My DAC was mentioned. The Cary Audio DMS-650. It does have an output volume feature, I can play with that. Doing a direct A/B swap, the difference is not at all small. Other people have concurred. In my mind, and maybe that is the key, it makes perfect sense that various material choices, shielding, insulation and other design elements could certainly make a difference. Why burn in does not apply also does not make sense to me. Metallic elements are in play, the same as amps and speakers. Louis Armstrong singing Ssss's went from unbearable to not an issue. Granted there are many questionable things going on in my mind, but I doubt that such a stark difference in tonality is one of them. I would imagine that it is possible that high quality-ow dollar vs high quality- high dollar would be negligible. But the notion that there is no difference at all, especially since I initially went in with the "I'm NOT spending big on cables" mindset is a tough pill to swallow. I am talking about spending hundreds, not thousands. I carefully chose my components under the bang for buck mantra. In summary, I guess that I'll just ask what the believers think about burn in. No need for the "you are a looney tune" crowd to keep chiming in. There is enough of that going on in the world regarding many other contentious topics.Thanks.