You’re talking in the range of vocals? How does anyone even know where to start on this one? Could be a million reasons outside of your 105D or the tubes. First thought is room treatment, placement of your speakers and listening seat. When you slap your hands do you get a ping or is your room already fairly dead? Any other of your components or speakers could be bright and not the 105D. Not sure I’d jump to selling your 105D though.
As mentioned earlier tube dampers are an option that might help. I like the Herbies best but they take some effort on where you place them.
I’d start with your room and speaker placement. Look up how Wilson Audio sets up their speakers in a room, on how they voice the room by using your own voice standing with your back to the wall and slowing walking out into the room until your voice sounds natural. Too close to the wall and your voice will sound chesty and too far out it gets thin. Should be able to find a better description of what I’m referring to but that’s basically it.
How many hours are on your tubes?
As mentioned earlier tube dampers are an option that might help. I like the Herbies best but they take some effort on where you place them.
I’d start with your room and speaker placement. Look up how Wilson Audio sets up their speakers in a room, on how they voice the room by using your own voice standing with your back to the wall and slowing walking out into the room until your voice sounds natural. Too close to the wall and your voice will sound chesty and too far out it gets thin. Should be able to find a better description of what I’m referring to but that’s basically it.
How many hours are on your tubes?