A kind of evolution of the EL34. The lamp has a more intense low, all of the same British mid-confident and well accentuated on horseback. In general we can characterize this as a lamp EL34 c more detailed and modern sound. You can give expression and "arrogance" of modern sound "combed" JCM2000, JVM from Marshall, Peavey JSX, etc. In addition, there is a longer average lifetime.
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.