I see quite a few google searches about “boost pedals” pointing to this site and I have had several questions about them not having the desired effect, so I think a short post about their use is in order.
To put it simply, there are three cases:
- The clean boost pedal is placed before your overdriven amp or your favorite distortion pedal: activating the clean boost will not increase the overall volume much or at all. This is because any overdrive or distortion is inherently compressed and levels the volume. It will instead increase the gain i.e the amount of overdrive/distortion. Before the arrival of high gain amps and pedals, a lot of guitarists used treble boosters or overdrive pedals to boost cranked amps in order to achieve big distorted tones. Brian May is a prime example.
- The clean boost pedal is placed after the overdrive of your amp in the effects loop or after your favorite distortion pedal in your pedal chain: activating the clean boost will increase the volume but not the amount of overdrive/distotsion. I recently wrote a post about using a clean boost pedal and other solutions to boost the volume for solos in a live situation. For overdriven amps without an FX loop, it is difficult to increase the volume through a pedal. Any clean boost will increase the amount of overdrive and not the volume (see case 1).
- The clean boost pedal is placed before a clean amp: it will increase the volume and might push the amp into “break up” which is a slight overdrive, depending on how much clean headroom your amp has got.
As I pointed out in a previous post, the only way to increase the volume for your solos is to somehow put some form of volume control (clean boost, volume pedal, equalizer, etc.) after your overdrive/distortion. It does not matter if this overdrive/distortion comes from an amp or a pedal. A clean boost placed before will increase the gain, not the volume so much whereas a clean boost placed after will increase the volume.