6C4EC90V.H.F. Triode
6C5Triode, vacuum Audio Frequency – Octal (Int.Octal, IO) K8A
6CA4EZ81Full Wave Rectifier (Often used in Australian Radiograms)
6CB6 A SYLRemote Cutoff R.F. Pentode used in video I.F. circuits of the 1950s and early 1960s.
6CF6 SYLVacuum Pentode RF/IF-Stage – Miniatur-7-Pin-Base B7G
6CG7Dual Triode (used in television and some audio amplifiers including modern solid-state designs often as a cathode follower, similar to 6SN7)
6CL6Power pentode
6CM4EC86Triode, vacuum RF/IF-Stage – designed for use as a grounded grid amplifier, oscillator or mixer for UHF television receiver front ends between 430 and 860 MHz.
6CM8Triode-Pentode Tube. Tube can be used as an IF amplifier, video amplifier, ACG amplifier, and reactance tube.
6CS6EH90Dual Control Heptode Tube. Designed to be used in a sync separator circuit.
6CT7EAF42Diode-Pentode RF/IF-Stage Controlling (mu) – Rimlock base B8A
6CU6 GEBeam Power Tube – Octal (Int.Octal, IO) K8A. exhibits high perveance, high plate current at low plate and screen voltages, and a high ratio of plate to screen current
6CU7ECH42exhibits high perveance, high plate current at low plate and screen voltages, and a high ratio of plate to screen current
6CW7ECC84Double Triode – Noval, 9 pin miniature (USA pico-9) B9A

6CX8medium Mu triode-sharp cut off pentode that was used in TV receiver applications. Fender used this valve in the Fender Super twin amplifiers and used the G.E valve as original equipment.
6CY5Screen-grid Tetrode
high-quality screen-grid vacuum tube that delivers exceptional sound quality for audiophiles. With its unique design, this tube provides excellent musical characteristics and clarity,
6CY7miniature, dual-triode vacuum tube, commonly used in audio amplifiers, particularly in preamplifiers and power amplifiers. It’s known for its warm, natural sound and is a popular choice among audiophiles seeking to improve their audio systems.
6CZ5 SYLThe Sylvania Type 6CZ5 is a miniature, beam pentode intended primarily for use as a vertical deflection amplifier or audio amplifier. Otherwise same characteristics as type 6973