Simple, good quality DAC

Hi

I would really like to upgrade my CD player with an external DAC, however I fear that my electronics skills would not be up to anything more sophisticated than building a power supply... Are there any good sounding evaluation boards out there? I did a search and found the Analog Devices AD1853 board, does anybody know if it sounds any good? And finally do you reckon there would be a noticable improvement in sound quality? (I have a $400 Marantz CD player)


Any input is greatly appreciated


cheers

jnxw2
 
Which Marantz player you have. I found that the best upgrade is adding internal DAC (or modifying the existing one) by omitting digital filtering and connecting a DAC directly from decoder chip with I2S interface (3 wires). As a DAC I would recommend either TDA1543 (only 5 parts really needed) or TDA1541, which I think might be more sofisticated in sound, but I'm not sure yet. Here's the schematic and earlier in the same thread a picture of TDA1543 DAC: http://www.diyaudio.com/forums/showthread.php?s=&postid=172294#post172294
 
Hi,

Both Crystal and BurrBrown (now Texas Instruments) sell evaluation boards. When I started out in this hobby I bought a Crystal CS4397 DAC evaluation board because it was so complete: regulated power supply, receiver, DAC, analog stage with top quality replaceble opamps, connection for outboard filter, receiver or clock. Well that baby get me going on since then, it is still my reference DAC. Expensive : yes 400$, BuurBrown will also be expensive.

But a Marantz may allready outperform it, so it won't be an upgrade. A simple Non OverSampling (digital-filter-less) DAC migth be something fresh, new and different. Both the TDA1541 and TDA1543 can be made to work relative cheaply and a lot of people here have experience with those chips.

Regards,
Thijs
 
Thanks for the info, I have the Marantz CD6000OSE. I think that adding an internal DAC is way above my capabilities unfortunatly. The Cirrus and TI eval boards look really good although a bit pricy...

Do you know if they sell them to individuals? Where would I be able to buy one?


Thanks


jnxw2
 
Cirrus/Crystal evaluation boards

jnxw2,

Cirrus/Crystal has a lot of information about their evaluation boards on their web site, and there is a locator for distributors in different countries. For the UK,

http://www.cirrus.com/en/contacts/sales/country/GB.html

In the US, Newark Electronics lists most Crystal EVB's as 21-day leadtime. The CDB4396 board is US $150, not sure if that is too pricey for you or not, but my guess is you would spend more than that building one. The CDB43122 is $400.

The supply for the CDB4396 is based on a simple wallwart with AC output, rectified on the board, which looks a bit thin to me (personal opinion only), so if you plan to use it as a DAC with other good audio gear you might consider another option for power. I think this board has provisions for an external +/- supply.

Crystal chips are used in outboard DACs made by MSB,

http://www.msbtech.com/

and for example in a high-end ($6K+) CD/SACD player from Tri-Vista which got a pretty good review in the May 2003 issue of Stereophile. So, I think you would get a pretty good deal starting with a EVB for $150, a box, and a few connectors... :)

PM
 

mb

Member
2002-12-04 2:51 am
Singapore
I was just invited to bring my Channel Islands VDA-1 dac to test on a Marantz 6000SE-KI. The owner wanted to verify if there would be 'subtantial' improvement with the dac. The answer was an emphatic yes. He also tested a Sony player and an Audio Alchemy dac, and the CI was the only item that sounded quite clearly better in soundstage depth, clarity, bass quality and speed.

The CI was not stock, but has the sonic signature of the stock unit, plus perhaps more control and better extreme top end. The mods were not out of the ordinary - diodes + caps. Some tuning by ear (not all mods were synergistic). You might consider this as an alternative to DIY starting from an eval board. Something like the CI is *much* better tuned to begin with than an eval board -- class-A opamp bias, Dale resistor and film caps where it counts, nice case and cosmetics.
 
I2S signals

I think Peter Daniel meant you need to add three wires to make a connection from the circuit board in a consumer CD player to a new DAC chip you are adding.

What this looks like and where the circuit traces are on your board would depend on what CDP you have, and what DAC chip is on the board. You would find the datasheet for your DAC, and start by identifying the pins with the correct signals.

This is really not such an easy modification to do in a new product if you do not have some experience dealing with small circuit board traces and SMT (surface mount) components.

Maybe post a question to find out if anyone has modified the CD player brand and model you have, and what the results were.
 
mb,

I also own a CIA VDA-1 DAC and would be interested in the mods you performed on yours if you would be willing to share. These mods may also be relevant to others designing their own, or modifying eval boards.

David

mb said:

The CI was not stock, but has the sonic signature of the stock unit, plus perhaps more control and better extreme top end. The mods were not out of the ordinary - diodes + caps. Some tuning by ear (not all mods were synergistic).
 

ThorstenL

Previously: Kuei Yang Wang
2002-11-10 5:35 pm
www.facebook.com
Koinichiwa,

miguel2 said:
My cdp is a marantz cd48. It uses a bitstream dac.

No, it does not use a Bitstream DAC, it uses "bitcheck" conversion using the TDA1545 DAC.

miguel2 said:
Anyone knows where I can find the I2S signals?

Not at all. The CD48 uses the 4 X Oversampling Digital Filter of the CD Decoder Chip. The Signal after that Decoder/Digital Filter is still I2S, but at 176.4KHz and with a Digital Oversampling Filter already applied. If you where a cynic you could use a 192KHz capable DAC Chip with internal 4/8 Times oversampling from BB/TI or Cirrus Logic (aka Crystal) and claim you modded CD Player does syncronous upsampling to 176.4KHz and then further 4/8 Times oversampling.

Sayonara
 

ThorstenL

Previously: Kuei Yang Wang
2002-11-10 5:35 pm
www.facebook.com
Koinichiwa,

jnxw2 said:

I would really like to upgrade my CD player with an external DAC, however I fear that my electronics skills would not be up to anything more sophisticated than building a power supply...

I am quite familiar with the abilities of both CD63/67 and CD6000 from Marantz. With some modifications they can offer very high sound quality, not easily exceeded with any of the common modern external DAC's, especially not with those found on cheap EVAL Boards.

If you could actually build a Powersupply for an external DAC that will perform well then you should have little problems building a simple DAC from scratch (after all, the Powersupply of any given circuit is about 50 - 80% of the sound).

If you want a sound that actually offers a sonic perspective that is notably different (I shall not say "better", as this is a matter of taste) I must strongly support Peter Daniels recommendation of the TDA1543 (or TDA1545) used in non-oversampling mode.

For someone with limited DIY experience you might find Scott Nixons DACKIT a good choice.

What is this DacKit thing? - [url]http://www.scott-nixon.com/dac.htm[/URL]

I used to have the earlier version of this approach based on Kusonoki San's 4 X TDA1543 DAC from MJ 1996 since late 1997 and found it a great choice and much better to my taste than my modded Marantz CD-67 CD-Player, as well as my modded Pioneer DV-505 DVD-Player (this is a surprisingly good CD-Player as it has Pioneers best but one Legato Link DAC Chip).

BTW, just as an aside, the Burr Brown PCM1716 and Cirrus Logic CS4329 DAC Demo Boards both where much worse than my modded Marantz Player.

Sayonara
 
I just modified my Marantz CD-94 and as a stand alone unit it is better than used as a transport feeding my recent CS8420/PDF1704/parallel PDF1704 DAC. I'm still using original PS inside the player, while my DAC had 8 transformers and at least 13 local PS based on LT 1035/1085 (or whatever numbers) chips.

The only thing I did to Marantz was bypassing digital filter, simplifying output stage to a single OPA627 per channel, removing DC reducing resistors network right at DACs output, changing all electrolytics to HFQ and Cerafines, adding local bypassing (Goudreu triplets). Well, the results are impressive and that player is producing the best bass I've heard so far. Sometimes simple ways are better indeed.
 
Not at all. The CD48 uses the 4 X Oversampling Digital Filter of the CD Decoder Chip. The Signal after that Decoder/Digital Filter is still I2S, but at 176.4KHz and with a Digital Oversampling Filter already applied. If you where a cynic you could use a 192KHz capable DAC Chip with internal 4/8 Times oversampling from BB/TI or Cirrus Logic (aka Crystal) and claim you modded CD Player does syncronous upsampling to 176.4KHz and then further 4/8 Times oversampling.


Hey Kuei,

I understand that if the I2S signal is already oversampled, a simple TDA1543 design is out of the question. And as I am not a cynic (I guess) :) I have to ask you if using a 192KHz chip would increase sound quality significantly. And which chip in which configuration (a schematic here would be just great)? Do you remember the exact chip of Decoder/Digital Filter, so I can spot it on the cdp and see where I can get the I2S?

Miguel
 
Thanks for all the suggestions!


The Dackit looks pretty good but I think i would prefer to use the TDA1543 if only because I reckon I could learn more..
I had a look at Peter Daniels Schematic of the TDA1543 circuit and PS, and I think I could do that easily enough, the only thing i dont know is where do I get the input signal from?


Thanks

jnxw2
 

ThorstenL

Previously: Kuei Yang Wang
2002-11-10 5:35 pm
www.facebook.com
Koinichiwa,

jnxw2 said:

The Dackit looks pretty good but I think i would prefer to use the TDA1543 if only because I reckon I could learn more..

Ahhm. The DACKIT is based on the TDA1543 and uses in fact the same circuit. I did not recommend buying the finished product, just the PCB and maybe chips... ;-)

jnxw2 said:

I had a look at Peter Daniels Schematic of the TDA1543 circuit and PS, and I think I could do that easily enough, the only thing i dont know is where do I get the input signal from?

Peter AFAIK works without receiver, which means you need tap off the I2S signal inside the Marantz CD6000. Get a Service Manual and work it out if you like.

The DACKIT PCB includes space for an S/P-DIF receiver, in this case you simply plug it into the Digital (Coax) Output of your CD6000.

Sayonara