A 6 layer PCB board is in general a 4 layer PCB Board with 2 extra signal layers added between the planes. The 6-layer PCB classic stackup includes 4 routing layers (2 outer layers + 2 internal layers) and 2 internal planes (one for ground and the other for power). This enhances the EMI dramatically by offering 2 buried layers for high-speed signals and 2 surface layers for routing low speed signals. The signal layers should be closed to the adjacent planes. 6 layer PCB Storm Circuit Technology Ltd , https://www.stormpcb.com
In use, the electron tube must have good ventilation and heat dissipation, and the overheating of the temperature will inevitably shorten the life of the electron tube, so the electron tube should be kept as low as possible. The electronic tube is afraid of vibration, so it is also important to take anti-vibration measures to avoid vibration as much as possible. If these two points are achieved, the service life of the electron tube can be at least doubled. To this end, there should be a proper space around the tube equipment, especially above it, so as to have good convection ventilation, and if possible, a fan can be used to help dissipate heat.
When the cathode of the electron tube has not reached the required temperature, that is, a high-voltage power supply is added, its cathode will be damaged, and the life of the electron tube will also be shortened. Therefore, if the electronic tube equipment has a preheating device, it must be used, for example, first turn on the filament low voltage power supply to preheat, and then turn on the high voltage power supply. If there is no preheating device, then don't rush to connect the input signal, you can turn off the volume to the minimum, wait for 20 to 30 minutes to turn on the machine and use it. If the bypass rectifier is used to supply the high voltage of the whole machine, it provides a simple and effective high-voltage delay. In addition, during normal use, do not switch the power frequently.
Of course, if you design the tube circuit correctly and avoid misuse, you can prevent the tube from "died early," and it should be normal for the tube to use thousands of listening hours. The most common errors in circuit design are the potential difference between the tube filament and the cathode is too high, the tube screen or curtain grid voltage is used to the maximum value, the tube filament voltage is too low or too high, and the improper tube installation position causes the electrode to overheat and high voltage The power supply has no delay device, etc.
How to extend the life of the tube amplifier?
Since the return of the tube amplifier to the audio stage in the 1970s, it has occupied a certain market. However, in the current tube audio products, the failure caused by the tube-including European and American tubes, is not uncommon. It causes a short life of the tube. Opinion, but this is often not a problem of the tube itself, but a defect in the circuit design and problems in use. It should be noted that a good quality electron tube must have a properly designed circuit, sufficient heat dissipation, and thoughtful shock absorption.