
Polarity is fixed.
Universal USB 9V Step-Up Power Cable
Customer Reviews
3.7
3 reviews
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Does the job
Good gadget to power various electronics from guitar pedals to differential probes. As others have said, the end bit is compatible only with centre-positive devices unless you cut the wire or open up the adapter end to reverse the wiring. As it only allows you to plug the end in one way (the pins are sized differently). Output voltage is around 9.3V without any load, lead is a little shorter than I would like at around 40cm? And yes, it works even on USB ports with 500mA limit as long as the 9V end doesn't draw more than 250mA-ish. Been working well powering differential probes that's been chewing through batteries.
It is not truly "universal" as the pins and holes are configured in a way that mean they only fit one way around. This means you can't actually change the polarity configuration on it and it can't be used with "tip negative" products Apart from this slight design flaw it does the job as intended
Does what it says on the tin (mostly)
I bought this around a year ago to run guitar pedals and a small amp off a powerbank. Despite the product name having the word "universal" in it, the tips only fit together with CENTER POSITIVE polarity. For my application, I had to open the case and solder the output wires the other way around to switch the polarity.