How do I know when it’s time to change a tube on my amplifier?



Asked by: Rohan Morton

With the amplifier turned on you can use a pencil to lightly tap each valve listening for and pings, zings, or crackles that’ll usually indicate it’s time for a replacement. Swap in a known good valve into that position and repeat the test to confirm.

How do you know when amp tubes need replacing?





A: These are the most common signs that tubes need replacement:

  1. Excessive noise (hiss, hum) including squealing or microphonic tubes.
  2. Loss of high end. …
  3. A muddy bottom end; Sounds like there is too much bass and note clarity is lost.
  4. Erratic changes in the overall volume. …
  5. The amp doesn’t work!


How do you tell if amplifier 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.

How often do tubes in a tube amp need to be replaced?

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 long does a tube last in a amplifier?





Depending on how often you turn on and turn off your gear, but tubes should last about 5,000 to 10,000 hours. For most people, they only need to be replaced every 2-3 years at most. But it’s good to have at least a spare set around just in case one of them decides to die on you.

How do you test audio tubes?

Put the tube into your guitar amplifier, tester, or other tube-using machine. Turn on the machine to activate the tubes, and look for an orange, red, or purple glow. If the heated filament inside the tube glows orange like a setting sun, it’s usually a sign that the tube is healthy. The filament may be hard to see.

What does a bad preamp tube sound like?

A bad preamp tube will become very noisy and produce hiss, crackle, and pop sounds, or create volume drops or loss. In some rare conditions, the tube can also lose its vacuum and fail completely. Bad preamp tube symptoms can lead you to the faulty one if you know what to look for.

How much does it cost to replace tubes on 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.

Do amplifiers deteriorate with age?

Everything degrades over time, regardless if it is solid state or tube based unit. The question is what degree. Some amplifiers from 1980s still show better measured results than you can find in new ones today. Generally you should only consider top of the line models from the past.



Is it OK to touch vacuum tubes?

Think of a vacuum tube as a light bulb. It is a glass envelope that generates heat as it is working. You shouldn’t be handling them all the time but occasionally touching them will not hurt. Let it cool off first though, they can get mighty toasty.

Can you touch amp tubes with bare hands?

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.

What should you not touch on a guitar amp?

Don’t touch the caps soon after unplugging, and you should have no problems. To be pedantic, you can touch the caps, but not the leads connecting them to the circuit. Mostly, it’s best not to touch any bare wires at all until several minutes after the amp is unplugged.



Is it better to leave a tube amp on?

Long story short, unless you plan on using your amp a lot throughout the day, you should turn off your tube amp when you are done using it. Here’s why: Tubes deteriorate with use, so leaving a tube amp on shortens tube life. Many tubes produce a significant amount of heat.

How do you break in new tubes?

We've seen online that people say to simply just leave the amplifier. On no music playing. And leave it on overnight or leave it on for a few days to burn in the tubes.

Can cold damage a tube amp?

It turns out that tube amps can be stored at reasonably cold temperatures without any issues. While temperatures of -40 degree Fahrenheit and beyond can be damaging to some electrical components, the biggest problem that results from storing tube amps in the cold is temperature fluctuation.