- I present a device with a pre-amplifier and a sound power amplifier integrated into one housing with perfect sound quality. The lamp has stabilized modes, in stereo it outputs a power of 350 W for each channel. In mono mode, if four 6p45C lamps are installed in the final stage, there will be 700 watts. The maximum power is indicated here - measured before the appearance of the limitation on the sinusoidal audio signal.
The picture is clickable. A large-scale scheme can be taken → Here
Natural musical power will be slightly less. If two lamps are installed in the output path, then naturally the power will also be halved. When assembling a tube sound amplifier, no special selection of tubes is required, since there is an adjustment function for each 6P45S tetrode. Therefore, everything is simple - take the diagram and start doing it.
Amplifier on tubes 6P45S
The tube amplifier assembled according to this scheme on 6P45S tetrodes has been repeatedly tested and works great. Two devices were made in a stereo version, if we consider it as mono, then we get four devices. This universal circuit makes it possible, without changing anything in it, to assemble the most simple lamp tube, such as, for example, an end amplifier and work with the remote control. Or make more complex designs, for example: with a built-in timbre block, or even more perfect - install additional input modules for connecting electric guitars, microphones or synthesizers.
Tube amplifier circuit, also allows you to make the amplifier both monaural and stereo. In addition, it is possible to install almost any amplification tube without making changes to the circuit. For example: instead of one 6P45S, 2 pcs can be used without problems. 6P36S or 6P44S. Based on this, it is easy to calculate: if the output stage is mounted on four 6P36S lamps, this will be equivalent in power to two 6P45S.
Output transformer
Also, the output transformer will work stably with an output stage consisting of both two 6P45S lamps and four 6P36S lamps. The output trance from the Soviet radio broadcasting amplifier U-100U4.2, which has an ideal frequency and excellent quality, has shown itself well in operation. If you find such a transformer, then it will remove a laborious problem for you - you will not need to rewind the output from scratch. In addition to this, the sound power turned out to be within 175 watts.
In this design, some of the nodes recommended by well-known radio amateurs were used. In particular, presented here tube amplifier circuit incorporates such output transformers. But you can install those that you have available and suitable in terms of parameters, everything will work fine.
Voltage regulator
A characteristic feature of this amplifier modification is the use of the stabilization mode function. The use of such stabilization eliminates the possibility of a negative impact on the device in case of strong drops in the mains voltage. Also, this tube sound amplifier is not sensitive to voltage surges in the power supply circuit, at which all modes of radio tubes work abruptly.
At the stage of assembling the structure, the apparatus was tested with and without stabilization of the modes - a huge difference between the two options was revealed. The device with a stabilizer was far superior to the second option in terms of reliability and stability in operation, clarity of the sound picture, and so on. Don't skimp on a pair of transistors. therefore the best solution will be for you if you additionally assemble voltage stabilizers. As a result, you will be rewarded with high quality amplifier performance and superior sound.
Installation of stabilizer transistors
For the convenience of installing transistors in the stabilizer circuits, you need to use transistors in a plastic case, which are easiest to attach directly directly to the amplifier case. Thus, providing good thermal stability to the transistors. In this circuit, I used transistors from a line scan and a power supply for branded TVs.
The constant supply voltage in the preliminary stage, supplied to the heating circuit of all the lamps installed there, perfectly coped with all kinds of manifestations of background distortion and noise. This is actually not audible at all. Naturally, I distributed the ground points that run from one stage to the next. And the last point is displayed on the common body at the cathode of the output tetrodes, and at this point the power wire converges high voltage by "minus". Pay particular attention to correct installation.
The use of the SRPP circuit (in the Russian sense - a cascade with a dynamic load) in the pre-amplification stages is completely justified by its resistance to overloads, excellent quality, and low output impedance.
The presented photos show the finished tube full amplifiers: The first is a full 700 W stereo amplifier; the second is a power of 300 watts.
The 6P45S power amplifier is assembled according to a common cathode circuit. Often, in the manufacture of such devices, radio amateurs pay insufficient attention to their coordination with the transceiver. The consequences of this approach are not long in coming - this is a small "swing" on the HF bands, and interference with television, and self-excitation (even failure of the transistors of the output stage of the transceiver), etc.
In this circuit (.), Thanks to the use of a low-pass filter (LPF) with a cutoff frequency of 32 MHz and a wide-band transformer T1 with a transformation ratio of 1: 4, it was possible to match the amplifier and transceiver with a VSWR of no worse than 1.2. In addition, the transformer T1 allows you to double the input voltage supplied to the lamp grid. Thus, with an input power of 5 ... 10 W, sufficient swinging of the 6P45S lamp is provided.
A way out of this situation was found long ago, but radio amateurs, as a rule, stubbornly make amplifiers according to classical schemes, and at the same time complain about the unsatisfactory operation of the device on the HF bands. Nevertheless, everything is done quite simply.The inductance L3 is connected in series with the capacitor C6 in the lamp anode circuit, which is selected in such a way that a P-circuit is formed together with the output capacitance of the lamp and the capacitor C10. Another circuit (common) is connected to this P-circuit, which also includes capacitors C10, C11 and inductance (variometer) L4, with the help of which the amplifier is tuned and matched to the load.
The RX / TX mode commutation is carried out by means of the relay К1 ... КЗ (fig. 2). With the SB 1 switch the amplifier can be switched to the “bypass” mode. In this mode, the output stage of the transceiver is connected directly to the antenna. If two lamps are used in the amplifier, the quiescent current of each of them must be set separately. For this purpose, it is required to connect another similar resistor in parallel with resistor R3. The output of the slider of the additional resistor is connected to the control grid of the second lamp.
The designs of the power amplifier on the 6P45S can be very diverse - it all depends on the capabilities of the radio amateur, therefore, the nuances on which its quality work depends will be indicated. The upper part of the amplifier case is partitioned into two halves. In (one of them is a power supply, the other contains a 6P45S lamp, an anode choke and elements of a P-circuit. All voltages supplied to the lamp and turnips must be supplied through the feed-through capacitors, including the channel voltage.
When installing the power amplifier on 6P45S, the input targets must be separated from the output by a screen. Input circuits- K1, T1, L1, L2, NW-installed at the bottom of the chassis. Lamp VL1, anode choke Dr1, parts of the P-circuit and K2 are located in the upper part. HF conductors should be kept short and as straight as possible. Relay windings K1 ... SC are blocked by capacitors.
Particular attention should be paid to the LPF. Structurally, the filter is made in metal case divided into 3 compartments (to exclude mutual inductive coupling between T1, L1 and L2). The filter capacitors must have an operating voltage of at least 100 V. In the first compartment there is a transformer T1, in the second-L1, C1, C2, in the third-L2, C4. The VD1 zener diode is mounted on a small heatsink isolated from the chassis.
The anode choke Dr1 is wound on a porcelain frame 020 mm with a PELSHO-0.31 wire, the number of turns is 150. The 50 turns closest to the anode are wound with a pitch of 0.5 mm. Coil L3 - frameless, 030 mm, wound with a silvered wire 02 mm with a pitch of 2 mm. L4 is a factory made variometer.
Capacitor C10 must have a plate gap of at least 1 mm. C11 - dual, or better built, from a broadcasting receiver. C6 must have an operating voltage of at least 2500 V. Relay K1 - RES55, K2 - pendulum, KZ - RES10. The DR2 choke is wound with two wires on a ferrite rod of 12 mm and a length of 70 mm made of F-600 material and has 40 turns of PELSHO 0.51 wire. DRZ - three-section, contains 150 turns of PELSHO 0.21 wire - 50 turns in each section, wound on a frame with a diameter of 5 mm, section height -10 mm. The broadband transformer T1 is wound on a Z0VCH K10x6x2 ferrite ring with two twisted PELSHO 0.41 wires (two twists per 1 cm of length) and contains 12 turns. The beginning of one winding is connected to the end of the other - thus the middle terminal is obtained. LPF coils L1 and L2 each contain 6 turns of PEV-2 wire 1.2 mm, the diameter of the coils is 12 mm, the winding pitch is 3 mm.
Establishment
Before turning on the power amplifier on the 6P45S, it is necessary to make sure that the installation is correct, that there are no short circuits, that all voltages are present and comply with the norm.
The setting procedure does not need any special explanation. The procedure starts at the highest frequency range. By compressing or stretching the turns of the L3 coil, the maximum output power is achieved in the middle of the ten-meter range. With the low-pass filter and P-circuit tuned, the output power will be about 120 W with an input power of 5 W. The low-pass filter should pass frequencies up to 32 MHz without significant attenuation. The LPF is adjusted by compressing / stretching the turns of the coils L1. L2 and changing the capacitances of capacitors C1, C2 and C4 (it is advisable to install trimmer capacitors). Tuning is carried out using the GSS at a frequency of 21 MHz, the RF voltage level is controlled on the control grid VL1 with the amplifier turned off. Next, the frequency response is checked for all ranges, and if a significant dip is detected in any of them, the LPF tuning process is repeated. The power supply circuit has no special features, therefore it is not shown.
“Messire, why are monsters? They are heavy, huge, and radiate intense heat. " To begin with, the magazine you are reading is not audiophile after all. What is audiophilia? This is a hobby for canned (in a good way!) Sound. The click of the power switch and ... enchanting sounds poured out.
Not from Edison's roller, not from a gramophone and not from a gramophone, but from yours, namely your acoustic systems. But how do you achieve magic, or charm with sound? Of course, using the appropriate components of the sound reproduction system. Let's not talk about turntables and speakers, let alone gold-plated cables and silver chassis.
Let's turn our attention to the amplifier circuitry. In the old days, in our vast country, all efforts were spent on "defense." Individual enthusiasts were involved in the issues of high-quality sound reproduction. There were few publications. The main achievements were obtained not with us, but somewhere overseas.
The main sources of information are also located there. Who have heard before about Cucing'a triode amplifiers, the famous D.T.N. Williamson'e or that the local transformer OOS in the cathode of the pentode was suggested by Peter I. Walker at f. Acoustical manufacturing, producing products under the Quad brand? Something has appeared in recent years with us. Although the information is still not enough.
- Firstly, these are lamps.
- Secondly, these are triodes.
- Thirdly, it is - (God forbid!) - not to use negative feedback (OOS) and class "B" (only "A"!).
Fourth, the simpler the circuit, the better it is. "One-stroke" is better than "two-stroke".
Unfortunately, I could not hear the actual “Ongaku” work. Among my acquaintances, there was no owner of this wonderful device from Audio Note. And all kinds of "Surf" and even one "Luxman" on the lamps sounded somehow equally "dull", and did not make an impression. But then, once, a familiar audiophile complained that the tube amplifier, which he assembled with his own hands in a year, did not justify expectations, did not "sound" and did not even give the required power.
I helped him adjust the lamp modes, reduce the background and get an output power of 6 W per channel, and also introduced a switchable OOS from the output to the input stage, i.e. covered three stages with it, which is often done in tube amplifiers. In addition, I added an RC circuit at the output (Zobel circuit) to eliminate RF oscillations at idle. For instruments, it turned out approximately the same settling time as without OOS, and the same exponent.
And so, we are listening to this amplifier. Sounds great! Deep, not tied to the speaker, surround sound is simply mesmerizing! We turn on instead of this tube "monster" American "Harman Kardon" (NK-1400) - transistor with OOS ("inexpensive", only $ 700). The sound is noticeably worse than that of a homemade one - there is no such volume and depth. We are launching the domestic lamp "Surf 50 UM-204S". The sound is even more “dry”.
Finally, the most decisive experiment. We turn on the OOS in a homemade lamp. At the same time, the bandwidth expands from 30 kHz to 100 kHz, the output power increases to 12 W with the same harmonic distortion (about 3%), and the output impedance decreases. Everything seems to be fine, but the effect is amazing! The sound becomes the same. as well as in “Priboi”. The charm has disappeared, the sound is "dry", there is no volume. not to mention the small details.
I don't want to listen. We remove the OOS - and the "magic" is restored! Again, I don't want to turn off the amplifier. I would have listened and listened ... Then we compared its sound with the sound of the Orbit UM-002 Stereo amplifier copied from the Quad-405, and found that Orbit was in the same place as the NK-1400, but the place is much lower than the homemade lamp.
It should be noted that the listening was carried out in the same room of 16 m2, with the same acoustic systems, with the same CD player, on the same discs (test, jazz, chorus, vocals, symphony orchestra).
The self-made amplifier is I. Morrison's amplifier, adapted to our configuration by A. Bokarev. I quote this simple scheme(Fig. 1) with the OOS circuit, which improved the objective technical parameters, but “spoiled” the sound. The amplifier uses a case and transformers from the UZCH "Priboy 50UM-204S".
The supply voltages turned out to be slightly less than indicated in. The power output was also lower. What does the use of triodes instead of pentodes in the output stage give? Rather, 6P45S lamps in triode switching, in class “A” and without OOS. In class “A” the output power is significantly reduced at the same supply voltage, compared to class “B”.
But for high-quality sound in small rooms (16. ..18 m²) and with speakers with a high output 6… 8 W per channel is quite enough. The triode connection gives a lower harmonic distortion than the pentode one, times 2 -5% and 10%, respectively (without OOS) at optimal load, and even less with an increase in the load reduced to the anodes, but at the cost of reducing the output power.
The internal resistance of the triode (Rj = ∆Ua / ∆Ia) is much less than that of the pentode. This can be seen from the given anode characteristics of the GU-50 (P-50, LS-50) pentode (Fig. 2). In a triode connection, the GU-50 and 6P45S have practically the same output characteristics. For 6P45S in a triode connection, they are given in.
The use of an output transformer designed for a pentode and having a high inductance of the primary winding makes it possible to greatly expand the frequency response towards low frequencies, since The Ri of the triode is several times smaller than the Ri of the pentode. For the same reason, the effective capacitances of the windings are recharged faster, and the frequency band expands to the high frequency side.
The small Ri of the triode gives a low output impedance even without OOS, although the low frequencies are somewhat emphasized. And finally, the most important thing. The absence of OOS gives a purely aperiodic transient process, without pulling and fluctuations (tyst = 10 μs to 99% of the steady-state value of Uout). The introduction of a resistive OOS with a depth of 20 dB (only resistor R7 is turned on) leads to large fluctuations in the transient response (CT). The oscillation amplitude reaches 60% of the pulse amplitude, and the oscillation period is 6 ... .7 μs.
Turning on the capacitance C2 = 1500 ... 2000 pF eliminates oscillations, the process becomes similar to exponential, tyst 5 μs. Oscillations with a period of 6 ... 7 µs indicate the presence of a resonant maximum or a dipole on the Bode diagram at a frequency of about 150 kHz, which can cause a delay in the HRC and “spoil” the sound. So choose! Or efficiency like a steam locomotive and great sound, or good performance and a desire to turn off the amplifier as soon as possible. Low efficiency will not frighten audiophiles. Their slogan is: sound quality - at any cost!
The article is devoted to some of the features of building an amplifier on the most powerful and relatively small-sized lamps from the series known as "television". Considerable amount of reasoning is given in the text on related topics. Oddly enough, it is the adjacent areas that are extremely important to ensure the resulting quality of the amplifier. For example, it is the matching transformers that radically affect the sound, not the lamps. Serviceable lamps have practically no effect on the sound amplification characteristics. However, the lamps look beautiful and glow in the dark. And this is probably why the names of the lamps give the impression of decisive signs of the quality of the product. Already by appearance the solidity of the pot-bellied glass cylinders 6P45S is noticeable. Taking into account the power reserve, traditional for sovdep-lamps, it is possible to build a push-pull amplifier in which the scattering of the anodes can be increased to 45-50 watts. With such a large dissipation, the heat release will be enormous. This is of course a disadvantage. But, according to the GURU, the sound quality in modes close to A, you can get excellent. My attitude to such extreme is cautious. I'm not a supporter of the "A" mode in a tube amplifier. The second inconvenience of 6P45S can be considered the upper location of the anode outlet. In addition, the incandescent current is 2.5 amperes and the lamps heat up very much, which is also inconvenient. Therefore, a structure with a closed mesh top, or at least with crossbars, should be envisaged. For heat dissipation, it is possible to recommend the use of low-noise computer fans at + 12VDC, which automatically turn on when the case heats up over 50 degrees.
Given the hefty wattage of the lamps selected, close attention should be paid to the design of the power supply. It should be noted that the traditional frivolous attitude of many TV viewers to the power supply of a tube amplifier is not suitable. An amplifier's power supply is its powerplant, the heart of its design, and the source of all its success. The power plant must be created extremely thoroughly and precisely according to the block principle. And novice lamp-builders need to learn how to quickly and accurately calculate the required power of power transformers. It is better to focus on the maximum consumption mode and approximately calculate the total power of the transformer windings. First, you need to calculate the power dissipated at all anodes. In the limit mode, 4 lamps can dissipate 40x4 = 160 watts. Small lamps dissipate 4-6 watts in the anodes. Then you need to add to the heap the power that is planned to be sent to the load, for example, 50x2 = 100 watts. Filament circuits of powerful lamps consume 2.5x4x6.3 = 63 watts. Small bulbs will consume 12-14 watts. In total, the resulting consumption is 260 + 75 = 335 watts. The design value of the efficiency of a two-channel amplifier does not exceed 30%.
The power of power transformers can be somewhat reduced, since the maximum mode is used extremely rarely. When designing transformer power supplies, the large overload capacity of transformers is taken into account. For this reason, this is usually done when creating serial amplifiers, reducing the installed power of the PSU by 20-30%. Such a solution is quite permissible, however, for high-level amplifiers manufactured in a single copy, it is better not to do this. In addition, the incandescent power cannot be reduced, since heat losses cannot be fooled. Nor should the value of the installed power of the transformers be overestimated, since this unjustifiably increases the weight of the product. Remember, with the calculated power value of the power supply transformers, the ratings obtained correspond to high temperatures exploitation. Therefore, heating the transformers to 60 degrees should not come as a surprise to the designer. If in the head of the viewer there is an idea that the iron should be cold, then all the power should be doubled and prepare for the fact that the mass of the 15 W amplifier will become 35-40 kg.
In my opinion, the most promising circuit solution for push-pull tube amplifiers of high energy efficiency should be considered a matching stage based on a differential pair of transformers. The advantages of such a scheme completely cover its disadvantages. Any reasoning about hand-to-hand winding of matching transformers in a tube amplifier, I attribute to perfectionism. To me, this seems to be one way of self-consolation for the designer or one of the marketing steps in justifying the extreme cost of the amplifier. Self winding is a harmful excess and stupidity. By itself, hand-to-hand winding of transformers into a push-pull amplifier is not technically difficult. But making a symmetrical pair is no longer an easy task. Manual manufacture of an identical four of transformers for differential series connection is a project unthinkable in complexity. For single-ended amplifiers, the creation of symmetrical trances is realistic, since according to Ignatenko's technology, tapping with a hammer can be used when adjusting the air gap on the glue, along the joints of the cores. The characteristics of iron for transformers with a gap are not of particular importance, since a gap of 1000 times or more dampens the magnetic properties of the core.
An example of a first level schema is shown below. Here the anode voltage is quite high, and the grids are connected according to an ultralinear scheme to the symmetrical 42% taps of the transformer windings, relative to the center of the anode supply of +330 volts. This is not good, because, in theory, the second grids should have a voltage lower than the anodes. And in practice, such an inclusion, along with the advantages of the ultralinear scheme, may have a disadvantage - the appearance of additional distortions described by Ignatenko. Therefore, we can consider an alternative version of ultralinear inclusion according to a different scheme, shown in the article below. A feature of these particular circuits is the inclusion of an output stage with a buildup from cathode followers. Amateurs know that television lamps are of low sensitivity. Therefore, you have to resort to additional tricks, use preliminary stages with dynamic loading, or install additional powerful drivers. The use of a pinch-coupled circuit somewhat complicates the setup, but avoids the use of blocking capacitors. A practical repetition of the schemes shown here should be performed using 6N1P lamps, with carefully selected halves according to the symmetry condition. And the output lamps in this version must be selected according to the equality of the bias voltage. There are general guidelines for building high-end push-pull amplifiers. You need to use symmetrical lamps, while hemorrhoids will be much less. And in these specific schemes, this is no longer a wish, but a demand.
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There are no gaps in high-performance matching transformers, so the result depends only on the quality of the winding, the equality of turns, the quality of assembly and the nonlinearity of the characteristics of the iron. The last two conditions are extremely difficult to ensure in reality. Here, on the fly, you need to lay the discrepancy of the operating parameters of about 10%. And this discrepancy can be established in practice only by measuring the finished product. And when a discrepancy is found, then the finished trance can be safely carried to the trash heap, since such a spread will not allow building an energy-efficient amplifier. For the requirement of jewelry accuracy, you can go along the path of selecting symmetrical pairs from a bunch of bourgeois output transformers, but how much it will cost money is hard to imagine. You need to understand that a very good result in the amplifier gives a discrepancy in the load characteristics of the transformers of no more than 2-3%. Moreover, it is curious that such a difference in currents XX does not at all guarantee equality EMF of windings when connected in series! This feature is described in my method of selecting transformers, here on the site. As a rule, out of 4-5 transformers with approximately the same no-load current of 10-12 mA, only two products provide a symmetrical pair. The rest disperse in 8-10% and they have to pick up a pair of adjacent values of 8-10mA or 14-16mA for currents XX.
The explanations presented here show the depth of the chasm in the path of building a high quality, energy efficient amplifier with a differential pair of output matching transformers. If the requirements for symmetry are somewhat roughened, for example, up to 15-20% of the EMF discrepancy, then the selection of pairs is much easier to perform. At the same time, at the stage of setting up the amplifier, the curvature of the operating system for alternating current must certainly be straightened by hand-to-hand adjustments on the devices. It will not be possible to find a direct connection with the quality of sound amplification here, since it is not there. You don't have to think that an amplifier with crooked transformers will sound much worse. Not to notice this by ear, even at medium power. Lamp circuits are generally auto-balanced and tolerate curvature easily. And the adjustment allows you to equalize the characteristics of the sound path. You just need to be aware that the limiting operating parameters of such a design will really be less. For example, a car with an inscription Bugatti at a speed of 299 will not go along the highway to Abakan. The available speed limit will be only some 150 km / h. I declare with full responsibility that blind listening to amplifiers with lamps operating in different areas, even of very different operating characteristics, will not be reliably identified by experts. There are no such people who distinguish between different spectra of harmonics, beautifully mixed within the musical range. Using the instruments, it is certainly possible to establish the difference in spectral composition. But only by instruments. Therefore, for the experts, there will be only smacking lips and shaking the head, they say they like it, but they don't like it. Moreover, it is not a fact that specific people with a worn out attitude will like a smoother frequency spectrum, without outstanding harmonics.
Novice designers should remember that in reality the situation is even simpler. If the requirements for the product are reduced even more, then when tuning the amplifier, it will be possible to straighten out a more significant curvature, or at least smooth out its consequences. In this case, the lamps themselves can be curves. But even using gnarled bulbs, you can push them to different performance characteristics. At the same time, being in curved modes, the lamps will be able, within reasonable limits, to deliver the power of an undistorted signal to the load, which is quite sufficient for comfortable perception of sound. The difference is easy to see in the comparison shown below. A beautiful and compact Chinese jack with an inscription of 12 tons, made without tweaks, will easily lift the Kukuruzer, but it should not be used for Kamaz. After all, he will raise Kamaz only once. And if such tough testing is not done, then the driver of the Kukuruzer will be satisfied with the small Zhiguli jack dimensions and the inscription of 12 tons and will never know the reality. This is ordinary marketing, oh, a mistake in the text, this is an ordinary deception.
An example of a Layer 2 circuit is shown below. The division into levels is, of course, conditional, the output transformers are exactly the same. The number of windings is fixed. And it is a matter of taste to adapt these windings to cathode OS or mesh. The main thing is to perform error-free wiring, for which there is an ordinary "scientific poke" method. A properly assembled and efficient amplifier is sufficiently sensitive to transformer feedbacks, therefore, any of their incorrect inclusion is fraught with a sharp deterioration in the regime. And there is only one option for the correct inclusion of the windings. This is what you need to find when setting up an amplifier with an OS.
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In general, we can conclude that the 6P45S lamp is an excellent motor suitable for building a dynamic and almost omnivorous amplifier. It is absolutely feasible to double the tetrodes to increase the power. We must be very careful with the authors of the pictures, in which, instead of the classic tetrode, the 6P45S lamp is depicted in the form of a pentode. This is a wrong image. Hence, one should proceed in assessing the reliability and the resulting authority of the circuitry and the author's reasoning. In the continuation of this article, another article is planned on the site - about the features of the selection of 6P45S lamps.
At the end of the presentation, I dare to assure you that all the pieces of iron described on the site can be purchased for rubles. In order to buy an amplifier based on 6P45S at a price of 45K, the buyer just needs to negotiate with the seller, preferably in Russian. The algorithm for fulfilling obligations under supply (purchase and sale) contracts is as follows. The interested party calls me on the phone at a reasonable time in the Krasnoyarsk time zone. We are vividly discussing the details of the contract. The buyer then credits my telephone number payment of 1% of the purchase price. This serves as a sign of the buyer's seriousness and allows me, if necessary, to promptly call back. After discussion on the phone, I send to email partner's commercial offer, with the characteristics of the goods, warranty obligations and delivery times. Further, by correspondence, negotiations are completed and the buyer transfers 20% of the purchase price to my account. The remaining 79% of the amount is transferred to the supplier's account after the buyer receives a notification about the readiness of delivery. Please remember, the advance payment for the hardware is 100%. Therefore, the buyer can immediately transfer the entire amount, already at the first stage of the correspondence, but only after my written approval. There is no movement on my part without prepayment. Tips are free. Delivery of pieces of iron by mail of Russia or a transport company at the expense of the buyer. Pickup is possible by agreement. If the buyer refuses the transaction, no refund will be made.
Evgeny Bortnik, Krasnoyarsk, Russia, November 2017
I bring to your attention an amplifier from Yuri Malyshev
Wideband amplifier designed for vocals or for mid-high frequency path in a 2-way club system.Can also be used as stage monitors.
Brief characteristics:
1.Frequency range 40-30000Hz (at zero)
2.Output power 2x170W (for outputs iron from TS-250 or PL20x40x100) On 6P45S lamps (preferably pairs) or 6P42S. You can use 4P44s, but already two in the shoulder and must be matched.
3.Sensitivity -0dB (0.775V)
4.Noise level -80dB
5. The harmonic coefficient is 1.5%, it is possible and much less with accurate balancing of the final stage.
6. Forced blowing of output lamps.
7.Power tr-r - paired TS-250 or twin on PL2040100 (preferable)
8. Execution "REC" - new
The circuit has been worked out and tested for many years. Several variants of amplifiers have been released (for 10 years about a thousand in Kharkov, under different names)
I will give you the output data, then I will write detailed measurements of it in the operation of the amplifier. And the correction from the calculated data is usually no more than 5% of the number of turns in the primary and secondary. Compared to your classics, I still check everything in a "live" product!
So, the iron from TS-250.TS-180, although the same in size, is much worse. Two frames made of fiberglass, although due to poverty (but rather laziness), you can take a frame from a press frame
On each coil, the primary with a wire of 0.355 -4 sections of 360 vit. Each section is two layers. On two coils, respectively, 2880vit.
Secondary 4-ohm 5sections 130vit each coil 0.45.Total 10sections. On top of each coil there is a home engine on the 8th 55vit.wire 1.06. It is easy to see that the coefficient of tr-tions on the 4th = 22.15
Insulation is desirable LAVARIL. Of the many hundreds of exits for 25 years, not one burned out, at least not seen such breakdowns.
Here I found a very interesting table on the detailed measurement of the amplifier with this transformer.
Briefly 28Hz-182W (output power) at Kg-6%.
28Hz-169W at Kg-3.4%
28Hz-156W already Kg-2.3%
30Hz -182W (4th load everywhere) -Kg-3%
40Hz-182W Kg-1.7%
1000Hz 182W Kg-1.3%
10kHz 182W Kg-1.3%
20kHz 182w Kg-1.5%
40kgk 182w Kg-2.0%
60kHz 156W Kg = 4.3%
100kHz approx 100W a blue glow is observed in the lamps and it is after about 2 minutes. fails.
And in normal operation, it serves for years with a good Jamikon fan, for example, with a height of about 100mm. The height of the front panel of the amplifier is 3U-standard. Width-19 "(482mm).
The instruments then were the G3-102 generator, the C6-8 distortion meter, the C1-83 oscilloscope, the V3-33 output voltmeter.
And here is the diagram of the output transformer. The primary color is red. In the section there are two layers of 0.355 wire, 180vit. in the layer.
Secondary grid feeding
