"The amplifier sound, transparent, natural, sweet, sincere, not tired, is humanized. In building harmony, good life, the courage has become a good companion, which is also become a kind Fashion.
In the incense, especially the single-ended liner sound quality is best. Single-ended, 845, the single-ended group, becomes the best, the sound of the sound, and people do not forget. However, the single-ended ampholigramine composed of 300b is not enough, and the output power is generally only 6.5W, and the power is small for the listening space of usually 20 m 2 or more. 845 gallbladder, single-ended, amphoteric output power, about 20W, can meet the listening requirements. Just 845 high pressure bile ducts, the operating voltage is 1200V, which is not only the cost of production, not too safe, the production is also large. So, is there a gallbladder, the output can reach more than 20W, the size is not large, suitable for building a homing machine?
Western Europe is almost EL156. Many people in ELL56 are unclear. This is no wonder that ELL56 has been developed in 1968 and is a more young generation in the gallbladder family. In the 1960s, it was the peak era of gallbladder development. He later began to take a downhill. By the 1970s, foreign transistors have been fully entered into the electronics industry, replacing the status of the tube. Therefore, although ELL56 is developed as the latest excellent bile, it has been submerged by the large tide widely used by the transistor in the future, so that the surname is buried and less known.
Ell56 is developed from the famous German German German German German Germany. The audio produced by the company is fine, the shape is elegant, the sound is balanced, and the pure and delicate, it can be said to be the best, and the British Dadhuang (Mullard) is connected in parallel, which is the first brand of Western Europe. Unfortunately, the Deville Roots also closed the bile duct production line in the tide of transistors. Ell56 has already been discontinued.
Fortunately, my country's Shuguang Electronic Pipeline is based on the original information, and the ELL56 has been revisited and becomes the only manufacturer of the tube. According to the factory, ELL56 exports a lot of Japan every year, has become a new love of Japan.
Ell56 is a cathodic cathode, and therefore has a higher cathode radiation current and a lower operating voltage. The tube screen is up to 50W, which is 10W higher than the KT88 strong power. I am afraid Ell56 calculates the king of the side of the heat-type cathode. Compared with 845 straight butter bile, the filament of ELL56 is 2/3, and the screen is only L / 3. The single-ended output power can reach 25W, and the performance of performance is sigh. The so-called "later people hosted".
I. Circuit work principle
The drawings are A23i consisting of ELL56. . 156T in the circuit. This machine is a two-channel stereo power. Only one channel amplifier circuit is given, and the other is exactly the same.
As can be seen from the figure, the unit is magnified by two levels. The pre-stage use ECF80 (domestic model is 6f1), the power amplifier is used to use ELL56 courage, which is single-ended amplification. Typically the preamplifting includes preampling and pushing two-level amplification to meet the promotion requirements of the gallbladder. However, the ELL56 has excellent performance, only 20V is required to be full of power output, so the pre-stage and promotion is enlarged to magnification. In Hi-Fi amplifier, the magnification level should be minimized, so that the distortion and deformation of the signal in the amplification process can be reduced.
The preamplifier is bold ECF80 is three-pole, and the five-pole complex, the five-pole partitioned signal is amplified, and the triode is used as the load in the five pole amplification. Three-pole is equivalent to a non-linear load resistance, with a certain offset of nonlinearity in the five-pole, thereby reduces the distortion of the output (the principle of work is from ZL94212716.1 patent technology). In addition, the gallbladder can reduce noise due to the presence of a spatial charge effect. A higher signal-to-noise ratio can be obtained compared to the resistance load, and the quality of the signal output can be improved. Three-pole cathode access adjustable resistor WK regulation WK can change the tri-pole gallbladder, so that the predetermined amplifier is in a suitable operating range, ensuring that the predetermined output has the dynamic range of the large dry 20V to promote the power amplifier ELL56 full output . In fact, this pre-existing output range can reach ± 100V, enough to promote any gallbladder.
The post-level power amplification uses a super linear circuit. The superlinear circuit has the high efficiency and the three-pole output characteristics of the triode, which is a bile duct's unique power amplifier circuit. Due to the low block of the triode, there is a strong control of the speaker, which makes the speaker dampen well, which makes clear voice, rich in layers. The ultraliner circuit of this unit is achieved by resistance division, and the negative feedback voltage of the curtain is determined by the ratio of R5 and R6, and there is no need to take a tap from the output cattle. This "resistance division superlinear circuit" is to obtain the optimal curtain dynamic negative feedback voltage by changing R5, R6, so that the performance of the superlinear circuit reaches optimal. It also reduces the difficulty of the output cattle (the principle is detailed in this journal in 2004, No. 12). Since the output cattle is relatively difficult, the output cattle of this unit reaches a higher performance, and the load is more than 120kHz, which lays a solid foundation for the high level of the power amplifier.
The power amplifier circuit uses a self-propelled bias. ELL56 cathode string has a stable pipe DWL and resistance RN. DWL produces a stable cathode voltage of around 20V, so that ELL56 has a suitable gate negative pressure operating point. Rd is only 47Ω, but it is not eliminating, it has a stable operating point and a signal negative feedback effect, which can effectively reduce the power level distortion.
Typically, the power amplifier-level cathode voltage is achieved by a cathode resistance parallel capacitance. This is a traditional practice, but the capacitance needs to be sufficient to ensure the low frequency lower limit of the amplifier stage. HiFi power amplifier low frequency limit is less than 10 Hz, and the corresponding parallel capacitance will reach hundreds of μF to thousands of μF. This actually only uses electrolytic capacitance, and the electrolytic capacitor is poor, high, low frequency performance is poor, and the quality of the power amplifier signal is serious.
Regulatory diodes (DWL) are currently widely used regulator devices. Low frequency response to DC (0Hz), high frequency response hundreds of kHz, excellent performance, much more than the electrolytic capacitance.
However, DWL has no DC stability, so RN must be serially connected to stabilize the DC operating point of ELL56.
The gate of the power amplifier has a RB and CB high-frequency boost circuit to compensate for the loss of the output cattle to high frequency components. Although these high-frequency components have exceeded the hearing range of human ear, the replay contains this part of the high-frequency component will be more realistic and natural. The improvement of high-frequency components can make the amplifier to be wide, flat, and achieve high performance of HI_FI. This is an effective way to consider problems in the global consideration, but also a valid approach to overcome the lack of output cattle frequency. Using this method, the amplifier frequency response can be resistant to the transistor machine, reaching 80kHz, and the tone is also more better.
High-quality power placing the power circuit must pay full attention. In fact, in the case where the amplification circuit has perfectly perfect, each step of the power circuit will increase the sound quality of the amplifier. The power supply circuit of this unit uses field effect tube electron filtering, electronic voltage regulatory circuits, better than traditional filtering circuits, and is unparalleled in performance. Its supply power amplifier circuit is even more than the premium amplification The requirements are close to the ideal power supply. There is also a feature of the field effect tube, that is, the even harmonics generated during the work of the field effect is similar to the sound quality, and the sound is soft and sweet.
The filament voltage is powered by AC to obtain a better sound quality. In order to overcome the possible communication sound, there is a balance potentiometer WL in the filament circuit, and WL can eliminate communication.
In the circuit diagram, the individual components do not give specific values, and these components choose different values and varieties of sound quality, and the tone has significant changes, but does not affect the working state of the circuit. We look forward to the reader to work, brain selection, call up the best sound quality to learn from the exchange.
Second, the selection and production of components
Traditional courage is based on the form of components at the time, and the production process is just a "hand welding" mode. This circuit process is mature and is suitable for the level of components at the time. Nowadays, the circuit craft has already evolved to printed circuits, and the level of components has improved, small volume, high-capacity components are quite popular, and it is widely used for printed circuits. Compared to "Welding Welding", the printed circuit can be said to be a more advanced circuit process, not only high efficiency, but also more easily for complex and precise electronic circuits. Due to the computer wiring, the printed circuit can easily achieve the shortest connection between two points and the ideal grounding form. For the HI-Fi amplifier prepared to pay attention to the wiring, it is more ideal for printing circuitry.
This machine adopts 2mm double-sided gold-plated printed circuit, which not only completed the ideal wiring of the circuit, but also the gold plating line ensures high quality of the connection, so that the signal is smooth in the circuit. In structure, this unit is different from traditional incense. It uses "upper flip" form, power cow, output cattle, printed circuit and connector are installed in the bottom box. The center of gravity is moved down, more stable, in line with the pursuit of sound fever. When making it, the welding is completely connected to the printed circuit. The printing plate is mounted in the bottom box and a small amount of wiring is connected to the power cow, and the cattle is output. After the debugging is completed, all the production is over, there is no need to turn over like a traditional courage, and the installation, welding, commissioning is very hard. Close the upper cover of the aluminum alloy, a beautiful view, beautiful high-quality courage is presented in front of us. The structure of this machine is very suitable for fan DIY.
The resistor all uses a metal film resistance to ensure the stainless background of the whole machine. Where R5, R6 is 3W, the rest is L / 2 W. R3 is heated, and the 6W small wire is used to facilitate direct welding on the printed circuit board.
The volume control RW is in the signal input, so the Japanese Alps high-grade square potentiometer is used, which not only makes the whole machine signal-to-noise ratio guarantee, but also keeps the double channel volume control height synchronization, not due to the volume change Located drift. The ALPS potentiometer is extremely synchronized, and many potentiometers cannot be compared to it. Semi-adjustable WK, WS uses a high quality organic solid potentiometer. WL uses a precision fine-tuning potentiometer to accurately balance the exchange, so that the suppression of the residual AC noise of the unit can be comparable to the transistor machine.
The rectifier adopts the BY wavefrier high frequency tube, which is conducive to reducing power supply noise.
The choice of capacitance has a large effect on the sound quality, and is more important. CL, C2 need to use CBB capacitance, C05, and CF using ceramic capacitors, C04 adopts an imported CBB capacitor. Power filter capacitors use imported (ruby) large-capacity electrolytic capacitors.
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Third, debugging and sound quality adjustment
This machine is generally welded and assembled can sound normally, but it is necessary to make simple adjustments. Adjust WK, so that the TL five-pole mat is 165V. At this time, the 6f1 pre-magnification output can reach ± 100V, fully satisfying the requirements of the post-level power gallbladder ± 20V push voltage. Since the pre-export margin is much greater than the driving requirements, even W. No adjustments can also work normally, but the adjustment is better.
Use a digital multimeter to access the output and dial in 200mv file. Adjust WL, make the communication disappear, and the left and right channels repeatedly adjusted. Usually, below LMV, the communication sound is basically not heard, and it can be considered to achieve better extent.
This machine is A23i that I have previously introduced before. 156J is based on improved, the working principle is the same, just the pre-premium zoom in the bile duct. It has the pureness of 300B, and there is an elegant EL34 as ambiguous, and it is not lost in KT88. It seems that ELL56 gallbladder is a collection of extracters, and does the style of Western Europe. The gallbladder reproduction also proves the hardece strength of China Shuguang Electronic Pipeline.
The DIY is generally not advocated to replace the components for the machine. However, the taste of the audio enthusiasts is different, and every improvement in the sound quality is imposed. Therefore, this machine allows you to change individual key components to adjust the sound of the sound quality.
The potentiometer RS slides up in the middle point, the sound quality tends to be gently; the losses are increased to the down. The midpoint is 90F in the standard case.
C1 is changed from the German Weima (0.22μF / 630V) capacitance, the sound is more moist, bright, and the stereotact is clearer, the sound is natural, the truth, the treble is round and not sharp. If the Niceuko capacitor (1μF / 250V) is changed to warm, soft. If the metallized paper dielectric capacitor (0.22 μF / 160V), the sound is expected to increase. Compared, the sound quality improvement effect in the use of German Weima (pink) capacitors. The C04 original design uses my country's Taiwan's HTC CBB capacitance, which is characterized by nature, warm, and transparency. Changed to the Rapid (0.22μF / 630V) capacitance, the sound is clear, and it has moistening and feeling. C2 is changed from the German Weima Capacitor (0.22μF / 630V), and the transparency of the tone is increased, and it is cloudless.
In general, there will be some changes in the tone after switch to the brand capacitor, but can it be suitable for personal taste, it is necessary to appreciate the level of your own feelings and audio. This is because the audio appreciation has a strong personalized color, and the adjustment of the tone reflects some style and taste on the basis of excellent sound quality. This may be the fun of the audio DIY! This output power is 22W × 2, and the frequency is 1 8Hz ~ 60kHz, the distortion is less than O. 8%, the load impedance is 4 to 8 Ω. You can use the AE speakers of the British brand, which is very suitable for music appreciation. "
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