Keywords: 6N3, amplifier
Comments: The following describes a pre-set amplifier circuit that is directly coupled to a two-stage circuit. The first stage is the voltage amplification, and the second stage is a cathode buffer output. It can be said to be a simple and easy circuit, but it is important to note that the signal output is reversed. The line output to the speaker should be better.
6N3 fare-level consolidated pure-grade amplifier sound quality due to its own 天 类 功 功 功 功 将 将 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级 级It is not possible to match the material required for a moment, and use the idle time to make a front of the tube with it.
First, the selection of circuits This time I hope to use the existing parts and lower costs on the hand. The famous machine circuit is definitely not in line with it. Because the electronic pipes used in these famous machine circuits have been bursted into high-priced, they must be a hundred One more than a thousand, it is not possible to withstand. 6N3 This is originally designed for TV broadcast VHF / UHF amplification double tripod, which is a very good tube, and there is no music between 6n11 and 12ax7. The most important thing is that the price is very low, importing similar tube 5670 mail priced price is only 8 yuan a very value. The price is low, it is rubbish, and the price is high or not, the top is top, one is that it is expensive, and the other is the speculation of the merchant. The main reason for the 6N3 and similar tubes so far is that universal and 6N3 and its similar tube production are too large. 6N3 Characteristic Curve See Figure 1, from the 6n3 characteristic curve, it can be seen that this is not a big dynamic tube. The screen is preferably more than 150V. The maximum gate negative pressure does not exceed -4V, there is a good magnification line, More than the -4V curve will bend. Working point is selected between -1.5V - 2.0V, and the input voltage should not exceed 0.7V. This machine is shown in Fig. 2, V1 is shared with 1/2 6 N3, and the V1 anode load resistance is less than 18K to obtain a larger anode current fluctuation range, and there is less distortion, and the calculation is magnified. About 14.5 times. V2 uses 1/2 6 N3 as a cathode output, and the circuit drives the circuit to have a constant voltage gain in different complex loads. Direct coupling between V1, V2, which makes a wide range of frequently sound, reducing the adverse effects of coupling capacitance. The amplifying circuit is very simple, and there is only a few resistance capacitor parts, which is the purpose of simplifying the circuit to reduce production costs. The amplifier circuit is relatively simple and the power supply is quite attaches importance. After the high pressure of the power supply portion is filtered through the two-way π-type filter circuit composed of C101, C102, R102, R103 after rectifying the rectifier diode, it is sent to a regulated voltage composed of Q1. The circuit is regulated. The advantage of using the bidirectional π-shaped filter circuit is to reduce the power source ripples and filter out all the interference orders from the power grid to get pure. The voltage regulator power supply is used to do a power supply adjustment tube. The field effect tube is different from the triode belongs to the voltage control device. It is similar to the electronic pipe. It only needs to drive the voltage without the need to drive the current, and the power supply of the power supply adjustment tube is used. High speed, low intain, sound quality is characterized. The filament is supplied from the constant current source of LM317, and the power supply feature of constant current source is good, but the adjustment is only suitable for amateur production.
Second, the board design enthusiasts are used in the production of ambiguous machine. They all have a biliary fever for many years ago, thinking that the shed is more sounded than the board wiring. In fact, this is a misunderstanding, whether it is that the shedr will not be a shed, the board wiring people do not understand the wiring, whether the sound is the level of the technical level, not the way the parts. This is better than learning efforts, not in learning Shaolin or Wudang's Kung Fu, but is the high and low power. Today, the circuit board wiring is much more convenient than a studio. Figure 3 is a circuit board wiring diagram of this unit, and below is several points of the machine board wiring design. 1. Global considerations on the layout, signal transmission from right to left, the power supply portion on the left, so that the mutual interference between the size signal, the power supply circuit, and the power supply transformer to the amplifying circuit. 2, the left and right channels are symmetrical, the power supply is powered in the intermediate ring wiring, all signal traces and signal transmission traces wiring on the upper and lower side. The inner ring in the middle of the electromagnetic field generated by the power trace does not interfere with all audio signals on the outer row line on the upper and lower side. 3, all power supply circuits in the same current loop must be connected in parallel, all signals of all signals must also be connected to the line, which can make the electromagnetic field generated by the power line and signal circuit traces will never overlap In intersecting, the electromagnetic field generated by the power trace does not interfere with the audio signal on all signal traces, and the electromagnetic field generated between the signal circuit does not interfere with each other. 4, use as wide as possible copper film traces, weak signals away from strong signals, high signal traces away from small signal traces, and signal strength and weakness will never allow long-distance parallel traces. 5. A large-scale copper is connected to the power supply in a large area where there is no trace, and the same cab case is a double screen to improve anti-interference ability. 6. Try to use more jumpers to make the trace shortest and most direct, so as to avoid the circle, so that the electromagnetic field generated by each current circuit overlaps each other with each other to affect the sound quality. 7, all the lines are based on how the current circuit is analyzed. How to route, there is no one-point star ground that teachers advocated, although a little star ground has a better signal-to-noise ratio but not the best wiring method, only according to current The loop goes to analyze how to travel, the mutual interference between each current circuit is the smallest, the signal transmission path is shortest, the signal-to-noise ratio is the highest, the sound quality is best.
Third, the material production of the PCB plate is designed to print on the smooth surface of the thermal transfer paper (the paper carrier of advertising paper) with a laser printer, and then transfer to the copper plate, causing all of the drills. Welding elements can be installed after the holes are applied. The input and output socket use the most costly RCA socket, the volume potentiometer has a large impact on the sound quality, and the ALPS 27 blue plastic housing potentiometer is selected. R2, R4 These two screen load resistors and cathode load resistance are used for British resistors, and the high-frequency tubes such as 6N3 are slightly draped on the sound, and the remaining resistance is selected for Dale resistance. Filter capacitors and decoupling capacitors use Philips Blue Hex Electrolysis, Philips Capacity Features is relaxed, stretched, smooth, is expensive and the price is low, and the more expensive. The rectifier selection domestic 6Z4, the sound is relatively weak compared to the import tube, but the price is low. There are three types of 6N3 and its similar pilot pen: domestic 6N3, Russia 6H3, US GE 5670, domestic 6N3 is severely shrinking in high frequency or low frequency, dynamic is all, the sound is narrow sound, the Russian 6H3 high and low frequency is comprehensive, extended Ok, the sound is meticulous, the center is slightly weak, and the 5670 high and low frequency of the US GE is equally fully extended, the dynamic is good, the sound is permeable, and the medium frequency is slightly full of 6H3, which is used for this machine 5670. Conditioners can use the WE396 of Western Electric, and the sound is unmatched by the above three management points, but unfortunately the price is too expensive and hard to find. Output coupling capacitors use Sibi 4UF 200V white film capacitance, sound is full and the price is extremely low in only 3 yuan. Power transformers use the power transformer of the five-lamp electronic tube radio produced in the 1960s, 6N3 filament power supply transformers selected power transformers from black and white television. These ancient transformers are careful. The domestic transformers that are sufficient to scatter now. Many domestic transformers. The disadvantage is that the silicon steel sheet used is large, and the sound is not full enough. The casing is modified with the old CD cab case, and the front panel is converted to the solid wood board, and the rear panel is replaced with a thin aluminum plate. In the machine, the power transformer and the circuit board are separated by a thin aluminum plate to prevent the power transformer from leakage magnetic interference amplifying circuit, and the two transformers are separated from the mutual interference between the transformers. The volume potentiometer is connected to the front panel through the transparent hose and the long aluminum axis to perform volume control, and then the heat shrink tube is fixed.
4. Indicators Testing the conditions for conditions All test results are from the estimation of the YDS996A function signal generator and the CA8120 dual trace oscilloscope. The tube used in test is a domestic 6N3. This machine is more than 12 times, which is quite close compared to the theoretical calculation value. The frequency response characteristic is reached from 1 MHz when the small signal output is up to 1 MHz. When the large signal output is about 150 kHz, the maximum non-distortion output voltage is about 14V. The test of square wave, triangular wave, sine wave, no on small signal output or large signal output, no oscillating, no, no distortion, very stable. From 10 kHz, as the angle of the frequency of the frequency is slowly changed, until 1 MHz square wave turns a sine wave. Access this unit to the Tianyi AD-66H consolidated power amplifier, open the AD-66H volume potentiometer to the maximum, tightly paste the speaker treble unit in the ear, only increased under the original noise of the AD-66H. The thermal noise of very mild sand, this grade is even more excellent than many transistors. 5. Listening evaluation The sound of this unit is neither a warm, nor is it cold and beautiful. Its voice is not hot, not Xu is not going to be mixed, belongs to fine, elegant, smooth and soft. The high and low frequency extension is quite excellent, and its low frequency does not belong to the hot, but the first "Tianquan" when playing TIS, "Tianquan" when playing TIS, "Tianquan", the bass drum is deep and elastic, bass stickers The ground is soaked in the ground, and the top of the five internal organs is trembled with a bass of immersed. The high frequency is meticulous and smooth, which will be high frequency grinding from the CD machine sparks, and then the sound of the triangular rank is smooth and transparent. The details are better, and more details are able to hear more than some other fare-levels. The intermediate frequency is not full, relative to other daring front-level intermediate frequencies, the intermediate frequency style of Tongdan speakers is a bit similar, which is a soothing medium frequency. This machine has strong personality, regardless of any sound source, its high, medium, low three-frequency energy distribution is substantially equal, the tone is also roughly equivalent, it can bring the rough fire filter from the sound source " Education, easy and pleasant. Such a simple circuit, such a low cost production, what does Fu Fu?
Our other product:
