Self on Audio, 2nd Edition

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High-performance preamplifier

Low-cost design with active gain control

This was my first ‘conventional’ preamplifier design to be published. It was my own reaction to the relative complexity of the Advanced Preamplifier just described; I set out to produce a preamplifier that was conventional, to see just how good it could be. At that time the available op-amps were looked at with entirely justified suspicion; they were relatively noisy and prone to crossover distortion in their output stages. Crossover might be inescapable in a power amplifier, but it was definitely not a good thing to have in a preamp. Hence the use of discrete Class-A circuitry throughout. (The 5534 op-amp was just becoming available at the time, but was ferociously expensive.) ...