Pre/Power Amplifiers

With a default unity gain (0dB), the 9000Q’s analogue preamp section includes a ±6dB ‘trim’, the +6dB setting realising a 2V output from a (balanced) 1V input together with a wide 98dB A-wtd S/N ratio (re. 0dBV), a response flat to within ±0.03dB from 5Hz–100kHz and distortion held to a super-low 0.0002–0.00054% (re. 0dBV). The 9000Q’s digital inputs – using the ES9038PRO-based platform seen in the partnering 9000A amp [HFN Aug ’23] and 9000N network streamer [HFN Mar ’24] – offer low-level resolution true to ±0.5dB over a full 110dB range, all from a 4V (re. 0dBFs) output with a fabulous 114.5dB A-wtd S/N ratio. Peak level distortion is slightly higher at 1kHz (0.0005% vs. 0.00025%) and especially at 20kHz (0.0013% vs. 0.00026%) in the 9000Q vs. the 9000N, respectively, though both settle out at a minimum of 0.00005% with upsampling switched off [see Graph 1]. Similarly, peak level digital inputs cause a digital clip of ~0.4% at 20kHz when ‘upsampling’ is engaged where there’s also insufficient headroom to accommodate intersample overs.

With 352.8kHz/384kHz ‘upsampling’ on, the 9000Q defaults to a gentle minimum phase filter offering a –0.4dB/20kHz, –9.6dB/45kHz and –4.8dB/90kHz roll-off with 48kHz, 96kHz and 192kHz inputs, respectively [see Graph 2]. Jitter is extremely low at ~9psec with 24-bit inputs regardless of whether ‘upsampling’ is engaged or not. The five digital filters include fast and slow roll-off linear and minimum phase types plus a fast roll-off hybrid option, these offering responses of –0.0dB, –3.4dB, –0.03dB, –5.0dB and –12.3dB (re. 20kHz with 48kHz files) traded against stopband rejections of 83dB, 14dB, 75dB, 18dB and 99dB, respectively. With 96kHz media the 45kHz responses are –0.5dB, –5.0dB, –0.2dB, –7.2dB and –23.5dB, respectively. PM