CSULB 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 in 1995. The amplifier is a close copy of an early Fender Deluxe model AB763 amp. It has two input channels, each with volume, bass, treble, and middle (tone) controls. The second input channel also includes a vibrato circuit, with corresponding vibrato speed and intensity controls. While the Fender Deluxe AB763 utilizes two 6V6-GT tubes in the power output section, this design differs in that 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.


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Antique Electonic Supply

Tubes, and lots of old parts
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