Astell&Kern A&ultima SP2000T Digital Audio Player Lab Report

Lab Report

As with the A&Futura SE200 [HFN Feb '21] and KANN Alpha [HFN Jul '21], the SP2000T is hugely flexible but not without its wrinkles. For example, in 'Line' mode the settings of 0.7V, 1V, 1.25V and 2V all yield 3.130V at the maximum ('150') volume via the unbalanced socket. Also 'Line' mode is phase inverting [see Graph 2, below] and digital media is downsampled to 96kHz while the 'headphone' mode is native. Neither is there a rating for the headphone amp's power output... In practice the SP2000T clips at 159mW/32ohm (or 2.25V) at volume '145' with a peak level (0dBFs) digital input, so the dial should not exceed this value. For the very lowest impedance 'phones the SP2000T offers just 13mW/8ohm (volume '111') before there's obvious noise modulation/THD on the output. So, while there's no doubting the sophistication of the SP2000T, for sheer 'grunt' it is seen off by the 630mW/8ohm Chord Mojo 2 [HFN Apr '22].

The ES9068AS DACs, first used by A&K in the KANN Alpha, are doubled-up here to yield a wide 112.7dB A-wtd S/N ratio (or 98dB re. 10mW/32ohm) and low distortion that falls to 0.000130.00055% (20Hz-20kHz) over the top 20dB of its dynamic range. This increases under load to a very uniform 0.0045% at 10mW/32ohm [see Graph 1]. Jitter is a little disappointing at 630psec (48kHz/24-bit data from internal storage) but at least the low ~1ohm output impedance ensures the SP2000T's response is largely unaffected by low or variable in-ear/on-ear loads. With its linear phase filter, the response is a very flat ±0.02dB (20Hz-20kHz), dipping to just –0.5dB/45kHz with 96kHz files. The minimum phase filter cuts above 18kHz to reach –5.0dB/20kHz and the hybrid filter is steeper still at –12dB/20kHz [Graph 2]. PM


THD vs. digital signal level at 1kHz (black, unloaded; grey, into 32ohm) and 20kHz (purple, unloaded; cyan, into 32ohm where 0dBFs = 159mW)


Impulse and HF responses for Linear/Fast (black), Minimum/Slow (red) and Hybrid (green) filters

Maximum output (<1% THD into 47kohm) 3130mV (single-ended)
Maximum power output (<1% THD) 159mW/32ohm (single-ended)
Output Impedance (20Hz-20kHz) 0.95-1.21ohm (single-ended)
A-wtd S/N ratio (re. 10mW/0dBFs) 98.0dB / 112.7dB
Distortion (20Hz-20kHz, re. 10mW/0dBV) 0.0043-0.0045/0.0002-0.0017%
Frequency resp. (20Hz-20kHz/45kHz) +0.00dB to +0.02dB/–0.5dB
Digital jitter (48kHz / 96kHz) 630psec / 550psec
Battery 4200mAh/3.8V Li-Polymer
Dimensions (WHD) / Weight 78x141x17.5mm / 309g
Price £1999

Seoul, South Korea
Supplied by: Armour Home Electronics, Herts
01279 501111