help with powering vintage electro harmonix bad stone 9v pedal

Started by bobster, March 29, 2010, 06:56:22 AM

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bobster

hi guys-
i have bought a ' soundlab ' regulated power supply which has adjustable polarity and sets for 9v with an adaptor [ like a reall small headphone male jackplug ] input for my old late 70s bad stone .
before i plug it in and toast this guy , does anyone know which polarity i should set it for?
i did try a seach by the way  ;)
boss pedals are centre negative right but i am not sure what to do with the bad stone as its input is different
any help appreciated
bob

theehman

Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

bobster


Mark Hammer

Unless it is an extremely "exotic" type of phone jack, the tip will always be used to switch between internal battery and external power source., and the shaft will always be ground.

The easiest way to confirm all of this is to get the answer to 2 basic questions:

1) Is the retaining nut on the jack connected to the chassis, and is the collet that it screws onto metal?  If yes, then the shaft connection on the jack/plug serves as ground.

2) Is there any indication of a battery connector going to the jack inside the pedal?  If yes, it will most likely be a red wire from the battery snap, meaning the tip is positive.  In the rare circumstance the wire will be black if the unit happens to be one with a positive ground.

bobster

thanks mark , thats great info to know for future ref.
i set up the adapter with tip pos and its working great no hum  :icon_smile: