Jim Kelly Line Amp 2022 - Zebra Wood

The newly designed amplifier is a two channel Line Amp, with Dual-Concentric controls for Gain, Treble, and Bass. The Main Gain (Master Volume) control for the overdrive B channel has a pull switch for Mid-Boost. The A channel is identical to the original Jim Kelley non-reverb preamp. The amp also has a guitar level, transformer coupled effects loop. The output section is the traditional Jim Kelley matched quartet of 6V6's. The amp has a traditional JK front ends with the Baxandahl style tone network. The back panel of the amp has a stand-by switch, effects loop jacks, speaker jacks, and a gain boost jack. The latter functions as a solo boost by decreasing negative feedback.

The Line Amp has evolved over the years, but the basic concept - the end goal, has remained the same all along. With this amp it has always been my intention to be able to achieve the same harmonic structure in the preamp as one gets by overdriving a quartet of beam power pentodes in a push-pull output section. The obvious advantage of being able to do this is that one would be able to have precise control of the volume without having to sacrifice tone. It has only been within the last 2 or 3 years that I have finally developed the small signal vacuum tube circuit that achieves the results I began looking for 35 years ago. The circuit is a dual-cascode differential amplifier and it produces the harmonics and feel of a well designed tube push-pull power amplifier at preamplifier signal level –or line level. Hence the name, Line Amplifier.

This latest version of the Line Amp is the culmination of 35 years of work toward finding a way to replicate the harmonic spectrum and dynamic characteristics of an overdriven push-pull output section, and produce it at preamp level.