Some double bass players like to use a condensor microphone to aplify their instrument.
A condensor mic needs an extern power supply of 48V though, called phantom power supply. And the Hevos 400C amp lacks a phantom power supply. From an electronic point of view designing a phantom power supply is a piece of cake. The reason why we did not do so is because very few bass players use condensor mics nowadays. Furthermore there is not much room left inside the 400C for an extra input.
To serve our clients well Hevos delivers an extern phantom power supply if desired. There are several typs/brands available, but we have a preference for these two because of their good quality:
Both types are small and have 2 inputs and outputs, so one can connect 2 mics if desired. A power adapter is supplied.