ELECTRO HARMONIX VOLTAGE

[windopz]

Hi. I have a problem with my EH 10-band graphic equalizer. I think it's the internal power transformer, because when I connect a 9V power supply it sounds, but not regulary; the sound is not different from the original (guitar+amp). It can be a voltage problem? I know that EH pedals haven't 9V circuit...please, HELP ME!!!  :?