Tube Condenser Groove Tubes Vintage GT67 (Mint Condition)

Connectivity

Wired

Type

Condenser microphone

Brand

Groove Tubes

The GT-67 is a multipattern tube condenser — essentially, a multipattern version of the GT-66 Cardioid tube condenser. It was for several years the flagship microphone in the Groove Tubes line. The GT-67 uses components familiar to the GT product line: a 32mm, center-terminated true condenser capsule with Aspen Pittman’s disk resonator system, a custom-wound nickel-core output transformer, and a GT6205M vacuum tube-based impedance conversion circuit. The mic has very high sensitivity, 35 mV/Pa, making it useful for quiet sources at the possible expense of clipping on very loud sources. The mic has a switchable -10dB pad to provide extra headroom in such cases, giving it a max SPL (padded) of 140dB. A switchable high-pass filter provides a -12dB rolloff below 75Hz. The mic provided four polar patterns: Cardioid, Omni, Hypercardioid, and Figure-8. From what we can discern, the polar pattern is selectable via a pair of mini toggle switches on the rear of the microphone body (confirmation forthcoming), rather than from the power supply. GT67 Cosmetic ChangesCosmetic changes during the course of the product’s lifetime included subtle finish and logo changes, and a change to the outer layer of grille material. The GT67 included an elastic shockmount (p/n SM4), a power supply, a 25-foot cable, and a hard mount (p/n HM1).