In these series I will write about, how I created my a guitar amplifier all by myself (with help from father and the internet).

Ever since I bought a guitar I wanted it to sound good too. After buying a cheap Marshall MG30dfx, which sounded quite bad, I decided that it would be easier to build a tube (tubes > transistors) amplifier myself, instead of buying one, cause they expensive. What I wanted was a standard tube amplifier with gain, tone and volume settings. So I searched the internet, and found that the best option for this would be Ax84 Hi-Octane project.

The Hi-Octane is like a juiced up rock and roll amp from the 80’s… only smaller. Like a P1 but with an extra preamp tube, this is a good choice for someone who wants more distortion and has built an amp or two before. Tone goes from cleanish to semi-saturated distortion, depending on gain settings and guitar volume setup. Responds well to pedals and retains your guitars tone.

AX84 Hi-Octane amp with spring Reverb

This amp is small and good for home use, since it’s output power is only 5 watts, and still that is a lot, especially when distorted. As far as sound goes, it has nice “warm” clean tone, more distortion gives a nice Blues tone, and, distorting the sound further, I can get nice crunch for metal like music.

Today, I finally recorded some sound samples of my self built guitar amplifier – Ax84 Hi-Octane with spring reverb.

Recording quality isn’t the best. There are clipping in some places because of the cheap microphone I used.

Clean

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Clean with heavy reverb

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Half-way distorted (Bluesy tone)

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Distorted, scooped tone (middle frequencies cut out)

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Next up, some pictures !

Building Ax84 Hi-Octane is quite easy, because everything is well documented. You can also buy a package containing all the major parts – tubes, transformers, and a chasis to hold it all together. Then all you need to do is carefully follow the documents and assemble the circuit together. All projects are quite simple and with basic soldering knowledge could be accomplished. Although, word of warning, that you must be very careful while testing the amplifier, because of the high voltage (~250V), which can easy turn out lethal.

Since I didn’t want to buy anything off the internet and waste any money on shipping, because I live far away from the United States. I needed to look for alternatives, so I searched local markets and shops for similar parts I could use. Most of the materials I found were produced in Soviet Union, so I used different stuff than in schematics. Like EL84 tube was replaced by 6P14P. The biggest problem was to find the transformers, especially the output transformer. At the end I  had to wind the output transformer myself. Yet alterations did not stop there. I also wanted to add a feature that would let me switch between the clean and distorted sound (known as channels). Later on I added spring reverb too.

In the end, I have an amplifier that suits me just fine – sounds wonderful and is versatile (tone wise).

Front panel

Front panel with an On, Standby and a reverb control at the top. 2 pairs of gain and volume controls. Tone – bass, middle, high – pots.

Back panel

Holes on the top for ventilation. Back panel with reverb in/out. Pedal switch. Loudspeaker connector for output. And fuses below.

Next article will be about tubes, what did I use, a little comparison between, other alternatives.