a-LeXx
100+ Head-Fier
- Joined
- Nov 30, 2004
- Posts
- 467
- Likes
- 259
I measured this with a timer, in stand-by DFC actually consumes 2.5x more power than a DFR.
On my iPhone 6, an average battery discharge in idle with DFR connected is 4% per hour. With DFC connected it's 10% per hour.
I did some research and found out the reason for this. Apparently, according to Gordon Rankin, DFC is operatig on USB in a High-Speed-Mode, vs. DFR in Full-Speed-Mode.
High-Speed-Mode needs A LOT more power just for the USB, as it allows transfer rates of up to 480 Mbps vs 12 Mbps in Full-Speed-Mode, has shorter latencies, more complicated packet structure and so on.
So, the question is: WHY?
At it's highest rate, DFC can work at 96/24, which means around 4.6 Mbps. This is almost 3 times less, than Full-Speed-Mode would allow to transmit. Conclusion is, Audio Quest must be planing to make higher sampling rates possible, up to 384 Ksps, which indeed would require High-Speed-Mode.
However, another question, why didn't they do it from the beginning? Why letting DFC running in a High-Speed-Mode (and this was the only reason for them to switch to a new MCU, because the old one was not power efficient/fast enough to run High-Speed-Mode, again according to Gordon Rankin, I'm not making this up) even though no higher sampling rates have been implemented? This unnecessary increases power consumption, and is doing NOTHING for audio quality, the energy is just wasted on USB protocol overhead...
Questions, questions....
On my iPhone 6, an average battery discharge in idle with DFR connected is 4% per hour. With DFC connected it's 10% per hour.
I did some research and found out the reason for this. Apparently, according to Gordon Rankin, DFC is operatig on USB in a High-Speed-Mode, vs. DFR in Full-Speed-Mode.
High-Speed-Mode needs A LOT more power just for the USB, as it allows transfer rates of up to 480 Mbps vs 12 Mbps in Full-Speed-Mode, has shorter latencies, more complicated packet structure and so on.
So, the question is: WHY?
At it's highest rate, DFC can work at 96/24, which means around 4.6 Mbps. This is almost 3 times less, than Full-Speed-Mode would allow to transmit. Conclusion is, Audio Quest must be planing to make higher sampling rates possible, up to 384 Ksps, which indeed would require High-Speed-Mode.
However, another question, why didn't they do it from the beginning? Why letting DFC running in a High-Speed-Mode (and this was the only reason for them to switch to a new MCU, because the old one was not power efficient/fast enough to run High-Speed-Mode, again according to Gordon Rankin, I'm not making this up) even though no higher sampling rates have been implemented? This unnecessary increases power consumption, and is doing NOTHING for audio quality, the energy is just wasted on USB protocol overhead...
Questions, questions....
Last edited: