What do you see as the downside of tubes?

Loose bass, forward midrange, bright glassy upper mids/lower highs, rolled off upper highs. Variable performance. Unreliable. High maintance. Difficult to get replacement parts. When they break, they offer the potential to break other links in the system. Excessive heat. Potential burns to children, pets and others. Can cause fires. Requires more care in placement. Limited to use with high impedance speakers. High cost per Watt. Greater sensitivity to speaker cables. Sensitive to vibrations.

Why all the fuss - most of this is quite true although it is a matter of degree. Perhaps Unsound paints an overly negative description for sure, but if you asked people to make a general list of all the cons against tubes they would probably come up with at least four or five items from Unsound's even longer list.

Of course there are a great many pros for tubes starting with their sweet organic, harmonically rich, engaging and musical sound but the OP didn't ask for that.

Dopogue- I had always used Phillips ECGs for power tubes, until the prices and availability(you try and find a NOS, matched octet of KT88s or 6550s of anything, anywhere), made that unrealistic for me. I've been VERY pleased with the latest interation of the Winged 'C'(St petersburg) 6550s(from Upscale). Still- My system needs six 6922s(early 60's Siemens CCa for me), and four 6SN7s(1 pair each- 40's Tung Sol CTL/6SN7GT round plates and Sylvania CHS/6SN7W, tall bottles please) The presentation makes any time/effort to locate, or any money spent, well worth it.

In the last two years I have owned my first tube amps. rogue audio m150s. I too was afraid of all the bad things that can happen with tubes. so far they [the promblems ] have not happened. when I first got them an output tube blew within the first few days, and it just blew a fuse, no damage to anything else, and rogue replaced the tube for free. after that ,not a singe problem. they drive my revel f32s with ease. they are very easy to bias because they have a built in meter, and by changing the bias level, you change the sound of the amps, way cool ! same thing with changing tubes, if you want your solid state amp to sound different, you have to buy a whole new amp. I have tried all sorts of 12ax7 driver tubes, and the cheap as dirt sovtek 12ax7 lps sounds best in my system. so much for only the realy expensive tubes sound best bs. I have also tried 6 different solid state amps against the rogues and no one of them has had the body or 3d sound of the m150s. I love them , so good luck, and happy listening ! chrissain.

I recently obtained on audiogon a Kt66 SET Sophia integrated amp just for fun and installed it in my system for a trial period driving Quad 989,s.It clearly was not in triode capable of driving to high volumes but sounded terrific doing the relaxed female vocal thing.28 watts in pentode and the quads were almost getting there with rock but not quite.This amp is a thing of beauty and a keeper so I decided to get a second hand pair of Living Voice Avatars so it could realy shine.And the combination is great,making some of the best music in the room ever.All was rosy until I plugged the Avatars into the VAC 70/70 for the first time and sat there mesmerized, I spent all evening well into the night digging out all kinds of music I had not listened to for eons.I had traded for these beautiful santos rosewood first generation Avatars In the thoughts of building the perfect low budget system and now am left wondering if I shouldnt consider moving up the living voice line and possibly replace the quads.So the down side of tubes are they are not all created equal,listening to them is addictive,Good ones usualy cost serious money great ones cost more,they cause you to spend money on other parts of the system.Something like great transistor amps.

"I spent all evening well into the night digging out all kinds of music I had not listened to for eons"

Don't you love it when that happens?