Sugden A21

Sugden A21

Sugden A21

Sugden A21

Every now and again we like to feature a product which we feel has earned a reputation for excellence in every area of it’s field. The Sugden A21 is such a product and is one of the most highly regarded amplifiers in the audiophile market. Customers love the sound of this amplifier and in terms of detail and musicality it is something of a giant killer.

Sugden are and have always been a Yorkshire based company. They founded in 1967 and one of the first products they worked on was the original A21 amplifier. The design was also the Worlds first production Class A amplifier and it immediately won the company much acclaim.

Sugden we unsatisfied with the typical class B amplification that was popular at the time. This was mainly down to inherent crossover distortion which they felt was both audible and a negative factor in an amplifier.


The Sugden A21 worked differently. The Class A amplifier is the simplest form of power amplifier that uses a single switching transistor in the standard common emitter circuit configuration as seen previously to produce an inverted output. The transistor is always biased “ON” so that it conducts during one complete cycle of the input signal waveform producing minimum distortion and maximum amplitude of the output signal. The only downside to this approach is that the design generates heat, especially when you turn it down or impede it’s output. In many designs fans had to be used and these generated noise and problems of their own. Sugden used clever circuit designs and efficient heatsinks to dissipate this heat and allowed their amplifier to simple sound pure and suffer from minimal distortion.


The A21 is still in production today, although it has been revised and subtly improved in both components and appearance.

Despite when many people think (and what the “product of the month” approach of the hi-fi press indicates) decent amplifiers haven’t changed very much at all. You only need to change something if you find a better way of doing it. In the case of the Sugden A21 this hasn’t been the case.

The A21 is a musical beast. Although 20 watts doesn’t seem like much power, audiophiles have discovered that it is the quality of those watts that counts far more than the quantity of them. The Sugden A21 is a textbook illustration of this.

Our customer are often surprised at how easily it drives expensive speakers and wonder at the power and quality it delivers. Often they’ve auditioned far more expensive amplifiers and found them lacking.

There are three version of this enduring amplifier; the A21 L, the A21 a and the A21 SE. Their prices are £2095, £2255 and £2995 accordingly.

Listening to them is a lovely experience and one you won’t forget. Class A done properly is something extremely special. Enthusiast and reviewers have likened it to valve amps without the high cost and low reliability. It has the warms and musicality of valves but the speed and detail of transistors.

Call in for a listen at your earliest convenience and discover this much loved and enduring classic.