conrad-johnson ART27A stereo power amplifier

Tubed power amplifiers
Conrad Johnson ART27A

Loudspeakers are a more complex question here. That limited power output does suggest the use of loudspeakers with a relatively high efficiency, but in many contexts it’s that first watt that is the most important and all else from there is icing on the cake. However, the reality is there are some loudspeakers with notionally easy driving capabilities that have nasty impedance dips that are more likely to challenge a lower-powered valve amplifier. Granted, the ART27A is better equipped than most to handle this, but the strictures imposed by the technology mean more care in speaker selection. I admit that I was extremely shocked – in a good way – in terms of just how far you were able to push the ART27A with loudspeakers that shouldn’t be a match with a relatively low-powered amplifier, so long as you stay within reasonable loudness limits. 

The question on people’s lips will always be ‘which one is best?’ but in fact it’s a false dichotomy at best. The ART300 and ART27A play to different strengths, work with different systems (especially in terms of loudspeakers and room, even if there is a lot of wiggle room on the part of the ART27A). The simple answer to the question is ‘yes’ or ‘they are both better than each other’. There is no set answer here. Both are outstanding in their own different ways and while there is a lot of crossover in terms of tonality and frequency extension. It’s much more than one has authority, the other has a sense of musical grace, just as it’s wrong to think one is for rock listeners and the other is for jazz fans. The truth is, you should listen to both, and then decide.

In very real terms, the conrad-johnson ART27A is a bit of a revelation. In fact, it’s several revelations rolled into one. It shows just how powerful a low-power amplifier can be in reality. It shows just what happens when a brand with a well-deserved reputation for making push-pull amplifiers turns its hand to single-ended designs. It shows in a world that has adopted the KT150, there is still lots of mileage in classic valves like the KT88, and it shows there is a lot of merit in thinking just a little bit out of the box. The end result is something of a ground-breaker for c-j. 

Somehow, I think the ART27A is not simply a limited-run amplifier; I think it’s the start of something in conrad-johnson. While I don’t think the brand – or its followers – are going to switch over from push-pull designs en masseany day soon, I can see a time soon where conrad-johnson may have both push-pull and single-ended amplifiers side by side in its line-up. I guess whether or not that happens depends on the popularity of the ART27A. Judging by its performance, I’d really love to see more designs like this one. 


Type: Triode-coupled Class A valve stereo power amplifier

Inputs: 1× pair single-ended RCA stereo line-level inputs

Outputs: 1× pair multi-way loudspeaker terminals (4Ω output) 

Tube complement: 3× 6922, 4× KT88 (matched pairs per channel)

Frequency response: 20Hz–20kHz ± 0.25dB

Power output: 36W (from 30Hz–15kHz, at no more than 1.5% THD into 4Ω, 8Ω and 16Ω taps available)

Hum and noise: 108db below rated power

Dimensions (W×D×H): 48.3 × 44.5 × 22.2cm 

Weight: 28kg 

Price: £24,500

Manufactured by: conrad-johnson design, inc.


Distributed in the UK by: Audiofreaks


Tel: +44(0)208 948 4153

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