I bought a fender rumble 100 bass amp . All things are ok . Just a question ,when I make overdrive on. The overdrive sound from speaker is not like videos in YouTube . When plug in headphone the over drive sound is good and high but when it start use 12" speaker it's not as powerful as in the headphone is . Is it normal ? Or the amp has problem ? I put lvl in 11 o clock and gain in 12 and over drive about 3 o clock .