Chinese entertainment for engineering students

The brothers got the drawings and the tasks assigned by Wang Xu.

Part of it is to make this drawing, which is not complicated. Even if the circuit diagram is etched by yourself, it will not be difficult for these brothers. It is estimated that it can be completed in one day. The parts are readily available here at Wang Xu. It is just a matter of installation and welding.

Welding is a technical job, and a few brothers may not be able to do it, but the department can always find competent people, so this is not a problem.

Finally, there are various tests and debugging. This is not a problem for the brothers. Borrowing the laboratory does not only cost money. They don't know that Professor Yan has already prepared the laboratory for them.

The second task is more troublesome. The overall design of this circuit diagram has low power and can only be applied to smaller speakers. It cannot push big ones with high impedance.

Wang Xu asked them to design two power amplification solutions on this basis, one using transistors and the other using electron tubes.

Don't look at just increasing the power. It's not as easy as replacing a few parts. If you don't clearly understand the idea of ​​the entire circuit, the content you replace at will may cause distortion of the circuit effect.

In other words, the originally designed high-fidelity output may become a modulated output that highlights one part and weakens the other.

In layman's terms, it's completely different.

And this is the problem Wang Xu gave them. Can Wang Xu do it? Of course he can, but Wang Xu can't do everything by himself. Leaving them a topic not only exercises their abilities, consolidates their studies, but also reduces their own labor. It kills three birds with one stone, so why not do it.

I believe that Teacher Yan also realized Wang Xu’s good intentions, so he happily promised all kinds of conveniences, and even the teachers who guided and urged them to study were ready.

While Wang Xu was secretly having fun, several roommates were still sighing secretly. Look at them, they are all sophomores, why is there such a big gap? It is really unacceptable to feel complacent after just reading the textbook.

In the past, I had only heard that there were many people in Shuimu, but now that I have seen it with my own eyes, I know how big the gap between people can be. It would be really disappointing if just one person came.

They are used to being top academics and have always been looked up to. They are the big devils that make people despair. Now I suddenly become a person who looks up to others, how can I be willing to do so? How can an arrogant student allow himself to look up? He immediately inspired endless power in his heart, I want to answer questions, I want to answer 100 questions.

Well, sophomore students are still young and haven't gotten used to being beaten by water and wood. There will always be people beyond people's normal thinking in such top universities. It's not uncommon for young people to give lectures to older people.

Only by working hard can you truly understand your own limits. Whether you finally recognize the reality or discover that you are actually very good and are still looked up to by others, the result is a good thing. While Wang Xu was having fun, he also had the intention of motivating them.

Since today's main goal could not be achieved, the brothers simply gave up the idea of ​​doing anything today and said goodbye. Wang Xu gave them a greeting and asked them to bring various materials and bring the circuit to Teacher Yan.

He also formally informed them with a smile that Teacher Yan had something to do with them, and the destination of the taxi was to go directly to Teacher Yan.

Wang Xu didn't know if his smile gave them the illusion of tightening their anus, but it was obvious that they felt the slightest chill, and even the strong Dadong shivered.

Wang Xu was humming and singing, and the life of the landlord's family was endless.

Then he continued his plan. He had actually designed a set of power amplifier circuits for his own use, taking the path of tube amps. Although tube amps were not generally recognized in this era, Wang Xu had always liked tube amps. Otherwise, just to look good.

It is also a listening room. If you put a bunch of square boxes, even if there are some LEDs, they will not look so high-end. But once the tube amp is turned on, it requires a sense of ritual to warm up. The weak electronic light during operation, accompanied by the music, constantly trembles and changes in brightness. It looks so high-end and classy, ​​so pleasing to the eye and heart-wrenching.

Okay, that's a bit exaggerated, but tube amps are indeed more fun. Compared with boring transistors, vacuum tubes do seem to be warmer. This is the common sentiment of most players. Otherwise, due to the troublesome use and maintenance and delicate quality of the tube amplifier, it is really not as easy to use as the transistor.

As for the temperature of the sound, it is very simple, because the electronic tube has a delay, and the delay of different electronic tubes is not consistent, and even the delay generated by the same batch of electronic tubes will be slightly different.

This delay will lead to a slight overlap of some waveforms, and because of the difference in delay, the resulting waveforms will not be exactly the same before and after, which removes the mechanical stiffness. This is the origin of the so-called temperature sense, which is essentially a flaw rather than an advantage.

Of course, it is the ability of music players to make clever use of defects, so it is acceptable that the tube amplifier can produce a warmer sound. But it’s not just tube amps that can do it. On the contrary, the tube amplifier cannot interpret that particularly smart sound. This is its real flaw.

But for normal vocals, it doesn’t matter whether it’s a tube amp or a transistor, just use whichever one you like. Wang Xu dares to say that the one you like is the best, and it's useless for others to say it.

Wang Xu had already handed over the printed circuits to be manufactured to the factory and received the finished products early, even earlier than the arrival of other parts.

Wang Xu even customized a set of all-aluminum alloy casing, which was an extremely luxurious act in the 1990s.

As for the materials brought back to the classmates, they are still used to build reputation, Professor Yan will understand. The principles I use are the same, but I focus more on the frequency band used for audio.

Everything is ready today, just need to assemble it.

It's a pity that some time ago, I was so busy that I forgot to make the speaker cabinet early, so I had to wait for the box before I had the amplifier.

Wang Xu’s hands are very fast and his welding skills are pretty good. This one is nothing special, just like a skilled worker. If you ask him to weld the Galaxy machine, he will definitely not dare.

So he quickly assembled the parts that had been prepared, and a device with a silver-white shell and seven large and small electron tubes exposed appeared in Wang Xu's workshop.

These tubes are not ordinary. They were produced in the Soviet Union. Well, it seems that they will no longer be used in a few days. Alas, the end of an era and reliving it did not stir up any waves in Wang Xu's heart.

Just when I saw the huge electron tube with Russian writing and five stars printed on it, I felt a little excited. It was wild, beautiful, and powerful, just like the dying Soviet Union.

After connecting the circuit and turning on the computer, the tube slowly lights up, giving me a sense of ritual and the power-on test is successfully passed.

"Beautiful," Wang Xu couldn't help but admire. Although he designed it himself, the result still amazed him.

——

(Four chapters today, so far)