Tube Amp Overhaul

As vintage guitar tube amps age, many of the components gradually break down until they finally fail. The performance of a tube amp slowly deteriorates in this way. Often, many of us do not realize that the sound has changed, we just play the amp less often, dis-satisfied with our sound as well as a little concerned that it hums more and has less tone than it used to. At our guitar and electronics workshop on the east side of Tucson, Arizona, we repair and overhaul tube amplifiers.

Tube Guitar Amplifiers contain dangerous, high voltage circuits. Tube amps commonly store voltages of 450V and greater for extended periods of time, even days after the amp has been turned off. DO NOT attempt to service your amp if you are not qualified to do so.

Looking for amplifier components and parts? Visit our Amplifier Parts department.

Power Supply Electrolytic Capacitors

One of the most critical areas of a vintage tube amp are the electrolytic filter capacitors in the power supply circuit. These wear out and chemically breakdown over the years of use. Chemical reaction causes gas build up inside the capacitor that causes the case top to bubble or even rupture. The caps become less and less able to smoothly maintain the dc voltages required to keep the amp running adequately. The output hums more because the dc power has increased ripple and audible 60 cycle hum is created as a result.

We replace the whole bank of capacitors with new, replacement capacitors of the same voltage and value. Since the capacitors in the power supply bank are large, they are vulnerable to vibration and shock. This vibration and shock can eventually break the capacitor leads. The filter board caps are restrained by a metal protective cover and foam strip inside the lid of the cover. During the re-cap, we also replace the foam to ensure that the new capacitors are fully constrained. The metal cover also protects against accidental electric shock and any unlikely capacitor burst.

Coupling, Bypass & Tone Caps

There are several electrolytic and other types of capacitors throughout the amplifier signal path, that we also replace and upgrade. Replacing these capacitors improves amp tone, clarity and can repair several types of problems your amp may be suffering from. Commonly using Orange Drop and Mallory 150 capacitors for parts that are not electrolytic, we upgrade the existing capacitors in the signal path.

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