The Behringer Crave synthesizer requires a power supply of 12V DC with a center-positive polarity. The power supply should provide at least 1.5A of current. This is to ensure the proper operation of the synthesizer. Behringer provides a power supply with the Crave synthesizer when purchased. If a replacement is needed, ensure the power supply meets the specifications. This is to avoid damaging the synthesizer. Additionally, it's recommended to use a high-quality power supply. This will minimize the risk of unwanted noise or interference in the audio signal.