Pre/Power Amplifiers

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