This is one of my favourite build. A real hardware spring reverb is the only way to go if you want the true sound of a spring reverb. This little box really does the trick and adds grate to the sound. The design is so well made that there is absolutly no tonal change what so ever to the original sound. Yet you can control the dwell witch is quite unusual on this kind of build. I have connected it to an accutronics type 8 (9" 3 sprigns) Originaly I wanted to use a type 4 (17" 2+2 spring) byt my speaker enclosure was 1/4 inch to schort to fit the 17" type