Integrated Amplifiers

While Talk Electronics' entry-level Edwards Audio IA1 is rated obliquely by the statement 'at its heart it has a 30W fully discrete class AB power amplifier section', in practice it manages a little less at 2x26W/8ohm and 2x39W/4ohm, the latter limited by electronic/relay-activated protection. But will the IA1 'sound' louder than this? In reality, yes, because under dynamic, music-like conditions there's sufficient reserve in the PSU to support 36W, 66W, 108W and 150W into 8, 4, 2 and 1ohm loads respectively (re. 1kHz/10msec/<1% THD). This is illustrated in Graph 1, below, along with the low 0.0025% distortion at 1W, increasing gently to 0.004% over the first 25W of its range. Distortion increases with decreasing load impedance – a not untypical behaviour – but still remains impressively consistent with increasing power output. Versus frequency there's the expected, but well governed, increase in THD at very low and high frequencies [see Graph 2], peaking at 0.035% at 1W and 0.08% at 10W (all re. 20kHz/8ohm).

The IA1's 0.02-0.08ohm output impedance maintains a response that's flat to within –1dB from 10Hz-22kHz/8ohm, rolling off (quite sensibly if used with DSD64 sources) to –11dB/100kHz. The plastic bonnet and fascia, while facilitating the option of different colours, is not as effective a screen as the traditional metal box! So residual noise is a moderate –65dBV and the A-wtd S/N ratio a very 'average' 85dB (re. 0dBW), all this from a full gain of +38.3dB, requiring 35mV to raise 1W/8ohm (0dBW). Finally, any DC offset is kept well under control at just 1-2mV, rounding off a very 'well sorted' performance from this compact but still fairly punchy integrated amplifier. PM