With a spring reverb, the actual enclosure that contains the spring(s) used to delay the signal to produce ambience. Even if the spring reverb is built into an amplifier, the reverb tank is generally a separate enclosure-within-an-enclosure.
With a spring reverb, the actual enclosure that contains the spring(s) used to delay the signal to produce ambience. Even if the spring reverb is built into an amplifier, the reverb tank is generally a separate enclosure-within-an-enclosure.