Other information

Price calculations

Guesstimated final cost: I don't even know anymore everything keeps changing...but here's a BoM that's correct as of the 21st of August, 2015. Unfortunately, it excludes shipping, the cost of the case and group discounts.

Dual DAM balanced set-up

Taken from here.
Two dam1021's with input switch and volume pot, no microcontroller.
This setup will allow volume control and input switching only. To make it work, you need to:
  • Make sure both DAM boards have the same firmware and filters loaded, and the same presets are configured in umanager.
  • Configure one dam1021 with mode=bal-left
  • Configure the other dam1021 with mode=bal-right
  • Connect the volume pot and input switch to the first DAM board.
  • Make sure an isolated 3.3V power supply is connected to ISO +3.3V and ISO GND pins of both DAM boards.
  • Connect ISO TXD OUT from the first DAM (with volume pot and switch connected) to ISO RXD IN pin on the second DAM.
  • Take balanced output from CH1/CH2 pins of DAM J7 connector (the unbuffered output)
  • Connect pin 1 of the XLR connectors directly to the grounded metal enclosure. For prototyping without an enclosure, connect XLR pin 1 to GND at the power supply. Do NOT connect it to the DAM board.
  • Parallel the I2S input lines on both dacs.
  • Parallel the SPDIF inputs from the TOSLINK connector.
  • Parallel the differential SPDIF inputs from the input transformer. Remove the 300R resistor. (Did not actually test it yet, this setup will result in 50 Ohm input impedance instead of the nominal 75 Ohm)

Transformer hook-up

30VA Transformer: 16VAC - 0 - 16VAC 0.6A center-tapped output and 2 x 9V 0.4A secondary windings

left channel +/- 12V bipolar supply:
  • 16 - 0 - 16 AC to +/-12VDC bipolar supply
Right channel +/- 12V bipolar supply:
  • 16 - 0 - 16 AC to +/-12VDC bipolar supply
5V USB and 3.3V digital supply:
  • 9VAC to 5VDC WaveIO usb power
  • 9VAC to 3.3VDC isolated I2S, Toslink Module

To do list

  • Understand how to use the DAM1021
  • Create a circuit to allow the DAM1021 to accept coax-in

  • Mod digital 1.2V, 3.3V and +/- analogue lines with capacitators
  • 1.2V and 3.3V: Nichicon 2200uF 4V FPCap RNU0G222MDN1 
  • Analogue lines: Panasonic 1000uF 16V 667-16SEPF1000M 
  • Compensation Cap: 270nF Vishay VJ0805Y274JXXTW1BC
  • Feedback Resistor: 499R ERA-6AEB4990V
  • Series Resistor: Jumper
  • VRef Caps: 16 (?) x Nichicon 2200uF 4V FPCap RNU0G222MDN1

  • Arrange supply chain for important components and custom enclosure
  • Get a price quote for the whole thing
  • Remove the opamps in the output buffer

Interest list:

  1. vhsownsbeta
  2. adobotj
  3. uncola
  4. x Relic x
  5. NLNH
  6. DeLuX
  7. rcoleman1
  8. Poimandres
  9. Stillhart
  10. audiofrk (?)
  11. Joeybgood
  12. maeveth
  13. aamefford

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