Integrated Amplifiers

This modestly powerful little amp is still rated at 2x45W/8ohm and 2x65W/4ohm but now offers a little extra current to support low impedance loads, and lower noise to yield a wider 91.5dB A-wtd S/N ratio (re. 0dBW), up from 88.8dB in the Mk I. In practice it achieves 2x52W/8ohm and 77W/4ohm with 71W, 125W and 124W under dynamic conditions into 8, 4 and 2ohm loads [see Graph 1]. Distortion is reduced over the Vena Mk I, holding to 0.002-0.003% over the rated 45W power range through midrange frequencies. Distortion increases at low bass frequencies (0.006%/20Hz) and higher treble frequencies (from 0.002%/1kHz to 0.034%/20kHz, all at 10W/8ohm). Quad has engineered the amp's response from –0.65dB/20kHz to –7.5dB/100kHz, thus ensuring it's the DAC that determines the final bandwidth when listening via its digital inputs.

To this end, Quad has replaced the CS4398 DAC used in the Vena with an ESS ES9018 part in the Vena II. This alone is responsible for the fundamentally improved jitter rejection, down from ~1500psec via S/PDIF and a huge ~20,000psec via USB to <20psec via all inputs and sample rates in the new model! The choice of digital filter has also changed – a slow roll-off linear-phase type influencing both the subjective sound quality and response, now –3.1dB/20kHz, –5.3dB/45kHz and –12.6dB/90kHz with 48kHz, 96kHz and 192kHz files. With the volume adjusted to a 'standard' 2V line out, distortion peaks at 0.0025-0.009% (20Hz-20kHz), falling to 0.0004-0.002% at –10dBFs and 0.0004-0.0007% at –30dBFs [see Graph 2, below]. With the DAC's improved peak level performance also comes a 1dB uplift in A-wtd S/N ratio (now 109dB). PM