of the pcm2902 to high ?

http://www6.head-fi.org/forums/showthread.php?t=109671
i guess a few more people wont have them set high either....

(it isnt hard to bridge from the Vcc pin right next to them if it matters)

 

[philodox]

Quote:

Originally Posted by comabereni You were going to build one anyway--why not this one?

You my friend are evil.........we'll see how much interest we get here before I commit.