Features:

• One I2S input / passthrough
• One Toslink S/PDIF input
• One isolated coaxial S/PDIF input
• More inputs (Toslink / Coax / AES/EBU) can be added with addon board
• I2S output (up to 192 kHz / 24-bit from S/PDIF)
• High performance to match with high performance DACs
• AK4115VQ S/PDIF receiver
• Compact size at 70 mm x 50 mm
• Can be used with W-DAC or any compatible I2S-input DAC

W-Input is part of modular Wee DAC system offering several boards to build a DAC with required features.

What's included?

Fully tested W-Input board with all SMD components assembled. All through-hole connectors are unsoldered.

More information, schematics, and BOM available at nihtila.com

What else is needed?

I2S DAC

This board outputs I2S and you should be at least somehow familiar with the format prior to buying. I2S output is connected to I2S input of a DAC (such as my W-DAC) and the format must match.

I2S input of W-Input board is direct passthrough to I2S output; this can be used for USB to I2S module, for example. When one of S/PDIF inputs is used, up to 192 kHz and 24 bits is supported.

I2S consists of:

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

When using S/PDIF, all necessary I2S signals are always generated, whether there is S/PDIF signal present or not.

Supplies

W-Input only uses VD supply:

• VD: 5 V, 20 mA

This is with 48 kHz signal and current may get slightly higher with higher sample rates.

VD cannot be higher than 5.5 V.

Note that there is no protection against over-voltage or reverse voltage; if you are unsure connecting please use a dedicated Wee DAC baseboard.

You can wire supplies directly to pinheaders or use one of the baseboards offered. There are both simple breakout boards and baseboards with all supply regulators in place.

Other information

Connections

External connections are marked below. These connections are made automatically when using other Wee DAC boards but with help of the diagram the board can be used in other systems.

Input selection

Only setting to the user is selecting input:

PCB

This is a 4-layer 70mm x 50mm PCB. Dimensions and distances between connectors are shown below.

Soldering I2S header

Note that correct side for I2S header J7 depends on the stackup used. If W-DAC is stacked on W-Input, this header should be on top side. If dual baseboard (W-BB Dual Breakout or W-BB Dual PSU) is used, the header should be on bottom side.

Optional input boards

Two extra S/PDIF inputs can be added with one of the two addon boards:

• W-Input+ Combo for isolated Coax and Toslink
• W-Input+ Combo XLR for isolated AES/EBU and Toslink

Addon board is stacked on top on W-Input. Note that if W-DAC is stacked on W-Input, no input addon can be used!

Wee DAC system

Please see my store for full range of Wee DAC system boards. Block diagram below illustrates components available and interconnections.