RPi-DAC-RCA or RPi-DAC - how to get it?

• Please order here: Gravitech US or Gravitech Thailand
• The RPi-DAC-RCA is branded as: Durio Sound.
• The project is completed - I am working on new projects (IoT, IoE and BLE related).
• All pictures shown here are my own setups. Durio Sound can look differently.

RPi-DAC SingleStereo with AC-DC rectification onboard (just AC transformer needed)

RPi-DAC SingleStereo board

RPi-DAC SingleStereo components with RPi-DAC-SPS (w/o AC-DC rectification)

RPi-DAC SingleStereo assembled (stacked), with RPi-DAC-SPS

RPi-DAC DualMono with RPi-DAC-SPS, RPi-DAC-FPGA and alternative RPi-DAC-SPDIF (substitutes RPi)

RPi-DAC SingleStereo with RPi-DAC-IF for RCA or as alternative SPDIF, USB, TOSLINK and XLR connectors (needs RPi-DAC-FPGA)

PCB Solder Options

The RPi-DAC PCB can be equipped (soldered) with different combinations of parts

• complete: DAC, LDOs, OpAmps, headphone amp, rectifiers, electrolyte caps - used to connect just AC transformer
• no rectifiers and no electrolyte caps - used with RPi-SPS or with DC inputs
• no headphone amp - breakout wires for final stage (symetrical after OpAmp)
• no OpAmp and no headphone amp - use your own I/V converter, just DAC and LDOs
• no LDOs - bypass LDOs and provide required voltages from your DC supplies
  helpful if you might be scared to solder the LDOs manually
• optimize blocking capacitors - not all needed or mix different types and size in order to compensate parasitic inductances
• with 24.576MHz XTAL - if used on FPGAs and other boards as clock source, not needed for RPi

RPi-DAC Kit Options

The RPi-DAC can be combined with several other modules in a flexible way:

• with RPi as network player or with Volumio
• with XMOS eval board (or any other USB-to-I2S) as USB sound card
• with RPi-SPDIF as S/PDIF, TOSLINK or (with XMOS module) as sound card
• with RPi-DAC-IF as interface module for an enclosure (with S/PDIF, TOSLINK, USB, optional Bluetooth)
• with RPi-DAC-FPGA module for upsampling, filtering or rotary encoder volume control

T-DAC Module System

T-DAC Configurations

Downloadable files and projects

You can download here ZIP archives related to the T-DAC and RPi-DAC,
e.g. ExpressPCB project files, Xilinx FPGA ISE [3] project to use PCM1794A [1] DAC board on a XynergyXS FPGA board [2]etc.

I cannot offer here a complete Linux kernel or image for the Raspberry Pi (with I2S support), I am sorry. Please see the steps on the

I will publish revision 3 PCB related information asap. Please find here revision 1 related information as a fist glance.

RPi-DAC-RCA - NEW

• cost-effective and feature rich alternative for HifiBerry
• have options to separate power for DAC from RPi, to power RPi
• keep the P1 connector on RPi free

Download UltraDAC_RPi_RCA.zip (35KB) - rev.2 new

Download PRi-DAC-RCA_overview.pdf (109KB) new

Download BOM_PRi-DAC-RCA.pdf (79KB) new

T-DAC ExpressPCB

• ExpressPCB project file for the generic T-DAC module (not RPi-DAC)
• It uses through-hole electrolyte capacitors for the DC rectifiers
• standard ExpressPCB format (a bit larger as RPi-DAC), Dual-Layer, with almost all components as SMD components (0603, 1206)

Download UltraDAC_singleHPAmp.zip (69KB)

RPi-DAC ExpressPCB

• Similar schematic, just optimized form factor for Raspberry Pi - same size, directly stackable
• direct connection to Raspberry Pi P5, assuming the header is mounted on the back side (as intended)
• it uses SMD electrolyte capacitors, soldered on the back side (as well as the connection headers)

Download UltraDAC_RPi_rev6.zip (81KB) - rev.6

RPi-DAC SingleStereo BOM

• Bill Of Materials (parts and components) for RPi-DAC
• including price estimate and Digikey [6] order numbers

Download BOM_RPi-DAC_rev6.pdf (60KB) - parts for PCB, optimized (with optional parts) - PCB rev.6 - new

RPi-DAC DualMono

• Bill Of Materials (parts and components) for RPi-DAC DualMono
• including price estimate and Digikey [6] order numbers
• part location of main parts (R, C for signal processing, jumpers, not other R and blocking C

Download BOM_RPi-DAC_DualMono.pdf (65KB)

Download RPi-DAC_DualMono_soldering.pdf (827KB) (main parts)

RPi-DAC SPDIF BOM

• Bill Of Materials (parts and components) for RPi-DAC-SPDIF
• including price estimate and Digikey [6] order numbers
• a User Manual for DualMono and RPi-DAC-SPDIF module

Download BOM_RPi-DAC-SPDIF.pdf (65KB)

Download Manual_RPi-SPDIF.pdf (492KB)

Solder and Assembling part locations - rev.6

• Remarks how to solder, parts locations, BOM, schematics
• based on PCB rev.6

Download RPi-DAC_rev_6.pdf (1MB) - new

How to operate rev.3 complete with RPi

• for customers who got the entire setup (RPi + RPi-DAC + RPi-SPS)
• how to connect AC transformer
• commands to play audio files
• requires to have modified Rasbian kernel for I2S on SD card

Download RPi-DAC-operate.pdf (85KB)

How to operate RPi-DAC DualMono with RPi

• complete setup with SPS, transformer, RPi-DAC DualMono and RPi
• Safety

Download RPi-DAC-operation_ger.pdf (85KB, GERMAN)

Separate PSU (universal)

• version 1: using LT317 and for +3.3, +5V, +/-15V
• version 2: using TI TPS7A45xx for all voltages, including negative -15V : requires transformer with separated coils

Download UltraDAC_PSU_LT317_337.zip (20KB)

Download PSU_TPS7A45xx.zip (25KB)

Stackable SPS PSU (for RPi-DAC)

• using 4x TI LMZ14202H (2A)
• directly stackable with RPi-DAC

Download RPi-DAC_SPS.zip (34KB)

Download BOM_RPi-DAC_SPS.pdf (54KB)

Download RPi-SPS_solder.pdf (396KB)

STMF4 Discovery USB Sound Card (Coocox Compiler)

• for STMF4 Disovery, STMFD4 Disco, board
• flash the board and use it as USB Sound Card
• Use onboard headphone or feed the RPi-DAC
• audio format: PCM 48KHz, 24bit, stereo
• in order to use - it needs the STM32F4 C project (see below) or the BIN file to flash
• please, see more details

Download DiscoveryAudioUSB.zip Coocox project (31 MB)

Download DiscoveryAudioUSB_BIN.zip BIN file (31 MB)

Xilinx ISE PCM1794A FPGA for XynergyXS

• for XynergyXS board, in combination with the STM32F4, connected via FSMC
• very simple Cortex-M4-to-FPGA bridge with FIFO to feed the PCM audio into DAC
• contains clock generation for DAC BLK and SCLK
• audio format: PCM 48KHz, 24bit, stereo
• in order to use - it needs the STM32F4 C project (see below) and intended for the XynergyXS FPGA board [2]

Download PCM1794A_DAC.zip (928KB)

Pico-C for XynergyXS STM32F4

• a quite complex project for the STM Cortex-M4 on XynergyXS board
• It contains a C-command-line interpreter with SD card support, FAT16 File System, Xilinx FPGA FSMC bridge (for DAC), USB OTG and USB Audio Class 1 driver and some other components such as ETH/LAN.
• It supports to use the XynergyXS with T-DAC as USB Sound Card on a PC or to play WAV files from micro SD card.
• It is a Coocox ARM Cortex-M4 project [5].
• intended for the STM32F4 on XynergyXS FPGA board [2]

Download picoc_Xynergy_PCM1794.zip (1,136KB)

Schematics Collection

• Find in PDF scatches, drafts, schematics, drawings etc., created and used during the project development.
• It contains the DAC schematics as well as the PSUs.

Download T-DAC_Collection.pdf (451KB)

References

[1] see detailed circuit datasheets of original manufacturers

[2] Bayer DSP XynergyXS

[3] Xilinx ISE FPGA suite

[4] ExpressPCB

[5] Coocox ARM Compiler IDE

[6] Digikey electronic parts