Some pedals are positive polarity some are negative.
I have adapter with 5 plugs for pedals and I think it's positive polarity. I can connect 3 positive and 2 negative and all will work.
Can it damage pedals?
And can polarity change cables damage pedals?
Please tell me more about polarity on adapters / pedals.
(http://www.bixmart.com/assets/images/CAB525MFDisplay-PolarityChange.jpg)
Yeah you wanna get that the right way round. Many circuits have something to protect them if it's wrong but NOT all.