Here's what I'm using with the Revel F328Be.
1. RPi4 to USB for streaming Qobuz ($100)
2. RME ADI-2 DAC as pre-amp and DAC ($1299)
Buy RME ADI-2 DAC FS Ultra-Fidelity PCM/DSD 768 kHz DA Converter featuring Studio-Quality 2-Channel USB DAC, High-End Headphone Amplifier, S/PDIF & ADAT Playback, DSD up to 768 kHz / DSD256, High-End Amplifier for iOS Devices, 32-Bit / 768 kHz Converters, Built-In DSP with EQ, Crossfeed & More...
www.bhphotovideo.com
3. Purifi amp (March Audio $1720 or VTV Eigentakt $1139)
The P452 is March Audios' first Purifi based stereo amplifier. This simply elegant product is milled from solid aluminium with a tough anodized treatment. Exceptional fit, finish and build quality. Featuring the new Purifi 1ET400A technology and Bruno Putzeys development of his nCore designs...
www.marchaudio.com
The RME ADI-2 can support a sub with a built in crossover using RCA out. Another option is the MiniDSP Flex once it ships next year. With Dirac, Balanced TRS, cables it's a bit under $900. This would offer better sub integration if that's important.
https://www.minidsp.com/products/minidsp-in-a-box/flex
If price isn't a concern you might consider:
1. BENCHMARK LA4 LINE AMPLIFIER $2600
The award-winning Benchmark LA4 may be the most transparent line-level preamplifier available at any price. The 100% analog signal path features a pair of fully-balanced relay-controlled attenuators with 256 steps and 0.5 dB resolution. Designed, assembled, and tested in the USA using USA and...
benchmarkmedia.com
2. Dual BENCHMARK AHB2 POWER AMPLIFIERS in bridge mode - $3000 each
Benchmark's new AHB2 Power Amplifier - "The Quietest, Cleanest Audio Amplifier on the Planet"
benchmarkmedia.com
3. Topping D90SE DAC - $899
Note: The D90SE and D90LE line has been discontinued. As an alternative, please explore the next-gen TOPPING D90 III DAC page. The Best Got Better Fans of the D90 will be thrilled to hear that the SE/LE retains many of its predecessor’s best features: full balance, Bluetooth 5.0 LDAC support...
apos.audio