Vacuum Tube Guitar Amplifier



This page gives a short description of the vacuum tube audio (guitar) amplifier I built for my undergraduate project at CSULB. The amplifier is a close copy of an early Fender amp. It has two input channels, each with volume, bass, treble, and middle (tone) controls. The second input channel also has vibrato built in, and has corresponding vibrato speed and intensity controls. Both input channels feed into an 80-Watt power section consisting of four 6L6 beam pentode power tubes.


A front view of the amplifier is shown above. The four control knobs furthest to the left are for the channel #1 volume, treble, middle, and bass controls. The six control knobs in the middle are for the channel #2 volume and tone controls, and the vibrato speed and intensity.
This is a top view of the amplifier. The output transformer sits in the upper-left corner, while the power transformer is in the upper right corner. Also, note the two 6L6 power tubes in the middle, the 5U4-GB rectifier tube in the bottom right corner, and the preamp and vibrato tubes in the lower left left corner / middle.
This is a back view of the amplifier. From the far left on the chassis are the power cord, and extra AC input, the fuse holder, power & standby switches, and a speaker impedance selector (to choose between 4-ohm, 8-ohm, or 16-ohm loads).
This is a bottom view of the amplifier. Note the large Sprague Orange Drop Electrolytic capacitors and the point-to-point wiring.


Other Electronics/Tube Resources

Antique Electonic Supply

Tubes, and lots of old parts
6221 South Maple Avenue
Tempe, AZ 85283
602-820-5411