The AKG SolidTube, the flagship of the Project Studio Line, is the first microphone that combines the sound of classic vacuum tube technology and the benefits of advanced solid state componentry at an affordable price. Mechanical ruggedness, high SPL capability, and low self noise are as natural SolidTube features as its warm tube sound. The heart of the SolidTube is the ECC 83 (12AX7) vacuum tube. It provides excellent transfer characteristics and is readily available from musical instrument dealers carrying spare parts for guitar amps. A ground lift switch on the power supply eliminates unexpected ground loops quickly and easily. Standard accessories include a spider type shock mount, pop screen, power supply, cable, and strong carrying case.

Tube microphones are very popular for their warm sound. The SolidTube emphasizes even harmonics and adds low-level distortion that the ear perceives as an enhancement to the sound.