@amirm Great video as always, thank you for taking your passion and sharing it with the community. As mentioned before in other threads, North America typically uses 14/2 or 12/2 wiring to go from the electrical panel to our outlets. This wiring is solid core copper or sometimes aluminum and has absolutely no shielding from the service panel to the outlet. Having a shielded AC cable for the last 6 feet makes no sense . A quality cable should be safe and certified, sized at least 14 gauge for a 15 amp circuit, flexible (multi strand wiring) and have properly sized conductors at the ends to make a solid low resistance connection and not risk damage to the outlet as you explained. As a side note, one of the biggest issues I have with extension cords and AC cables in North America is that you can take a cable that’s only 18 or 16 gauge, rated to safely pass 7.5 Amps and plug that into a 15 Amp circuit. There is no requirement for protection on the cable itself to prevent excessive current from heating the wire and causing a fire.
In light of this, I would like to suggest a more meaningful test that can better show how well these cables perform under pressure, a voltage drop test. Typically when we measure the resistance of a wire with an ohm meter, the device passes a very low current through the wire while measuring the resistance. In any conductor, the more current that passes through, the more heat is generated. The generation of this heat consumes voltage and results in less power available to the device. It’s my understanding that the GR Research B24 uses a “24 wire braid” resulting in a conductor that’s equivalent to an 8 gauge wire. Because these cables are not certified, my concern would be the internal termination of those 24 wires. Any time you pass electricity through a connector or join two conductors together, mechanically or through soldering, you will have a voltage drop of some sort. If manufacturing issues result in some of those conductors being not properly terminated, the effective current capability of the cable will be reduced, generating more heat and a potential hazard, and less power to your device.
I think it would be interesting to see a voltage drop test of the GR Research AC cable compared to the cheap no name one. Big thick power cables are usually only required for long cable runs where you want to minimize voltage drop or on devices that draw a lot of current. They will make no difference on a device drawing 15 or 20 watts because in either case, the voltage being delivered by the cable will be the same. Now, if you have a massive 7 channel power amplifier that could pull 1400-1600 watts if all channels were driven almost to clipping (unlikely with real world material but this is worse case scenario) and the AC cable could only pass say, 108 volts, you would be robbing the device of power. The DC voltage rail of the power amp, that could be designed to operate at something like 72 volts let’s say, would fall to around 62 volts. So at 72 volts DC you have a power supply that’s able to generate at best 50.904 volts RMS in AC (72 x .707) at clipping (roughly 325 watts into an 8 ohm load continuous). If that 72 volts were to drop to 62, the RMS AC voltage would be 43.834, which is only 240 watts into 8 ohms at clipping.
The more power consumed through the cable, the less becomes available to the device and the device cannot operate at its full potential. So ideally we would want to see no voltage drop on any of our wiring, but of course this is not possible. If the GR Research and no mane cable were each asked to conduct 14 Amps, I’d be curious how many volts would be lost in each cable. There are circuit testers for the home that will do this test at the outlet, but an easy item to use that almost everyone has is a hair drier. Most draw 1600 watts or more, simply measure the voltage across either end of the conductor (in parallel) and you will see how much is being lost to the cable.
Thanks again, Amir, for all you do to contribute to this great hobby.
Chris.
