How to Tell Pre-Amp Tubes From Power Tubes in Guitar Amps

Tube or valve amps became popular in the 1940s and remained popular through the 1970s. After the creation of the solid state amp, tube amps' popularity dropped. Many people still use tube amps because they like their sound. Each tube amp is made with pre-amp and power tubes.

Difficulty: Easy

Instructions

1. Know what the tubes do. The pre-amp tubes transfer the sound as it enters the amp. The power tubes produce the sound, quality and variations on the sound.

2. Check to see what kind of amp you have. There are 3 basic types of amp: 2-stage, 3-stage and solid-state. A 2-stage amp has pre-amp and power tubes inside. A 3-stage amp has pre-amp, power tubes and solid-state equipment to control the sound. A solid-state amp does not require any tubes.

3. Open the front, back or vent cover of the amplifier. Look at the metal and glass tubes at the top.

4. Look at the short round metal tubes. These tubes are the pre-amp tubes. The glass tubes with the metal inside are the power tubes.

Tips & Warnings

• It is possible to replace tubes in amplifiers if they go out. Solid-state amps must be taken to the repair shop if they go out.
• Do not try different sized tubes in an amp. Each tube amp is made to fit a specific size of tube. A guitar tech or amp store knows how to change the tube size out.