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Old 17th October 2018, 08:13 AM   #1021
Zoran is offline Zoran  Serbia
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Hi
I have discrete I2S and DSD dac. Interface is Amanero. I had some issues with Mute control. I tried different circuits but the "clicks" when changing states somehow was present...
I made this mute circuit to control I2S and DSD brenches by disable chips. Enable is negative low 0, disable is hi 1. Since digital interface is isolated from the diskrete circuits, this mute circuit use optoisolator which inverts the input state. This signals can additionally tie together + and - outputs...
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Next I have to add mute signal to manage relay switch to analog end - to connecting and disconnecting DSD or I2S from interstage transformer and buffer stage, because they are common for booth dacs.
.
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Old 17th October 2018, 02:16 PM   #1022
barrows is offline barrows
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Default Do you...

Quote:
Originally Posted by Zoran View Post
Hi
I have discrete I2S and DSD dac. Interface is Amanero. I had some issues with Mute control. I tried different circuits but the "clicks" when changing states somehow was present...
I made this mute circuit to control I2S and DSD brenches by disable chips. Enable is negative low 0, disable is hi 1. Since digital interface is isolated from the diskrete circuits, this mute circuit use optoisolator which inverts the input state. This signals can additionally tie together + and - outputs...
.
Next I have to add mute signal to manage relay switch to analog end - to connecting and disconnecting DSD or I2S from interstage transformer and buffer stage, because they are common for booth dacs.
.
Do you re-clock after the opt isolators? They introduce substantial jitter and the signal should be re-clocked after them.
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Old 17th October 2018, 03:02 PM   #1023
niner is offline niner  United States
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Originally Posted by ppy View Post
The BOM shows the registers of the Nexperia manufacturer.
But the highest quality version was with the old registers AHCT595 Phillips or NXP.
Unfortunately, the old Phillips/NXP isnít equal to the new Nexperia.
Hi ppy,

Can you expand on the difference between AHCT595 from Philips and Nexperia? From the datasheet, I couldn't detect any difference.

Thanks!
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Old 18th October 2018, 06:51 AM   #1024
ppy is offline ppy  Russian Federation
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Yes, according to the documentation, there is no difference between Phillips/NXP and Nexperia.
But in reality, there is a difference in sound and power consumption. New Nexperia is 1.5 times smaller power consumption.

Last edited by ppy; 18th October 2018 at 06:55 AM.
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Old 18th October 2018, 08:20 AM   #1025
Zoran is offline Zoran  Serbia
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Originally Posted by barrows View Post
Do you re-clock after the opt isolators? They introduce substantial jitter and the signal should be re-clocked after them.
This time I not recklocked after ISO. Because the master clocks are 22.xxx and 24.xxx MHz. And they are not high enough to recklock below 192KHz of Sampling rate. BCK (and DATA) becomes high as MCK and I think clocking could not be done. MCK should be at least 2x higher than BCK (and DATA) at given SR to be reclocked.
.
Other issue is that if You want true ISO and RECKLOCK after isolation barrier, You have to isolate MCK signal as well... To be clock in Flip-Flop cascade...
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I just want in this experiment to try to use differential transmitter and diff. receiver after ISO. And acheive inverted -DATA for ballanced DAC operation. Simply by inverting + and - diff transmition line...
.
And its working very good up to max SRs 35x and 38x KHz booth I2S and DSD
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Old 19th October 2018, 03:44 AM   #1026
darkstargtk is offline darkstargtk
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Just got my PCBs tonight. First time soldering SMD, I’ve got a few bridges, need to wick away some of the extra solder and straighten out some components...but I dont think it’s too bad?!

Click the image to open in full size.
Click the image to open in full size.

Let me know if you guys see anything amiss, before I let the smoke out!

Thanks a lot Pavel and everyone else who helped out with this project!
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Old 19th October 2018, 06:59 AM   #1027
ppy is offline ppy  Russian Federation
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Quote:
Originally Posted by Zoran View Post
This time I not recklocked after ISO. Because the master clocks are 22.xxx and 24.xxx MHz. And they are not high enough to recklock below 192KHz of Sampling rate. BCK (and DATA) becomes high as MCK and I think clocking could not be done. MCK should be at least 2x higher than BCK (and DATA) at given SR to be reclocked.
I am sure that when using an isolator, a recloker is required. Here is my diagram of the latter version. Gerbers need to fix minor bugs. Therefore, I will post them in a few days.

BBB or Amanero work in slave mode and get MCLK from high-quality NDK 45/49Mhz generators.
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File Type: jpg IMG_20181019_090035.jpg (988.5 KB, 480 views)
File Type: jpg IMG_20181019_085932.jpg (985.7 KB, 463 views)
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File Type: pdf DSC2.pdf (243.8 KB, 133 views)

Last edited by ppy; 19th October 2018 at 07:26 AM.
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Old 19th October 2018, 12:24 PM   #1028
ppy is offline ppy  Russian Federation
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Quote:
Originally Posted by ppy View Post
Here is my diagram of the latter version. Gerbers need to fix minor bugs.
Sorry. In the circuit error. Instead of PO74G38072A there should be PO74G38074A.
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Old 19th October 2018, 08:51 PM   #1029
Zoran is offline Zoran  Serbia
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Quote:
Originally Posted by ppy View Post
I am sure that when using an isolator, a recloker is required. Here is my diagram of the latter version. Gerbers need to fix minor bugs. Therefore, I will post them in a few days.

BBB or Amanero work in slave mode and get MCLK from high-quality NDK 45/49Mhz generators.
Yes in some cases could increase the jitter. But reckloking with just one flip-flop can do the same. Additionally, when using 1 x flip flop, the output data is shifted just 1/2 period of clocking time... And going into meta-stabile state.
It should be reckloked with 2 x flipflop. Only in that way the outputs will be in Line and same rising or falling edge. Additionl care shoul be taken because some USB to I2S/DSD interfaces has opposite phase MCK, falling edge, and it diiffers from the standard rising edge of MCK and BCK lines... I mesure it with a digital scope. Some XMOS interfaces have faling edge of MCK... Amanro have right phase of the MCK.
.
But reckloking is wery conveniant for getting + and - data lines for ballanced operation. I used RCKL many times but in the way I wrote. Also I tryed with diff transmitter/receiver to obtain +,- digital bus lines, and that is working great.
.
I think that in amaneros slave mode some pins are loosing functions when becomes inputs for the exernal MCKs? And as I am remember one is Mute?
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Old 19th October 2018, 09:10 PM   #1030
Zoran is offline Zoran  Serbia
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I have pretty good sound outcome experimenting with 3-state logic. Made this new concept of 1bit DSD dac with idea to match differences in PNP and NPN output stages of logic IC and use ENABLE as input. While Inputs are tied to +Vcc and ground. So when the data is 1 this module is disabled and so on... It will be more clear from the sch.
.
In this version I used ISO and RCKL it was more easy to get +, and - data lines. But I clocked with MCK. Not BCK as usual. With MCK I found better sonic results...
.
Now I am thinking to extend this experiment for 32 bit version with shift registers 595, but 128 driver HC540 ICs per channel I have to order...
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Last edited by Zoran; 19th October 2018 at 09:21 PM.
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