6550

The 6550 is an electron tube in the design as a beam or beam -power tetrode ( octal ) with 20 W output power (Po) and a maximum anode dissipation of 35 W. The tube is used because of the low distortion bass amplifiers. The pin assignment is the same as a 6L6 or KT88. With the latter, the 6550 is also interchangeable.

The 6550 was developed by Tung- Sol in 1955, based on the design of the 6L6 and had greater stability and performance.