Vintage

Tested via its 'Radio' (R) input, this vintage specialty achieved a full 18.6dB gain from its ECC83/EL95 triode/pentode combo, requiring 332mV for 1W/8ohm (the standard line level was 500mV in the day). Class A operation was claimed and the 26W dissipation is, indeed, unchanged whether the AG9016 is at idle or full power. The rear of the amplifier has a single set of outputs optimised for a 5ohm load – a good compromise even with today's '4-8ohm' loudspeakers – and rated at 2W/channel under unspecified conditions. In practice it achieved 2x1.3W/8ohm and 2x1.2W/4ohm at 1kHz with 2% distortion, increasing under dynamic conditions to 1.8W and 1.7W into 8 and 4ohm loads, respectively. There's a current limit of ~0.65A so the output falls into lower impedances, the AG9016 achieving 0.8W/2ohm and 0.4W/1ohm at a full 5% THD [see Graph 1, below]. There's no escaping the fact that the AG9016 must be used with speakers offering a 4ohm+ nominal load and very high 92dB+ sensitivity.

Aside from low power, the AG9016 retains plenty of other 'character'. Distortion increases with output level and at low bass/high treble frequencies [see Graph 2], from 0.4-1.15% at 100mW (0.1W) to 1.3-15.5% at 1W/8ohm (all from 100Hz-20kHz). Distortion increases markedly below 100Hz as the output is filtered – the response gently declining to –3.0dB/10kHz, –4.9dB/20kHz (and –22dB/100kHz) but peaking at +1.9dB/70Hz before rolling away to –23dB/20Hz [blue trace, Graph 2]. There's a corresponding 'bump' in output impedance from 1.4ohm to 3.7ohm at 70Hz while noise, from the rectifier in particular, resulted in a high –46dBV (5mV) residual and below average A-wtd S/N ratio of 72.1dB (re. 0dBW) in our sample. PM