[Part 4]Creating a FIR Filter Channel Divider

  Creating a FIR Filter Channel Divider [4] (Hardware @ SPDIF→DSP→DAC Edition)

 

For creating a DIY FIR filter-equipped channel divider (chan-deba) for a multi-amp system, you can find a list of related articles here!

 

Items needed:

For more details, please refer to this link.

  • ADAU1467 board
  • USBi (programming tool)
  • SPDIF board (WM8805)
  • DAC board (PCM5102A)
  • A suitable breadboard (for power relay wiring)

In addition, you'll need:

  • A Windows computer
  • A device capable of outputting optical or coaxial SPDIF
  • An oscilloscope (not recommended, but you can also use an amp and speaker setup that you don't mind potentially damaging)
 

  Wiring materials

For the wiring, you'll need a combination of male-to-male and male-to-female connectors.

Having a set of materials like this is convenient:

  Power wiring

For the above:

  • ADAU1467 board
  • SPDIF board (WM8805)
  • DAC board (PCM5102A)
You need to connect the power wires for each of them.
First, you'll receive power from the computer via the USBi (programming tool).
First, let's look at the connection points on the ADAU1467 board. They are located at the bottom left, indicated as 5V and GND.
 
From here, you'll wire the connections to a breadboard or similar, and then connect them to the SPDIF board and DAC board.
It will look something like this. Connect the power (Vdd) and GND for each board.
Please be extremely careful here. Making a wiring mistake can damage the circuit board!
 
 

 

  SPDIF

Next, we'll connect the input side, specifically the I2S.
Connect the SPDIF output to the I2S input 0 channel (xxxxi0) of the ADAU1467 board.

 

SPDIF → ADAU1467

  • LRCK → LRCKi0
  • SDAT → SDATi0
  • BCK → BCKi0

By the way, the pin designations may vary:

  • LRCK can be labeled as LRCLK
  • BCK can be labeled as BCLK
  • SDAT can be labeled as SDATA
  • Keep this in mind.

 

  DAC

For the DAC, follow the same procedure as the SPDIF:

Connect the ADAU1467 board's I2S output 0 channel (xxxxo0) to the DAC's input.

 

DAC ← ADAU1467

  • LRCK ← LRCKo0
  • SDAT ← SDATo0
  • BCK ← BCKo0

 

When you connect the SPDIF and DAC, it should look like this.

 

  USBi

To connect to SigmaStudio (DSP design software), connect the USBi.

On the surface of the ADAU1467, there are 10-pin terminals where you'll connect it.
Just be careful about the orientation of the cable.

 

  oscilloscope

To verify the output signal, let's also connect an oscilloscope.

I've made a rather forced connection to the audio output section of the DAC.

 

  Try supplying power

Try connecting the USBi to your computer.

The ADAU1467 board and the LED on the DAC board should light up.

If the LED doesn't light up at this point, immediately disconnect the USB and double-check the wiring.

※ If your connected computer displays messages like USB not recognized, don't worry about it here (it should not be displayed if SigmaStudio is installed).

 

First, with this, the preparation is complete.

 

To be continued