Modified Single-ended output transformer with ordinary EI core power transformers, How to make output transformer
Keywords: Uppermachine output transformer production
Author: Peng Yuforeing
For the remote areas and ordinary hose enthusiasts, they have to make a spoiler, a "gallbladder". It is undoubtedly very attractive. However, this aesthetic desire is difficult to achieve, especially the key devices - output transformers, especially key devices - output transformers. Although many newspapers and online introductions have many finished products, it is very expensive. Two people to buy cattle in the second mountain will always be doubts. And some articles describing the use of power transformers to modify the amplifier output transformer. Some are too simple. The modified transformer does not meet the effects (such as high-tone highlighting, severe bass, etc.), in order to solve this problem. From the waste purchase station to buy a few pairs of exact EI-type power transformers with a very cheap price, it is satisfactory after the restructuring. Now introduce to everyone, the method is as follows:
First, the selection of a pair of 35 ~ 50W models exactly the same EI power transformer, the voltage coil in the two electricity tables, this problem is easy to solve, currently in the remote area, black and white TV is largely treated as waste treatment The power transformer in the machine meets the restructuring requirements. It is best to choose an old black and white TV. It is resistant to the transformer in it, and each layer is folded with an insulated paper. The old-fashioned electric meter is substituted by a new generation of card-based digital tables, and it is easier to find. I believe you can use a very low price to take these two things in the waste purchase station.
Second, the production 1. First carefully remove the core of the transformer and the voltage coil. This process must not break the wire pack or damage the transformer silicon steel sheet. Of course, the voltage coil iron core is not required, only the coil is used. Check if the silicon steel sheet of the transformer is intact, if rust or insulated paint, then remove the rust, then use the insulatory paint to be used, dry to be used. Carefully remove the secondary windings on the transformer wire pack and retain the primary coil. Demolition of the number of turns in the time of the time, and calculate the primary coil of the transformer according to the transformer ratio of the turns ratio.
2. The reason for the low frequency lower limit of the output transformer is mainly the primary inductance, the number of turns of the primary coil is too small, the inductance is small, the bass is insufficient. Generally black and white TV set EI power transformer primary turns around 1000 turns, and the number of primary coils of the L0W output transformer is about 3,000 turns. Therefore, in order to ensure the low frequency lower limit of the output transformer, the primary power transformer wire pack is wound. The total number of turns after the wound is preferably about 3,000 turns, too much will make the high-strength, and of course, it is necessary to approach the size of the space. The wound wire is taken from the enameled line in the voltage coil. What to say here is that it is almost impossible to buy a good enameled line in the remote area, and the electric meter is generally the formal large factory production. The quality of the enamel line should be guaranteed, the line diameter is 0.17mm. It is suitable for 10W Output transformer use.
3. Barning. In order to make it easy, it is suitable for beginners to wind, here to avoid cumbersome calculations, take about 3,000 turns of primary turns, then determine the secondary 4Ω, 8Ω or 16 Ω level. The calculation method is: the square ratio of the first-level turns is equal to the initial secondary impedance ratio. E.g. Primary impedance 5KΩ, number of turns 3000, secondary impedance: SQRT (5000/8) = 3000 / N
The secondary turns: n = 3000 * SQRT (8/5000) = 120
If the efficiency of the transformer is 75%. Then n = 120/0.75 = 160 turns. The number of turns wound in the primary is minus the primary turns of the original power transformer. After the first-level turns is determined, it began to be wound. If there is no winding machine, you can make a simple handwind. That is, the hand is wrapped around the line, and it will not be introduced here. Find some diameter of 0.33mm quality paint wrapping line winding, secondary division three-layer winding, first in the original line package (the original secondary) 3 line and bypass half of the number of illegitudes, Adding paper. Insulated paper can be sold for the wall coating of the wall coating, a very thin paper, which is very easy to use. Then around the primary, the wound primary is divided into two layers, each layer is one-half of the number, and the first level of the first level is clipped in the third level. The winding direction is consistent with the principal direction of the transformer. The latter two-level level is one quarter of the total turn. Pay attention to the order of the wire when winding. The lines of each level should be connected to the end, and the lead line is connected. Interested friends can also leave a tap at 43% of the primary turn. A curtain feedback line serving as a superlinear connection. It can effectively reduce the distortion of the amplifier and reduce noise.
After the wire pack is wound, the core is smooth, and the two-layer thick O.1mm is padded in the middle of the EI core. Then fixed the tightening iron core. The transformer adds a 100V voltage in the primary, then measure the secondary voltage, depending on the secondary impedance of the transformer is equal to the square of the voltage ratio, see if the secondary voltage is required, if not required. It may be that the primary outline connection is incorrect, identify the correct line connections. Until the requirements are met. Conditional friends can impregnate the winding output transformer, and there is no condition or not immerse.
The output transformer of this modified output transformer is very good, that is, the most common 6P3P is used, there is a considerable manifestation, the beauty of the tone, and the general transistor amplifier can be more than.
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