Dougie085 said:Be nice if we could get a PCB designed for this for DIY useI'm extremely interested in building a 2 channel DAC using this chip.
This is exactly what I want to do, but I need to be able to purchase some samples. Still no answer to my sample question...
I would very much appreciate being able to buy a few samples.
Thanks!
Russ
Russ White said:
Hi Russ. I am working on a schematic for a layout also. I have been 'experimenting' with the demo board.
How are your skills at the PIC micros? This part will need a I2C controller on board. I am thinking a PIC16F677 at minimum, maybe a PIC16F882 if I want it to do some other processes.
Found this:
http://www.cmoset.com/uploads/4.2.pdf
It looks like Dustin has been giving some seminars !
http://www.cmoset.com/uploads/4.2.pdf
It looks like Dustin has been giving some seminars !
Modded the demo board
I modified up the demo board a little bit.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_xfmr_out_1.jpg
At the bottom, an 110 ohm AES/EBU cable brings in SPDIF to a PCB on the far right. That PCB features a Wolfson WM8804.
The Wolfson receives the SPDIF and decodes it to I2S. It also features jitter reduction, so I am using the lowest PLL bandwidth register setting in the ESS Sabre 8.
Other PCBs to the left of the Wolfson board are a low jitter clock and a low noise AVCC regulator.
I removed the 40MHz crystal osc section from the demo board.
You may also notice that all seven op amps have been removed. Yes, the first three pages in the schematic are gone.
The analog output now consists of a few resistors, some mica caps, and two Jensen 4:1 transformers. The transformers are expensive, but I had two in my parts box that have been sitting here unused for a couple years.
JT-10KB-DPC price is US$71 each.
http://www.jensen-transformers.com/datashts/10kbdpc.pdf
When I read the Sabre8 whitepaper, I realized the Jensen 4:1 transformer would be a good match for the Sabre8 as long as the load is 10K or greater. The transformer lowers the output voltage, presents a lower impedance to the load, and a high impedance to the Sabre8.
There may be some better transformers for the job, but I don't have any of them right now.
The general strategy for the transformer coupled output started from this document.
http://www.jensen-transformers.com/as/as093.pdf
I modified up the demo board a little bit.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_xfmr_out_1.jpg
An externally hosted image should be here but it was not working when we last tested it.
At the bottom, an 110 ohm AES/EBU cable brings in SPDIF to a PCB on the far right. That PCB features a Wolfson WM8804.
The Wolfson receives the SPDIF and decodes it to I2S. It also features jitter reduction, so I am using the lowest PLL bandwidth register setting in the ESS Sabre 8.
Other PCBs to the left of the Wolfson board are a low jitter clock and a low noise AVCC regulator.
I removed the 40MHz crystal osc section from the demo board.
You may also notice that all seven op amps have been removed. Yes, the first three pages in the schematic are gone.
The analog output now consists of a few resistors, some mica caps, and two Jensen 4:1 transformers. The transformers are expensive, but I had two in my parts box that have been sitting here unused for a couple years.
JT-10KB-DPC price is US$71 each.
http://www.jensen-transformers.com/datashts/10kbdpc.pdf
When I read the Sabre8 whitepaper, I realized the Jensen 4:1 transformer would be a good match for the Sabre8 as long as the load is 10K or greater. The transformer lowers the output voltage, presents a lower impedance to the load, and a high impedance to the Sabre8.
There may be some better transformers for the job, but I don't have any of them right now.
The general strategy for the transformer coupled output started from this document.
http://www.jensen-transformers.com/as/as093.pdf
That picture was yesterday.
This is what it looks like now.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC1.jpg
This is what it looks like now.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC1.jpg
An externally hosted image should be here but it was not working when we last tested it.
The little rack box I bought had a eight watt power supply. I dont need +/- 12 volts any more so it only uses a 5 volt supply. Without the op-amps, this is probably using only a watt.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC2.jpg
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC3.jpg
OK, so the back of it is ugly.
It has the transformer isolated outputs on the left,
RCA digital in in the center. USB and TOSLINK middle right.
I didn't put in a switch, so if I want to switch use either the coax or TOSLINK I have to rewire it to the one I want.
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC2.jpg
http://home.columbus.rr.com/rossl/images/mod/sabre_demo_DAC3.jpg
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
OK, so the back of it is ugly.
It has the transformer isolated outputs on the left,
RCA digital in in the center. USB and TOSLINK middle right.
I didn't put in a switch, so if I want to switch use either the coax or TOSLINK I have to rewire it to the one I want.
I bought the rack mount chassis on ebay.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190195409458
I don't know what this thing did in it's former life, but now it's a high end DAC that sounds really good.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190195409458
I don't know what this thing did in it's former life, but now it's a high end DAC that sounds really good.
Dougie085 said:
I don't know the answer to that question. I am listening to a SACD right now though. See the thread where I mod the Oppo 981.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=95972
The MediaTek MT1389 controller chip converts DSD to 24/88.2 PCM. It sounds great. However, you need to mod the player to get the 24 bit/ 88.2KHz out of the box.