JAM is optimized for electric instruments, like guitar and bass specifically. However, with its 40 dB of input gain, JAM can be used with certain dynamic microphones using an XLR to 1/4” cable or adapter. We have tested both Shure SM57 and SM58 dynamic microphones and each worked well when recording loud sources such as a singer. We recommend you purchase an impedance matching transformer if you choose to use JAM for vocals. Additionally, since JAM is a guitar interface, Phantom Power (48v) is not included. Condenser microphones which require Phantom Power will not work unless they have their own built-in power supply, such as a battery. It should be noted even with a built-in power supply, the amount of gain available is more suited to instruments rather than microphones.