By using two isolated outlets the 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. Type 4 is with a green 5,5/2,5mm centre positive DC plug and mainly seen on older EHX pedals for 24V or 40V. 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. Most common 18V pedals are those from MXR, Pigtronix, some Whas and drives like OCD which accepts higher voltage than 9V. Please note that the Stack Flex 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. 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.
