To celebrate its fortieth anniversary, Jadis has decided to reissue some of its most iconic products, such as the JPL and JA30. But the Carcassonne-based manufacturer has also released some brand new powerhouses, the JA170, which in turn adopt the new square chassis that we love so much. This duo provides a pleasure in sound reproduction, warmth and inimitable musicality that should not fail to seduce far beyond the brand’s unconditional fans.
The JA170s feature the new, very successful square look that Jadis introduced with the I70 and I300 integrated amps. The same care has been taken in the design and production of the case, which features nameplates to enhance its elegance. These power amplifiers are no exception to the rule of stainless steel casing and 24-carat gold plating, this
‘Jadis Touch’ for which the brand is also renowned, combining classicism and elegance.
Although these amplifiers take their name from the tubes that make up their power stages, it is interesting to note that Jadis operates these tubes under conditions that preserve a more than comfortable safety margin. This means that the JA170 blocks are always able to meet the challenge of reproducing certain works with the greatest of ease. The heart of each JA170 is therefore centred around a dual push-pull of Tung-Sol KT170 tetrodes. These are latest-generation tubes that combine power and quality. Furthermore, in order not to lose any subtlety of the sound message, Jadis has chosen to make these push-pulls work in pure class A.
It should be noted that it is one of the few manufacturers to use this type of configuration. The vast majority of others are content with class AB or even B operation. However, while full class A undeniably offers significant gains in terms of finesse and subtlety, it has the disadvantage of making the tubes work with a relatively high quiescent current. This high current also flows through the primary of the output transformer. It is therefore essential that it can withstand this high quiescent current while maintaining the primary inductance required to ensure a satisfactory response at the lowest frequencies. Ago therefore had to design transformers specifically for working in these conditions. These transformers are mounted in barrels and damped with resin, eliminating any risk of parasitic vibrations within the windings.
In total, no fewer than six tubes are used to meet the requirements of the JA170 audio circuit. In addition to the four KT170 beam-driven tetrodes that equip the dual output push-pull, a high-gain ECC83 double triode and a medium-gain ECC82 double triode are used to manage them. These gain and driver stages have a classic configuration, similar to the manufacturer’s other push-pull designs.
The JA170 is powered by a specific transformer with multiple secondary windings to match the specific structure of these blocks. It separates the power supply for the double push-pull from that of the amplification and driver stages. This architecture prevents any interaction, particularly on the current-hungry transient modulation peaks. Finally, the high voltage is regulated by a transistor circuit whose heatsink can be seen on the chassis. The filament heating is also regulated and stabilised to eliminate any risk of induced noise.
Here, the layout of the exclusively analogue and unbalanced connectors has been dictated by the internal implementation of the air-wired circuits that the manufacturer has improved. The connectors grouped together on the rear panel use high-quality RCA sockets, as do the magnificent proprietary speaker terminals.
The set-up
The manufacturer from Carcassonne has always favoured unbalanced analogue connections. We therefore connected these blocks using RCA modulation cables. We were able to test them on several occasions in very different environments and with various speakers.
Each time, we were able to clearly see that the new JA170 mono blocks are capable of powering a very large number of speakers with great ease. That said, they are still very heavy. It will therefore be necessary to place them on the floor on a dedicated anti-vibration platform. The preamp will be installed near the sources in a more conventional rack.
The sound
We have been ardent fans of the Languedoc brand since its beginnings. But we have noticed a subtle evolution in its products over the years. First of all in terms of the look, as mentioned above, but also in terms of the sound. The adoption of the new KT170 tetrode certainly has something to do with it. Its particularly low distortion rate combined with true pure class A operation makes it possible to produce an amplifier capable of providing a quite exceptional sensation of presence. Available in a monophonic version, this electronics is every bit as good as the legendary JA30, 80 and above, so imperial is the sound. Its main characteristic is therefore the exceptional anchoring of the sound stage within your listening space. It is impossible to listen to these Jadis with a distracted ear, so much do they impose themselves on you. The term holographic construction has rarely had so much meaning. From your sofa, you are transfixed by a spatial reproduction that is so remarkably structured that it seems almost to be embodied. It is first and foremost the precision of the elements and their position in space that is so surprisingly realistic. You almost feel as if you could walk around the various musicians. Their positioning is unmistakeable. And then there are the proportions, which are striking in their coherence. JA170 reproduces the bodies with a rare homogeneity. Finally, it is through the fluidity of the movements that we can easily follow the musicians‘ movements on stage. All this is certainly a great show, but it is also the result of the designers’ hard work to respect the signal phase to the letter. Then let’s talk about the spectral balance so specific to the brand. It is clearly suffused with a delectable warmth and roundness, but it has gained considerably in accuracy and clarity since the early days of Jadis.
This inimitable flavour is still recognised just as quickly, this grain that is the hallmark of the brand’s creations and has forged its reputation with dense and lustrous but impeccably accurate stamps. You only have to listen to the brass, a voice or a piano to understand what the notion of presence can bring to sound production at this level. You will therefore understand that with such a high level of performance in terms of image and timbre, listening to an opera with this Jadis electronic trio is a delight. But that would be nothing without dynamic behaviour worthy of the name. And here too is a favourable terrain for our duo, which fulfils its mission without fail. This excellent energy management not only allows for a clear and comfortable listening experience on any type of message and at any modulation peak, but also guarantees excellent listening comfort over very long periods, even at high volume levels.
Our conclusion
Last spring, we were delighted to go and immerse ourselves at Jadis in order to feel the energy that emanates from this team on the spot. We had seen the very first JA170 blocks, but were sworn to secrecy, of course! Today, we are delighted to give you a preview. Because by the time you read these lines, VUmètre will be the first magazine in the world to mention them. We are constantly amazed by the creativity of the Villedubert manufacturer and the freshness of its passion. The brand’s historical references are still present in the catalogue after more than 40 years and have been able to evolve intelligently over time. But it is with these latest achievements that Jadis seems to us to be best able to reinforce its unique status as a manufacturer of tube amplifiers. Firstly because it has complete control over the R&D and manufacturing chain (the famous power supply and output transformers), but also because its vision of the subject is as profound and accomplished as ever. You will have to pay a very large sum to acquire this elite duo, but not only will you be able to keep it for life, you will also be able to pass it on. These are products which, by nature, are not subject to obsolescence and are made to succeed us.
Authors: Estève Fabry and Laurent Thorin
Technical sheet: Jadis JA170
- Origin: France
- Price: €25,500 (per pair)
- Dimensions: 400 x 265 x 400 mm
- Weight: 34 kg
- Power: 85 W
- Bandwidth: 10 Hz to 63 kHz
- Sensitivity: 555 mV
- Tubes: 8 x KT170, 2 x ECC82, 2 x ECC83
- Power consumption: 320 VA per block