The pa21 maximizes all our efforts with more power, more dynamics and greater flexibility. The full-sized chassis allows us to use larger transformers and bigger caps and resistors, delivering greater control and detail.

The result is 55 watts of pure pentode output per channel, and improved stability throughout the amplifier. We do implement a very modest amount of global negative feedback to make the amp rock solid.

With more room at their disposal, our engineers continued to search for improvements, such optimal efficiency, the lowest signal degradation and the greatest immunity from noise and hum. They accomplished just that, with carefully separated and laid-out signal ground, power supply ground and chassis ground schematics.

We’ve also advanced our proprietary Adaptive AutoBias board with a special circuit that re-calibrates it for EL34s or KT88s. One flick of a switch allows you to run either tube at its optimal level. And as always, the board continuously monitors each tube, tweaking it to its sweet spot. There’s no biasing, no need for matched tubes, no worries.

Combine the pa21 with its matching full-size ca21 preamplfier, and experience a truly reference-quality system, without a typical reference-quality price tag.