What do you see as the downside of tubes?

Unsound, taking your word that your not hitting the pipe, you may want to re-read your first post alongside the most recent post. The comparison may be revelatory and theraputic(just like good tube amps).

I haven't found a "downside" to tubes. My love for the sound of the real thing, and the frequency at which I get to hear it, demands that I get as close to it as possible at home. Ditto the cost of the best NOS tubes. My view of their cost is directly related to my love of music. Further: Tube rolling is an inexpensive/easy way for a person to give the sound of his/her system a gentle nudge in a particular direction. A flexible, purely subjective method of adjustment available, relative to the listener's tastes. Regardless of what aural preferences one may have: rolling a couple tubes can take one from merely, "OK" to Audio Nirvana. Try that with your SS system.

About tube-rolling, I was always a fan of NOS tubes and am now having second thoughts. I was using xf1 Mullard EL34s as driver tubes in my SET monoblocks and tried some of the reissue Genalex/Gold Lion KT77s instead and was floored at the improvement. Since the KT77s, while not exactly cheap, are MUCH less costly than the Mullards, it was definitely a win-win. Dave

Krauti:

You cannot run a tube amp 24/7 because the output tubes pass a lot of current and will wear out too quickly. This is generally not the case with gear like tube preamps or tubed DAC's that use small-signal tubes (little tubes) - 24/7 operation with small-signal tubes usually extends life and yields better sound, as turning gear on and off subjects the tubes to harmful thermal cycles, as well as a voltage rush on power up if the gear uses solid-state rectification, which is most gear. The latter factor is the biggest problem, which is another advantage of tube rectification and why a lot of tube preamps have a "soft-start" feature which applies voltage slowly to the tube filaments on power-up.

And as others have noted, a tube amp with a lot of output tubes will heat up a room (extreme cases, like ARC's 600 series reference amps, basically require a separate room or custom air conditioning unless you are running them in a gigantic room).

I have a solid-state amp (darTZeel) and tube amp (VAC Renaissance 70/70) in my living room, and run the solid-state amp most of the time because, like the poster who spawned your question, I like the convenience of being able to listen whenever I want. The VAC sounds good in 10 minutes, but sounds better after a few hours of operation, and I don't like powering up the amp and exposing it to a thermal cycle when I'm only going to listen for a few minutes. I do run the VAC in the spring and summer when there are frequent electrical storms, as I work far from home and am not able to get home to power down the darTZeel during electrical storms.

Just to be clear, the issue with tube amps and 24/7 operation is that the big output tubes pass a lot of current, even while idling, and this creates undue wear. Small signal-tubes, on the other hand, pass very little current in most circuits, and as I have written ad nauseum in other threads on this forum, when left on 24/7, they tend to either die within 200-250 hours from "infant mortality" (defective manufacture), or they basically last forever.

Maineiac, in my first post on this thread, I answered the Krauti's question. In my subsequent posts, I replied to the responses to my posts. "Revelatory, theraputic (just like a good tube amp).)"? Perhaps stepping way from the tubes for a while might offer you some perspective. It's not as though I am insensitive to many of the charms of tubes. I have yet to hear any speakers that do better with tubes that I care to own.