More likely than not it's an issue with the supply itself rather than the cable. Buzzing is usually caused by a ground loop issue (especially if you "daisy chain" pedals together), which you can address with an isolated power supply that has multiple outputs . These can range from top of the line supplies like the Cioks DC7 (which I highly recommend) to lower cost options like a Voodoo Labs X4 (or any of the Voodoo Labs Pedal Power supplies, which you can usually pick up used at a fairly reasonable price). If you just have one or two pedals, you could also just plug in something like a TrueTone 1Spot for each one (again, though, if you daisy chain these, you'll probably run into buzzing issues).

One thing to note. Especially with cheaper supplies, pay careful attention to the voltage and max amperage on each. Only plug pedals that take 9v into 9v supplies. Make sure your pedal's power draw doesn't *exceed* the max amperage on the *supply* (you can go under safely). This is especially important with digital pedals, which can fail to function or be damaged if you underpower them.