Sound is such a hot discussed topic. I hope I do not tell too much nonse below.
At least this is my personal impression. But I might be wrong
@Daniel, are we all really saying the same thing in this thread?
I think you're possibly talking about easily perceptible sound differences, that a device doesn't add anything to the sound, transparent conversion. All RME devices certainly fall under this category, regardless of the age of the converter and the price.
Now, a counter example: KaiS prefers the slow filter on his ADI-2 Pro FS because he has found in listening comparisons that percussive sound sources are easier to locate. I haven't been able to determine that myself in my (acoustically unoptimized) environment and the mostly lower volume levels, but I believe him. In my opinion, he has the necessary background and the methodology to find out something valid.
Recording interfaces do not use D/A converters, where you can set different filters. I think there are only default filter in use with the highest possible linearity over the entire frequency response / low latency. Where the differences are, if I understood KaiS exactly, are mostly only hearable when using single speed.
But does that automatically mean that with different recording interfaces, nothing is happening around D/A conversion?
From discussions on audioscience review forum, I read some interesting postings on that topic. There appears to be a recognizable consensus that converter technology is basically at a high level. The main thing here would be the quality of the amplification stages behind it, which bring the signal to line level. Certainly also things like signal routing, activation of the converters in the firmware and whatever else.
Well, I can't prove it and I don't know if my ears are made for the job. But to be honest, I can't really imagine, when I take in all these impressions and information, that it doesn't really matter whether you're using a fairly old FF800 with converters from 2004 or a top current device like the UFX III or ADI-2 DAC/Pro .
That would also make your "promotional videos" like the Converter Shootout, where an ADI-2 Pro FS competes against HEDD and Lavry, somehow "ad absurdum". First, regarding the statement that Mr. Einstmann prefers the ADI-2 Pro for certain styles with its linearity/resolution in the bass (if I recall that correctly). I think he also says in the video that he prefers one of the three converters, depending on the sound material. At least here the good news, RME delivers devices that are nearly as good as high-end studio converters (specialized for AD and without add-on features) to a fraction of the price.
Well, RME may design the devices carefully, converts them transparently and squeezes out the last bit of quality. But, conversely, does that really mean that there are absolutely no differences, no matter how far back in time you go with the converters?
As I said, I can't prove it, but somewhere I can understand when such topics irritate in a certain way.
Am I doing right buying this or that etc ...
To sum up, up to a certain degree, I see it like you, RME does a high quality transparent conversion with all products.
But I doubt a little that there is nothing more to say than that.
Personally, I see it all quite pragmatically. With RME devices, I have a great sound at home, also with high-end HiFi devices. I trust RME the most here, without any (marketing-) Voodoo, to deliver the best quality with current converters.
But I really think everyone should find out with their ears because not all ears, rooms, setups, tastes are the same.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14