By using two isolated outlets the Voltage Doubler (Stack Flex) gives you the sum of voltages of the two outlets used. Stack Flex type 1 is fitted with a black 5,5/2,1mm centre-negative DC plug also called the BOSS standard at the pedal end.
If your power supply doesn’t have a dedicated 18V outlet you can use type 1 Stack Flex to power an 18V pedal using two isolated 9V outlets. The most common 18V pedals are those from MXR, Pigtronix, some What and drives like OCD which accepts higher voltage than 9V.
If you need to power a pedal with 18 or 24V with a type 2 red DC plug have a look at the Series adapter Flex. If you want only to use one outlet to power an 18 or 24V pedal look at our two Booster Flex types.
Please note that the Voltage Doubler makes a series connection of the two outlets used. These two outlets must be isolated from each other. You get the sum of voltages (V) and not the current (mA). If you use it with two 9V outlets with a 100mA rating each you’ll get 18V and still a max. the current of 100mA. If you use it with two 9V outlets with 200mA each you’ll get 18V and max. 200mA. If you use it with two outlets rated to max. 200mA both set to 12V you’ll get 24V and still max. 200mA.
BE CAREFUL when using Stack Flex. There is a risk of damaging one of your 9V pedals by powering it with too high a voltage. Check the specifications of the pedal and if you still have some questions, you’re welcome to send an e-mail to firstname.lastname@example.org and get some useful information.