live for superlative

The importance of stable of the vacuum tube


  Many enthusiasts have encountered such a situation. After buying a new pair of tubes, it is necessary to adjust the bias frequently (except for devices with automatic adjustment). The number of times the bias needs to be adjusted will be less and less over time, and in the end it will hardly need to be adjusted. This process is a process in which the electrical properties of the tube gradually become stable. It usually takes several tens to hundreds of hours. From then on, the tube begins to enter the good environment. But there is another extreme situation, that is, the bias voltage is always not adjusted to the correct position. In severe cases, even the fuse and the transformer is burned. What is the reason?

  As we know, an important indicator for judging the merits of an electronic component is whether the parameters are stable and reliable under the long-term working condition of this component. Most of the newly completed tubes have unstable electrical performance parameters. In order to stabilize the tubes quickly, the factory will burn-in all the tubes. For reasons of economic efficiency, factories generally only burn-in for hours. According to our long-term testing and observation, taking ordinary KT88 \ EL34 as an example, after the factory’s burn-in process, about 80% of the products can enter a relatively stable state, and then enter the tube test and the matching process, the remaining 20% of unstable products, most of them during the customer’s use of the amplifier will stabilize,(there will be a big discount on pairing), but very few products will be unstable for a long time, even short circuit, overcurrent, etc., these products should be judged as unqualified products, they will causing serious damage to the tube amplifier.