YBA Passion IA350A Integrated Amp/DAC Lab Report

Lab Report

Although the IA350A embodies many of YBA's core design ideals, it is not a 'half power' version of the AMP650 [HFN May '18]. I discuss the relatively low +23.6dB gain and cleverly sculpted frequency response offered by the IA350A in my boxout, and while it does betray a similar 2nd/3rd harmonic distortion trend to the AMP650 (consistent at ~0.02-0.03% over 1-80W/1kHz/8ohm) the levels of PSU noise are lower and the A-wtd S/N improved by 10dB to 81.5dB (re. 0dBW). Versus frequency the modest levels of compensation (feedback) employed by YBA mean that distortion climbs quickly above 10kHz, reaching 0.14%/20kHz and 0.35%/40kHz at 10W/8ohm. Subjectively this is not troublesome because the harmonics lie well outside the audioband. Power output is just within specification at 2x120W/8ohm and 2x180W/4ohm while there's sufficient latitude in the power supply to accommodate 163W, 302W and 450W into 8, 4 and 2ohm loads under dynamic conditions [see Graph 1, below].

The digital board is based on the (very) tried-and-tested CS4398 DAC, originally launched in 2002, and supporting up to 192kHz/24-bit LPCM. Maximum preamp output here is 2.3V from a 96ohm source impedance, the stage offering a generous 107dB A-wtd S/N ratio and a response that rolls away to –0.13dB/20kHz with CD/48kHz media down to –1.7dB/45kHz (96kHz files) and –7.5dB/90kHz (192kHz files). Jitter is well suppressed (typically ~75psec) and while distortion increases slightly over the top 10dB of its dynamic range [see Graph 2, below] reaching 0.0006-0.009% at 0dBFs, it drops to a minimum of 0.0005-0.0006% at –15dBFs. PM

1119yba.lab1

Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 16.4A

1119yba.lab2

Distortion vs. USB 24-bit digital signal level over a 120dB range at 1kHz (black) and 20kHz (blue)

Continuous power (<1% THD, 8/4ohm) 120W / 180W
Dynamic power (<1% THD, 8/4/2/1ohm) 163W / 302W / 450W / 270W
Output impedance (20Hz–20kHz) 0.059–0.088ohm (96ohm, pre)
Freq. resp. (20Hz–20kHz/100kHz) +0.95 to –0.45dB/–4.8dB
Digital jitter (USB at 48kHz/96kHz) 70psec / 73psec
A-wtd S/N ratio (re. 0dBW/0dBFs) 81.5dB (Analogue) / 106.7dB (Dig)
Dist. (20Hz-20kHz; 0dBW/–3dBFs) 0.028–0.12%/0.0006–0.0090%
Power consumption (idle/rated o/p) 51W / 396W
Dimensions (WHD) / Weight 430x108x380mm / 15.4kg
Price £4500

COMPANY INFO
YBA
Bures sur Yvette, France/Shanling, China
Supplied by: Nintronics Ltd, Herts
01707 320 788
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