What polarity is the plugpack on Boss pedals?

[Caleb Chia]

Hi,
The plugpack I am using is one of those multi voltage adaptors with 3-4.5-6-7.5-9-12v so I thought it would be regulated, but when I measured it on the 9v setting, it measured 10.6 volts. I just put it on the 7.5v setting and it measured 9.6v and it works fine, it has not blown up yet.

[Enzo]

Those are not regulated, just adjustable.

Wall warts are rated for a voltage and an output current. The voltage should appear when the rated current is being drawn. If you draw 100ma from a 800ma wall wart, the voltage will indeed read very high.

ChrisA - speaking only for myself, I wasn't guessing. I am aware that the Boss power adaptors are negative center from experience. I own and operate a pro audio service facility.

I would add that the real Boss wall warts, while not regulated, are better filtered than the average wall wart. SO if you replace theirs with something from Radio Shack, you MAY wind up with more hum than with the original wart.

Many many Boss pedals are protected by a diode across the incoming power - often an 11v zener, but also just a plain rectifier. Reverse polarity (and excessive voltage) applied is shunted across by this diode, which usually shorts out. the shorted diode then prevents any other damage. Replacing the shorted diode is one of the most common Boss pedal repairs.

[locust]

Hi. I have a question somewhat related to this topic...

My friend gave me a Taiwan-made DS-1 that was "blown" by someone using wrong polarity wall wart. I opened it up. The D1 was broken, cut in half. Then I forgot the pedal in a box, until I recently bought a pile of components for other effect projects. Since the pile included a couple of 1N4007 diodes, and my girlfriend is in need of a distortion pedal, the DS-1 is now on my desk. Just got the diode (originally 1N4004) replaced, but the thing still don't work. Does it make a difference in this case if the diode has a different voltage rating? I thought it doesn't...

Referring to the last part of the previous message, shouldn't the diode be the only part to break in the case of reverse polarity wall wart used? The pedal went silent instantly, so I was told...

[Jarno]

Could it be that they've used a powersupply outputting too high a voltage? Certainly looks as if reversed polarity will be shorted by the diode, if not, there'll be some actives to replace. But, luckily, distortion pedals are easy enough to make :-)