I'm downsizing and going to an SWR Super Redhead. I've owned one in the past and was always very please with its performance. My question is which preamp tube affords the best tone on that particular amp? It came stock with a Groove Tubes 12AX7A, but I'd like opinions on brands and models that give it a warm tone. Of course, these are strictly opinions but if a majority of you feel a certain brand and model works best, I'll go with it. I play mostly blues, old school R&B, some funk but am not a slappy-tappy wanker, and some classic rock. Thanks.