Jadis Diapason Luxe Integrated Amplifier Lab Report

Lab Report

While the Diapason Luxe is intended as a stepping stone into Jadis's world of artisan audio, this low-powered amp still employs the choice passives and tubes that we've seen in its far costlier single-ended designs. This integrated is a push-pull design, and biased into Class AB, but Jadis's customarily enigmatic specification still holds sway – power is rated at '15W' without reference to load, distortion or frequency! In practice the available power rather depends on the level of distortion you'll tolerate, increasing from 0.2%/0.5W to 0.4%/1W, 1%/2.9W, 2%/6W and 3%/11.6W (all 1kHz into 8ohm via the 8ohm tap or 4ohm via the 4ohm tap). Relaxing our tolerance to 5% THD, and testing the Diapason Luxe under dynamic conditions (1kHz/10msec), reveals a significantly higher 26W (8ohm tap), 26W (4ohm tap), 27W and 17W into 8, 4, 2 and 1ohm loads, respectively [see Graph 1, below]. So while these are not high figures, and sensitive speakers are a must, the amp will still likely sound louder than you might expect.

The tonal balance, however, is influenced by both its high 2.4-4.06ohm source impedance and the increase in distortion either side of the midrange. At just 1W/8ohm THD is lowest at ~0.5% from 200Hz-2kHz while the limited feedback allows 1%/6kHz to 2.5%/20kHz [Graph 2, below]. Transformer core saturation is also at least partially responsible for the increase in THD at low bass frequencies – 1.9%/1W up to 5.5%/5W (both 20Hz/8ohm). Cautious compensation typically means a higher overall gain (+38.2dB) and, in this instance, a slightly below-average 78.5dB A-wtd S/N ratio (re. 0dBW), the latter a combination of both hum and white noise. PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max current is 4.1A


Distortion versus frequency at 1W/8ohm (black, 5Hz-40kHz) and 5W (red, 20Hz-20kHz)

Power output (<3% THD, 8/4/2ohm) 11W / 12W
Dynamic power (<5% THD, 8/4/2/1ohm) 26W / 26W / 27W / 17W
Output impedance (20Hz–20kHz) 2.4-4.06ohm
Freq. response (20Hz–20kHz/100kHz) –1.6dB to –1.0dB / –14.2dB
Input sensitivity (for 0dBW/10W) 35mV / 110mV
A-wtd S/N ratio (re. 0dBW/10W) 78.5dB / 88.5dB
Distortion (20Hz-20kHz, 1W) 0.4–2.5%
Power consumption (Idle/Rated o/p) 86W / 110W (1W standby)
Dimensions (WHD) / Weight 370x165x350mm / 12kg
Price £3498 (£3598 with USB option)

Villedubert, France
Supplied by: Absolute Sounds Ltd
0208 971 3909