Doc B.
Member of the Trade: Bottlehead Corporation and The Tape Project, LLC
Quote:
In what type of audio device do you see a 100K ohm load? I admit I haven't used my electronics training in more than 25 years...
Also, although I acknowledge this might apply to cables and interconnects, how would it apply to a digital (USB) cable?
Tube gear like preamps and amps often has an input impedance in the 50K ohm to 250K ohm range or even higher, like some guitar amps.
USB cables need to address some different issues than analog audio cables, like round trip delay. The copper in the cable must be able to operate very close to its theoretical maximum transmission speed (velocity factor) when streaming high res file data. Thus there is some indication that wire quality will be very important as well as cable geometry. USB cables also share with analog cables the common concerns for proper shielding and solid connections, which can both degrade the signal if less than optimal. All of these kinds of requirements tend to be addressed best with fatter or less flexible cable types and thus the balance of performance and convenience can be a tricky one. Surely at some point someone will make a USB cable that looks like a garden hose and costs beau coup bucks.