Audio Analogue Bellini/ Donizetti Anniversary Pre/Power Amplifier Lab Report

Lab Report

Power output, and the Donizetti Anniversary's ability to drive low impedance loads, is deeply impressive thanks to its 49A dynamic current capacity (<1% THD/10msec) and exceptionally 'stiff' power supply regulation. In practice the rated 250W/8ohm output is beaten with power to spare at 2x350W/8ohm and a very solid 2x680W/4ohm (this +2.9dB uplift is very close to the theoretical ideal of +3.0dB). Stiff PSU regulation also means there's limited headroom under dynamic conditions, but with 350W, 690W, 1.35kW and 2.40kW available into 8, 4, 2 and 1ohm loads [see Graph 1] the Donizetti will surely drive any likely partnering speaker with ease. The 'zero (global) feedback' topology sees distortion increasing quite markedly at HF (from 0.03%/1kHz to 0.35%/20kHz at 10W/8ohm) along with a moderate 0.14-0.15ohm source impedance and merely 'average' 86dB A-wtd S/N ratio (re. 0dBW).

Into a non-reactive 8ohm load the response falls by –0.28dB/20kHz and –3.8dB/100kHz while the matching Bellini preamp is flat to within ±0.02dB out to 100kHz but shows a broad but subtle uplift in bass of +0.06dB/100Hz, +0.08dB/20Hz and +1.0dB/5Hz. The Bellini Anniversary also incurs markedly lower levels of distortion than the Donizetti [black vs. red infills, Graph 2 below]. Distortion is much more consistent too, almost purely 2nd/3rd harmonic and a 'flat' 0.0035-0.0039% right across the 20Hz-20kHz audioband (re. 0dBV) with a minimum of 0.00065% at 600mV output. The maximum balanced output is 13.5V from a 72-73ohm source impedance and overall gain is a sensible +10.9dB (balanced in/out), bringing the total pre/power gain to +37.1dB. Noise is low, yielding a wide 99dB A-wtd S/N ratio. PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 49.0A


THD versus extended freq. for Bellini pre (1V out, black trace) versus Donizetti (10W/8ohm, red)

Continuous power (<1% THD, 8/4ohm) 350W / 680W
Dynamic power (<1% THD, 8/4/2/1ohm) 350W / 690W / 1.35kW / 2.40kW
Output imp. (20Hz–20kHz, pre/power) 73ohm / 0.138–0.154ohm
Freq. resp. (20Hz–100kHz, pre/power) +0.1 to –0.10dB / +0.0 to –3.5dB
Input sensitivity (for 0dBV/0dBW) 285mV (pre) / 139mV (power)
A-wtd S/N ratio (re. 0dBV/0dBW) 98.6dB (pre) / 85.7dB (power)
Distortion (20Hz-20kHz, 1V/10W) 0.0035–0.0039%/0.015–0.33%
Power consumption (Idle/Rated o/p) 101W/945W (18W, Preamp)
Dimensions (WHD, Pre/Power) 450x140x380/450x221x428mm
Prices (pre/power amp) £4999/£8999

Audio Analogue
Tuscany, Italy
Supplied by: Decent Audio, Stockton-on-Tees
05602 054669