Please don't take offense, but FWIW, sounds like a short term approach and you might be better off figuring out what other component isn't natural enough sounding and making you feel like extra warmth is needed.
Sbank, none taken and I'll look into your suggestions.
I don't feel this is a short term approach, I've chosen wisely with the budget I've had (also spent a lot on power conditioning). The synergy between amp, speaker cables and Gallo speakers have a very natural and realistic image. I've substituted preamps and could hear the realism of a string quartet...it sounds lovely.
To quote you, "what other component isn't natural enough sounding..." It's the preamp; it is analytical with every type of tube. That's it's design and my mistake was during my audition it was paired with a tube amp.
I appreciate your advice and perhaps "warmth" is not the way I should describe it, but there's no doubt that a preamp upgrade is called for.