It looked good, the package and the transformer, but once I plugged it in to power 2 overdrives a chorus and a delay I couldn't believe the amount of noise that was coming out of the speaker. Powered the pedals with another transformer and got the confirmation that the problem is from the Rockboard Power Ace. Simply unusable.
At first it seems like a very sturdy and high-quality product, but when I plugged it into my pedal, I heard this really unpleasant high-pitch noise (loud also). Then I took my friends adapter with the same stats, just to see maybe there is a problem with my pedal, but this one was silent, LIKE IT SHOLD BE. So, I don`t recommend this product at any measure.