I've never looked after switching from my SS Hafler 500 to tubes over 15 years ago. I've owned tubes ever since and I've had no problems. Zero. I have never owned ARC or Conrad Johnson gear as I've heard of people having to spend $$$ on repairs for amps from those manufacturers. I've read that some tube amps have very complex circuitry and they run their tubes hot with a high bias. It's been stated that this leads to short tube life, or even worse, a tube failure along with some circuit damage when the tube blows. You want an amp with more simple, rather than complex circuitry, that runs the bias relatively low to avoid these problems. I came to these conclusions by asking friends, people at stereo shows, and even dealers I could trust about reliability issues. I've owned McIntosh MC 30, Dynaco Mk III, MkII, ST70 and I currently have Quicksilver V4's for the front, Quicksilver Silver 88's for the rear surround speakers, and a Dynaco ST70 bridged to 70 watts mono for the center channel in my home theater. I had a Counterpoint SA2000 hybrid tube preamp that I used for over a decade without a single problem. The Quicksilvers are very simple to bias, you just press a button, look at the readout on the meter on the amp, and turn a screwdriver. I checked them once per week when I first got them and now I've checked them about every 6 months. I very rarely have to adjust them, because the tubes are not run hot with a high bias, so they rarely sway from their initial bias setting. Auto bias is a fine convenience, but you don't really need it if you have a simple gauge set up like the Quicksilvers have. The Sonic Frontiers line of amps had this simple bias adjusting set up as well. I am in heaven now that I recently acquired a Zesto Leto preamp and a Zesto Andros phono stage. These two will be keepers for the long haul! What's kept me with tubes all these years is the freedom from grain, the liquidity, and the sheer honest beauty of the sound. I get the illusion of an actual cello, violin, guitar, or oboe physically there in the room with me. Not just a great sounding instrument also located in a similar place within the soundstage like I get when listening to solid state, but an actual airy physical presence emanating from within the instrument in a defined space within the soundstage. A holographic illusion that just keeps me coming back for more. I get the illusion of a singer physically in the room, and backup singers in the room as well. Everything just seems so much more airy, real sounding, and visceral through my tube gear than through my good friends' solid state systems. And they've spent more than double what I've got into my system at this point!
