Integrated Amplifiers

At the heart of Aavik’s I-188 amplifier is a Pascal L-PRO2S Class D module, rated at a maximum 800W/4ohm, and offering a total 28dB gain – with the I-188’s configurable preamp set to 9dB the overall gain was, indeed, +37dB. Aavik sensibly rates its amplifier at a more conservative 2x300W/8ohm and 2x600W/4ohm, figures exceeded in practice at 390W and 770W, respectively, at 1kHz with a <1% THD limit. Pascal’s UREC switchmode supply, and UMAC amplifier design, does offer headroom under dynamic conditions (not a given with all Class D amplifiers) amounting to 425W, 850W and 1.55kW into 8, 4 and 2ohm loads (re. 1kHz/10msec at <1% THD). Into very low 1ohm loads the module is protected at 980W [see Graph 1] although this 31A should be sufficient to grapple with the most difficult loudspeakers.

Viewed together, Graphs 1 and 2 illustrate that distortion increases with both level and frequency, the latter a function of the inductive filter network on the L-PRO2S PCB. At 1kHz/8ohm, distortion remains <0.001% up to 10W output, increasing thereafter to 0.0022%/20W, 0.006%/50W, 0.012%/100W, 0.02%/200W and 0.033% at the rated 300W. Versus frequency, THD spans 0.0005-0.026%/1W, 0.0009-0.06%/10W and 0.01-0.12%/100W (all re. 20Hz-20kHz). The frequency response of earlier Pascal modules [HFN Dec ’21] was influenced by speaker load impedance, but the improved Class D architecture of the L-PRO2S ensures the I-188’s response is relatively immune to your choice of speaker. In practice, thanks to its ‘flat’ 0.02-0.05ohm source impedance (re. 20Hz-10kHz), the I-188’s –0.1dB/20kHz/8ohm roll-off holds to –0.25dB and –0.55dB into 4 and 2ohm loads, respectively. For matters of noise, see our boxout on p63. PM