Where do tubes matter most???

Tubes in the pre-amp are easier to do and maintain, but the biggest difference in sound is, IMHO, found in the amp. I have an all tube system and I have to admit that I could use a good passive or a neutral ss preamp without loosing much but I just couldn't give up the tube amps. If your speakers can handle tubes and you can make the mental adjustment to maintenance of tube amps, thats the best way to go. Hybrids are popular and are nothing more that the consolidation of a tube preamp with a ss amp. There are tube integrated which have, essentially, passive line (pre-amp) sections and tube output's.

The biggest sound difference, tubes vs. SS, will be in the power amp, hands down. Having said that, I do not use tube amps for that very reason: they sound too much like tube amps, and I can't live with that much deviation from neutrality. Tubes are vastly better suited for the impedances seen in electronics, not speakers. This is one of those iron laws of physics that no one can do anything about. The closest I've seen to a real solution to this problem is the Berning ZOTL approach, but that limits your choices quite a bit. In the end, you need to listen for yourself, in your system, with music that you enjoy, and decide. The good thing about tube amps on Audiogon is that you won't lose much resale value if you buy carefully.

If your speakers are moderatly efficient , I prefer all tubes. They add a natural richness and level of realism that many SS components can not approach. Tubes do require a small amount of involvement for biasing , replacing tubes, tube rolling. I think its fun. I reccomend Audio research gear to get you started. Its very reliable and well made. My first ARC piece changed my 30+ years of audiophile experences.The sound is so amazing you will not believe how beautiful the sound can be from tube equiptment is.