You can expect a conventional amplifier tube to have a service life ranging
up to 10,000 hours
. Tubes with military specifications are built to last up to 100,000 hours.
How often do tubes need to be replaced?
On average, tubes can last from 500 to 1,000 hours, so if you play with your amp two to three hours every day, you can safely expect to get
around a year or less
from your vacuum tubes.
How do I know when my tubes need replacing?
- Excessive noise (hiss, hum) including squealing or microphonic tubes.
- Loss of high end. …
- A muddy bottom end; Sounds like there is too much bass and note clarity is lost.
- Erratic changes in the overall volume. …
- The amp doesn’t work!
How do you know if tubes are old?
Sometimes you will hear
strange sounds, loss of power, or heavily distort sound
. These are signs that a tube is failing. Often power loss that seems like the amp is performing at half power or less will be one or more bad power tubes, or even a dying phase inverter tube.
Do tubes degrade over time?
Yes, tubes degrade over time
and eventually have to be replaced. The good news is that they continue to sound good up until the time they need to be replaced. When tubes die, they either stop working or you’ll hear that they aren’t doing well.
What makes a tube go bad?
The main reason why tubes get a little too hot is they have either
too much power are too much voltage running through or a combination of both
. Keep in mind, that the heat coming from the amp can be from other components, not just the tubes.
Can I replace power tubes without biasing?
With preamp tubes, you don’t need to worry about things like biasing or using matched pairs as you do with power tubes
. As long as your new tube is the same model as what you’re replacing (12AX7, 12AT7, 6SN7, etc.), you’re good.
How long do 12AU7 tubes last?
Tube Life. Small signal tubes like 12AX7 and 12AU7 typically last
between 5,000 and 10,000 hours
. You don’t need a tube tester to determine if your tubes need replacing. Simply plug in a new pair and let them settle in for at least 100 hours.
What tubes are in a Blues Junior?
A set of
three matched Groove Tubes 12AX7 preamp tubes and two matched Groove Tubes EL84 power tubes
, graded according to Fender’s specifications, are used in all factory Blues Juniors.
What does a blown tube look like?
When a vacuum tube develops an air leak (a small crack or bad seal by a pin for example) this getter color will change to
pure white
. If you see this you know with 100% certainty that the tube is bad. Third, look for a purple glow that is very focused around specific elements inside the tube.
What does a bad tube sound like?
Preamp tubes usually cause problems through noise or microphonics. If noise, you will hear
hiss, crackling, popping or similar issues
. If you hear squeal, hum or feedback, it is typically a microphonic tube. Noise from microphonic tubes will typically increase with a volume increase.
What color should power tubes glow?
This type of glow is usually
violet
in color and most noticeable around the inside surface of the glass bulb. It is most pronounced on power tubes and is the product of electron bombardment of the glass taking place within the tube.
How much does it cost to replace a tube in an amp?
It will probably cost
around 100 USD
to buy them and have them installed and your amp rebiased. The price will go up if you have more tubes.
How do you check for microphonic tubes?
Tap each tube with the eraser end of a pencil.
If you get feedback or a bell-like ringing sound, the tube is microphonic
. If you hear a dull thump, the tube should be fine and perfectly usable.
How do you check amp tubes?
Do vacuum tubes wear out?
But
tubes have limited lifespans
. Depending on how they’re used, how well they are manufactured, tubes eventually need to be replaced. In some circuits that’s a year—in others, far longer. Tubes rarely die quickly.
How long do KT88 tubes last?
Genelex reissue tubes don’t last long. For the KT88 and depending on batch and how hard it is driven in the amplifier you should get
around 2500hrs
. Old English MO-V made KT88 last up to 6000 hrs or more.
How do you burn in new power tubes?
How long does a 12AX7 tube last?
Small signal tubes like a 12AX7 or 6922 will work well on average for about
10,000 hours
. If you leave your equipment on 24 hours a day, well you do the math: There are 8,760 hours in a year.
Can you touch vacuum tubes?
Handling Vacuum Tubes
Simple:
DON’T
. Tubes don’t appreciate contact with oils and such from your hands. Oils and dirt build up on the glass envelope of the tube, eventually causing it to run hotter than it should, shortening its life.
What happens if you don’t bias tubes?
If you changed to tubes with a lower resistance without biasing the amp
you would quickly burn through those tubes and potentially damage the amp and yourself in the process
. This is because the amp is still pushing out current at a higher level than the valves are able to take.
Can you put any tubes in a tube amp?
With power tubes, you can swap different brands of the same tube
. (For example, 6L6 tubes from different manufacturers.) But do not swap different types of power tubes unless you are absolutely sure you know what you are doing — damage may result.
How do you clean vacuum tubes and sockets and pins?
How long should I let my tube amp warm up?
As a rule of thumb, your tube amp needs to be warmed up for
20 to 30 minutes
at least before you can start playing your guitar. Most of the time, tube amps have warm up specifications included in their instructions for use.
