USB interface NOS DAC??

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Have just gotten bitten by the DIY bug after building some gainclones and would like to build a NOS DAC with a USB input. I have checked out several threads on this but all seem either to lack some component or sound quality, or as in the case of Peter Daniel's DAC a USB input. (built some of Peter's gainclone kits and the quality was first rate)

Please don't try to convince me not to build a USB DAC, I am fully into hard drive based audio, have some other usb/pc gear already so this is for a second system. (Have Modded Squeezebox into modded Benchmark, am demoing Empirical offramp turbo as well).

Could anyone provide some reference to one they have actually built and what they feel the sound quality and parts quality are like? Also if it has the option of balanced outs that is a plus, not too worried about cost but don't want a money pit either, let's say $200 limit for parts not including enclosure as a max.

Thanks in advance for all of your help!
 
Here... Ill give you where i am on this.

http://www.audiodiylab.com/shop/product_info.php?products_id=45
http://www.enjoythemusic.com/magazine/equipment/0706/hagerman_technology_chime.htm
http://www.myexposition.com/diy/usbdac/overview.html
http://www.ecp.cc/HPDAC.html

I found two things that have stuck out at me.
1. the best gear uses transformers to decouple the ouput from the DAC
2. I can't seem to find a USB DAC chip that does 24-bit.

For me 24-bit is important - it lets you play SACD DVDCD audio, as well as audio recorded above 24-bit without downsampling to 16-bit. Most people wont care about this at all, but I have some personal recording done at 24-bit so I do.

If all you want is a USB powered 16-bit dac then it's easy as pie... look above. If you want a 24-bit version it's a little harder.

Milo
 
In addition to my HPDAC (linked above) I did this one too: http://www.diyaudio.com/forums/showthread.php?threadid=76821 and this one: http://www.ecp.cc/NOS-USB-DAC.html

You should also look at Scott Nixon's boards if you don't want to design your own.

If you stick to the I2S input chips (TDA1543 and TDA1541A) it is really easy. If you want to use something else (TDA1545, AD1865) it is a bit more work.

A final option is a usb to spdif board. The advantage there is that you can use a transformer to couple the spdif signal which is a great way to eliminate computer noise. Check out Hagtech's board http://www.hagtech.com/hagusb.html
 
I've got the AW-D3 usb dac kit from Audioworkshop.com. Reasonable price and decent quality parts. Gives the option of 2 dacs, a Burr Brown which can be used as a headphone amp and a TDA 1543 nos. To me the Burr Brown just has the edge on my M-Audio 'Audiophile' soundcard. Detail is very good. Noisy if you use the 5v from the PCs usb though. No noise problem if running from a laptop on battery. I power the nos dac from the same PC psu that powers my modded T-Amp. Did try cutting the usb 5v line and using external power but it wouldn't play.

The nos dac has a pleasant analogue type of sound but is less detailed than the Burr Brown. Some rock recordings sound better on the Burr Brown. I did an ABC blind test with some friends using Nina Simones' version of 'I put a spell on you'. 2nd up was the Burr Brown and they preferred it to my M-Audio soundcard. As the intro was playing on the nos dac they said the Burr Brown was better but when she started singing they changed their minds.

Many usb dacs use the PCM2706 family of chips and there are a few posts here reporting troubles with it freezing when mains appliances switch on and off. It's been driving me crazy, I now turn the fridge off before starting a movie.

Like you I'm into PC audio. Maggie, Charlize and Monica arrived today from DiyParadise along with Yeos' usb controller. It uses a PCM chip so I might have the same freezing problem. Am using Maggie (transformer volume control) right now and the AW-D3 still freezes.

It evens freezes with a laptop running on battery if the laptop is close to my desktop Dell. I shut down the Dell, no joy. Pulled the mains plug from the Dell and then the dac running from the laptop on battery was solid, no freezing at all.

I don't want to use a battery powered laptop as an audio server so am going to have a go at fixing the freezing problem. Hopefully Yeos' usb controller will give me less problems.
 
Thanks

Thanks for the feedback, lots of ideas here in your posts. I do agree that finding 24bit designs seems out of reach, but this is not so much a priority to me.

I have looked at the Hagerman kits before but too much $$ for this project, want to keep under $200USD for parts not including chassis. The DDDAC looks very interesting but is a bit more than my budget will allow for the project as well.

I am particularly interested in the DDDAC and the Audio DIY labs kits as they seem pretty simple and do what I need of them. I noticed that the Audio DIY Labs kit used Dayton capacitors, not sure of whether in their use they are very critical, but I know these performed just so-so when used in speaker building so wasn't sure if these would be something to upgrade or not, or perhaps just buy the board and populate with better parts??

Any comments specific to this design?
 
Power

oh, also many have recommended battery power to get away from the noisy computer power supply. The Nixon dac seems to have USB power only and no separate battery supply, but the website is not very clear. Any others that have a battery supply and preferrably balanced outs?
 
I'm happy to report that the usb converter from diyparadise hasn't frozen on me. The acid test was using a mains voltage controller I got from Maplins. When used to lower the output of a 400w heating element I never got more than 20 seconds before my AW-D3 froze. Yeos' converter was solid with the mains controller running for almost an hour. Been up all night listening and listening. Bliss.

Monica2 sounds real good even though the Blackgate N caps are said to need 50+ hours of burn in.
 
Re: Power

sbrtoy said:
oh, also many have recommended battery power to get away from the noisy computer power supply. The Nixon dac seems to have USB power only and no separate battery supply, but the website is not very clear. Any others that have a battery supply and preferrably balanced outs?

I am using the SN USB DAC. It runs on an external power source i.e. SLA battery, SMPS, etc. It only uses the 5v from the USB cable to light up an LED on the board that indicates connection with the PC. Power to the board itself is via the power supply. I confirmed this with Scott as I was concerned when I bought the DAC.

It is a good sounding DAC and easy to build.

Best,

Paul
 
sbrtoy said:
Have just gotten bitten by the DIY bug after building some gainclones and would like to build a NOS DAC with a USB input. I have checked out several threads on this but all seem either to lack some component or sound quality, or as in the case of Peter Daniel's DAC a USB input. (built some of Peter's gainclone kits and the quality was first rate)

I will have the USB version of my NOS TDA1543 DAC ready and available very soon: http://www.diyaudio.com/forums/showthread.php?postid=1159337#post1159337
 
Wow, I found a thread I was looking for years!

I am in the really same situation:
1. I love the sound of NOS DACs
2. I beleive in direct USB > I2S > DAC way, using
- no SPDIF stage between
- no USB bus-power
3. I have a budget about 200 Euro.
4. I don't want to play with SMD parts, and I welcome assembled kits, if they are not 2x more expensice.

AFAIK I have found the following:
1. Diyparadise Monica2 with USB card: 125 + 30 USD
I've read many very good reviews about monica2 using cd-players, and yeo finally made a USB card, you have to solder into monica's board to have usb input, but I haven't read any review about the performance with usb input. All I know is that monica produces such a low output that it's unusable for power amplifiers.

2. DDDac's USB-12 Kit: 182,00 EUR

3. Scott Nixon's: usbdk Basic kit: 110 USD

4. Peter Daniel's: soon

5. AudioDIYLab: USB DAC - 201 - kit: 86 USD


I don't know how I2S works. Is it a standard, or it's something specific to each receiver/dac chip? I mean using diyparadise's $30 USB>I2S board, is it possible to make an USB input into _any_ NOS DAC design, or we can only use it for designs using TDA1535?
 
Member
Joined 2003
Paid Member
Just finished a kind of "junior" version of a single chip 1543 NOS DAC with (PCM2707) USB input as a single board solution (which can be expanded later on with DAC-12 modules. Any way, this is a nice start up solution to start experimenting with USB and NOS dacs

Here is a link to schematics and PCB layout: click here

These Schematics describes also how to implement a PCM2707, so, that there is no backvoltage to the USB port when the PC is powered down (as most designs does) without the problem, that the PC does not recognize the DAC after DAC power down, without unplugging the cable (like my old design)

or check my Site My Site

Doede
 
Member
Joined 2003
Paid Member
Forgotten a picture ;)
 

Attachments

  • usb-receiver32-004.jpg
    usb-receiver32-004.jpg
    80.8 KB · Views: 966
dddac said:
These Schematics describes also how to implement a PCM2707, so, that there is no backvoltage to the USB port when the PC is powered down (as most designs does) without the problem, that the PC does not recognize the DAC after DAC power down, without unplugging the cable (like my old design)

Hi Doede,

I'm looking at your schematic and I wonder why did you use that AND gate? Wouldn't it be much simpler to connect pull up resistor directly to the node of LED1 and R12 (3.3V), or simply to Vbus if 5V is OK here?

That should take care of what is mentioned in application notes: "To avoid back voltage in self-powered operation, the device must not provide power to the pullup resistor on D+ while VBUS of the USB port is inactive."
 
Do you have anz comparision about the quality of direct USB>I2S vs. USB > SPDIF > I2S? The guys at headfi are telling me, that I should by an USB > SPDIF conversion module, and use it with any ordinary DAC.

My problem is, that I cannot beleive that USB > SPDIF > SPDIF > I2S is a proper solution. Can you hear the difference between that and direct USB way?
 
I2S Direct

Eroz- I haven't been able to do a matched head-to-head on this, but I have a feeling direct I2S is superior based on some listening I have done with commercial designs from Empirical audio with modded Benchmark DAC's. Obviously less conversions and parts in the signal path is almost always a good thing. It sounds like Peter and Doede are going this route so there must be some merit. Also Twisted Pear is about to offer their Opus design which is not a NOS, but looks very interesting as well.

Sam
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.