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miklau  
#1 Posted : Monday, April 23, 2018 6:15:06 PM(UTC)
miklau

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Hi Twisted Pear Audio

I am running a COD v2.0 dac with IVY. Using a raspberry pi with a Kali Reclocker module from Allo.com. I have a OTTO 1 switch between the reclocker and COD as I also have a WM8804 v2.0.
The I2S signal from the Kali reclocker module is connected to the normally closed contacts and common to COD. The COD is set to Stereo mode with all DIP set to "-" for logical "0".

I do get a very small click when I start to play music and when I skip to another song.
The kali reclocker only outputs a I2S signal when a song is played and turns the signal off every time a new song is played to ensure the correct frequency.

I am running Volumio (newest V2.389) with a "Generic I2S Driver" and I can see the I2S signal is sent from the Kali as the LED on the board,for the different frequencies, are lit.

Do you have any ideas please?

Best regards Mikkel

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Edited by user Monday, April 23, 2018 6:19:15 PM(UTC)  | Reason: added Kali pinout

Brian Donegan  
#2 Posted : Monday, April 23, 2018 6:52:30 PM(UTC)
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Does the WM8804 -> COD setup work okay?

Have you tried connecting the KALI directly to the COD?

What sampling rates are you trying to play?
miklau  
#3 Posted : Tuesday, April 24, 2018 1:10:05 PM(UTC)
miklau

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Thanks for your help.

I have tried VM8804 -> COD = no sound, only very high static noise, so turned off my amp. very fast!
I have four green led when i send a signal to the WM8804 from my CD player; 44.1 kHz. I have not connected the DOUT. Ground is connected via the I2S input. The WM8804 is supplied by the same LCDPS that is powering the digital section on the COD @ V7.55.

KALI -> COD no sound at all. The same, with very low clicks when song skip. I am sending 44.1 KHz and I think it is 16 bit but i am note sure.

The caps and electrolytic caps are getting warm when turned on and no music is sendt to the COD. Is this normal?

I have not soldered in the feedback caps due to a comment from Russ at DIY audio COD forum for improved SQ.

The Patch cable wires on the picture are only connected to the OTTO switch, not anything else!
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Edited by user Tuesday, April 24, 2018 3:30:37 PM(UTC)  | Reason: Not specified

Brian Donegan  
#4 Posted : Tuesday, April 24, 2018 3:53:38 PM(UTC)
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What is the board under the WM8804 Transceiver?

I would recommend mounting the WM8804 over or under the COD to make the I2S lines as short as possible. (The analog lines can be longer).

I assume you mean feedback caps on the IVY...

Can you show the top of the COD in a picture?
miklau  
#5 Posted : Tuesday, April 24, 2018 4:05:42 PM(UTC)
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The otto switch is located under the WM8804. I will try to move the Wm8804 under the COD and shortend the I2S wire. Should i be worried by the loud static noise? Should i measure a A/C signal instead?

Yes it is the feedback caps on the IVY :-)
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Edited by user Tuesday, April 24, 2018 4:07:47 PM(UTC)  | Reason: Not specified

Brian Donegan  
#6 Posted : Tuesday, April 24, 2018 4:22:54 PM(UTC)
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Usually loud static noise is caused by long I2S lines, or I2S lines crossing power lines (between PSU and digital modules).

If you have room, it would be best to stack the OTTO, WM8804 and COD together. This will offer the shortest possible I2S lines.

All that said, with a simple WM8804 receiver to COD with S/PDIF input should work as you have things set up. Try that without the OTTO in between first, then add OTTO back once it is working.
miklau  
#7 Posted : Tuesday, April 24, 2018 6:38:30 PM(UTC)
miklau

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Hi Brian

Thanks again for your good advice.

I have now tried to stack them to reduce the length of the I2S wires. Unfortunately I still dosen't get any sound. If i touch the DIN wire i do get static noise out at the speakers.

I power the WM8804 together with the COD from the LCDPS. With no load i have V 7.55 but when loaded the voltage drop to V 7.25. Is this an issue?

Is there any other good ways to troubleshoot? :-)
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Edited by user Tuesday, April 24, 2018 6:53:07 PM(UTC)  | Reason: Not specified

Brian Donegan  
#8 Posted : Tuesday, April 24, 2018 6:56:29 PM(UTC)
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Ah, in that last picture you have the WM8804's DIN connected to the COD DIN. It should be DOUT to DIN.
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miklau on 4/24/2018(UTC)
miklau  
#9 Posted : Tuesday, April 24, 2018 7:28:37 PM(UTC)
miklau

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And there is MUSIC!!!Dancing Thank you so much Brian, my mistake :-)

I will work my way backwards to see if I can get the Kali and Raspberry Pi working together with the OTTO Switch.
My plan is to connect the Kali this way:

KALI -> COD

BCLK -> BCK
LRCLK -> LRCK
MCLK -> SCK
DATA -> DIN
GND? -> GND?

Would it be fine to simply take the common ground from the Kali/Raspberry GPIO pins and connect it to the I2S GND at the COD?
The raspberry pi is supplied by another linear PSU, but I have not connected the ground to the other PSU's ground. Not sure if i should or the I2S ground would be sufficient?

Edited by user Tuesday, April 24, 2018 7:31:00 PM(UTC)  | Reason: Not specified

Brian Donegan  
#10 Posted : Tuesday, April 24, 2018 7:43:22 PM(UTC)
Brian Donegan

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I would connect PSU grounds and leave the I2S ground unconnected everywhere else. This will reduce the risk of a ground loop.
thanks 1 user thanked Brian Donegan for this useful post.
miklau on 4/24/2018(UTC)
miklau  
#11 Posted : Saturday, April 28, 2018 9:05:36 AM(UTC)
miklau

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Hi again Brian.

I am still having problems with tha KALI and the COD. I can't get any sound from the COD.
Do you have any experience with a Raspberry pi 3b connected directly to a COD? I am not sure how to connect the System Clock from a RP3?

I have found a similar thread with a opus dac: http://www.twistedpearau...7-Raspberry-Pi-and-Opus. So not sure why i can't make it work with Kali...

Picture: The black mini coax wire is the master clock from the KALI, connected at a u.FL connector just under the board. I have also tried to connect the master/system clock from the Pin headers at the Kali without any result. The I2S wires are under 5cm/2" long :-)

Thanks again :-)

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Edited by user Saturday, April 28, 2018 9:17:48 AM(UTC)  | Reason: Not specified

Brian Donegan  
#12 Posted : Monday, April 30, 2018 11:28:28 AM(UTC)
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I have no experience with that board.

I assume you are connecting only the center conductor of the u/fl cable to the SCK terminal on the COD. It might be good to check and make sure that terminal has no continuity with GND.

miklau  
#13 Posted : Tuesday, May 1, 2018 11:08:36 AM(UTC)
miklau

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Hi Biran.

Once again thank you for helping.
Good point regarding the u.FL connector and i checked it again but it should be fine.

I looked at your manual once again and saw your recommendation regarding 24-bit audio so found some 24-bit songs and that gave music! :-) The strange thing is that if 24/44 kHz files are played the volume is turned down to a ¼! 24/96 plays fine and the same with 24/192. I understood there should be an Autodetect for the system clock. Didn’t expect the sample rate to change anything.

I found the “Audio data format select” in the PCM1794 datasheet: used 0 0 1 0 (FMT1:1) at the Dip switch for 16-bit audio, but this gave 20% music and 80% static.

Does this make any sense? And it is understood correctly that 16 and 24-bit is only hardware selectable?

I have used the upsampling function in Volumio set to 24 bit and that plays 16/44 songs but again at a 1/4 of the volume. The volume is back to normal if I set the target sample rate at 96KHz. The volume is the same at 192KHZ.
That said I am not sure what is actually passed on to the COD with a hardware reclocker module and volumio software upsampling...

Edited by user Tuesday, May 1, 2018 11:09:59 AM(UTC)  | Reason: Not specified

miklau  
#14 Posted : Wednesday, May 9, 2018 1:17:31 PM(UTC)
miklau

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So I decided to go all green on PCB’s and they look good ;-) Out with the KALI and in with the Metronome:-)

This works when all songs are played at 24bit and volume levels are the same at all frequencies. Can the Metronome be set to accept input both at 16 and 24-bit I2S?



I can recommend MoodeAudio for others that are using a Raspberry pi together with a COD/PCM1794. There is a build in I2S driver for a “DDDAC1794 NOS” that works perfectly.
If using Volumio select the "ApplePi DAC" driver since it also was designed for a board using the PCM1794.
IMG_6087.JPG (143kb) downloaded 7 time(s).

Edited by user Monday, September 24, 2018 1:30:04 PM(UTC)  | Reason: Not specified

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