Q: I saw the Tech Tip on July 30 on swapping 5881 tubes with 6L6 tubes. What is the sonic difference between these two types of vacuum tube?
A: We have to speak in generalities here, because tube types vary widely, depending on the manufacturer and vintage of the tube. In tech terms, 5881 tubes generally have smaller plates, which are not able to withstand plate voltages as high as 6L6 tubes can tolerate. This results in 5881 tubes having less output power than a 6L6 (how much difference depends on the specific tubes) and also lower clean headroom, meaning a given 5881 may start to distort at a lower level than a given 6L6.
Other potential sonic differences, such as bass, mid, and treble response, will vary depending, again, on the specific tubes as well as on the specific amp in which the tubes are installed.
