Integrated Amplifiers

All amplifiers tested in HFN are subject to an accelerated (and fully automated) 30 minute burn-in – in this instance the hottest section of the Progression Integrated's heatsinks reached 50oC while the technical performance stabilised after ten minutes with distortion increasing from 0.10% to 0.19% (1kHz/10W/8ohm). Under likely listening conditions the heatsinks will run cooler and distortion will settle closer to 0.15% – a figure maintained very broadly with both frequency and output level over the amplifier's 200W/8ohm rated range [see Graph 2, below]. So while distortion is not especially low, with extended 3rd/5th/7th odd-order harmonics, it is impressively consistent (unchanging) with both volume and content. This is partly a feature of the limited feedback applied, as is the moderate 0.33ohm output impedance, and gently rolled-off treble reaching –0.75dB/20kHz and –8.2dB/100kHz.

The stepwise volume control operates in ±0.5dB steps over the top 33dB of its range, then ±1dB over the next 17dB (–50dB volume) before offering a coarser ±2dB over the final 20dB of its span (maximum range is 71dB). Overall gain is a sensibly modest +31.7dB and the A-wtd S/N ratio just a little 'above average' at 88.1dB (re. 0dBW). But the Progression Integrated's trump card is power – its 200W/8ohm and 400W/4ohm spec. beaten on the bench at 2x265W and 2x425W, respectively. Under dynamic (music-like) conditions there's a further boost with momentary outputs of 325W, 600W, 930W and 1030W into 8, 4, 2 and 1ohm loads. Note that under dynamic conditions distortion is higher at low power and also increases uniformly when driving lower impedance loads [see Graph 1, below]. PM