Troubleshooting Types of Amplifier Noise - Part 2
Friday, February 20th, 2009You want to use your tube amp at this weekend’s gig, but when you sit down to practice or jam with friends, you get a horrible popping noise. The noise goes away and comes back, but no amount of adjusting the knobs or cables gets rid of it. What you have, is a static problem.
Causes of Amplifier Static
Tube Amp
Some of the causes of static in your amp may include:
- Loose connections
- Bad solder joints
- Arcing capacitors
- Bad resistors
- Faulty ground
- Arcing between components
Of course, other causes may exist.
How do you find the cause of static?
The two best ways to find the source are the same as those used to find the source of hum.
The process of elimination
First, you can use the process of elimination. You do this by methodically removing and replacing your pre-amp tubes, beginning with your phase inverter tube.
The chopstick method
Begin with a visual inspection of the components. Sometimes that is enough for you to see if a resistor is burnt or a capacitor is damaged. If you don’t see anything upon visual inspection, you can use the chopstick method. This method allows you to find the source of the problem without the risk of shock or burn. It is also simple and inexpensive to do.
To conduct this test, remove the chassis from the cabinet. Hook up a speaker and turn the amp “on” and set it to “play” mode. Turn the volume controls up all the way. Using a wooden chopstick to probe, gently poke the components at their joint, wire and component connections. If a component is loose, you will hear noise when you poke or tap the resistor.
Make sure you check every component, because the noise may come from the resistor you are tapping, but one close to it. Go through the components in the same systematic way you did with the pre-amp tubes.
Next steps
Once you are absolutely certain you have found the source of your static problem, you can fix it.
If you cannot find the source of the static in your amp, or if you are a novice, take it to a reputable technician for repair.
