"Check the iPad DACs thread to make sure it works, just to be 101% certain somebody else has tried it."
I did and I found a forum and this is what someone said. Why is he telling me to buy an extra usb hub?
Exactly the same reasons I've put down in my previous posts,(1)
and why I told you to check that thread, as to whether it works and how exactly :
it depends on the implementation and circuit design vis a vis the power supply/battery. My Meier Cantate.2 for example uses its own PSU to power the USB DAC, which is basically just the DAC-USB receiver chip and some analog output chips, at a cost of only 0.2volts drop in the peak-to-peak voltage swing of the amplifier (in other words, negligible). Some DACs rely totally on USB power, which obviously are the ones that have no power supply nor battery, like the uDAC. In some cases, the DAC-HPAmp or even just a DAC may have its own power supply,
but some chips in the circuit might rely on the USB power, like the Superpro707 DAC, which sounds totally different using USB (more powerful, louder, than the optica/coaxl input), and sounds exactly like if it were using a 19v power supply with the optical/coax. This is because, if it uses USB, it takes 5v of power from the USB bus for the USB receiver and DAC, leaving the stock 15v power supply to power only the analog output stage. The 707 even if it could do well with just the stock power supply using optical+coax will by default require power from USB, which also has no selector switch but automatically selected when it detects USB power. On one USB port on one older laptop we had, it wouldn't run, because that port only sends out the bare minimum for running some thumbdrives or mice.
In the case of the E17, given this person has tried it but he needed a hub, that means that at the very least the USB receiver chip is using power from the source through the USB cable.
(1) As quoted below, the italicized portion you quoted to ask why, but the answer is right there, now highlighted in bold letters and underlined.
Quote:
Check the iPad DACs thread to make sure it works, just to be 101% certain somebody else has tried it. My concern there, again, is that I do not know how that thing is wired up. It may have its own battery, but the USB receiver chip or even the DC chip may be powered by the USB bus 5v from a computer, and can cause compatibility issues if that's the case.
Also on these posts from Page 1, one of which you might have "re-read...many times":
Isn't there a Lightning CCK already? Wasn't this just for when Lightning was new and basically everyone still had the old 30-pin CCK? Also that battery pack and USB hub are only there because the DAC being used is designed for use with a PC outputting all the 5v necessary to run it, as it doesn't have its own power supply. Other devices have their own AC power supply (note that in some units some parts of the digital side are still powered by USB) or battery, and as long as the circuit is designed to totally run off either one, then as long as the iOS (or Android) device can stream digital audio, then it would.
No, iOS7 actually supports a large number of DACs when using the CCK, the problem precisely is powering the DAC. Again, some DACs might need power coming off the USB, which in some cases can be for just the USB receiver (particularly when it auto-detects and uses it by default when it does), or in some cases, all the way to the DAC chip, despite having another power supply, whether it's AC or battery.
