Sometimes you may notice a blue hazy glow inside your amp tube. This glow is rarely a sign of a defect and is fairly common especially in modern power tubes. This type of glow is called Fluorescence. This phenomenon is due to electron bombardment of the glass taking place within the tube.
Should tubes glow blue?
A tube that is glowing blue is often wrongly perceived as a defect, however, it’s really just a side effect of a power tube — a fluorescent glow in the blue spectrum. The tube is fine! It actually indicates that the vacuum inside the tube is very good, which is what allows this phenomenon to occur.
DO 300b tubes glow?
None. Every 300b based amp I’ve seen in the past had that blue glow, so I thought there might be something wrong. But, the amp worked beautifully. I have a Line Magnetic 300b based integrated and the tubes have never had a blue glow.
What causes blue glow in vacuum tubes?
Blue Glow – We often get asked if blue glow inside of a vacuum tube is a sign of a defect. It is most pronounced on power tubes and is the product of electron bombardment of the glass taking place within the tube.
What color should tubes glow?
Not to fear: Tubes often glow blue, and it is by no means an indication that the tube is bad, or about to go bad. In fact, tubes glow blue on a normal basis and it should not raise alarm in any way whatsoever.
Should vacuum tubes glow?
To summarize, almost any blue glow you see inside a tube is perfectly fine and will not cause any problems in your amplifier. However, if you see bluish/violet glow around a single element such as a wire for example, it could indicate an air leak into the tube.
Do vacuum tubes light up?
You can use AC or DC voltage to power the filament of a vacuum tube. The filament will glow when powered up which is what you are referring to as “lighting up”. So a battery is fine.
How do I know if my amp tubes are bad?
Crackling, squeals and feedback, excessive noise and muddiness or low output are all evidence of tube problems. Power tubes. The two main symptoms of a power tube problem are a blown fuse or a tube that begins to glow cherry red. Either are typically indicative of a power tube failure.
What are 6L6 tubes used for?
The modern-day 6L6 variants come equipped with a specialized ultra-black plate finish, grid cooling fins, solid grid wires, and plates for supporting the high voltage and power ratings. At present, 6L6 tubes favor guitarists and bassists excelling in musical genres such as jazz, blues, and rock.
What is the difference between a 6L6 and 6L6GC?
On the other hand, the 6L6GC has a maximum rating of 500V and 30W plate dissipation. You can use a 6L6GC in an amp featuring 6L6 but not vice-versa. If you’re still using the 60’s and 70’s Fender Deluxe Reverb, you’ll need 6L6GCs.
Is 6L6G glass the same as clear glass?
This does not mean the tube is burned out, but both clear and grey glass versions are interchangeable. 6L6G This is a large “coke bottle” tube, and was one of the earliest glass types of this tube. It has the same plate and screen ratings as the GA/GB types listed above, and also of the 6L6 metal listed below.
What is the difference between 6L6GA and RCA tubes?
The most desirable of these tubes is probably the RCA blackplate, which was only produced until the later 1960s, however other NOS greyplate USA made versions are excellent and still available. 6L6GA / 6L6GB: These two types are nearly identical, and as far as electrical ratings are the same.
