G'day Fellow Members, I have a Lone Star Special 1x12. All of a sudden it has started getting a very muddy flabby bass, even though I have not changed my settings from how I normally have them set. It makes no difference whether it is on 5, 15, or 30 watts, channel 1 or 2. I have replaced the valves some time ago to JJ matched set and the speaker, again some time ago, with a Celestion Gold 50w. Any clues? Main guitar is a Fender 2000 American Delux, stock standard.