Tube Amplifier Knowledge

                                                 Tube Amplifier Knowledge

Vacuum tubes, in most people's minds, were popular when Grandpa was young. Why did it become popular again? And I heard that the sound is great, and it is played by rich and tasteful enthusiasts. The above seems to be most people's impression of vacuum tube audio. Is it so difficult to buy audio and listen to high-quality sound playback? Although there are indeed many audio products and prices that are exaggerated to the extreme, it does not mean that the general public has no opportunity to enjoy high-level audio products, because there are many high-end audio products. , is also very civilian.

What are the main configurations required for a set of integrated stereos? In principle, "sources" are required, such as CD players, radios, and even ipods. Then you need "amplifier". There are many types of amplifiers. I believe that beginners often get confused. I suggest you don't care about vacuum tubes or crystals, and don't care about A-type or AB-type. Just remember one thing, either buy an "integrated amplifier", or a combination of "pre-amplifier" + "rear stage". Of course, you'll also need a pair of speakers and the necessary cables.

As for the way of purchasing, I suggest you first: set out an acceptable budget, no matter how much or how little the budget is. Find another trustworthy store and inform the store of your needs and budget. This is absolutely smart. Then try to find time to audition, or to understand the characteristics of the equipment. It is the only way to audition frequently and not be afraid of trouble. Novices should not ride a donkey to find a horse, otherwise they will spend more money in the end, but buy even less suitable equipment. How to judge a store with good service and reasonable price? There are several important factors. First of all, whether the combination they recommend really meets your budget, and then whether the store's description of the characteristics and performance of the equipment is detailed and accurate. Furthermore, according to the equipment you are interested in, does the agent or store have the ability to guarantee future maintenance? Finally, it is the way the store operates. Is it a decent operation? Is the price fair and open, and is the customer reputation positive? They are all clues to find a good store. Remember, there is no such thing as a free lunch in the world. There are people in the business of beheading, but no one in the business of losing money. Don't be greedy for petty gains, this is the basic principle of self-protection.

1. Do vacuum tubes really sound better than crystal machines?

This question is really classic. There are constant debates. It must be that the audio will exist for a day, and this question will never end. The characteristics of vacuum tubes and crystals are just like men and women. They have different structures, different personalities, and indeed different sounds. Which one is better? Both are good.

Finally, we return to the level of "needs". Perhaps the pace of modern society is too tense and fast. Many people go home to listen to music to relax, and the mellow and soft sound quality of vacuum tubes just meets the needs of many people, so they are very popular. Furthermore, the fire light after the vacuum tube is lit does bring a more interesting visual experience. Compared with the mighty crystal machine, it adds a lot of fun to play.

2. How can I choose a vacuum tube speaker?

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There are hundreds of vacuum tube machines, which one should I choose? The principle is very simple. First of all, choose a product from a good manufacturer, and there will be differences in product design and future warranty. Furthermore, choose a model that can be matched with the speakers. You need more suggestions and auditions from the store. Regarding the selection of models, don’t be preconceived to judge whether it’s good or not; don’t judge the performance based on “Class A”, “output power”, “strutting” or “PCB”, or even the number of vacuum tubes used. standard. A good machine must be designed by excellent engineers, which has nothing to do with which vacuum tube is used or how it works. In reality, scaffolding is much more ugly than PCB production. Smart audio designers design products with their own taste and experience. You have to listen to the product introduction of the store or the original manufacturer's instructions to understand it. In the end, you still have to listen to it to confirm whether it meets your needs. However, the price range of vacuum tube audio varies greatly. In addition, there are many types of products on the market, and the quality and price of many manufacturers have a large gap. It is undeniable that mainland China is currently the processing center of vacuum tube audio in the world, and there is a huge gap in quality, with some excellent products and others of weak quality. In the actual purchase, there is no need to know the place of production, because the more the place of production is advertised, the more careful manufacturers who have no word on product design and production quality should be. The actual situation is that manufacturers who can honestly report the place of origin and production status are often more able to stand the test.

3. Is the vacuum tube still in production?

Of course!! There are currently two major vacuum tube production bases in the world: St. Petersburg, Russia and Changsha, Hunan Province, China. The vacuum tubes produced by these two manufacturers account for more than 90% of the world. Others have some manufacturers engaged in sporadic and small batch production. For more than 90% of audio tubes, almost all of them are in continuous production. You don't have to worry about whether you can't buy vacuum tubes in the future? At least for the next few decades, the supply of vacuum tubes will not stop. The good news is that modern vacuum tubes are almost exclusively for audio tubes. Therefore, the requirements for sound quality are getting higher and higher, and the sound and quality have almost reached an unprecedented peak. In this day and age, it would be a pity not to have fun with vacuum tubes.

4. Should I worry about the life of the vacuum tube?

Vacuum tubes do have a lifespan problem, but they are not as short-lived as most people imagine. For a model with a normal design, the life of its vacuum tube should be able to last for several years for players with normal usage frequency. Of course, there are also models that consume the life of the vacuum tube very quickly, after all, these are very few. A model launched by a good manufacturer will definitely consider maintaining the life of the vacuum tube so that buyers can use it for a long time. Generally speaking, power tubes can last thousands of hours, or even tens of thousands of hours, and signal tubes will last longer. But vacuum tubes are the same as light bulbs at home. Some of them last for several years or even decades, while others stop singing suddenly. The rate of premature death is mostly less than 1%, which is low among industrial products.

5. What does the model of the vacuum tube mean?

Different 300B have different sound, even the appearance is different

Vacuum tubes have been developed for more than half a century, and there are many varieties of vacuum tubes, and the naming of vacuum tube systems varies from country to country. Therefore, there will be tubes of the same specification, but with different numbers. For example, for the most commonly used small signal tube 12AX7, 12AX7 is the American commercial number, in the US military number, it is 5751, in Europe, it is ECC83, and there are even British military code numbers, Russian and The Chinese system, but the model is different, refers to the same specification tube. It sounds complicated, so don't take it too seriously, in fact, you only need to ask a professional store to know which tube can be used on your machine.

6. Why are there so many brands of vacuum tubes of the same type? Is the sound bad?

As mentioned above, tubes of the same specification are available in all countries, and of course every manufacturer may produce them. This is like "car tires". The same size and specifications are made by several manufacturers, but their performance and price are different. Therefore, there may be several brands and even several different numbers of vacuum tubes of the same specification, but they can all be inserted into the same place for use. As for the sound, will it be different? Because the internal structure and materials of each tube, such as glass, internal metal, vacuum degree, filling gas, and the design and technology of various materials, the sound is of course different. Which one sounds better? Ask the store.

7. What if it is a vacuum tube + crystal model?

Since vacuum tubes and crystals have their own advantages, isn’t it better to mix them together? It seems that this theory is correct, but the characteristics of both are relatively reduced. Going back to the previous discussion, a good machine requires the taste and experience of an excellent designer. As long as you see the right model, the sound and performance meet your needs, why not? But for enthusiasts, choose pure vacuum tubes The combination of preamplifier and pure crystal postamplifier is very popular. This kind of thinking logic is to have the spiritual sound quality of the vacuum tube and the high thrust of the crystal machine, and if you want to change your taste in the future, you can choose to change only the front stage or only the rear stage, which is also a flexible method.

8. What is the pairing of vacuum tubes?

First, let’s explain why vacuum tubes need to be paired. Generally, the design of tube machine is nothing more than two working modes of "push-pull" and "single-ended". In the "push-pull" design, the power tube will hope that the current of the vacuum tube at the two ends of the transformer can be averaged, which can improve the efficiency of the transformer when it is working. At this time, the pairing of the vacuum tube current is necessary. For the single-ended design, in addition to hoping that the power tube currents of the left and right channels do not differ too much, if there is no negative feedback model, the difference in the amplification rate of the vacuum tube itself must be paid attention to. If the difference is too large, the left and right channels will be inconsistent. The signal tube has relatively low matching requirements. Generally speaking, it can be used within a reasonable range, unless there is a special need for the circuit, but this situation is very rare. A professional store must have professional matching equipment. You may wish to ask how to do the matching? What kind of equipment is used for pairing? Is the given data current value or magnification index? After multiple inquiries, those stores that are "matched by word of mouth" will appear one by one

9. Is the so-called "old management" worth buying?

Based on the current market situation, if you don’t know much about the types and historical development of vacuum tubes, how to judge the aging status of vacuum tubes, and the actual market, buying old tubes is as risky as buying antiques. Especially if the machine needs matching tubes, unless the seller has a large number of old tubes in stock, matching is almost impossible. If you do not have knowledge about vacuum tubes, I advise you to consider the risks behind buying old tubes; moreover, as mentioned earlier, the sound quality of modern vacuum tubes has almost reached its peak, so why bother to look farther away?

10. How to maintain the vacuum tube machine?

The use of the tube machine is nothing more than attention: enough space for heat dissipation, the power cord/speaker line/signal line, etc. must be properly inserted, remember to turn off the power if you don’t listen to it, reduce the consumption of the vacuum tube, keep the machine itself clean, and do not disassemble the machine casually, etc. focus. In addition, I would like to put forward a note, don't pull out the vacuum tube if there is nothing wrong, it will cause a lot of damage to the tube seat and the vacuum tube pin seat. Furthermore, if it is found that the tube machine is not working properly, such as burning tubes, burning fuses, etc., it is best not to deal with it blindly by yourself, and you should notify the manufacturer to inquire about the disposal method. In the case of burning the fuse, it is likely that there is a vacuum tube failure (such as a rectifier tube or power tube flashover); continuous testing of changing the fuse will cause great damage to the transformer. In short, if you encounter problems, let a professional come, and you will not go wrong.