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Jadis JA-80 MK II mono valve power amplifier

Jadis JA-80 MK II mono valve power amplifier

Sometimes it’s weird how these things come together. In quick succession, we have tested two amplifiers from different sides of France, both with a very shiny finish, both with a very distinctive way of doing things, and both with a very loyal following among the music loving fraternity. In all other respects, they could not be more different, and they reflect the huge dichotomy that exists within the audio world today.

Based in Villedubert, just outside of Carcassonne and some 50 miles as the crow flies from the border of France and Spain, Jadis made its first amplifier back in 1983. That was the JA-80 mono power amplifier. Such is the design methodology of the company that although there had been several revisions to the original circuit, the JA-80 stayed effectively unchanged for more than three decades, only now morphing into the JA-80 Mk II. Most companies would have churned through maybe seven different versions of the amplifier design in the intervening years, but Jadis is not like that.

The reason for the change from JA-80 to JA-80 Mk II came about because of change in the output valve world. Back in 1983, KT88 or the similar 6550 were all the rage, widely available, and standards were high. In today’s market, these valves are more likely to be used past failure, new but of very poor quality, or ruinously expensive New Old Stock. Meanwhile, other, more modern designs became available that addressed the problems in build quality inherent to the KT88 and offered improved performance, to boot. Unfortunately, they are incompatible with the original JA-80 design, and thus the JA-80 Mk II was born. This, however, also gives the Jadis JA-80 Mk II greater flexibility of output valve options.

Where the original JA-80 used two pairs of KT88s per side to deliver a conservative 60W per channel in pure Class A operation, and could be reworked to include a wide range of output valves, the new JA-80 Mk II takes advantage of the new Tung-Sol KT150 output tube. The distinctive, gherkin-shaped ‘kinkless tetrode’ KT150 is one of the most talked about recent designs: one of the few genuinely new, designed for the audiophile, valves on the market today, designed for high power and low harmonic distortion. These power tubes have proved exceptionally popular in high-end audiophile circles, being almost universally adopted by companies like Audio Research. 

The use of two pairs of KT150 power valves per side give the new JA-80 Mk II mono amp a potential power output of 90W. It’s also possible to rig the JA-80 Mk II to run different valves, if you find it impossible to source KT150s, or for some bizarre reason didn’t like the KT150. You could swap them out for KT88, KT90, KT120, 6550, EL34, or 6CA7 valves – but only in push-pull, ultra-linear operation. However, to engage in this kind of valve substitution does require sending the Jadis amplifiers in for subtle changes in the internal wiring of the valve seats. However, this is possible because it is internal wiring, and not a simple circuit board. Companies more set on profit margins and production engineering targets might have taken this redesign opportunity to move from the tried, trusted, and time consuming point-to-point wiring. Jadis instead stayed true to the path because it sounds better.

 

The rest of the design remains almost identical to the original JA-80, because change for its own sake is anathema to Jadis. The other valves in the circuit are an ECC83 as line driver and a ECC82 as phase shifter, which are flanked by four blue coupling capacitors. All the valves are housed at the rear of the amplifier chassis and can be kept from prying hands thanks to a supplied cage that no-one will ever use because the amplifier looks so much nicer without. In fairness, it looks pretty, even with the cage, but if you can drive the amp without the cage, you will at every opportunity because  – unlike most of humanity – the JA-80 Mk II looks so much better with its clothes off!

The power transformer at the front of the chassis is elegantly chrome-capped, while the output transformer is shielded, and has a gold name plate on its top. This is a core part of the Jadis ‘secret sauce’ and is proprietary and made in-house. A pair of larger high-capacity capacitors fill the gap between the two transformers. Real-estate is limited on the JA-80 Mk II chassis, and this means the layout of the power amp is perhaps slightly back-to-front, with the power inlet socket on the top and to the front of the chassis, and the valve layout at the rear of the amplifier near the single central RCA line input, and the two sets of speaker terminals. These are bi-wire terminals, rather than different taps for loudspeaker impedance. The amplifier is wired as standard for loudspeakers in the four to eight ohm impedance range, but internally altered for anything from one to 16 ohms. 

Once set and installed, user input is limited. The valves are automatically biassing and there are LED indicators next to each valve to indicate potential failure of that ‘bottle’. These are almost the only concessions to modernity, though. The amplifier has two large toggle switches on the front fascia. The first powers up the heater circuit, turning the amplifier from ‘off’ to ‘standby’, and the central indicator LED glows red. Ten or so minutes later, you are advised to throw the second ‘Operate’ switch, which moves the amplifier into full play mode, and that LED now glows green. Turning the amplifier off is to run the process in reverse, although there is no need for the intervening ten minute delay. The delay between the two actions allows the valves to come to their correct thermal operating temperature before play time, and shortening the time between throwing the two switches ultimately also shortens the life of the tubes. Most modern power amplifiers incorporate some kind of microprocessor or relay circuit to move from heating to full operation. Jadis places the onus on the responsible listener. However, if you are responsible enough to know never to fire up a power amp without turning the preamplifier on first, you are responsible enough to drive the JA-80 Mk II.

 

The Jadis design is not demanding but deserving of good partners. You could easily hook this to some very humble, relatively prosaic-sounding equipment and it will sound lovely, in part because the sound of the Jadis is always lovely, but hook it to the really good stuff to show what it is capable of, and you will be served up so much more than just ‘lovely’. The conservative, built-for-the-long-game nature of the design means the valves are rarely stressed, and this makes the amplifiers uniquely well suited in ‘fighting above their weight class’ partnership (for example, despite an upper bass impedance dip that can stress many valve power amps, the JA-80 Mk II drove my Wilson Duette II with effortless ease like it was born for the task, and most of my listening centred around those loudspeakers). In use, I did feel that the Jadis tended more toward the fast, detailed sound of Nordost Valhalla 2 and Odin 2 over the more rounded, expressive performance of Cardas Clear cable. but even here this was more seasoning to taste rather than a clear-cut ‘never use’ proclamation. 

I am a part of the soundbyte generation, and it’s difficult to not give into this when an amplifier has an overarching characteristic that fits snugly into such simple descriptors. And in the case of the JA-80 Mk II, that descriptor is ‘beguiling’. Music springs to life in the presence of the JA-80 Mk II, and listening is more about being enthralled, both by the musical content, and especially by that music’s lyricism. 

This amplifier duo is all about the musical passion, and you are inexorably drawn to music that highlights that passion, at least at first. This is the amplifier for opera lovers, who appreciate the beauty of a soprano’s voice rather than the sort of stark detail that allows you to visualise the shape of her vocal chords.

That beguiling, almost seductive sound extends to the imaging. A pair of JA-80 Mk II have one of the most holographic soundstages out there, with its outstanding depth and even great height worthy of note. My go-to disc here is the overture to The Pirates of Penzance by the LSO [Decca SXL, original LP] and the combination of a natural linear flow of music from theme to theme and a soundstage that seems to go on forever just makes you smile. Or at least smile away those tumultuous few weeks in late May to early June in the UK. Politics and terrorism be damned: the Jadis combo helped music bring salve to the disquieted soul. That sounds pretentious, but the Jadis really does bring that sense of musical beauty and refinement to almost everything it touches.

I am mindful that this might begin to sound like the JA-80 Mk II amps are all ‘surface’ with no ‘meat’, but that is far from the truth. These are also dynamically expressive, cogent, detailed designs, with a surprisingly deep, taut bass. They easily passed the ‘wub, wub’ test of James Blake’s eponymous first album [ATLAS/A&M], but they also achieved both depth and precision when faced with the deep bass electronica chattering of Kraftwerk’s ‘Numbers’ [Minimum-Maximum, Kling Klang] and Trentemøller’s ‘Chameleon’ [The Last Resort, Poker Flat]. The Jadis amps also allowed powerful rock guitar that sense of drive and energy it so needs, and yet beyond all this, I found myself drawn to acoustic instruments and the classical or jazz spectrum because that lyrical beauty the JA-80 Mk II is so great at reproducing really makes a difference here. If you want to know the difference between some pick-up jazz piano  noodler and Bill Evans, the expression in every note comes through perfectly here. This difference is easy to parse in the live event; many good jazz pianists are talented and highly skilled, but what separates them from the true masters of the art is that ‘between the notes’ expressiveness that is fleeting and sometimes never makes it all the way through the replay chain. The JA-80 Mk II is remarkably revealing of musical intent in this way, and although it ticks all the audiophile boxes along the way, it’s this ability to make sense of the musician’s intent that separates the Jadis from much of the audio pack.

 

OK, so the JA-80 Mk II’s sublime character is still ‘character’ and those after absolute neutrality in their power amplifiers will never opt for Jadis. In fact, they will probably never opt for a valve amp of any description, but that beauteous nature of the JA-80 Mk II sound is more about beguiling (that word again) character than stark honesty. But those who seek that character in their audio systems do so for a reason, and will frequently reject stark honesty for being too stark. This is not ‘lush’ or ‘rich’, it’s just music that sounds damn beautiful, and that is extremely attractive.

There is something refreshingly old-school about Jadis, and that is reflected in the products it makes. The sound these JA-80Mk II amps deliver is just so damn lovely, you’ll be hard pressed to find better at any price. It’s the reason why the company made the same amplifier for almost 35 years without a significant change, and there is every reason to expect the JA-80 Mk II to carry on that tradition. If you want your music beautiful, beguiling, and extremely entertaining, the JA-80 Mk II is highly recommended.

TECHNICAL SPECIFICATIONS

Type: pure Class A mono valve power amplifier

Valve complement: 4× KT150 power tetrodes, 1× ECC82 and 1x ECC83 double triode per channel. Other power valves can be substituted

Power Output: up to 90 watts per channel

Frequency Response: 20Hz to 27kHz

Loudspeaker impedance: from 1Ω to 16Ω

Bias: Automatic

Sensitivity: 500mV

Power consumption: 190W per channel

Dimensions (W×H×D): 24x26x62.5cm
per chassis

Weight: 35kg per chassis

Price: £7,998 per channel

Manufactured by: Jadis

URL: www.jadis-electronics.com

Distributed by: Absolute Sounds

URL: www.absolutesounds.com

Tel: +44(0)20 8971 3909

Tags: FEATURED

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