QUAD factory matched 6550 6550-TK Telefunken Elektroakustik tubes. These are precisely matched at the factory and the results are marked on each set.
The TELEFUNKEN 6550-TK is a high output power tube suitable for use in guitar amplifiers and Leslie speaker systems. Ideal for use in classic Marshall, Fender and Ampeg tube circuits, the 6550-TK offers outstanding performance and stability.
Tung-Sol developed the 6550 in 1955 for use as a servo amplifier and in industrial applications. The design is based on the 6L6, but with more gain and better stability.
Like the 6L6, the 6550 is a beam power tube design (or power tetrode) that can painlessly deliver 35 watts at its output.
Any bass player with an Ampeg SVT knows the beauty of the 6550 sound, as well as the raw power they can deliver. One of the best features of the 6550 is the tube’s long life characteristic, which will grant the user fewer tube changes over the years.