Reverb is a delay effect that can make instruments sound bigger and more bombastic. Before digital delay circuits, there were a few physical ways to create reverb. In a studio, plate reverb was common. This sent the analog signal across a huge metal plate, suspended by springs inside a box. Then a pickup would be somewhere else on the plate, giving a reverb sound. But plate reverb units are massive, so for live music, another variety was needed. This is the spring reverb — the sound is quite literally sent across a spring under tension! To properly use a spring reverb, you need a driver circuit, and that’s what Mad Hatter Electronics has developed.
Spring reverb units come in many shapes and sizes – some have one spring, and some have multiple. They can be made from different materials to get different tonal qualities. Many musicians like to experiment with random springs to see what kind of sounds they can get, and that’s where a circuit like this comes in. The analog input needs to be amplified and the spring needs to be driven pretty hard to get the sound through. After going through the spring, there’s another stage of amplification before being sent to the amplifier.
Spring reverb is popular across many genres of music, and because spring reverb units (often called “spring tanks”) are so small, they can be built directly into amplifiers. This unit is small enough that you could definitely modify an existing amplifier to add a custom spring reverb! All you need is a bipolar supply (quite common in amplifiers anyway), with +/-15V suggested. So bust out your guitar, soldering iron, and grab some springs and make some crazy sounds!
Credit : Source Post
