Audiophilepure

https://www.innerfidelity.com/content/quad-pa-one-headphone-amplifier-review

“The PA-One+ utilizes an two-channel ‘audiophile grade’ HyperStream ESS Sabre 9018K2M ‘Reference’ DAC chip capable of both asynchronous and synchronous 32-bit/384kHz PCM and DSD256 decoding. For this review I ran a Roon Nucleus+ into the PA-One+ with 16-bit/44.1kHz (FLAC rips) 24-bit/192kHz, DSD64/128 local-drive downloads and TIDAL and Qobuz streaming files. I did not tube roll the Quad as even though I have acquired (and continue to acquire) ever more tubes, they tend to input/line/phono applications, and I had no varietals of 6SL7/6SN7). I did not use it as a pre-amp either, rather, I focused on it’s headphone amp/DAC abilities. I used a variety of headphones, of varying impedances and sensitivity from the Audeze LCD-2 Classic, Mr. Speakers Aeon Closed, HIFIMAN HE1000se to Quad’s own Planar-Magnetic ERA-1, which had real synergy with the PA-One+ and that I settled on for all my critical-listening and review sessions.”