hi everyone, I wanted to talk about dual head usb cables construction, therefore with separate data line and power supply line. I always use for data rail a certified usb cable in order to be sure to comply with the usb protocol requirements. The power supply rail, on the other hand, I have always chosen cables with a larger section, perhaps ofc and with low inductance and shielded. What I am not clear about is the screen: on the dac connector type B and pc connector type A connected both sides, but on the power supply connector side? i usually use xlr connectors on the power supply. Perhaps it is better to choose an unshielded cable for the power branch, perhaps a quad star ...
What I do depends on the particular USB board. For some its better to wire power directly to PCB and cut or disconnect the +5v PCB trace coming from the USB connector. Also, maybe use a dedicated transformer winding for the clean 5v supply so that you don't create ground loops through the power cabling. In that case any decent USB cable is okay for data.
I use a self-built linear power supply, where there is a transformer dedicated to the 5V line. this line is then connected to a usb connector and an xlr on the back of the case.
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If a USB board is an Amanero or an Chinese Amanero clone, the preferred way to bring in clean power is to remove the component near the USB connector labeled L1. In real Amanero its a ferrite bead, for a clone it may be zero ohm resistor. That disconnects the USB +5v. Soldering a power lead on the load side of L1 and ground wire to ground plane on the bottom of the PCB arguably makes a better quality connection than going through the USB connector. A pin header can be installed on the L1 pads so that USB power can easily be restored with a jumper.
Some other USB boards have their own preferred ways to bring in clean power. A dual head USB cable is only one of the options.
Some other USB boards have their own preferred ways to bring in clean power. A dual head USB cable is only one of the options.
Okay, I see. https://lnx.m2tech.biz/wp-content/uploads/2018/08/Young-MkIII-Nonsoloaudiofili-June-2018.pdf
Looks like there is an XMOS chip on DAC PCB. Have you checked to see if the USB +5v is actually being used to power anything inside the DAC? It might just be used to detect a USB connection was just made or just disconnected, not for powering anything. If that were the case, then maybe no benefit to an external +5v supply.
Looks like there is an XMOS chip on DAC PCB. Have you checked to see if the USB +5v is actually being used to power anything inside the DAC? It might just be used to detect a USB connection was just made or just disconnected, not for powering anything. If that were the case, then maybe no benefit to an external +5v supply.