I bought a Hartke 1410 combo used. Thats the 1400 amp head with two ten inch aluminum speakers. I didn't noticed when I was trying it out at the store, but now that I have it home, it sounds great on all notes except the fourth and fifth fret on the E string. All three of my basses make the same static/crackle noise on A and Ab on the E string, even with the volume turned way down. All other notes sound great. I paid $250 for the amp and the store is too far away to return it. I am going to take it to a local repair shop but I thought I would ask for opinions/diagnosis/guesses here. What do you think?