I hear it I think. I've run other amps at 4 ohms & to me 4 sounds slightly louder, a little brighter, you could call it clearer. That's what I hear. I tend to like the fuller sound at 8 and 16. I am used to hearing an amp there so it sounds right to me. Comfort zone thing you know? When you use 16 ohm you are using all the winding in the output transformer. The next tap is at 8 and 4 ohms uses the least amount of coil windings in the transformer. So, some say if your output transformer is a good one, and you want it to contribute to the tone, use it at 16. I don't know how far I buy into it. I hear a difference I guess I just don't necessarily agree that it positively "better" sounding at 16 in every case.