Electro-Harmonix Holy Grail
In their rather extensive line of reverb pedals, this is the simplest that EHX has to offer. The one knob functions as a volume/resonance control for one of three reverb types. This pedal is just the right type of machine for a pedal beginner or for those who can’t be bothered to turn all sorts of knobs and change all sorts of settings.
External Control: None
This one almost falls into our favorite single knob category. The only other moving part is the switch, which allows you to select any of its three reverb styles. Incredibly simple, incredibly intuitive.
While the Holy Grail does have a few different styles of reverb, it is vastly limited in its manipulability. Although one knob is a great way to simplify your life, you might be saddened by the inability to change any parameters other than what the one knob will allow.
Quality of Effect: 3.5/5
Although the flerb effect is extremely original and useful, the regular spring and hall sounds accentuate the high end, and take away some of the body of the sound. This can be a particular detriment when playing trumpet or the higher register saxophones.
Live application: 3.5/5
The effects are passable in quality, and the ease of use is wonderful, making this a great choice for a live pedal. If you like its sounds, and you crave simplicity, then this is the pedal of your dreams.
Simply the finest "spring" reverb available
Smooth "hall" reverb tailored to the guitar
Flerb combines flanging with spatial reverb for a unique ethereal sound
96DC-200BI power supply included
Product info from the EHX website