voltage

Hi! I bought a new fan a few weeks ago, Panasonic FV-20NLF1 WhisperLine 240 CFM. It's very quiet, but I have put a speed controler on it because it blow too much for my little tent! :laugh: But with it I have the "hum" noise from the fan. I've read that a Variac would make no noise, but...

High! I'm in the process of shopping for digital ballasts for my up and coming FIRST grow and wanted to ask y'all a question before I spend a couple of hundred dollars on this piece of equipment. I noticed there's an option to buy a 120V OR a 240V digital ballast - I'm not an electrician...