Flatmax Studio Audio Injector Ultra Sound Card is Designed for Raspberry Pi Boards (Crowdfunding)

Flatmax Studio has launched several audio cards for Raspberry Pi boards on Kickstarter in recent years,  and their latest board is called “Audio Injector Ultra Sound Card”.

The board is said to give high fidelity input and output audio @ 192 kHz, is equipped with digital output (S/PDIF) and offers dual microphone capability. An extra balanced HAT – will send and receive balanced stereo input and output – is also available.


  • Direct Inputs – Unpopulated Analogue Connectors (stereo RCAs provided)
  • Direct Outputs  – Unpopulated Analogue Connectors (stereo RCAs provided), Digital Optical SPDIF (Optical transducer provided)
  • Potentiometer Inputs – Unpopulated Connectors and potentiometer (stereo pot. not provided).
  • Potentiometer Outputs – Unpopulated Connectors and potentiometer (stereo pot. not provided).
  • Microphone – 2x high quality ultrasound (model – SPU0410LR5H) surface mount microphones populated
  • Audio Codec – Cirrus Logic CS4265 stereo codec
  • Sample rate – 192 kHz, 24 bit
  • Jitter control – Low jitter clock oscillator
  • Hardware Compatibility – Works with the Raspberry Pi 2, Pi 3, Zero, etc.
  • Metal film capacitors in the line driver/receiver audio paths yielding low harmonic distortion levels.
  • TI DRV632 line drivers on output giving 2Vrms (5.66 V peak-to-peak)
  • Mute line driven outputs – for silence !
  • Breakout pins exposing 5v, Rin/Lin, InGND, Rout/Lout, GND, Mute.

As mentioned in the introduction, and pictured above, you can add Balanced Ultra board to the sound card with the following specifications:

  • Balanced line drivers (TI DRV632 5.66 V peak-to-peak)
  • TI INA1650 balanced line receivers
  • Output connectors – 1/4″ TRS connectors (unpopulated)
  • Input connectors – 1/4″ TRS connectors (unpopulated)

AFAICS, there’s no specific software for the boards, just use your preferred program. Check out the video below for an overview of the sound cards.


The project has launched on Kickstarter with a $11,000 AUD goal (US$ 8,542).  A pledge of $19 US should get you one Ultra Sound card, while you’d have to spend $38 US for the Balanced Ultra board + Ultra sound card. Other rewards with packs of cards are also offered. Shipping is $5 to $7 to the US and Europe, and a bit more to the rest of the world. Delivery is scheduled for August 2018. If you have any question, you can ask the developer in Audioinjector forums.

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