Old-style fuzz pedals use PNP germanium transistors which are electrically opposite polarity to every other pedal you have, so they must be run on a separate power supply. Most people who have a pedal(s) like that, run them off a second 1 SPOT. That way, you’re still not using up valuable pedalboard space or power strip space… and it’s still a lot less expensive than one of those brick-sized power supplies.
Note : You will also need the Reverse Polarity Converter if your pedal has a barrel type of power jack (like Boss pedals) and indicates that the power jack is wired center positive. If your pedal has a mini-headphone type of power jack, you will need the 3.5mm Converter.