Welding technology essentials for tube amps
Since the components of the tube amp are large in size, and the grounding wire is directly connected to the metal base plate, the heat dissipation during welding is strong. Therefore, it is necessary to use an internal heat type soldering iron of about 55W in soldering to ensure the full melting of the solder. However, the 25W soldering iron used for soldering transistor components is not enough, which is prone to false soldering or desoldering.
Flux used in soldering should be rosin or a normal neutral flux to avoid the use of acidic flux. Because acid solder not only has corrosive effects, but also causes circuit leakage. For the welding of one component, it is better to maintain a tilt angle of about 45 degrees between the soldering iron and the component, so that the contact surface is large and easy to solder. The welding time is generally maintained for 1-2 seconds, and the welding time of the grounding wire can be lengthened.
Before the component is soldered to the bracket, the component leads should be wound around the bracket or hooked into the hole, and then soldered. Before the component is soldered, the oxide layer on the surface of the lead must be wiped with sand and soldered.
When the component is soldered to the ground wire, the ground terminal and the ground wire must also be fastened. Or hook it to the solder hole and solder it.
For the components that need to be adjusted, lap welding can be temporarily used, and the welding is completed after the debugging is completed.
I don't know if the enthusiasts noticed that most of the world's high-priced audio equipment, in the publicity, said that it uses scaffolding welding technology, especially the high-priced amplifier, almost all of this time-consuming and laborious practice, and let go Universally used printed circuit boards. The main advantage of this is to further improve the sound quality of the playback, so that the traces between the circuits become more reasonable. Practice has proved that scaffolding welding is indeed better in the expression of sound. Therefore, it is also amateur enthusiasts
The experimental object of the party.
Conventional printed circuit board soldering is the mainstream of the electronics field due to its compact structure, beautiful appearance, relatively small size, and easy mechanical welding. However, because the printed circuit board is coated with a layer of copper as an electrical conductor, the quality of the copper skin is oxidized, the N factor and its thickness are limited. In order to be neat and tidy, most manufacturers use computer platoons. The board design draws, their copper skin conduction path angles are sharp, and the thickness can not be absolutely consistent, the current is not smooth when flowing through these places, and the resistance of the circuit board itself can not be randomly selected as the scaffolding type, and the phase The capacitance between the adjacent copper foils cannot be made very low. Taking a biliary machine as an example, it is easy to cause a sparking discharge on a copper foil in a sharp corner and a high-voltage copper foil on the circuit board. Since the internal resistance of the amplifier and the power supply voltage are high, the copper foil between the circuit boards is Partial capacitance also affects it, damaging indicators such as transparency of sound reproduction. In the design and manufacture of the amplifier, in order to reduce the interference and improve the signal-to-noise ratio, the gate leakage resistance of the gate is required to be connected to the input gate in the most recent way, preferably directly soldered to the gate of the gate, and the cathode The resistor also requires and is preferably grounded at the same point as the gate-drain resistor, and also reduces the potential difference between them, which is difficult to achieve on a printed circuit board, but can be easily accomplished by scaffolding. In fact, not only the amplifier, but also some disadvantages other than the above, even for the speaker in the speaker, the connection between the speakers, have a great impact. Now most of the speaker's crossovers are made of printed circuit boards, although neat and beautiful, but the influence of conductive copper foil is also there, because the speaker's crossover often has to pass a large audio current, the circuit The cross-sectional area of ​​the copper foil cannot be made too large, so that some power will be lost. Even if you increase the cross-sectional area to a certain extent, the quality of the copper foil has not been heard until 6N to N. High purity, which is more or less a regret for the current fever concept. Ali Audio Equipment Factory has done a lot of work and comparison in this respect, and has resolutely laid down the circuit board assembly, all using the scaffolding structure, making the circuit work more harmonious and smooth, and the sound quality has been further improved.
The so-called scaffolding production is to directly jumper wire welding at each joint with different quality and thickness wires, or to directly weld the wire by the lead of the component, with thick wire for large current and thin wire for small current, due to wire. There are insulation intervals, naturally no short circuit is formed, but the technology of scaffolding is relatively difficult. Pay attention to the direction between the wires, avoid the parallel arrangement that can produce coupling interference, and arrange the grounding point of the whole machine reasonably. The layout is arranged, the more intuitive and simple, the shorter the effect, the better the design can minimize the resistance of the circuit, the current circulation is smoother and unobstructed, and the distributed capacitance can also be made low in the scaffolding welding, so that the mutual The interference is further reduced, improving the quality of playback.
The highly skilled scaffolding welding is a buzzing lamp AC tube radio, which is almost exclusively produced by scaffolding welding technology. Nowadays, the popular crystal radio and recorder are inferior to the sound quality.
Due to the scaffolding welding, it is guaranteed by manual and superb technology. Therefore, compared with the printed circuit board, they are manufactured much more slowly, and the cost and price increase will follow. It is also expected. Among the results.
There are also successful examples of hybrid production, that is, the combination of printed circuit board and scaffolding. The main body is designed with printed circuit boards, and the key parts are manually combined and welded. In this way, it is also a clever way to reduce costs and improve efficiency without sacrificing the ability to express sound quality. The famous audio brand Sonic FronTIers is one of the best. Some products in Zhuhai Spark are also produced in this way, and the Ali speaker is another example of all the application.
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Jingkesai Electric Co., Ltd. , http://www.hobaoelec.com