Valves

Visit any decent hifi store these days and you will likely see a plethora of glowing tubes sitting on top of hifi gear. Aren’t they something from back in the 50’s and beyond? Well over the last several years they have made a comeback and more are on the way. Is it nostalgia or is there something about the sound these vacuum tubes produce that makes them so popular? Well it is probably a bit of both!

Sure, they look great and who wouldn’t want a beautiful piece of hifi sitting on the shelf with a warm glow, especially on these cold nights? Interestingly there are a lot of people who would disagree and think that valves should be consigned to the museum. Other think they are the best things since vinyl made a comeback. The truth is as usual with these things somewhere in the middle and depends on your personal preference.

Valves tend to have a certain warm sound that can be very easy to listen to. When valves are run into levels that distort, they have what is called even harmonic distortion and that does not sound as bad as odd order distortion that solid-state gear suffers from. So what does that exactly mean? Harmonics are overtones of the fundamental note. So the second harmonic is twice the frequency of the fundamental note, the third, three times and so on. The thing is that even numbered distortion tends to sound like it is in tune with the music hence doesn’t sound as bad as odd order which is out of tune. This is why valves distort in a “nicer” way. But they still distort and also can distort well before solid-state gear. As valves are usually lowered powered relatively speaking, people will turn them up more and may have these sorts of issues even if they don’t know it is happening. Distortion really is any altering of the sound, so even the warmness of valves may not be welcome to some.

That all said, they are very popular and for good reason. A lot of people like the warm sound and you can listen for a long time before fatigue sets in which can happen a lot earlier with solid-state gear. Plus there are very few people who don’t like the look of them! They do have their place though; I have yet to see a valve powered surround sound amplifier… So they generally do duties in higher-end hifi gear although some less expensive models are now appearing. In Asia valve hifi is very popular and it is no surprise that much of the products come from that area, especially China and Japan. There are so many brands now that have at least some valve-based units in their line-up. Some use a hybrid solution to obtain the best of both valves and solid state. This can be in the form of integrated amplifiers that use valves on the input stage (pre-amp section) and transistors on the power output stage. This will give you higher power but the sound will be warmer due to the influence of the input valves. CD players are also available with valves on the output; this is great for when you want the valve sound from your existing system but don’t want to change for a newer amplifier.

More and more new devices using valves are appearing, small amplifiers are now available that integrate with portable music players; pre and power amplifiers for car audio are out there with valves; computer motherboards can even be had with valve powered audio outputs! Some fake valve products have even appeared with lights to make them glow but these are usually gimmicks. As with any type of hifi product, you must give it a good listen and make sure you have the appropriate ancillary equipment. As mentioned earlier, valve amplifiers may not be as powerful as their solid state cousins, so speaker matching is often more important. Some valve gear, but certainly not all, is of very low power and really will only sound good with very high efficiency loudspeakers. Horn speakers are often used in these cases and have a sound all of their own; again personally preference comes into it.

So what to look for when trying valve based products? Make sure it is well built and has adequate cooling for the valves; they can tend to run warm. Protection from touching power output valves is useful especially when you have small children. Make sure you can easily get replacement valves, while they wont blow every month; they do not last as long as transistors do, so an ongoing supply is necessary. As many valves are still being manufactured, most brands use new valves that can easily be bought or you can even do valve “rolling”. Rolling valves is the name given to changing and trying different ones. There may be different brands of valves and types that are compatible with the originals. In this case you can change the tone or even upgrade the performance by using different valves. Make sure they are 100% compatible or the unit can be adjusted to accept the new valve otherwise you may cause some damage and even void your warranty. Some brands may even offer different types when you purchase the product as an option.

Written by Leon Gross, originally published in Audio & Video Lifestyle magazine.