The design is inspired by the guitar amps of the 1950s and ... single-ended one with a two stage double triode preamp and a single power output tube. The transformers are usually the difficult ...

[Justin Scott]’s tube preamplifier is a great example, with its novel use of a pair of Nixie tubes to indicate the volume to which it has been set. The audio side of the preamp comes courtesy of ...

Solid-state tube replacements are innovative devices that can act as a substitute for traditional tubes in your guitar amplifier ... the sound and response of preamp tubes like the 12AX7.