Power DAC

The PowerDAC is a high-powered Discrete DAC which is capable of driving speakers directly...

In its current form, each board is capable of delivering approximately 0.5W to a speaker, although this mainly depends on the impedance of the ladder (and its power handling) - the MOSFET drivers employed can handle huge currents, and a few watts is comfortably achievable.

Every MOSFET driver for each bit is fed from its own individual isolation chip, which spans isolated digital and analogue grounds... this stops clock signals and interference from finding their way into the analogue output.

Rather than use an output capacitor, a set of output transformers have been used with a gapped core - the kind normally used in SET (Single Ended Triode) amplifiers... these can tolerate a certain amount of DC, thereby eliminating the need for a coupling cap.  They also provide a better impedance match to the speaker by trading voltage against current.

The PowerDAC is typically run at around 25V, which gives an excellent signal to noise ratio.  Being a unipolar DAC, though, there is a significant amount of switching distortion around the mid point, exacerbated by the considerably higher currents flowing in comparison to the line-level Discrete.

Back