Lamm Industries L2.1 Reference. It isn’t "warm" - it’s extraordinarily natural, and I’d argue that’s what you meant in your description and the only thing you’d want for long term satisfaction.
Here’s a review in Stereophile magazine: https://www.stereophile.com/content/lamm-industries-l21-reference-preamplifier, and another in The Absolute Sound: https://www.theabsolutesound.com/articles/lamm-industries-l21-reference-line-preamplifier. It's a special piece.
Industry disclosure: I’m a Lamm dealer.
Here’s a review in Stereophile magazine: https://www.stereophile.com/content/lamm-industries-l21-reference-preamplifier, and another in The Absolute Sound: https://www.theabsolutesound.com/articles/lamm-industries-l21-reference-line-preamplifier. It's a special piece.
Industry disclosure: I’m a Lamm dealer.