At the time of writing, the prestigious Jadis company will be celebrating its 40th anniversary. Like all the brand’s products, the Jadis I300 is aimed at audiophiles who love the warmth of tube sound ‘à la Jadis’, a unique taste in sound. In keeping with the convictions of the most purist of audiophiles, this amplifier represents a real return to our roots. It’s a choice that argues for simplicity in tube systems using one of the most iconic tubes, the famous 300B power triode. To equip its amplifier, Jadis chose the 300Bs produced by Electro Harmonix for the quality of the sound they produce and their reliability.
However, while the musicality that this tube confers on the amplifier is universally recognised, getting the best out of it and allowing it to express itself fully implies certain constraints. The 300B triode is a direct-heating tube. Most tubes are indirectly heated. In other words, their filament is placed inside a small metal cylinder which it heats and which forms the cathode. On the 300B, this cylinder is absent. Instead, the filament itself acts as the cathode. This specificity means that all the lamp’s power supply circuits must be capable of delivering a very clean voltage, free from fluctuations or interference.
To meet the purists’ demand for simplicity, the I300 is designed around a simple 300B push-pull with no reaction. It must therefore meet the power supply requirements imposed by these tubes in order to benefit from all their musicality and the emotional listening they can offer. So, in addition to the fact that each stage has its own power supply, particular care has been taken with that of the 300Bs themselves. To achieve this, the i300 has no less than seven separate power supply circuits. As with all Jadis units, the heart of this power supply is based on a transformer designed and manufactured in-house in the brand’s workshop. It uses an EI M6X magnetic circuit of a design that gives it stable, noise-free operation with low heat build-up.
To drive the 300Bs, the pre-amplification stages use an ECC82 followed, after phase shifting the signal using a Schmitt phase shifter, by 6SN7 triodes which deliver a signal sufficient to make them work under optimum conditions. This is where another key element in the behaviour and temperament of any tube amplifier comes into play: the output transformer. This element, once again entirely designed and manufactured in-house by Jadis, uses a double CV38 magnetic circuit built to Jadis’ own standards. The I300 is the only integrated system equipped with such output transformers. All these features make the I300 seem much more powerful than the 10W per channel it actually delivers.
Finally, Jadis attaches particular importance to the design and cabling of its products. The I300 is no exception to this tradition. It benefits from the rules and manual techniques of in-air cabling, taken from the world of high-frequency electronics, which allow the equipment produced by Jadis to express itself fully and sign the brand’s sonic aesthetic.
What’s more, each product undergoes a rigorous series of tests and checks carried out throughout its assembly by highly qualified technicians. They are able to supervise the entire manufacturing process, while contributing their own specific technical skills. All stages of assembly are subject to detailed checks using the most advanced technologies. Any product showing even the slightest defect during a test phase is immediately withdrawn from the production line.
Finally, in terms of design, the I300 remains true to the Jadis spirit, with sober, elegant lines that honour the tubes that make up its soul.
The set up
With a square footprint measuring 40 cm on each side, this integrated amplifier is not all that imposing. However, it does weigh 30 kg, which means it needs an extremely rigid and stable support. If you wish, you can have a thick wooden shelf made to measure. We connected this amp to several quite different loudspeakers, even with outputs that weren’t necessarily very favourable. Despite its advertised 10 W, the I300 was able to meet the demand perfectly. We’ve always found that tube amplifiers deliver subjectively higher power than advertised. This was confirmed in this case.
The sound of the Jadis i300
As we’ve said on several occasions, there’s something undeniably magical about the sound reproduction of Jadis amplifiers. And it’s clearly not all about tubes. It’s true that tube circuits provide unique sensations: euphonious, spatial, warm and airy reproduction. Listening to the Jadis I300, you’ll find all that, but with that extra touch of seduction that the Carcassonne-based manufacturer has been distilling for 40 years. We’ve been lucky enough to work with the brand for many years now. We know full well that the magic of its sound waves can also be explained by the excellence of its proprietary transformers. This full-bodied, responsive sound is not available to everyone. Far from it! On our ZU loudspeakers, which proudly boast an output of 100dB, the I300 gets around.
The soundstage is superbly vaporous and at the same time provides extreme punctuality of sources in space. The position of the musicians is instantly apparent. And the framework of the performance evolves from track to track, from record to record. It is never the same. On the other hand, it perfectly captures the ambience of the recording. On its speakers, the luminosity is sublime. The pairing between the I300 and the Soul mk2s is remarkable. Switching to the Nel Extrême reduces output by 10 points, but the amp never falls apart. It retains a very fine quality of tension on the bass lines. Generally speaking, all the melodic lines are magnificently drawn by this amplifier. It certainly doesn’t deliver the quality of impact that more conventional transistorised electronics can boast. But in exchange it offers a variety of timbres and a strikingly beautiful spectral balance.
Our conclusion
Once again, the manufacturer from Carcassonne has hit the nail on the head. Taking on the legendary 300B was not necessarily an obvious choice. The company’s history is clearly more dominated by the pentodes that it loves so much. But he has long had a special place in his catalogue for 300Bs and 845s. This latest interpretation of the power triode theme is a complete success. This compact, dense amplifier delivers a vibrant, airy sound that you can savour with immense relish. The musicality ‘à la Jadis’ is always a blend of fluidity and nervousness. Once again, history repeats itself, much to our delight.
Author: Estève Fabry
Technical sheet: JADIS i300
- Origin: France
- Price : €13,500
- Dimensions : 400 x 255 x 400 mm
- Weight : 30 kg
- Power: 2 x 10 W pure class A
- Frequency range: 20 Hz to 55 kHz
- Input sensitivity: 100 mV
- Tubes: 4 x 300B, 2 x 6SN7, 3 x ECC82 Automatic bias
