I bought these electronics to replace the default(read cheap) ones from a Harley Benton 4 string P-J bass. The installation went smooth; i have consulted their official site for diagrams and schematics, since the package contained no such thing. Since i switched form a 2band to a 3band eq, i cannot really say if the sound changed because of the electronics, or the setup of eq. But it definitely did not became worse. When it comes to the build quality, the pots the ones that drag it down. They spin super easy, and feel a bit cheap. The volume pot is having a weird logarithmic feel;the first and last 10% do not change the volume; going down from 90% to 80% though is a huge difference. Under 80% the volume is too low for me.