If you've checked out my advice page, you'll know that there're a lot of lovers of 'glass audio'. Even Hansen, originally a big McCormack fan, has moved up to a Conrad Johnson Premier tube amp. Personally, I wouldn't mind a CJ amp myself if I had the $$$ :)

The question I deal with here is: should you consider getting a tube amp.

You can also read the bottom line at the end for a quick summary.

Lets go through the commonly asked questions point by point:

Maintainance
Generally, tube amps are no hassle. You have to change the tubes when they go. They'll last a couple of years (it varies... a lot). If its not autobiasing, you'll have to adjust the bias (to make sure the L/R channels are equal), and really you'll need ideally a multimeter for precision.

High heat will cause thermal degradation of parts. You should operate your tube amp in an air-con room. But still, a piece of equipment that runs hot should wear out/ break down faster than a piece of equipment that runs cool. This doesn't mean that the equipment is lousy, as all parts eventually wear out, the only question is when.

Hassles
One thing I don't like about tube amps is transformer buzz. If you read MC's review of the CJ CAV-50 in Stereophile, you'll note that he reviewed it in England, where the power supply is similar to ours. You'll notice that he attributed transformer hum to England's 50Hz power supply, and noted that people in the US would not have heard such hum.

By the way, I've never heard CJ amps in the Kingsley showroom hum or buzz.

At least the buzz is only at the transformer and doesn't go down the cables to the speakers. I've heard some 'home-made' amps exhibit quite amazing transformer buzz that could clearly be heard on the speakers. The shopkeeper explained that it was because the speakers were unusually sensitive... Well anyway, I'm not saying that all tube amps buzz or hum. Certainly, those with cheap transformers (the major part of the cost of a tube amp) are high-risk.

Warning: If an amp is silent in the showroom, it may still hum or buzz in your house and vice-versa. Ask the shopkeeper what happens if you bring home the amp and it buzzes really loudly.

Price & Performance
Personally, I feel that tube amps have a low price-performance ratio compared to solid state amps at the starting end of the price scale. But because diminishing returns set in earlier for solid state amps, at the upper end, tube amps and solid state amps have similar price-performance ratios (ignoring the cost of replacing tubes - otherwise, solid state still has an edge). Basically, a tube amp needs a good transformer. And this costs $$$.

I have not found a cheap tube amp that I like. Personally, they all sound quite opaque to me (let the flames begin....).

However, tube amps are easily upgradeable. You can do a 1-1 swap for a silver wound transformer, purchase some incredibly expensive capacitors etc. So, I can still recommend tube amps to people willing to do this. But bottom line is that you've got to be interested in doing all these things. You'll probably start out with a cheap $1-2k amp and end up spending $5k. But all the upgrading is part of the fun eh?

Can emotion compensate for opacity?
Tube advocates will talk about the emotion in the music etc, as if it were only the province of tube amps (no matter how crappy). Others will talk about harmonic distortion.

Actually, only the Single-ended triode amps exhibit this 'emotion' thing very well. I agree that it is very appealing for certain types of music (and you can think 'It can only get better as I upgrade the parts'). The budget SET amps (under $2.5k?) are a 'niche' thing, and if you listen to female vocals etc, it can be recommended. But note that on points, solid state amps still run them over.

As for push-pull, ultralinear and other non-SET tube amps. At the budget level forget it. They don't have the advantages of SET, so they just end up sounding like inadequate solid state amps. If you need more watts than SET at the budget level, buy a solid state amp. At this price level, you want emotion+power? No way. Upgrading non-SET tube amps is more tricky (you may be amazed at how simple a SET circuit is); make inquiries with your dealer.

Aesthetics
Jadis. Drool.... Gotta admit that tube amps (except Audio Research) look positively opulent compared to Krell/M-L (which look impressive in the bank-vault sort of way). However, some of them a so large/long that they don't fit into your rack, so put them on the floor in front of the rack and all sorts of cables get draped along the floor. There goes the aesthetics.

Audio 88 which sells cute little 'Houston' tube amps, takes photographs of customers' hi-fi rooms and displays them proudly (State of the Art, perhaps with a richer and more privacy-conscious clientele, also has photos but they're kept in an album for show to those who ask). When I look at the mass of cables all over the floor in some of them, I wonder what the wife thinks. When hubby bought that cute gold coloured tube amp she probably thought it was so cute and he can just place it discreetly on a shelf somewhere. He didn't mention that it would have to be placed on the floor and they would be connected to interconnects, speaker cables, and a power cord each the diameter of a garden hose.

Just because you buy a tube amp... it doesn't mean you're going to have wife-pleasing aesthetics. Its what you do to the rest of the room. :)

• Owning a tube amp comes with a few hassles
• Tube amps cost more because of the basic cost of a good transformer
• Cheap tube amps are bad because of a cheap transformer
• SET amps have virtues that can compensate
• Cheap Non-SET amps just sound like lousy solid state amps
• Luckily, tube amps are easily upgradeable, and there are a few DIY tube amp shops to help out.
• Expect to spend quite a lot on a good tube amp or to spend a lot upgrading your cheap tube amp to get good sound.
• It seems easier to tweak a tube amp to provide a sweeter sound than it is to tweak a solid state amp to give that kind of sound. However some tube amp manufacturers prefer to tweak their amps to compete with Krell/Mark-Levinsons.
• In the end, quite a lot of good tube amps sound a lot like solid state, so are we buying them because we like glowing tubes?