1 Jack Skellington 8 months ago Check your bias. Not a political statement. An amp must do. I feared doing it myself but glad I did. Got vintage tubes put in a DRRI. It had a certain sound but never really bonded with it as a main amp. Changed speaker. No meaningful diff. Always though adjusting bias was best left to techs and that it would have been set properly when tubes were done. But prior to putting it up on Reverb I stuck a screwdriver in there and found it had been dialed all the way cold. All The Way. It read 5.5 on the multimeter. I dialed it up to where both power tubes were about 23-24 and it sounds great. So simple (once i researched how to do and got a little multimeter adapter on Amazon) to do and such a diff. Way bigger diff than speaker swap. Happy and wiser.