Whether you've got a lackluster guitar or an amp that doesn't sparkle, the FX-40b can help you out. A massive 18db Boost or Cut in either direction gets the power flowing through seven separate bands of EQ. If you can't solve serious tonal issues with this thing, you may as well give up. The unit is clean sounding and we didn't notice any noticeable tone loss when engaged. We've had small gripes with the DOD switches over the years but this newer models performed perfectly. These are reasonably priced and offer a lot of bang for the buck. Aside from the obvious guitar applications, we've thrown these on vocals, keyboards, and even patched it into drums tracks for a few lo-fi recording projects. An equalizer is a must have in any effects arsenal for its ability to shape up signals or mangle them beyond belief.