Newbie question about sound quality

[dmonds]

Hi there,

Before I ask my question here's a very little bit about what I have and what I'm trying t do.

I've recently been trying to evaluate different computer based digital audio streaming solutions.

My current setup is 2x Raspberry Pis, 1x 3B+ and/or 1x 4B.
USB to a Topping E50 then RCA to my amp then Duntech Marquis speakers.

I have my CDs ripped to FLAC and SACDs to DSD and sitting on a NUC running Win10 and available via a network share.

I'm currently trialling Volumio and Moode and trying to do AB listening tests.

Configuration of both is stock standard straight out of the box....no plugins, no CamilaDSP etc.

There is a slight but almost imperceptible difference between an RPi3B+ and the RPi4B with either software.

I was however surprised to hear quite a difference between Moode and Volumio.

Considering both should be able to deliver bit perfect streams to my DAC, can anyone advise why Volumio ad Moode sound different?

Thanks in advance.