Passive RAKK dac Output
 

 

  

 

 
The current output of the PCM1794 is high enough to enable use of a Lundahl LL1674 1:4 step-up amorphous core transformer for a passive output stage. A special connection of the primary is used to very effectively cancel the DC bias voltage present on the output terminals of the PCM1794. A high quality Mills resistor in the secondary circuit of the transformer provides for the current-to-voltage conversion. This output stage is actually small enough so that it is physically the same size as the RAKK dac board and can be stacked on top of it for a particularly compact installation.

For further information on the use of the passive output board, refer to the Passive Output Article. 

Here is the schematic diagram of the passive output board.
 

 

Output Specifications
 
Output level at 0dBfs 2vRMS
Output impedance 3000 Ohms
Frequency response 
   10Hz to 20KHz , +0.7dB, -0.4dB  
Size
2.35 inches by 4.9 inches