Physically connect a Bluesond Node 2i to a downline, stand alone Chord Qutest DAC

I have a Node 2i and Qutest and they are hooked up as follows:
Node 2i RCA analog out into channel 1 of amp. Node 2i coax/optical digital out into Qutest then RCA analog from Qutest into channel 2 of amp. So I can A/B test.
I'm baffled. They both sound EXACTLY the same.
Not even the subtlest difference. Switching between channels 1 and 2 on the amp sounds like not switching at all.
The amp is a Roksan Caspian M2 integrated so should reveal differences if there are any. But they sound IDENTICAL.
I have A/B tested the Qutest with other DACs and can clearly hear how the Qutest outshines them. But through the Node 2i ... no difference between the Node's own DAC and the Qutest. 
Optical vs coax makes no difference either to my ears.
I have had friends listen and agree there is no difference. 
Any ideas?

Hilly230, set the output voltage on the Qutest to 3 volts and see if it still sounds the same...

ddude003, Thanks, I’ve tried that. With (manual) level balancing, still same SQ. Both very good, but from past experience with Qutest vs other DACs I would expect the FPGA 'Chord sound’ from it compared to a more standard Burr-Brown implementation as in the Node 2i.
Either the Node’s DAC is as good as Qutest or it is passing data to the Qutest in a way that hampers the latter somehow.
It’s not ’different but equally good’ but the EXACT same.
I would expect SOME difference.
Based on this experience I could sell the Qutest and be happy. But the FOMO part of me feels that Qutest is not fully singing with the Node 2i as transport.
Others report clear differences with the same streamer & DAC combo.
Wondering if I’m missing something.

@hilly230
My experience with the Bluesound Node2i / Chord Qutest combo is that the Node2i via its analog output using its own DAC produces a polite (some might say forgiving), warm sound that leans to the dark side; by comparison, with the Qutest the sound is richer, more detailed, and the sound stage is both wider and deeper, and may I dare say more ebullient.
In my system it's a very noticeable difference.
Given that you have already experimented with trying different output voltages, my next thought would be to look to the interconnects, especially the digital interconnects. The quality and character of the interconnects can make a big difference.

jazzman7 I've always been a cable sceptic, but this might send me down that rabbit hole. Got a digital coax cable you recommend?