I cannot think of another thread where more useless advice has been given to a person. The OP has his system setup in a large geodesic dome. A geodesic may be the single worst type of listening space imaginable. Sounds from a loudspeaker will be both scattered by the multiple reflective surfaces and focused by the multitude of surface angles. You can whisper softly into an angle of a geodesic and be heard clearly in some angles on the opposite side of the dome and not heard at all in nearby angles. In such a space how is a preamp, tube or power cord really going to make a difference?
My advice to the OP is to not make any changes in equipment and experiment with speaker/listener positioning.
Again, a photo of your listening space would help.
My advice to the OP is to not make any changes in equipment and experiment with speaker/listener positioning.
Again, a photo of your listening space would help.