Bit depth conversion when using DSP Equalizer

[Hajime_Okano]

Roon Core Machine

Model: NUC11PAHi5
CPU: i5-1135G7 Processor (8M Cache, up to 4.20 GHz)
RAM: 16GB
OS: Ubuntu 20.04 LTS

Networking Gear & Setup Details

network: Ethernet(1000BASE-T)
Roon bridge: ZEN Stream

Connected Audio Devices

Accuphase: DP-410(USB input)
Above device accept 19kHz/24bit.

Number of Tracks in Library

about 10,000 tracks

Description of Issue

I use the DSP Equalizer and Headroom adjustment of Roon. My question is why the bit depth is converted to 16bit, though the original source 192kHz/24bit. The example of signal path is attached below.
Is it because the DP-410 is not identified by Roon?

The detailed settings of Roon are as follows. Volume control is set to Device volume. Max sample rate(PCM) of Audio device is set to Up to 192Hz, but set maximum bit depth is not specified because the corresponding menu was not found.

[ged_hickman1]

I believe it only does 192 24 when driven using the windows USB driver. It’s probably defaulting to usb 1 or something like that.

[Hajime_Okano]

Thanks, is there any way to output 192 24 from Roon Core on Ubuntu?

[ged_hickman1]

I don’t know, you’d need to talk to Accuphase about their USB implementation.

[Hajime_Okano]

It is resolved by the factory reset of the ZEN Stream. I do not know why, but it seems that ZEN Stream was temporarily malfunctioning.

The USB implementation of Accuphase was as nominal.

Thank you for your kind advice.

[ged_hickman1]

I should have thought of that too