The dam1021 is a DAC module based on a discrete R-2R sign magnitude DAC design, with FPGA based FIFO buffering/reclocking and custom digital filters, < 1 ps jitter clock generator, with 28 bit resolution so there is headroom, oversampling up to 3.072 Mhz. Up to 24 bit / 384 Khz input from SPDIF, I2S and USB (via USB to I2S interface board), with isolation on the I2S interface. The board is very flexible, with digital volume control and filter parameters that can be downloaded. The board is fully firmware upgradable over a simple serial connection, which enables new features later on. For now we plan to add digital crossover filters soon.
The basis R-2R network has an output voltage of 1.4V RMS and output impedance of 625 ohm and can therefore drive a lot of things directly. There is also onboard balanced output drivers that can drive high impedance (>= 300 ohm) headphones directly. The power supply is also onboard, just add a 5W+ toroid transformer.
What is the difference between boards using 0.01%, 0.02% or 0.05% resistors ?
Only the harmonic distortion gets better with more precise resistors, and typically they will sound much the same as the resistors initially are better than specified. But the more precise resistors have smaller temperature drift and better long term stability, and therefore will be better in the long term.
Please note: This product is not manufactured by Soekris Engineering, Inc. It is manufactured, supported, and warranted by a separate company, Soekris ApS in Denmark. All support/warranty questions should be directed to: firstname.lastname@example.org
For an excellent description of the technical details of this product line, please visit HiFiDUINO's blog.