What do you see as the downside of tubes?

300b tubes are readily available as are all the other tubes mastersound uses. These tubes are all in current production. So many choices in new tubes plus if you want to roll tubes lots of vintage choices.

One of my output tubes flamed, welding itself to the socket and otherwise doing some damage to the amp. The amp's fuse blew, but not before a power surge blew out all the resistors in the crossover to one of the tweeters. The amp manufacturer repaired the amp, and the speaker manufacturer repaired the speaker. The speaker manufacturer maintained that the tolerances of the resistors would have withstood a surge from a solid state amp. My system is now all solid state. I like a quiet life.

Kusina, wow!

Gotta admit that as someone who just wants to spend as much time as possible listening to good sounding music for reasonable cost high power tube amps employing many tubes in particular do scare me. I'm sure they are fantastic when things are going right but when something goes wrong, then what? Even in lieu of a big bang like Kusina relates, it must take considerable time and energy to replace just the bad tube or tubes when needed.

I have one tube in my DAC, 3 in my phono section and 3 in my pre-amp line level stage. I've been running this setup for about half a year now without issue, but frankly, the thought of dealing with a tube amp capable of delivering in my system scares the crap out of me.

If I used high efficiency horns or some other high efficiency speaker design that did not require lots of juice to sound good, I might take the plunge.

Actually, my 2nd 2 channel A/V system running the Triangle Titus 202s fits that bill. Maybe someday there.....

I've seen a few mythologies espoused on this thread so maybe we can sort some out.

Triode-based amplifiers tend to have very consistent performance over the life of the tubes, which in general also lost longer. In this case, Krauti is considering a triode amp. Pentode tubes do degrade much faster, with far less consistent performance.

The idea of 'damping factor' is confusing and not helpful. It is certainly **not** required to produce deep, articulate bass with plenty of authority and slam. All speakers and amplifiers do not work together; if for example you think that because you have a solid state amplifier it will drive anything, think again. There are plenty of speakers out there that it will not be able to drive correctly, just as if you have a tube amp, there are plenty of speakers out there where the same applies. It is in fact a matter of equipment matching in all cases, see
http://www.atma-sphere.com/papers/paradigm_paper2.html for more info.

Heat: if properly designed, the components in a tube amp will last as long as they will in a solid state amp. Its as simple as that- otherwise we would not see vintage tube amps still in service after 50 years...

Also, it is a fact that class A operation makes for the best sound (all other things being equal that is), whether tube or transistor. So if we are talking about a tube amplifier, the heat it makes will be only slightly higher than a transistor amp that makes the same power. Granted, the heat **sources** are more concentrated in a tube amp, but for the record the difference between tube and solid state **if we are talking about class A operation** (and we are in this case), is only about 15%. IOW, the heat comes from the class of operation, not so much the device. Try running a transistor in class A with no heat sink and see how hot it gets (hint- it can melt plastic)!

What a great thread! I have been fascinated by tube amps for years and have never had the money or gumption to go that way,though the systems that I have heard have been magical.I am leaning more and more toward taking the plunge and going with a tube rig.I have a set of the original Snell "E 1s" and they should be a good fit for a tube amp or integrated.My main system has Acoustat 2s and unless I could aquire some serious big mono blocks would be a problem to drive.(If this is faulty thinking please say so)
The Dynaco ST70 and the upgrades/restorations available seem like a good starter path.Also I was thinking a tube preamp for the Acoustats might bring a touch of the tube sweetness I long for.
The Dynaco refurb route has a certain symmetry for me because I am driving the Acoustats with a Hafler 220,so I would have David Hafler's early and latest designs to compare a contrast.Also, it seems to me that since there are so many of them in use still that they must be doing something right.
The idea of tweaking and tube rolling sounds fun and interesting to me as well.Nothing is more fun than tweaking and discovering new magic in your system;after all,this is a hobby.
As for tubes going away in production;it seems that the Chinese and Russians are making them (military grade)in great number.(planning for Nuclear winter?)
Now if this recession/depression would just turn around,I could start shopping.:-)