Update 5 July 21: A small batch of v1.3 now in stock. This is almost identical to ADC AK5572 v1.2 except PCB is green.

Features:

• Up to 768 kHz / 32-bit audio
• Very high measured performance: 121 dBA DR / SNR, -114 dB THD+N (balanced input)
• Balanced differential input, 4Vrms input level (for unbalanced it is best to use RCA to XLR cables, note though that some dynamic range is lost due to high input level)
• Stereo or mono operation
• I2S output; Master or Slave
• HW configurable (supports I2C as well)
• Optional AC coupling circuit (component placeholders but not populated)
• Input clipping LED

Specifications (typical):

• 121 dBA dynamic range and SNR (124 dBA in mono mode)
• -114 dB THD+N (-1 dBFS, 1 kHz), most boards reach -115 dB with balanced input; using single-ended input is around 3 dB worse
• -117 dB THD (-8 dBFS, 1 kHz)
• -130 dB crosstalk (10 kHz)
• Maximum input level: 4.0 Vrms differential

Detailed information and measurement results are available.

What's included?

Fully tested board comes as in the 2nd/3rd photo: all SMD components soldered, supply screw terminals soldered, XLRs and jumper header unsoldered but provided with the board along with a few jumper links (except Mono boards have also XLR and headers soldered). There are component placeholders for AC coupling circuit but these are not included as it's not normally needed. There is a digital HPF in the ADC to remove small DC offset.

By default the board powers up in Slave I2S mode where clocks don't need setup, digital HPF on, and default digital filter Sharp selected. If you want to change any of these, solder the 2x8 header and use the jumper links; see documentation for settings.

System requirements

Signal level

Signal level is 3.3 V.

Master clock

Supports a range of clocks but 24.576 MHz is recommended. Note that master clock is needed also in Slave mode.

I2S receiver

This ADC has I2S output and you should be familiar with the format prior to buying.

I2S consists of:

• Data
• Bit clock (BCLK)
• Frame/word clock (LRCK or WCLK)
• Master clock (MCLK)

The board can be configured as I2S Master or Slave. A wide range of sample rates is supported up to 768 kHz.

When used as Slave and in Auto clock mode, no clock configuration is needed. When Master, clocks are set using jumper links.

Supplies

Following supply voltages and currents are required:

• 5 V digital, 12 mA
• +15 V analog, 95 mA
• -15 V analog, 57 mA

±15 VA are used for opamps so they are not very strict. I wouldn’t go higher due to excess power consumption but it can be lower. 5 V cannot be higher than 5.5 V.

The board gets very warm in normal operation.

Settings

There are jumper links to set various settings such as clocking and digital filters. Please see the factsheet for more information. You need to solder the header to change settings with jumper links.

The ADC can also be operated in I2C mode by soldering a bottom side resistor and using the 2x8 header for I2C signals. Refer to AK5572EN datasheet for I2C control details and register map.

Note that this board cannot be (easily) used in DSD mode; likely coming in a future revision.

More information

Please see:

• Provided 2-page factsheet
• Linked Youtube video below (for older version v1.1 board)
• nihtila.com ADC AK5572 v1.1 for lots of detailed information, measurement results, and schematics on v1.1, and nihtila.com ADC AK5572 v1.2 for updated information on v1.2; current v1.3 is practically the same as v1.3 but on green PCB.

If still unclear, please drop me a message.

Options

Stereo or Dual Mono

Default configuration for the board is stereo, meaning two balanced analog inputs and conventional stereo I2S output.

Another option is mono where most of the input circuit is doubled to give 3 dB gain in dynamic range and SNR. In this case there is a single balanced input. Output is still 2-channel I2S but both channels are identical. Mono boards are sold in pairs as Dual Mono option.

I2S to S/PDIF

I have another product for sale which converts I2S to S/PDIF, and it is compatible with this ADC. It also has a special feature of creating one stereo S/PDIF from two of these ADCs in mono mode. This board always operates as Master, the ADC(s) being Slave(s).

Thus, if you want to build a very high quality analog to SPDIF setup, you can use either one Stereo ADC or two Mono ADCs along with I2S to SPDIF and suitable power supplies.