Damping factor varies from 200-800 for solid-state but only 2-11 for tube amps
Evidence
In 1975, I wrote an article for AudioScene Canada called “Damping, Damping Factor and Damn Nonsense.” I still like the title because is a succinct statement of reality. The point of the article is summarized in Figure 16.2c. The internal impedance of the power amplifier is used to calculate something called the damping factor (DF) of the amplifier (DF = 8 divided by the output impedance); the number 8 was chosen because it is the nominal load (resistive) used to measure the power output capability of amplifiers. The logical inclination is to think that larger is better. Solid state amplifiers have damping factors ranging from about 200 to 800, using the impedances quoted earlier in this section. Tube amplifiers in my survey ran from 2.4 to 11.4 because of their high output impedances. — , Toole, Floyd E - Sound reproduction-…, 1779
Categorization
- DEFINE: Defines the damping factor concept and quantifies the gap between solid-state and tube amplifiers.
- XREF: connects to: Amplifier damping factor above 20 produces no audible effect on loudspeaker transients — , Toole, Floyd E - Sound reproduction-…, 1782; Tube amplifiers sound different mainly because their high output impedance alters loudspeakers