How to Troubleshoot a Crate Blue Voodoo
The Crate Blue Voodoo is Crate's top-of-the-line amplifier. It is an all-tube amp that has 120 watts of power, which is a lot of power for a guitar amplifier. The Blue Voodoo easily can power several speakers. The Blue Voodoo, like any other tube amp, can be temperamental. It is important to know basic tube amp troubleshooting skills that allow you to diagnose and correct any potential problems at a gig.
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Things You'll Need
- Spare guitar cables
- Spare batteries
- Spare fuses
- Replacement tubes
- Contact cleaner
- Wrench
- Screwdriver
- Soldering iron
Instructions
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Check the power sources if the Blue Voodoo won't turn on or if it experiences a loss of power. Make sure the amp is plugged into a power source and that the power source is turned on. Check the fuse. The fuse is a safety device that protects the amp from a power surge. Replace a blown fuse to get through a performance. Take the amp to a professional tube amplifier repair person for a checkup after the performance. A blown fuse may indicate a more serious problem with the amp.
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2
Check all the guitar cables and effects pedals if the amplifier turns on but emits no sound. A short in a cable won't permit the electric signal to travel from the guitar to the amplifier. Inspect all the cables between the guitar and the amp. Start by plugging directly into the amp and bypassing all the pedals. Make sure that all of the cables are completely plugged in. Step on each pedal and look at the LED light on the pedal. If the LED light doesn't come on, the pedal is underpowered or has no power because of bad battery or a bad power cable. A bad pedal also interrupts the electrical signal between the guitar and amp.
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3
Inspect the power tubes if the amp seems underpowered or if the tone is muddy. The Blue Voodoo uses four 6L6 power tubes. The tubes emit a warm orange glow if they are functioning properly. A blue/purple glow indicates a weak tube. A tube is broken if it's not glowing. Old or weak tubes diminish the volume and tone quality of a tube amp. Replace bad tubes with new 6L6 tubes. It is less common for a preamp tube to go bad; however, a scratchy sound is the indication of a bad preamp tube. The Blue Voodoo uses four 12AX7 preamp tubes. Remove and replace the preamp tubes one at a time until the sound is clear and distinct.
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4
Turn the amp off and manipulate the volume and tone pots back and forth if the pots are making cracking and hissing sounds. Dirt, grime and debris work their way into the pots of an amplifier and produce irritating sounds. Vigorously manipulating the knobs back and forth several times loosen up some of the debris. Clean the pots with contact cleaner. Remove the knobs and spray the pots with contact cleaner. Rotate the pot back and forth several times, and replace the knobs.
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5
Inspect the input jacks and other connections. A loose input jack prevents the amplifier from producing sound or produces sharp screeching sounds, especially when the amp is turned all the way up. Turn the amp off. Tighten the input jacks with your fingers or a wrench. Re-solder any loose wires.
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Tips & Warnings
Read and refer to the manual when working on and troubleshooting your amp.
Keep spare tubes, fuses and tools in your gig bag.
Always unplug a guitar amplifier before working on it. Guitar amps contain dangerous levels of electrical current even in the "Off" position. Refer to the manual for safety tips and information on draining the electrical current.
