Suggestions for Balanced cable between Luxman C900U and M900U.

I agree that when using balanced interconnects, I have not noticed important differences among them in most cases. The exception was when using the expensive ones mentioned above; in blind tests with experienced listeners, they were considered disturbingly colored.

I am curious if anyone has used the External Pre-input source of the c900u. That is attached an external preamplifier, such as an Anthem STR preamp with DSP. I understand that the External Pre-input signal will be sent to the amp connected to the c900u even if the c900u is turned off. That begs the question whether the c900u can do anything to the External Pre-input signal such as the application of Tone controls or the Loudness button.

Since the RCA output are only available for this scenario, XLR not enabled, I was also curious if there is a difference in the sound quality between c900u’s RCA and XLR output, assuming same brand and make interconnects.

I am trying to understand the user case for the External Pre-input.

If the system is truly balanced, cables should not make a difference.

In the case of the c900u it does not support the AES48 balanced standard. This is a wiring issue and maybe not related to 'Truely Balanced". I asked Luxman Japan this question.

I recommend the Mogami non quad cables as well - couldn’t tell a difference in my fully balanced ARC system.

Audience AU24SX Balanced IC's. Use them between VTL 7.5iii preamp and Krell FPB 300cx amp and they are near-perfect. Detailed, full-bodied, natural sounding, don't do anything wrong. And reasonably priced. Can't go wrong.
Neal