From Thermionic Studios
Here is a list of tools that a tube amp tech typically uses in the process of building / testing / troubleshooting tube amps in order to get them to peak operation.
- Schematic: This is a diagram of the topology of the circuit in the amplifier. Using a schematic is almost always necessary when working on an amp so that the tech can refer to it and understand how the current is flowing through each part of the amplifier s/he is working on.
- Chopstick(s): Wooden, acrylic, or plastic (non-conducting) probe (basically a stick) to safely move wires in an amp chassis to help determine possible interferences of signal running across the wires that may be inadvertently created by the in-chassis wiring.
- Capacitor Drain Jumper: Alligator clips that have been modified with a resistor that are used to drain otherwise dangerous high-voltage filter capacitors.
- Digital Multimeter: Also called "Digital Voltmeter", this is a digital version of the Vacuum Tube Voltmeter, with a much higher degree of granularity. It also tends to offer more numerous functions and tests that a simple VTVM cannot match.
- Vacuum Tube Voltmeter: Uses a vacuum tube to obtain and display electronic measurements.
- Signal Generator: Generates a tonal sine wave (a musical note) that is fed into an amplifier, or pedal, for testing or tube biasing.
- Variac: Variable AC Transformer
- Tel-Ohmike TO-10: Capacitor Tester
- Sencore PR57 "Powerite": An isolation transformer for testing possible ground loops - also useful for reforming old electrolytic capacitors.
- Tektronix 422: A particular model of oscilloscope we have here at Thermionic Studios
- Tektronix 456: Another oscilloscope that we have and probably don't need
- Lightbulb Limiter: A rudimentary "variac" that uses the wattage rating of a lightbulb to limit the amount of current going to an amplifier, and uses the function of the lightbulb to also indicate when the filter capacitors have "filled" with electrical charge.
- Speaker Load: Also known as a "Dummy Load", this tool consists of a resistive network that acts like a speaker and can take an amplifier's full output without generating any sound.
- Bias Probe: Used to measure the bias current to one or more power tubes to make sure that they have been biased to the desired rating.