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Should vacuum tubes glow?
There are a couple very obvious things to look for. First, every tube will have a heater filament that, when working, will cast a nice warm orange glow. In some tubes it’s more intense than others, but this is not a problem. What matters is that it is glowing to some degree.
What were some problems associated with the use of vacuum tubes?
Vacuum Tubes: Disadvantages Bulky, hence less suitable for portable products. Higher operating voltages generally required. High power consumption; needs heater supply that generates waste heat and yields lower efficiency, notably for small-signal circuits. Glass tubes are fragile, compared to metal transistors.
Can you touch vacuum tubes?
It is OK to handle ambient cooled vacuum tubes with bare hands, IF THEY ARE COOL, and skin oils will seldom cause a problem, even if it chars.
Are tubes supposed to glow orange?
Unfortunately the orange glow is just the heater element. It’s often impossible to tell if a valve is working by simply looking at it. There are some exceptions however and I will explain below.
How often should preamp tubes be replaced?
You should replace them when they are dead. There is no set rule for how long they last, but in general, they last longer than power tubes. Maybe twice as long or better life expectancy for power tubes. They are also self-biasing of course, so don’t be afraid to change them yourself.
Is the blue glow in vacuum tubes a defect?
Blue Glow – We often get asked if blue glow inside of a vacuum tube is a sign of a defect. Thankfully, it is rarely a sign of a defect at all. In fact, many tubes have a blue glow, especially modern tubes. Photo 1 shows a tube with a healthy blue glow. This was also seen in tubes from the golden age of vacuum tube production.
What causes the filament on a vacuum tube to glow?
Regardless, if the tube is warm and sound is coming from the tube amplifier, the heater filament is functioning no matter how bright or dim it appears. Finally, another type of tube glow that needs mention is red-plating or “cherry” plate glow. This happens when a tube is incorrectly biased, causing the plate to overheat and literally get red-hot.
Why do voltage regulators have a pink glow?
The proper function of gas types such as thyratrons, voltage regulator and voltage reference tubes, requires the presence of this glow as an indication of proper tube operation. Some voltage regulators use neon instead of argon and as a result exhibit a pink-orange glow.
What do blue glows on a tube mean?
Blue Glows are not tube detriments per se. They are, however, suspects in the eyes of many receiving tube users for lack of a full understanding of their origins. There are several types of Blue Glow which can be described as follows: