The Legendary JE Sugden A21 Series 2 Simply one of the Finest Amplifiers ever made Class A Gold Bargain at this price

Simply one of the greats of the Audiophile world
Just Google this as its very special

A bargain at this price


The Sugden pure class A design provides affordable high-end performance from a beautifully engineered amplifier. Compact in size with a simple but stylish design, the A21 is possibly the only amplifier you will ever need.



Warm And Generous
As for the treble, the A21 Series 2 gives an undeniably bright sound yet at the same time some instruments and vocal styles come across as rolled-off and diffuse. This was noted during a full run-through of Kate Bush's 'A Sky Of Honey' – a suite of recordings specifically intended to be listened to as a whole from her album Aerial [EMI 0946 3 43960].

Lisping vocals and cymbals that hissed rather than sparkled were two examples of this limitation. That said, the performance overall exceeded my expectations and did little to betray the unit's near 50 years of age. As is common to all good equipment, I soon forgot about this shortcoming.

The character of the bass was not unlike that of a small valve amplifier of the immediately preceding generation, being warm and generous but ultimately limited in control. The sharp rimshots in the percussion lines on Dire Straits' 'Calling Elvis' from the album On Every Street [Vertigo 510 160-2] lacked the delightful 'thwack' you get when playing this track through a more modern amplifier, such as the JVC A-X4 from 1980 [HFN Oct '17]. This time the sound was more of a thud, although the A21 Series 2's low-end presentation seemed to gel with the bass guitar whose tone was portrayed as both deep and atmospheric.


Back in the day, Sugden specified this amplifier's THD at '0.25% for 10W and 0.01% at ½W' – figures that are not unrealistic across midrange frequencies. In practice, the A21 Series 2 achieves <0.25% THD from 100Hz-10kHz at 10W/8ohm with a minimum of 0.11% at 2-3kHz [black trace, Graph 2] although this necessarily increases through low bass (1.7%/20Hz) and high treble (0.8%/20kHz) frequencies. Distortion also falls at lower output and, indeed, is ~0.005% at 0.5W, or <0.02% at 1W/8ohm from 100Hz-10kHz. The ±1dB 30Hz-20kHz frequency response was closer to 18Hz-16kHz with our sample, the 2nd order 7kHz HF filter yielding –3dB/5.5kHz and –18dB/20kHz here. Of course, the moderate 0.335ohm output impedance (rising to 1.1ohm/30Hz) will also have some impact on system response depending on your choice of loudspeaker. Noise is not inconsiderable either, with hum at –54dBV and white noise pushing the A-wtd S/N back to 72.5dB (re. 0dBW). PM

Power output (<1% THD, 8/4ohm): 13.5W / 10W
Dynamic power (<2% THD, 8/4/2/1ohm): 15W / 19W / 12W / 6W
Output impedance (20Hz–20kHz): 1.10 to 0.33ohm
Freq. resp. (20Hz–20kHz/100kHz, 0dBW): –0.6dB to –1.5dB / –13.6dB
Input sensitivity (for 0dBW/12W): 58mV / 205mV
A-wtd S/N ratio (re. 0dBW/12W): 72.5dB / 94.1dB
Distortion (20Hz-20kHz, 10W/8ohm): 0.11–1.7%
Power consumption (Idle/rated output): 70W / 70W
Dimensions (WHD) / Weight: 394x127x229mm / 10kg