Do streamers make a difference?

Anyone heard the $6k Lumin U2 streamer. I just looked at a photo of it, and I see that it has a fibre optic input. I was under the impression that it was only the $10k Lumin U2x that had the fibre input. I used to own the Lumin X1 and it was a great streamer, but just a so-so DAC. The U2 and U2x are only streamers.

Streamers are different from each other just as other components are.

I wish I had ears that could make this determination – I do not.

I have done extensive A/B comparisons – between amplifiers (I can usually detect relatively large audible differences between many amps), between  preamps (subtler for SS comparisons but tube preamps vary widely), between DACs (still quite detectable but sometimes vanishingly small differences, depending on the units). But streamer differences – almost nothing compared to the others – for me.

My inability to hear may be a prejudice based on my understanding of how these things work – which may be wrong.

As I understand it, of all the components in the signal chain, streamers have the weakest theoretical basis for audible differences. A streamer's job is to pass a bitstream intact to the DAC — and on a functioning network, that's exactly what it does, regardless of price. Unlike amplifiers, preamps, or DACs, it operates entirely outside the analog domain and adds no gain, no impedance interaction, and no signal processing.

The one technically coherent argument is jitter, but modern DACs with asynchronous inputs and onboard reclocking largely eliminate whatever jitter the streamer introduces before conversion even happens. So even that argument depends on a poorly designed DAC to have traction.

Contrast this with amplifiers, preamps, and DACs, where differences are not only audible but measurable and theoretically explicable — gain, distortion profiles, impedance interactions, reconstruction algorithms. There's a clear prior reason to expect variation before you even sit down to listen.

This makes streamer comparisons hard for me. If I bought an expensive streamer, my expectations would be high and there'd be ideal conditions for motivated perception. 

These are the prejudices I have which might be preventing me from hearing differences. Or, it could be my physiological hearing, which is getting worse as I age.

@hilde45 hey you have quite the setup and room.  In one of your photos I see you have a Bluesound Node.  Have you actually tried other streamers because the NODE is more of a lifestyle product. While the Node is a good entry level streamer and DAC it's limited. I tried a couple different NODES and compared them to Lumin and Innuos on McIntosh, Yamaha, Prima Luna, and Accuphase components and NODES don't sound nearly as good as other notable streamers, not even close.  So I'm curious as to which other streamers you tried with your system.

I do not know if streamers make an audible difference or not, but ensuring the best connection for whatever transfer format one uses (USB, S/PDIF, I2S, etc.) seems to be universally supported, with the connection to the DAC being regarded as the most critical.

While I am able to say I hear an audible improvement going from a Roon streamer to a Nagra, it may just be because I removed a cable from the equation.

@yyzsantabarbara I A/B compared the Lumin U2 and Sonore OpticalRendu Deluxe with the same Finisar 1318 SFP. The Lumin had an inky black background and a smooth presentation. However, I preferred the more lively presentation of the OpticalRendu. I asked the Lumin dealer if there is a sound quality difference between the U2 and the U2X and he said that he could not hear a difference.