T+A PA 1100 E Integrated Amp/DAC Lab Report

Lab Report

The PA 1100 E's Class D amplifier bests its rated 140W with 2x160W/8ohm and 2x265W/4ohm while, under dynamic conditions, there's headroom to service peaks of 215W, 415W and 720W into 8, 4 and 2ohm loads with protection limiting output to 405W into 1ohm [see Graph 1, below]. Otherwise performance is influenced by the Class D architecture, including its slightly below-average 78dB A-wtd S/N ratio (re. 0dBW) that would be closer to 73dB if various ~18-22kHz spuriae were included. The reactive output impedance climbs from 0.040.05ohm/20Hz-1kHz to 1.1ohm/20kHz, peaking at 18ohm/52kHz, and influencing the amp/speaker response accordingly. Distortion also rises with frequency from <0.0035% through bass and midrange to 0.05%/20kHz and 0.1%/40kHz, but is typically 10x higher under dynamic conditions over the first few watts. This is clearly illustrated in Graph 1 while, under continuous output conditions, distortion increases more linearly with output from 0.001%/1W to 0.004%/10W, 0.014%/100W and 0.019% at the rated 140W/8ohm (all at 1kHz).

The PCM1795-based DAC stage offers a 104dB A-wtd S/N ratio from a 1.2V preamp output. Good jitter rejection is achieved at ~80psec (all sample rates, all inputs) while distortion falls to a minimum of 0.0009%/1kHz and 0.0022%/20kHz over the top 20dB of its dynamic range [see Graph 2]. The default FIR digital filter offers responses of –0.3dB/20kHz, –1.6dB/45kHz and –3.9dB/90kHz with 48kHz, 96kHz and 192kHz files, respectively. T+A's own Bezier IIR filter eliminates any pre/post ringing in the time domain but alias rejection is poorer and the responses are –4.6dB/20kHz, –5.7dB/45kHz and –7.6dB/90kHz. PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 20.1A


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

Continuous power (<1% THD, 8/4ohm) 162W / 265W
Dynamic power (<1% THD, 8/4/2/1ohm) 215W / 405W / 720W / 405W
Output impedance (20Hz–20kHz) 0.042–1.18ohm (518ohm, pre)
Freq. resp. (20Hz–20kHz/100kHz) +0.08 to –0.90dB/–7.8dB
Digital jitter (USB at 48kHz/96kHz) 75psec / 85psec
A-wtd S/N ratio (re. 0dBW/0dBFs) 77.8dB (Analogue) / 104.0dB (Dig)
Dist. (20Hz-20kHz; 0dBW/–3dBFs) 0.0014–0.007%/0.0005–0.009%
Power consumption (idle/rated o/p) 17W / 345W
Dimensions (WHD) / Weight 440x115x380mm / 14.0kg
Price £3660 (+£390 for HDMI card)

T+A elektroakustik GmbH & Co. KG
Supplied by: Kog Audio, UK
01353 721089