A quick-release tremolo lock device for installation into a tremolo or vibrato assembly recess or cavity, and for mounting to a movable bridge or a tremolo or vibrato block of a stringed instrument such as a guitar. The tremolo lock device includes a spring mount that is adapted to be fixedly attached to at least one wall of the tremolo or vibrato cavity to prevent relative motion between the spring mount and the cavity. The spring mount is also configured to capture an end of at least one tremolo or vibrato return spring. A slide key is also incorporated into the quick-release lock device, which is connected to the spring mount about a proximate portion of the slide key. The releasable tremolo lock device is also adapted with an adjustable quick release slide receiver that is adapted to receive and to releasably capture a distal portion of the slide key to, when engaged, capture and fix the position of the receiver relative to the slide key. A tail piece member is also part of the lock device and is joined to the quick release slide receiver. The tail piece is further configured to be mounted in the tremolo recess to the tremolo block of the guitar. In any of the embodiments of the invention, the lock device may also incorporate various types of joints that are adapted for movement in multiple degrees of freedom to compensate for natural and induced misalignment between the tremolo block, the recess wall, and the tremolo lock device.