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Input and switch boards for Soekris DAM1021 DAC

At this time all the boards are sold out!

This is a group buy for a set of input and switch boards for the Soekris DAM1021 DAC.

Documentation can be downloaded here (PDF on Google Drive).

The Gerber files for the latest versions of the boards are posted in #580.
The schematics for input and switch boards are posted in #332.
Schematic and PCB design for a power supply are posted in #325.

More information about the muting module can be found in posts #237, #259 and #263. The schematic is posted in #262. Muting boards are now sold out. Gerber files for making your own boards are posted in #454.

Input board BOM: https://docs.google.com/spreadsheets/d/1ENt40kTZhL9ITpYthZ8c4qUfL6y8ajTpFsxg7ic-8vU/edit?usp=sharing
Switch board BOM: https://docs.google.com/spreadsheets/d/1gz4L44eWwEkDHWcEnBIwdIYa3pOwWgeSbLcd3dcf6AY/edit?usp=sharing
Muting board BOM: https://docs.google.com/spreadsheets/d/1mkKxl3J7ERI1Ij2h5PFqQ5qZ6s5hMIRs1WoFZ5Vm1gg/edit?usp=sharing

The default RPi connector PCB for V2 boards is designed for Raspberry Pi 2 and B+ models. If you are interested in connectivity for older Raspberry Pi A/B models or Arduino, and have not indicated it on the original signup sheet, please post on the thread.

Pricing:
Input board bare PCB: Sold out
Switch board bare PCB: Sold out
Assembled input board kit: Sold out
Assembled switch board kit: Sold out
Additional input board parts for balanced build: 5 EUR
Shipping anywhere in the world: 9 EUR

Assembled muting board kit: Sold out
Additional muting board parts for balanced build: Sold out

Input V2 features
  • Stacks on top of DAM1021.
  • Directly connects to J3 and J2 headers on the DAC without additional cabling.
  • Directly connects to Amanero USB adapter without additional cabling.
  • Directly connects to DIYINHK USB interface (the non-isolated version) without additional cabling.
  • Easy ribbon cable connection to WaveIO USB interface.
  • Directly connects to Raspberry Pi without additional cabling.
  • Additional connector PCBs can be designed to use other microcontrollers such as Arduino, BeagleBone Black, etc.
  • Can be controlled using the isolated serial port.
  • Serial port control from Raspberry Pi.
  • Coaxial SPDIF input with BNC connector footprint.
  • Optical TOSLINK input with footprints for Toshiba TORX147L and Cliff Electronics ORJ-5 receivers.
  • U.FL sockets for other I2S sources (can be installed, but not used simultaneously with Amanero/DIYINHK).
  • Optional U.FL sockets for Amanero MCLK OUT, I2S MCLK OUT, FPGA SLV and FPGA MCLK OUT lines.
  • External connections possible to ALL pins on DAM1021 J2 and J3, and to Raspberry Pi GPIO connector.
  • Two selectable I2S inputs.
  • Built-in regulated power supply for the isolated digital part/muting module/USB/RPi/other microcontrollers.
  • Amanero/DIYINHK USB status lines readable from Raspberry GPIO pins. WaveIO USB status lines can also be connected by manual wiring.
  • Supports true balanced configuration with two DAM1021 DACs. A single input board is needed for dual-DAM balanced build.
  • For true balanced configuration the second DAM1021 stacks directly on top.
  • Supports serial port chaining for true balanced configuration.
  • Supports separate access to each serial port for true balanced configuration.
  • EMI filters on I2S lines to reduce high frequency noise pollution.

Switch V2 features
The switch board allows DAM1021 input selection and volume adjustment by use of mechanical switch and potentiometer. It is not required if DAM1021 will be controlled exclusively by a microcontroller via serial port.
  • Includes a rotary switch for input selection
  • Input selections are "Auto", "TOSLINK", "COAX", "I2S-1" and "I2S-2".
  • Allows connecting a potentiometer for volume control.
  • Footprints for front panel indicator LEDs for DAM1021 POWERLED and input selection.
  • Includes ribbon cable for easy connection to the input board.
  • Supports true balanced configuration with two DAM1021 DACs. A single switch board is needed for dual-DAM balanced build.
  • It is an optional accessory for the input board and is not useable separately.

Muting board with alternative output buffer option.
Muting is done by shunting the unbuffered outputs to ground with normally closed relay contacts. When the relay turns on, mute is off. Since the DAM1021 pin18 muting control does not work properly as of the current firmware release, and it can be quite difficult to attach wiring directly to that pin, the mute control is implemented independently.
  • Stacks directly onto DAM1021 J7 header (the unbuffered outputs).
  • Fits even with the onboard XLR connectors mounted (although I do not recommend using them).
  • Power-on muting uses a delay circuit which turns on the outputs approximately 8 seconds after power is applied.
  • Power-off muting uses AC detection and will mute the outputs within approximately 30 ms after loss of AC power.
  • Optionally these timer based circuits can be bypassed and pin18 driven control can be implemented.
  • Includes PCB footprints for implementing SE to balanced output buffers using THAT1646/DRV134 chips using easy to solder through hole parts.
  • Supports true balanced configuration with two DAM1021 DACs. A single muting board is needed for dual-DAM balanced build.
  • Includes PCB footprints for implementing true balanced output buffers using THAT1606 chips (only available in TSSOP-16 packaging, quite fine pitched SMD parts).
  • For true balanced configuration the second DAM1021 stacks directly on top.

It should be possible to use the balanced unbuffered hardware setup for a 2-way crossover in single ended mode, although it has not been tested.

This wiki page contains documentation for the old V1.1 release of the input board.
 
Last edited:
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
 
Hi smanz,

Your suggestion makes sense, but it would prevent using narrower enclosures such as Galaxy 230x230 from Modushop or the narrow protruded types such as this one from Ebay. So I am going to stick with my layout.

The length of DAM1021 with the input board attached will be approximately 215mm not including the protruding connector parts.

As an alternative, it is possible to use 26 pin male header on the input board and use a short ribbon cable to DAC. Then you can mount it sideways if you prefer.
 
Last edited:
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
 
Added my order:

leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
algar_emi: 2 bare boards + 2 sets smd components
 
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
jeremysk: 1 set bare boards + 1 set smd components
algar_emi: 2 bare boards + 2 sets smd components
nbivol: 1 assembled board
 
Last edited:
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
nbivol: 1 assembled board
jeremysk: 1 set bare boards + 1 set smd components
 
Hi normundss.

This is my assembly. As you can see, the cables that connecting Amanero and DAM are too long. It is a very bad disposition. The chassis is Galaxy Maggiorato GX338 330x280.

Od3c1bU.jpg


Regards
 
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
nbivol: 1 assembled board
jeremysk: 1 set bare boards + 1 set smd component
SebastianL: 1 assembled board
 
Take care guys when you do a cut and paste, you removed me. Added my order again...

leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
algar_emi: 2 sets bare boards + 2 sets smd components
nbivol: 1 assembled board
jeremysk: 1 set bare boards + 1 set smd component
SebastianL: 1 assembled board
 
leehan: 1 assembled board
tubesguy: 1 assembled board
robertrowett: 1 assembled board
secanbj: 1 assembled board
RollE2k: 1 set bare boards + 1 set smd components
misterrogers: 1 assembled board
bambadoo: 1 assembled board
randytsuch: 2 bare boards
danny_66: 1 assembled board
bappe: 2 bare boards
algar_emi: 2 sets bare boards + 2 sets smd components
nbivol: 1 assembled board
jeremysk: 1 set bare boards + 1 set smd component
SebastianL: 1 assembled board
hsi68: 1 assembled board