I was curious about the potential of an internal ADC-DAC conversion with RCA to the Denon and asked Gemini's "Thinking" LLM mode... Apparently you need to set things in a very specific way, on a full moon, in order to make PureDirect(TM) actually pure... I enlarged the suggested Denon config to make it work, but the instructions are NOT verified:
Gemini:
"The Two Signal Path Choices
| Feature | Analog Path (Uses WiiM DAC) | Digital Path (Uses Denon DAC) |
| Connection | WiiM RCA Out $\rightarrow$ Denon RCA In | WiiM Coax Out $\rightarrow$ Denon Coax In |
| DAC Used | WiiM Ultra (32-bit SABRE) | Denon 4300 (AKM 4458) |
| AVR Mode | Pure Direct (Required) | Any Mode |
| Processing | Bypasses all Denon DSP | Uses Denon DSP (Audyssey, etc.) |
Why "Pure Direct" is the Ticket
To leverage the WiiM's modern DAC and internal High Pass Filter (HPF) processing without interference, the configuration you described is the most technically "pure" for an audiophile setup:
- WiiM Settings: Set the Crossover in the WiiM app. This applies the HPF to the RCA outputs and the LPF to the Subwoofer output.
- Physical Connection: Use high-quality RCA cables from the WiiM Ultra to an analog input on the Denon (e.g., "CD" or "Media Player").
- Denon Mode: Select Pure Direct.
- In this mode, the Denon acts as a "straight wire with gain," routing the analog signal from the WiiM directly to the volume control and power amps.
- It bypasses the ADC (Analog-to-Digital) stage and all internal DSP.
- Subwoofer: Must be set to None/Off.
- Note: If the Denon thinks there is a subwoofer or "Small" speakers, it may attempt to engage its own crossover, which would require digitizing the signal.
Technical Speculation
The ES9038 Q2M in the WiiM Ultra generally offers better signal-to-noise ratios and lower total harmonic distortion than the aging AK4458 inside the Denon. By using the analog path in Pure Direct, you ensure that the only processing occurring is the Parametric EQ and RoomFit performed by the WiiM in the digital domain before its own DAC converts the signal to analog.