How do I Easily Build a Tube Guitar Amp?

Some of the highest fidelity amplifiers have simple configurations.

Tube technology was superseded by transistors in the 1950s. But tube amplifiers remain popular due to the warmth of their tone. Building your own tube guitar amp is a great way of saving money on expensive equipment. The easiest way to build your own tube amp is to purchase a guitar amplifier kit. The kits are shipped with pre-assembled components, wiring diagrams and assembly instructions. To successfully assemble the amplifier kit, you will need a soldering iron and screwdriver.

Things You'll Need

• Tube guitar amp kit
• Soldering iron
• Screwdriver

Instructions

1. Source your parts. Tube amp kits are available through vendors online. It's best to purchase a complete kit, rather than sourcing parts individually. This guarantees that your parts will be compatible. There are three main components to a tube amplifier: The speaker, the pre-amp and the power amp. The pre-amp turns the guitar signal into an electrical current. The circuitry of the pre-amp determines the tone. The power amp adds voltage to the pre-amp signal and sends it to the speaker, where the volume is generated.

2. Inspect your parts. Before you begin assembly, double check that everything is in good order. Pay attention to the printed circuit board. Look for loose capacitors and resistors. If you spot any defects, return the kit.

3. Read the schematic. This is your guide to the circuitry. It illustrates the layout of all electrical components and the values of the resistors. Follow the schematic when wiring the parts together.

4. 

   Although it looks complex, the instructions will guide you through circuit assembly.

   Complete the printed circuit board. This will come pre-drilled. Follow the schematic and place the various capacitors and resistors in their places. Solder the underside of the board and be careful to not drip any solder. Solder blobs can cause problems later. Once you have completed the circuit board, load it into the chassis and solder the input jack in place. Screw down the top of the chassis.

5. Load the pre-amp chassis. It will slide into a pre-cut compartment in the cabinet. This is normally located at the top.

6. Install the power amp. Depending on the model, this is located either next to the pre-amp or on a separate shelf below it.

7. Screw in the speaker. There will be a series of holes around the circumference of the speaker. Screw through these holes into the struts that run horizontally along the top and bottom of the cabinet.

8. Solder the wires. Follow the schematic carefully. Solder a wire to the output terminal of the pre-amp and then solder that wire to the input terminal of the power amp. Solder a wire to the output terminal of the power amp. Connect that wire to the speaker as per the assembly instructions.

9. Install the tubes. These will slot into their housing. Push them in firmly but carefully. Although they look similar to light bulbs, don't twist them.

10. Screw on the back panel, and then test your amplifier.

Tips & Warnings

• Practice soldering with spare wire and scrap metal.

• Wear latex gloves to handle the tubes. This prevents hot spots from forming on the glass.

References

• Nobel Prize: The Transistor in A Century of Electronics
• London Power: Selecting a London Power Instrument Amplifier

Resources

• Electronics Tips: Soldering Techniques