Single crystal copper 5N Cu + Ag OCC degree silver enameled wire wound 20Ω 40Ω: 3K6 permalloy LP MC phono balanced output transformer.
20Ω: 3K6 boosts 13.5 times. 40Ω: 3K6 boost 9.5 times.
Most MC phono step-up transformers on the market are single-ended outputs, and there are few balanced outputs. Permalloy LP MC phono balanced output transformers wound with single crystal copper 5N Cu + Ag OCC silver enameled wire are rarely used. The MC phono step-up transformer with good material winding balances the output, and the lifting effect is obvious.
Features:
1: Years of experience in winding step-up transformers, dissecting a variety of imported tripod transformers, for reference and improvement, with the pedigree and genes of tripod transformers, the effect is extraordinary, and super cost-effective.
2: Primary and secondary multi-wire winding, single crystal copper 5N silver-plated enameled wire winding, five wire winding, unique in China.
3: Copper foil shielding inside and outside of the wire-wrapped iron core, permalloy foil shielding, multi-level shielding. Permalloy cover plus two copper-plated iron covers, a total of three shields.
4: Two upper and lower double-sided circuit boards, 4 layers of copper foil, strengthened shielding.
5: Broadband response: 10Hz ～ 170KHz -2.8DB
6: Sweden LUNDAHL impedance converter test, the data is accurate.
The above is not available in other domestic businesses.
This part uses Shanghai Jiquan series single crystal copper enameled wire material to wind the transformer. As long as your playback equipment is good, you can listen to it, you can clearly hear the difference, especially the AB switch contrast immediately.
The use of single crystal copper wire (OCC for short) for the production of audio wires is a major breakthrough in the audio wire manufacturing industry in recent years. Scientific experiments have proved that single crystal copper is a kind of high-purity oxygen-free copper. The entire copper rod is composed of only one grain, and there is no "grain boundary" between grains. "Grain boundary" will reflect and refract the passing signal, causing signal distortion and attenuation), so it has high signal transmission performance.
5N Cu + Ag OCC single crystal copper silver-plated gold film series enameled wire is quite different from the general enameled copper wire, especially in high conductivity or anti-interference characteristics and various efficiencies, high density and smooth The lacquered surface is not comparable to the OFC copper and low-purity copper enameled wire. It has a wide range of uses, especially for audio, which has a positive impact on sound quality.
The use of single crystal copper wire (OCC for short) for the production of audio wires is a major breakthrough in the audio wire manufacturing industry in recent years.
5N OCC single crystal copper enameled wire is used for audio signal transformers, vinyl MC phono step-up transformers, amplifier input and output transformers, passive step-up transformers, audio signal lines, etc., with excellent performance.
This MC phono balanced transmission transformer has three lines of input and three lines of output. The phono balanced amplifier is used together.
Suitable for 3Ω to 100Ω MC cartridges. Can also be customized according to demand!
A MC phono step-up transformer is added to the front of the MM phono amplifier to become an MC phono amplifier. There are a variety of MM phono amplifier boards in this part. .
LP records are attenuated at low frequencies and pre-emphasized at high frequencies. They need to be compensated according to the RIAA equalization curve during playback. Advanced record players use MC moving coil cartridges, whose impedance is only a few ohms to a dozen ohms, and the output voltage Only 0.05 ~ 0.5mV, need to boost the cattle plus pre-amplification.
The primary impedance of the booster transformer is 3 to 5 times the output impedance of the cartridge, which is more reasonable. If the impedance of the MC cartridge is 10Ω, the primary impedance of the transformer is 30 to 50Ω, the transformation ratio is set to 1:10 and the impedance ratio is 40: 3600. In order to avoid the interference of the electromagnetic field on the transformer, it is necessary to use double-layer or multi-layer isolation shielding of permalloy sheet and aluminum or copper to prevent interference.
The imported material with 85% nickel content and high permeability nickel material is punched and sheared, placed on a high-speed punching machine and punched with a special tungsten steel mold, and placed in a hydrogen furnace after a complex heat treatment process, which does not rust. Corrosion resistance can be used for a long time. This EI sheet has an initial permeability of 100,000 and a maximum permeability of 400,000. Used to replace the common transformer iron core can greatly improve the inductance of the transformer iron core, qualitatively improve and leap in sound quality, the best material for MC phono transformers.
Using this EI film to wind LP phono booster or signal coupling transformer with small size and large inductance has a good effect. Iron core size: length 25.5mm × height 19mm × stack thickness about 12mm, transformer thickness is only 0.16mm.
This transformer is an audio LP vinyl MC phono step-up transformer. It is disassembled and dissected to improve the winding of many famous cows. The copper foil shielding uses a complex winding method to reduce leakage inductance and distributed capacitance and expand frequency response.
Luge LG 20Ω 40Ω: 3K6 Permalloy LP MC phono transformer, the measured parameters of the transformer are as follows:
Frequency response: 10Hz ～ 170KHz -2.8DB
Transformer primary, copper resistance is about 24Ω, inductance is about 4.6H.
The secondary copper resistance is about 270Ω and the inductance is about 380H.
20Ω and 3K6. The turns ratio is 13.5 and the boost is 13.5 times.
40Ω and 3K6. The turns ratio is 9.5, and the boost is 9.5 times.
Test Equipment:
Signal generator: Japan LEADER LAG-120A
Level meter: Japan KENEOOD VT-186
Oscilloscope: Japan KENEOOD CS-5175 100MHz
Bridge: VICTOR victory 4090B desktop precision digital.
Transformer data measurement, welcome to visit the site
The inductance is subject to the VICTOR victory 4090B desktop digital precision bridge 100HZ frequency test.
When sold, the transformer is marked with test parameters and selected to match closely. Permalloy shield with circuit board as shown below.
The upper and lower shields of the permalloy screen and the double-layer circuit board are installed as shown below. The upper and lower two double-sided circuit boards, 4 layers of copper foil shielding, this is also a process and configuration that other businesses do not have.
Transformer plus three-layer shielding cover, double-layer circuit board, shielding cover is welded on the circuit board, effectively isolate and dry together. This is also a process and configuration that other businesses do not have.
The outer two layers are shielded iron covers, and the inner layer is permalloy shields, which can shield most of the magnetic field and electric field interference. Copper shields, aluminum shields, and iron shields cannot be compared. This is also a process and configuration that other businesses do not have. This is why the permalloy shield is used for the recording head, MC phono transformer, and MC microphone transformer. Otherwise, it is very easy to pick up or induce interference, and always engage in unclean communication.
The color of the cover is green and silver, and it is shipped randomly.
How to make an MC step-up transformer is first of all a theoretical design, and then the choice of materials and winding process.
The first choice material is Permalloy material with excellent performance and heat treatment of nickel containing more than 85%. Why should we choose this precious metal material? What happens with silicon steel sheets? The practical silicon steel sheet is not easy to make, and the index is not up, the effect is far less than using permalloy material.
reason:
1; MC output is only below 1MV, which requires a very large initial permeability, which can not be achieved with ordinary silicon steel sheets.
2; More than 10 times the transformation ratio, the secondary needs a large inductance to support the ordinary silicon steel sheet, because the permeability of the ordinary silicon steel sheet is not enough, the silicon steel sheet should be used to achieve this inductance, the volume should use the transformer iron state above EI48, which itself The iron loss and copper loss are almost exhausted for the 1MV signal. Moreover, its large volume of distributed capacitance and leakage inductance are very unfavorable for high frequency attenuation.
Permalloy is actually an iron-nickel sheet, which is divided into PC and PB according to different import standards of nickel content, which are about 85% and 50%, respectively. The corresponding Chinese standards are IJ85-75 and IJ50, which actually represent nickel content.
The importance of the nickel-containing ratio is that 70-90% of nickel-containing sheets are the most expensive and are mainly used for small signal pickup, such as cassette heads and LP cartridges. Using the advantages of Permalloy's high initial permeability, extremely low iron loss, and excellent frequency characteristics, it is suitable for use in MC transformers or pre-stage cattle.
A good iron core should have a good enameled wire. The wire warp used in this booster cattle is thinner than the hair wire, because the large iron core will bring large leakage inductance and large distributed capacitance, MC does not require large current, which determines the use of relatively small iron core The wire is wound with thousands of turns. This thin wire can be directly welded without QA specification without paint stripping, and the small dielectric loss of the paint film is helpful for high frequency. If it is not a high-grade pure copper, it is impossible to pull out such a thin wire, so the thinner the wire, the higher the purity of copper.
E25 permalloy is more suitable for LP booster than E19 permalloy, and this department has experimented many times.
Leakage inductance is the culprit of high frequency and detail, and the winding process is the means and method to reduce the leakage inductance.
To minimize the loss of copper resistance on the signal, material and design optimization is important.
The high-frequency wax dielectric used for impregnating materials has low loss.
Use good materials and good CNC mechanical winding equipment.
For MC cartridges with very low voltage output, it must have good impedance adaptability, increase the voltage of a few millivolts by 10–20 times, filter out clutter, and increase the signal-to-noise ratio. The high transformation ratio brings high difficulty. Through a lot of practice, the frequency response of the MC phono transformer is finally solved.
The adaptability of this MC phono step-up transformer to impedance is tested from variable frequency and variable source impedance of 2–100 Ω. The indicators are basically consistent with the design and the effect is satisfactory.
The output impedance of a general signal source is 50-600Ω, and the output amplitude is also much greater than the voltage amplitude of the phono. During the test, an external impedance converter is connected to the signal source output 600Ω impedance to 10Ω impedance, so that the source impedance matches the test transformer impedance That is, Zr = ZL, the test result is accurate. This impedance converter uses the famous Swedish LUNDAHL Lunda converter.
Test situation
1 Inductance, relative to the MC cartridge with a primary impedance of 10Ω, meets 20Hz (-1dB) and requires an inductance of about 0.19H. Considering the 0.2mV voltage of the cartridge, the cartridge transformer must have a sufficiently high inductance to avoid attenuation To reduce the insertion loss, it is a pity that the 0.2mV voltage is attenuated a little, and it will also affect the music details. For the effect, the low frequency 20Hz is further reduced by 10 times, that is, 2Hz, the primary inductance is required to reach 1.9H at -1dB, and the measured primary transformer transformer L 4.6H is much larger than 2H (bridge 100Hz 1V test). The secondary inductance reaches 560H.
2 Optimized design of primary DC resistance, measured R = 24Ω.
3 Frequency response 10Hz ～ 170KHz -2.8DB, 1KHz 0dB reference point.
4 Square wave test frequency point, 20Hz, 40Hz, 100Hz, 1KHz, 10KHz, 20KHz.
The above test data can confirm each other. For example, the primary inductance is less than 1.9H, then the frequency response index of 2Hz (-1dB) cannot be reached.
