The High Octane Amplifier


Here are some pictures of my HO, which is an AX84 design, executed from a Ceriatone kit. It has three gain stages from 2 12AX7 preamp tubes, a cathode follower, a solid state rectifier, a JCM 800-type TMB tonestack and a single EL84 output tube. Alternately, it has an octal tube holder for a 6V6, 6L6 or 6EZ5 output tube.

There are two separate volume controls for each preamp tube and a master volume for overall volume, making this perfect for practicing with high gain but less volume. When cranked, however, 5 watts is pretty big...


"A Five Watt Class "A" Single-Ended Tube Amplifier

The small box to the right is an attenuator.

Here are three audio clips.  This one with master volume dimed...HOTestOne.mp3

This one has the master volume on 1/2. The first two clips are using an old Mullard EL84...HOTestTwo.mp3

This third clip is using a JJ el84. The gain channels are barely on, each set at 9:00 o'clock. The master volume is dimed. The first portion of the clip is without boost. The remainder is with my homemade Dallas Rangemaster type booster, an NPN-germanium-transistor-based pedal. It is the beginner project at diystompboxes.

Here's the clip.  HOandRangemasterBoost.mp3