Posted on Wed, 11 Apr, 2018
Posted by Bob

Icon Audio Stereo 40 integrated valve amplifier: a modern take on classic technology, reviewed and rated!

Icon Audio is a British company which specialises in 100%, pure-blooded, all-valve Hi-Fi equipment. Based in Leicestershire and headed by lead engineer, David Shaw, Icon Audio keep prices low and quality high, thanks to a lean company structure and efficient manufacturing.

With a degree of excitement and anticipation, your reviewer settled into the comfy sofa at Audio Affair’s Custard Factory HQ and warmed up the valves…

Icon Audio Stereo 40

Icon Audio Stereo 40

The Icon Audio Stereo 40 is a straightforward design which offers all the traditional Hi-Fi enthusiast needs and nothing they don’t. There are no tone controls, no Bluetooth, no wireless multi-room streaming, no printed circuit boards, no-nonsense. With that said, there are some clever design touches…

A four-position switch, accompanied by a vintage styled backlit meter, allows the user to check and adjust the bias of each valve via top-mounted trimmer pots. The range of bias adjustment allows for a choice of outputs valves to be fitted, including EL34 (as tested) KT88, KT66, 6550 and other types; opening up the possibility for sonic experimentation.

The Icon Audio Stereo 40 allows the user to run the output valves in pentode, ultra-linear operation for the highest output, or in triode mode. Triode mode results in half the power output but a slightly sweeter, more “open” tonality; it was in this mode the day’s listening tests were conducted.

The remaining valve complement consists of a 274b rectifier and octal based pre-amplifier valves including the 6SN7 and 6SL7. Three switchable inputs are provided along with a tape monitor, and conveniently, remote control of the volume.

Anyway, enough of the jibber-jabber, what does this thermionic beauty actually sound like?

Listening time

The source for the day was Linn’s excellent Klimax DSM network player streaming hi-res audio from Tidal. Today’s speakers of choice were Tannoy’s oh-so-lovely Tannoy Prestige Kensington dual-concentrics. Yummy!

Deciding to jump straight in with a test of bandwidth, dynamics and timing, Todd Terje’s 80s synth homage, Delorean Dynamite was cued up. From the first few bars, the unmistakable sound of valve amplification filled the room; warm, full and characterful.

If you’ve never heard a valve amplifier before, it can be a revelatory experience compared to solid-state designs. There’s a high-end extension which is bright, sweet, smooth and airy in a way you’ll probably never hear from a solid state amplifier.

There’s a unique character to the upper mids in particular; a real sweetness which lifts detail elements from the track without being fatiguing.

Icon Audio Stereo 40

By the same token, the bass and low-mids have a depth and weight which is both seductive and addictive. The rhythmic force of Delorean Dynamite carries through nicely with a real heft to the kick drum and arpeggiated bass synth. This is very much the “valve magic” in evidence.

Continuing the theme of melodic electronic music, CHVRCHES provide the emotion with their track Lies. Lauren Mayberry’s vocal sits beautifully in the mix, again benefitting from that wonderful sweetness and airiness the Stereo 40 offers.

Anyone who claims valve amplifiers lack depth, low-end extension and speed really should listen to the Icon Audio Stereo 40. Kick drums and bass synths positively rumble and roll with the punches whilst percussion is persuasive and powerful with character and emotion. It’s a massively impressive presentation.

Technically Impressive

It’s one thing to be able to deliver on compressed, highly produced material, but how does the Icon Audio Stereo 40 perform on material which is more open and acoustic in nature? Is there finesse to match the bombast and bravado? In short, yes, there is!

Turning once again to the beautifully recorded and performed piano performances of Lang Lang, his performance of Tchaikovsky’s Dance of The Sugar Plum Fairy from The Nutcracker Suite demonstrates great control and finesse. Transients are managed extremely well, with no audible or discernable distortion.

Once again there’s a natural and engaging sweetness to the performance; the notes all follow each other with a fluidity which is captivating and (there’s that word again) engaging.

The Valve Magic

The Icon Audio Stereo 40 integrated amplifier, neatly embodies the discussion surrounding valve amplification in Hi-Fi. Is this the last word in accuracy and precision? Laboratory test equipment would possibly say not; however, there’s that special kind of “pixie dust” that valves sprinkle on any piece of audio fed through them.

If your ears are anything like this reviewer’s, and you value entertainment and enjoyment from your Hi-Fi above all else, you’ll probably reach a similar conclusion; how quickly can I add an Icon Audio Stereo 40 to my Hi-Fi rack?

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