ProtoDAC TDA1387 X8 project

[Tim Curtis]

The log shows that protoDAC has not been configured in Audio Config yet

Code:

20241219 101825 worker: Audio device:  0:Pi HDMI 1

[smokey_mountain]

The log shows that protoDAC has not been configured in Audio Config yet

Code:

20241219 101825 worker: Audio device:  0:Pi HDMI 1

Tim, thank you! I was so per-occupied with HW that totally missed the SW config piece, did not realize that it is I2S. I get sound now! You are mentioning a Stereo Test file where do I source that to check levels and polarity?

[smokey_mountain]

Found the test file. Sorry for the dumb question, I hear him saying "My voice is out phase" what shall I hear, I hear some strangness but not sure what I should be hearing

[Tim Curtis]

Found the test file. Sorry for the dumb question, I hear him saying "My voice is out phase" what shall I hear, I hear some strangness but not sure what I should be hearing

The male voice on the test file says:

This is my voice on the left
This is my voice on the left hand side
This is my voice on the left

This is my voice on the right
This is my voice on the right hand side
This is my voice on the right

This is my voice in the center
This is my voice coming from both left and right
This is my voice in the center

My voice will be out of phase on three
One, two,  three, four, five, six, seven, eight, nine, ten
-in phase-  ----------------- out of phase ------------------ (it will sound thin and hollow)
My voice is out of phase

The track is a 16-bit 48 kHz FLAC file and so very high quality. There should be no distortion or any other audio artifacts whatsoever.

I would also follow @hifinet advice and reexamine the solder joints.

[smokey_mountain]

Thank you, it works and sounds very good. It was a sw config mistake on my part. Using CamillaDSP for Polarity Inversion and flat dithering at 16 bit at the moment.

When Camilla Polarity/Flat dithering implemented, CamillaDSP takes over volume control. I control volume on my vintage Arcam integrated so to bypass CamillaDSP volume control, do I set it for 100 volume and go control it on the integrated amp? Just trying to minimize volume control chain.

Thank you again for all the help making it. Another donation is coming.

[Tim Curtis]

Thank you, it works and sounds very good. It was a sw config mistake on my part. Using CamillaDSP for Polarity Inversion and flat dithering at 16 bit at the moment.

When Camilla Polarity/Flat dithering implemented, CamillaDSP takes over volume control. I control volume on my vintage Arcam integrated so to bypass CamillaDSP volume control, do I set it for 100 volume and go control it on the integrated amp? Just trying to minimize volume control chain.

Thank you again for all the help making it. Another donation is coming.

Glad it's working :-)

To switch to fixed volume output do the following:

Menu > Configure > Audio
Set Volume type to "Fixed (0dB)"

This setting results in MPD outputting 0dB (no attenuation).

[hifinet]

An update regarding the most recent batch of TDA1387 X8 modules I have received from HuaXinHuiDianZi Store. Rejection rate is now about 10%. Those are ones with poor channel balance, and indicate one of the chips is bad in one channel. About 2/3 are balanced and measure in the 1.20-1.30 VAC RMS with 0dB 50 Hz sine wave (Fluke 11). These are the ones I ship with the kit. The other 1/3 of the "good ones", which are balanced and measure in the 1.10-1.19 range. I have listened to these and they sound perfectly fine.

[eculcea]

I am using PicoPlayer and I am trying to add an IR remote. The default data pin used for IR is IR GPIO 25 (pin 22) . Is this pin by any chance used by ProtoDAC?

[eculcea]

An update regarding the most recent batch of TDA1387 X8 modules I have received from HuaXinHuiDianZi Store. Rejection rate is now about 10%. Those are ones with poor channel balance, and indicate one of the chips is bad in one channel. About 2/3 are balanced and measure in the 1.20-1.30 VAC RMS with 0dB 50 Hz sine wave (Fluke 11). These are the ones I ship with the kit. The other 1/3 of the "good ones", which are balanced and measure in the 1.10-1.19 range. I have listened to these and they sound perfectly fine.

I used the same store and I ordered several of those in October. Is it possible to provide a more detailed explanation on how you test those chips? I am an hobbyst, not an engineer by far.

[hifinet]

I am just a hobbyst as well. I recently added the test method in Post #1 of this thread.

Make a simple module test rig with one of your spare PCBs with GPIO soldered, three I2S resistors (R1-R3), a socket for the module (14 pin DIP socket OK), two metal film 430R I/V resistors (U7/U8) and 2000uF power supply decoupling cap (C3/C4). There is no need for any other parts on the test rig. Download this 60s_Sine_50Hz_0dB.wav file and play on Moode with repeat track on. Measure AC RMS voltage at the two test points, which are the output coupling cap pads at the I2S resistor end of the PCB. Measure between test point and ground. Voltage should read 1.2-1.3 Vrms, and the two channels should read very closely. I reject modules for the kit that can't pass this test. I do think modules that read 1.10-1.19 are good, but I only include 1.2-1.3 Vrms modules with the kit.

I hot swap modules and wear a grounding strap.

Most DMMs are accurate at 50 Hz, and accuracy suffers as the frequency increases.