Modern upgraded classic 6550. It is one of the most powerful and at the same time the sound of the massive bulbs. Stocks frequency range, dynamics, brightness and detail when installed in a good amplifier will not leave anyone indifferent. Widely used in all devices where it is possible to install 6550. From of old Marshall JCM800 (necessary modification) and bass Ampeq SVT to modern monsters from Diezel, Orange, Fryette. Also, a huge popular among fans of tube audio equipment of the highest class.
Like all power-lamp during the operation can reach high temperatures and will serve much longer and retain its characteristics, subject to the necessary warm-up, ventilation and absence of vibration amplifier housing.