T+A Caruso R All-In-One Player/DAC/Amp Lab Report

Lab Report

Every source that finds its way into the Caruso R is either digitised via a 48kHz ADC (analogue inputs), downsampled to 48kHz (LPCM via S/PDIF, network or USB) or upsampled to 48kHz (44.1kHz CD). The response is therefore limited to –0.2dB/22kHz and –1.35dB/23kHz before dropping to –21dB/24.3kHz as T+A's choice of minimum phase digital filter – offering a modest 44dB stopband rejection – bites. The Class D amplifiers demonstrate their own load sensitivity and so the response of the main output is further modified by speaker impedance, peaking at +0.8dB/20kHz into 8ohm, a 'flat' 0.0dB/20kHz/4ohm before the treble is progressively rolled off into lower impedances at –1.7dB/20kHz/2ohm and –4.7dB/20kHz/1ohm. The impact of the amplifier's inductive output filter is also reflected in its source impedance – increasing from 0.07ohm through bass and midrange to 0.2ohm/10kHz and 0.65ohm/20kHz.

Once again, distortion, particularly at high frequencies, is dominated by the Class D output stage. Via the DAC/preamp, distortion falls to as low as 0.0012-0.0025% (20Hz-20kHz) over the top 30dB of its dynamic range [see Graph 2] but this increases to 0.0065–1.09% at 10W/8ohm. Noise, too, is low via the DAC/preamp, yielding an A-wtd S/N ratio of 105.1dB even though the value of 80.5dB (re. 0dBW) via the Class D amp is, relatively speaking, below average. Power output is necessarily tightly regulated by the switchmode PSU and Class D output, reaching a hard clip at 2x50W/8ohm and 2x100W/4ohm under continuous conditions and 61W, 112W, 200W to 300W into 8, 4, 2 and 1ohm loads under dynamic conditions at <1% THD [see Graph 1, below]. So the Caruso R is compact but very punchy! PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 17.3A


Distortion versus digital signal level at 1kHz (USB, red; CD, black) and 20kHz (CD, blue)

Continuous power (<1% THD, 8/4ohm) 50W / 100W
Dynamic power (<1% THD, 8/4/2/1ohm) 61W / 112W / 200W / 300W
Frequency response (20Hz-20kHz) +0.0 to +0.78dB (Amplifier)
Frequency response (20Hz-20kHz) +0.06 to –0.02dB (DAC/preamp)
Digital jitter (CD / USB) 195psec / 1850psec
A-wtd S/N ratio (DAC/Amp) 105.1dB (0dBFs) / 80.5dB (0dBW)
Distortion (20Hz-20kHz; DAC/Amp) 0.002-0.046% / 0.0065-1.09%
Power consumption 17W / 115W (16W idle)
Dimensions (WHD) / Weight 210x290x290mm / 7.5kg
Price £3000

T+A elektroakustik GmbH & Co. KG
Supplied by: The Audio Business, UK
01249 704669