384kHz Asynchronous USB to I2S/SPDIF CM6631A PCB
  • 384kHz Asynchronous USB to I2S/SPDIF CM6631A PCB

384kHz Asynchronous USB to I2S/SPDIF CM6631A PCB

  • Three NDK NZ2520SD Ultra low phase noise oscillator
  • Uses external 3.3V regulated power supply(remove L4) or USB power
  • Free optical SPDIF output socket included(until stock last)
CM6631A Option: CM6631A PCB with Type-B USB socket

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2 $10.00 $20.00

This item includes PCB with all SMT component soldered, thru-hole component are not soldered.

CM6631A 32bit 384kHz Asynchronous USB2.0 to I2S / SPDIF PCB for Windows/MAC/LINUX

Free optical SPDIF output socket included(until stock last), this pcb can be used standalone as an USB to SPDIF convertor

(Optional Digital Volume Control PCB for computer with Windows os only)


1) Two dedicated audio oscillator 45.1584Mhz 49.152Mhz for lowest jitter operation and highest clarity audio.

2) NDK NZ2520SD Ultralow phase noise oscillator are sourced from Japan directly (guarantee no fake product from China) According to the official datasheet, the phase noise is much better than the famous crystek 957 under 25khz(human listenable range)
For easier comparsion(lower is better), we overlay the two phase noise graph at the same scale, under 25khz(human listenable range) nz2520sd(red line) is better, over 25khz(human unlistenable range) crystek 957 is better.

3) 0.1% Low noise thin film resistor and murata capacitor are sourced from digikey (guarantee no fake product from China)

4) Two I2S output is available. Diyer can flash the firmware and enable Headphone I2S(non-isolated) and Speaker I2S(isolated) if needed.

5) Solid ground plane (a must for high speed digital circuit) and No via in active circuit (via inductance always create jitter problem)

6) Gold plated USB connector with lowest contact resistance and highest signal integrity (Molex, FCI, or other depends on stock)

7) Compact size 50mm x 50mm

8) SPDIF 3.3V 8mA (coaxial /optical) connection is routed out for diyer to mod if needed.

9) 100% tested before shipped (each sampling rate 44.1/48/96/192/384kHz i2s output are checked individually)

10) Powered by external regulated supply connect to the 20pin header labelled 3.3V and GND.

11) New version of this pcb includes onboard low noise 3.3v regulator installed, and it s connected to our dac pcb by 20pin flat cable and external 3.3v is supplied from the 20pin flat cable, L4 must be removed to disconnect the onboard 3.3v regulator from the USB power.

(i.e. If L4 on the PCB is removed, the onboard regulator is disabled, external 3.3v can be supplied on the 20pin header labelled 3.3v/gnd)

Windows 7/8/XP Driver is available to download from our website
*USB2.0 is a must for 32bit/384kHz operation
*Use a fresh install of windows and a dedicated USB port always avoid problem and run stable
*The length of I2S connection to the DAC chip should be as short as possible for best result and below 10cm is recommended

Please check the following I2S signal specification to decode each sampling rate:

*We have tested AK4399 ES9023 PCM1794A for 192kHz and ES9018 PCM5102A for 384kHz and they can work with this PCB perfectly.

44.1kHz 2.8224Mhz 22.5792Mhz
48kHz 3.072Mhz 24.576Mhz
88.2kHz 5.6488Mhz 22.5792Mhz
96kHz 6.144Mhz 24.576Mhz
176.4kHz 11.2976Mhz 22.5792Mhz
192kHz 12.288Mhz 24.576Mhz
352.8kHz 22.5792Mhz 45.1584Mhz
384kHz 24.576Mhz 49.152Mhz


For 2018 new version: User can short L4 to use the onboard regulator for USB power. (Do not connect anything on the 3.3v /gnd at the 20pn header)

When L4 is removed, user can use external 3.3v regulated power supply connect to the 20pin header labelled 3.3v and gnd.

*This item is in limited stock, maximum 5pcs per buyer. Please contact us if you want to buy more than 5, thanks.

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