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  1. thetubestore Blog
    https://blog.thetubestore.com/how-to-tell-if-your-tube-is-bad

    How To Tell If Your Vacuum Tube Is Bad - thetubestore …

    • We’ll start with visible signs. 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 inten… See more

    Amplifier Will Not Power on

    In the event your amplifier will not power on, it is almost certainly due to a blown fuse. … See more

    thetubestore Blog
    Microphonics and Noise

    Problems with preamp tubes are often due to microphonics and noise issues. A microphonic tube will ring and amplify any outside noises such as bumping the amp, tapping on … See more

    thetubestore Blog
    Loss of Power and Other Odd Noises

    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 … See more

    thetubestore Blog
    low voltage - Lighting up an old vacuum tube - Electrical Engineerin…
    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. The v…
    Electrical Engineering Stack Exchange
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    Table of Contents
    Amplifier Will Not Power on
    Microphonics and Noise
    Loss of Power and Other Odd Noises
     
  1. 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. The voltage required by a particular tube is given by the initial digits in the part number. Thus your 12dt8 requires 12 volts to light up the filament.

    low voltage - Lighting up an old vacuum tube - Electrical Engineer…

    electronics.stackexchange.com/questions/41488/lighting-up-an-old-vacuum-tube
    electronics.stackexchange.com/questions/41488/lighting-up-an-old-vacuum-tube
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  2. People also ask
    Can a vacuum tube cause a bad sound?
    This problem will arise in guitar combo amps but is much less common in heads or hifi stereo amplifiers as vibrations are greatly reduced in these applications. Sometimes you will hear strange sounds, loss of power, or heavily distort sound. These are symptoms that a vacuum tube is failing.

    How To Tell If Your Vacuum Tube Is Bad - thetubestore Blog

    blog.thetubestore.com
    What happens if you blow a fuse on an amp?
    If you blow a fuse, replace it. If it happens again, replace your power tubes. If the tube glows cherry red, shut the amp off immediately. As power tubes are wired in pairs, a failure of this nature in one tube can cause the other tube in the pair to fail with it. If you encounter this problem, as noted, shut the amp down immediately.

    DIAGNOSING TUBE PROBLEMS — Diamond Amplification

    diamondamplification.com
    What are some common tube amp problems?
    In the world of tube amps, it seems like any number of issues can arise. However, there are a few broad problems that will occur in just about any amp at one point or another. These are problems that almost every tube amp owner has encountered over time: Tubes not lighting up, fuse (s) blowing, and bad ground connections.

    Common Tube Amp Troubleshooting Scenarios - Mojotone

    mojotone.com
    How do I fix a dim light bulb on my amp?
    If your amp has a rectifier tube then remove it and power up the amp. If the bulb goes dim then the rectifier tube or socket is the problem. Try another rectifier tube and inspect the rectifier tube socket. If the bulb glows bright check the rectifier tube socket and its wiring. If you don't find a problem move to the Power Transformer.

    Tube Guitar Amp Troubleshooting - Rob Robinette

    robrobinette.com
    How do I reintroduce a preamp tube?
    If all is well throughout the reintroduction of preamp tubes, install the rectifier tube, make sure all of your filaments are working, and let the amp sit for a couple of minutes. Next, place the amp in standby (if equipped). If your amp does not utilize a standby switch, then connect a speaker (or load) to the output jack.

    Common Tube Amp Troubleshooting Scenarios - Mojotone

    mojotone.com
    What causes a squealing noise in a combo cab AMP?
    Weird noises, including squealing, wooshing, clicking, static, honking, motor boating, etc. can be caused by: A bad tube so swap out the tubes one at a time for known, good tubes. A microphonic tube or other component can cause rattles, buzzes, rings and other strange noises in combo cab amps.

    Tube Guitar Amp Troubleshooting - Rob Robinette

    robrobinette.com
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  3. Electrical Engineering Stack Exchange
    https://electronics.stackexchange.com/ques…

    low voltage - Lighting up an old vacuum tube

    May 12, 2020 · 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. The voltage required by a particular tube …

    Another question about lighting up vacuum tubesNov 16, 2022
    Lighting up old vacuum tubes and making them turn on/offFeb 29, 2020
    See more results
  4. Rob Robinette's Car and Tube Amp Website
    https://robrobinette.com/Tube_Guitar_Amp_Troubleshooting.htm

    Tube Guitar Amp Troubleshooting - Rob Robinette

  5. Steve Hoffman Music Forums
    https://forums.stevehoffman.tv/threads/tube-not...

    Tube not lighting up... is this a problem? - Steve Hoffman Music …

  6. audiokarma.org
    https://www.audiokarma.org/forums/in…

    Correct way to use variac to bring up old tube amp

    Jul 19, 2019 · A simple light bulb will sub fine for a current meter. Not as accurate, but it serves as an indicator of gross faults and limits current enough that it will keep things from going horribly wrong. My own test rig involves a …

  7. Images of Vacuum Tube Amp lit Up

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  8. Mojotone
    https://www.mojotone.com/blog/common-tube-amp...

    Common Tube Amp Troubleshooting Scenarios - Mojotone

  9. Tropical Fish
    https://www.tropicalfishvintage.com/blog…

    Common Tube Amp Malfunctions: My amp makes no …

    Apr 22, 2020 · Possible causes include: The speaker is completely blown. The output transformer is open or otherwise faulty. The speaker jack is not wired correctly. The speaker wiring has deteriorated, or the jacks have rusted to the …

  10. Diamond Amplification
    http://www.diamondamplification.com/bl…

    DIAGNOSING TUBE PROBLEMS - Diamond Amplification

    Sep 18, 2016 · Preamp Tubes. 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. …

  11. Tubes for Amps
    https://www.tubesforamps.com/the-most-common...

    The most common vacuum tube problems - Tubes for Amps

  12. reverb.com
    https://reverb.com/news/the-basics-of-tube-amp-upkeep

    The Basics of Tube Amp Upkeep and Maintenance - Reverb

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