Hi, I thought it was my ears, but I've confirmed today that playing on my Flextone III the treble will drop after a while and it sounds muffled. I tried turning the various controls (most obviously treble and presence pots) but these don't make it sound clear again, so it doesn't seem to be an intermittent pot. However, if I turn the rotary switch (which selects the amp), then put it back onto the same amp again, the treble comes backs again for a while. It happens on various amp models, some more obvious than others. I know it's quite old and not particularly valuable, but it was my 40th birthday present from my OH and family who all pitched in to buy it for me. As much as I'd like to replace it with a DRRi (and I may buy one as well) I'd like to try to get to the bottom of this issue. If anyone has any suggestions, or knows if this is a common problem, please let me know.