I got a Dunlop MXR 90 pedal the other day, and when i plug it into a nine volt cable it just makes a high pitched whining noise and wont turn on. Whats wrong i cant figure it out.
Does it work with a battery? Maybe try another adapter to power it? If it still doesn't work return it or exchange it for another one.
Fender Highway One HSS Strat
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Is the 9V adaptor pin negative or positive?

Most Dunlop pedals use Boss-style pin negative power supplies. You may have fried the pedal if you used a pin positive.

^ Using an incorrect adaptor and frying it will make exchange impossible, as well.

Edit: which of these is on your adaptor?

Re-edited to reduce massive picture size from wikipedia.
Everyone is entitled to an opinion.

Feel free to express yours so I can make an informed judgement about how stupid you are.
Last edited by bubb_tubbs at Jan 9, 2010,
Ya it works with the battery. I hate batterys though. I just don't want to have to return it and go through the hassel but i might have to. I did use the negative tip though.