10 watt guitar amplifier with single ended power amplifier
My first fully self-built guitar amp worked with only one EL34 in the power amp. With a simple design, I wanted at least a little more power, as was achievable with an EL84 in SE operation (SE = single ended). Otherwise, I had can continue to take my old Telefunken Opus tube radio, which until then had to serve as a guitar amplifier.
I built the device as a portable combo amp. The case was made from an old cabinet drawer in which I inserted a baffle with the two speakers. On a small front-mounted aluminum plate, the input jack and the potentiometers for volume, bass and treble were mounted.
Since I could not organize a suitable for the EL34 SE output transformer, I used a slightly larger intended for the EL84 output transformer. Due to the secondary-side load with two five-ohm loudspeakers connected in parallel, the primary impedance was suitable for the EL34. The resulting loss of bass was acceptable for guitar sound. Finally, the transformer was designed for high-quality music playback and was able to transfer markedly lower frequencies at five-ohm termination, as delivered by an electric guitar. The amplifier made with its good 10 watts for rehearsals with the school band enough "noise".