AUDIO RESEARCH LS28 TRIODE STEREO PREAMPLIFIER $8,500 REVIEW
September 1, 2019 § Leave a comment
“THD+N vs. Frequency yields the following graph. It always stays below 0.08%. The two channels are slightly different, but that is just the way tubes behave. Because the tube is electro-mechanical (filament, grid, plate), and because the tube gets hot during use, performance is slightly variable from tube to tube. These small differences are only measurable on a spectrum analyzer. They are not audible.