many thanks for explaining the main issues regarding the design of your new dac boards.
looking forward to seeing further details and pics.
best wishes
Hi Enrico. Just to clarify with your 8 boards are you still using a buffer board, I can't see it in the pictures but are you using output transformers, thanks
You are blessed
You can have it playing well and no longer wonder "what if"
There is a point where the i2s resistors become a bottleneck reducing clarity focus and resolution of the sound
When I had a dddac 1794 removing these resistors had a negative effect and of course z foils sounded good
At the time I was doing lots of experiments on the dddac with CCS , output iv and PS and with the extensive soldering I eventually damaged the DAC board beyond repair
Because if size and expense of DAC boards I built all anew on smd adapter boards I tried it with and without i2s resistors and without was like everything snapped into focus
I assume these resistors were put there in intital there as a form of isolation
I was just thinking maybe your design doesn't require this isolation and these resistors are possibly doing more harm than good
Hi Sovereing, the buffer board is required when you are using one DAC board.
I am using the Sowter trafo from Doede and I used them even with the buffer and they really worth all the money.
Even if the buffer is a huge improvement with one board I still prefer the multiple boards...
Regards,
Enrico
Hi Nige,
Thanks, what you describe is really interesting... I am really tempted to reopen the box and modify the boards. It's just too easy with the "bus_dac" 🙂
When I have sometime I will do it and let you know.
Cheers,
Enrico
Thanks for your help.
Have you ever tried the DAC directly connected to the RCA plugs with no cap or output transformers?
Attached are some more pictures of the motherboard, the DAC and the buffer boards
The main improvements in the motherboard:
- Dedicated LT1762 LDO for the 5V for the logic part
- Separated 12V for Analogic and Digital circuit of the DAC boards. They are optional through pin selectors. The 4 terminal blocks are in the left side (Left A-D and Right A-D). Each one of them can be selected through the J2-J3-J4-J5. I.e. you can choose to separate the 12V for the Analogic and use the Main 12V for the Digital or use only the Main 12V
- Option to separate the GND for the Analogic part through J1 and J6
- Dedicated terminal blocks for the + and - 12V of the Buffer (right side of the picture)
- Dedicated terminal blocks for the Buffer output
- Additional pads for the SMD 0805 SUSUMU as highlighted by Ross
- The 2 input are the 24 pins FFC connector for the EDEL and the 3 UFL connectors for the I2S.
- The bus connectors are the Hirose 60 poles FX2CA serie
The DAC board:
- The 4 GND (Left A-D and Right A-D) are separated. The Digital GND will be connected only to the motherboard. The analogic as I said above can be separated from the motherboard (only in case you use the separated 12V for the Analogic)
- 2 dedicated LDOs for each PCM1794. One trimmed at 8V for the analogic side and one fix 3.3V for the digital. As you can see in the picture the LDOs are designed right near to the VCC and VDD pins of the chip. In the digital LDOs there are different pads for the input caps. Linear D/S is very detailed regarding the decoupling caps and there are 10uF and 100nF X7R in the input and the outupt of the LDO. The output caps are installed in the back side of the board to be near to the LDO pins.
- Dedicated pads for the CCS circuit (the pads for 6.04K are still there , R11 and R12)
- Particular care to the distribution of +8V and +3.3V to the chip pins.
About the buffer board there in no much to say, is exactly the same circuit with same parts that everybody know.
I think that i didn't forget nothing... 🙂
Best Regards,
Enrico
Attachments
I try one time to connect the DAC without the Sowter using the caps that Doede send me in the kit but I didn't like and I am back to the Sowter
I can't imagine anything bettering direct pos and neg out to floating gnd mono amps
Very few can do that because of gnd been earthed on DACs amps etc as neg would be shorted to ground and without mono amps the two negs will more than likely be merged meaning half the left signal is going to the right and Visa versa also causes a deading of the sound
Building a system fully mono would have many benefits I'll eventually build it this way myself
You can't use pos and gnd not decoupled because there's 2.7v DC on it
Maybe your amp has decoupling on inputs?
Maybe try a smd acrylic/pps film cap about 1-10uf for decoupling
I know not very boutique of me
Or like that?... 😀😀😀
The 8 board is my beloved DAC
Yep,
Definitely something like that 😛
How does this sound compared to the modified DDDAC?
emyeoui, your design seems more tailored to pre populated (like twisted pear) instead of diy. Any chance you are planning to sell your boards this way? If so any chance for AES/EBU input and Balanced out?
Sent from my iPad using Tapatalk
Sent from my iPad using Tapatalk
Really really sweet and the 3D is simply amazing 🙂
Nobody ask me about the EDEL renderer that in my opinion make the overall sound of the DAC 3 steps ahead. I have tried the rpi with the acko reclocker, then I try the BBB with the miero botic and the twisted pearl but I never get them working properly. Sure because my lack in the software part but anyway I spent good money to struggle for months with codes, firmwares, sd cards etc...
Acko kindly address me to the EDEL NMR and will never change it. It's a real plug and play renderer that interface any I2S DAC with your lan and I can play my music that is the NAS through bubbleunpn in my handphone... no glices, no jump, just sweet music 🙂
Regards,
Enrico
Hi msgarris,
First of all the DAC is Doede design and I don't want to sell something that become from the work of somebody else... somebody can disagree but this is my choice.
Also, I am just an hobbyist like many of the people in this forum. I have no time and no willing to follow all the problems that can raise with a project like this.
There is also a problem of costs. Because I am an hobbyist I purchase my parts mainly from Mouser or Digikey. I suppose that organizations like Twisted Pearl, acko and even Doede purchase their parts from other dealers with different costs
That said I can think to build a maximum of three 8 boards DAC only if you are ready to accept that:
- I need to have the green light from Doede
- The costs will be based on Mouser/Digikey (please don't ask me now because I have to recalculate everything)
- You give me the time to build them, let say 3/4 weeks for the first DAC and the others one week later
- I will not sell as a kit but only completely built and tested. The I/V resistor will be SUSUMU 0805 1%. If you need other fancy resistors they are very easy to change
The motherboard have 2 inputs: standard I2S UFL and 24 pin FCC for the EDEL and I will not change the design.
The output is already balanced (as per Doede design)
Best Regards,
Enrico
the logic side and the manipulation of analog voltage/iv/iref are certainly deode's design the rest id consider communal
id agree soldering is one thing customer service for dac kits is certainly another
audio creative might have an issue if they think your competing with them
however 3 builds should not be worth kicking up a fuss over
btw theres some extra analog v/ iref/ iv manipulation possible because of ccs Implementation if i remember correct you have to change values of iv and ccs together while monitoring vcom
beware you can blow the chips🙂
beware you can blow the chips🙂
Nige,
Can you provide a link where that was discussed... or at least point to the right thread?
TIA!
Greg in Mississippi
OMG
Enrico,
You're such a nice person and I want you to know how great improvements my DAC had because of your "work team". But maybe you just opened a "window"...
Regards
Pierre
BTW I agree with you about high performance LDO regulators. That's what I installed also.
Enrico,
You're such a nice person and I want you to know how great improvements my DAC had because of your "work team". But maybe you just opened a "window"...
Regards
Pierre
BTW I agree with you about high performance LDO regulators. That's what I installed also.