There are many possible explanations as to why you hear differences, not the least of which placebo and expectation bias, but there's more to it than that. That's why I mention DBT (double blind testing). It has been proven over and over that sighted comparisons simply can't be trusted.\n\nSo there is nothing to the thought of one receiver vs another being "warm or cool" Also some are better paired with specific speakers? Let's say you have Klipsch speakers that are very bright, you don't want to pair them with a specific receiver. \n\nI have slight tinnitus and unfortunately my ears tell me the difference between my setups using the same speakers. They will start aching and ringing with HT setup in 2 channel mode.