Originally Posted by analogue 3
I'm just wondering which Belkin hub you're using here? I've been advised to try different USB hubs in an effort to find one which provides clear digital audio signal out of tablet to Cambridge Audio DACMagic. Currently going direct from USB OTG to DAC via manufacturer (DAC's) provided USB cable results in a noisy audio signal. I figured your Belkin hub would be a good place to start auditioning for a working setup.
Will also be researching USB battery packs to provide power rather than relying on AC->DC adapter. I don't suppose anyone has an input on a 4 port USB Battery pack vs a 2 port USB Battery pack and whether the 4 port model is more likely to interfere with the digital audio signal going from the android device to the powered USB Hub to the USB DAC. Battery capacity, voltage, amps etc is identical for both models. For all I know the number of ports is irrelevant to electrical disturbance.
My Belkin powered USB hub is the following:
It was the smallest USB hub I found in the shop around the corner.
About electrical disturbance, a solution: USB Y cable?
“What’s wrong with the current USB cable design for audio use?
Many cables combine power and data into a single cable, causing crosstalk between power and data.
The key of course is the “twin connection” design. It separates the signal ground from power ground and shields the signal and power connections from each other."
The most constant voltage-regulated USB battery pack?
"The battery supplies of the usual mobile equipment require a DC/DC converter to step up the required output voltage."
"Our U Power's two 3.7V cells net 7.4V power which gets stepped down to the 5V with a superior low-noise linear voltage regulator."
"A typical linear regulator diagram is shown in Figure 1-1. A pass transistor is controlled by an operational amplifier which compares the output voltage to a reference. As the output voltage drops, the op-amp increases drive to the pass element, which increases output voltage. Conversely, if the output rises above the desired set point, the op amp reduces drive. These corrections are performed continuously with the reaction time limited only by the speed of the op amp and output transistor loop."