High-quality sound amplifier do it yourself. Scheme of two simple amplifiers transistor amplifier with your hands 805
High input resistance and shallow OS is the main secret of warm lamp sound. It is no secret to anyone that it is on the lamps that the highest quality and expensive amplifiers are being implemented, which relate to the Hi-End category. Let's understand what a high-quality amplifier is? High-quality has the right to be called that the power amplifier, which completely repeats the form of the input signal at the output, not distorting it, of course the output signal is already reinforced. In the network you can meet several schemes of truly high-quality amplifiers, which have the right refers to the Hi-End category and the lamp is not necessarily required. For maximum quality, the amplifier is needed, the output stage of which operates in a clean class A. The maximum linearity of the scheme gives the minimum number of distortions at the output, therefore, in the structure of high-quality amplifiers, special attention is paid to this particular factor. Lamp diagrams are good, but not always available for self-assembly, And industrial lamp digests from branded producers are from several thousand, up to several tens of thousands of US dollars - such a price is definitely not for many people.
The question arises - is it possible to achieve similar results from transistor schemes? The answer will be at the end of the article.
Linear and ultra view schemes of power amplifiers there are quite a lot, but a scheme that will be considered today is a high-quality ultra-linear scheme that is implemented in total on 4 transistors. The scheme was created back in 1969, a British sound engineer John Linsley-Hood (John Linsley-Hood). The author is the creator of several more high-quality schemes, in particular class A. Some connoisseurs call this amplifier to the highest quality among transistor UNG and I was convinced of this a year ago.
The first version of such an amplifier was presented on. A successful attempt to implement the scheme forced to create a two-channel UNG on the same scheme, collect everything in the case and use for personal needs.
Scheme features
Despite the simplicity, the scheme has several features. The correct mode of operation may be disturbed due to improper wiring of the board, unsuccessful component location, incorrect power, etc.
It is food - especially important factor - Intremely I do not advise you to feed this amplifier from all kinds of power supplies, optimal option Battery or power supply with parallel battery.
The power of the amplifier is 10 watts with a 16 volt power supply to the load of 4 ohms. The scheme itself can be adapted for heads 4, 8 and 16 ohm.
I created a stereo version of the amplifier, both channels are located on the same board.
The second is designed to roll the output cascade, set KT801 (it got enough difficult enough.
In the very day of the cascade, there was powerful bipolar return conduction keys - KT803 precisely with them received undoubtedly high quality Sound, although experimented with many transistors - CT805, 819, 808, even put powerful composite - KT827, with a lot of power with it, but the sound is not compared with CT803, although this is just my subjective opinion.
Input capacitor with a capacity of 0.1-0.33mkf, you need to use film capacitors with minimal leakage, preferably from well-known manufacturers, the same with an output electrolytic capacitor.
If the scheme is calculated under the load of 4 ohms, then you should not raise the supply voltage above 16-18 volts.
The sound regulator decided not to put, he also affects the sound, but in parallel the entrance and minus it is desirable to put a resistor 47k.
The board itself is Macaten. With the board I had to tinker for a long time, because the lines of the tracks also provided a kind of influence on the sound quality as a whole. This amplifier has a very wide range of reproducible frequencies, from 30 Hz to 1 MHz.
Setup is simpler. To do this, we need a variable resistor to achieve half of the supply voltage at the output. For more accurate tuning it is worth using a multi-turn variable resistor. One chup view of the multimeter with a minus power, the other put to the output line, i.e. the electrolyte plus at the output, thus, slowly rotating the change of the change in the outlet half.
Today I will talk about my very first average power amplifier on transistors.
The amplifier is really cool, I really liked it. At the exit are CT803A transistors
The author of the scheme is J. Linsley Hood. I sketched the scheme with some old magazine. Naturally all foreign transistors, but they can be replaced by our domestic.
Here is the scheme of this miracle
C1 \u003d 220mf
C2 \u003d 100NF
C3 \u003d 100mf
C3 \u003d 100NF
R2 \u003d 2.7K.
R2 \u003d 220.
R3 \u003d 2.2k.
R4 \u003d 8.2K.
R7 \u003d 100K.
R8 \u003d 39K.
R9 \u003d 100K.
R10 \u003d 10.
VT1 \u003d KT361 (2N3906)
VT2 \u003d CT602BM (2N3697, CT630D, KT801)
VT3.4 \u003d KT803A (MJ480)
Some nominal details are taken from this table
The adjustment of the amplifier is reduced to the setting of the R9 resistor voltage at the counter.
Weekend transistors are recommended to be installed on radiators of 200 square meters. See for each transistor. And it is impossible to connect radiators so that there is no short circuit. I used on the tests of the simple two plates from the DVD housing / but I will torment the rules into the box. Radiators
Put the amplifier I am from pulse block Nutrition. And I will say that there was no self-excitation. All thanks to the C5-R10 chain.
Here is the photo of the collected amplifier
Signet. Road view
Print for the amplifier 10 W class A on KT803A
PSIf you need to spend high-quality electrical installation work, that is, a good office V220.KIEV.UA. Do high quality and fast
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Readers! Remember the nickname of this author and never repeat its schemes.
Moderators! Before I am banned for insults, think that you "submitted to the microphone" of an ordinary gopnik, who even closely cannot be submitted to radio engineering and, moreover, to the training of beginners.
First, with such an inclusion scheme, through the transistor and speaker will go large d.C.Even if the variable resistor is in the right position, that is, music will be heard. And with a large current, the speaker is damaged, that is, sooner or later he burns.
Secondly, in this scheme there must necessarily have a current limiter, that is, a permanent resistor, at least 1 com included in series with variables. Any self-relocine will turn the adjuster of the variable resistor until it stops, it will become zero resistance and a large current will go to the transistor database. As a result, the transistor or speaker will burn.
The alternating capacitor at the input is needed to protect the sound source (this should explain the author, for the reader immediately found, who removed him just like this, considering himself smarter than the author). Without it, only those players will work normally, in which there is already such protection at the exit. And if it is not there, then the yield of the player may be damaged, especially as I said above, if you unscrew the variable resistor "in zero". At the same time, the output of an expensive laptop will serve a voltage from the power source of this penny bauble and it can burn. Self-skinny, very love to remove protective resistors and capacitors, because something "works!" As a result, with one source of sound, the scheme can work, and there is no other, and even may be damaged by an expensive phone or laptop.
A variable resistor, in this scheme should only be confirmed, that is, adjusted once and closed in the case, and not output with a comfortable handle. This is not a volume control, but a distortion regulator, that is, they are selected the mode of operation of the transistor so that there are minimal distortion and that the smoke does not go out of the speaker. Therefore, in no case should not be available outside. Adjust the volume by changing the mode it is impossible. For this you need to "kill." If you really want to adjust the volume, it is easier to turn on another variable resistor sequentially with the capacitor and now it can be displayed on the amplifier housing.
In general, for the simplest schemes - and to work immediately and in order to damage anything, you need to buy a TDA type chip (for example, TDA7052, TDA7056 ... Samples on the Internet set), and the author took a random transistor who was lying around in his table. As a result, trusting lovers will find exactly such a transistor, although it has a total gain of only 15, and an allowable current of paragraph 8 amp (burns any speaker without even noticing).
This sound amplifier scheme was created by all the favorite British engineer (electron -er-sounder) Linsley-bad. The amplifier itself is assembled in only 4 transistors. It looks like an ordinary scheme of the amplifier of the LF, but it is only at a glance. An experienced radio ample will immediately understand that the output stage of the amplifier operates in class A. Intelligent, that simply and this scheme is proof. This is a superlines scheme, where the output shape does not change, then, we have the exit we get the same signal form that at the entrance, but already reinforced. The scheme is better known called JLH - ultra-linear amplifier class AAnd today I decided to present it to you, although the scheme is not new. This audio amplifier, with their own hands can collect any ordinary radio amateur, thanks to the absence of a microcircuit in the design that makes it more affordable.
How to make a speaker amplifier
Sound amplifier circuit
In my case, only domestic transistors were used, because with imported strained, and standard transistors of the circuit, find it is not easy. The output stage is built on the powerful domestic transistors of the KT803 series - it is with them that it seems better. To roll the output stage, the CT801 series of the CT801 series is used (managed to find with difficulty). All transistors can be replaced with others (CT805 or 819 can be used in the output cascade). Replacements are not critical.
Tip: Who decides to try on the "taste" of this homemade sound amplifier - use Germany transistors, they sound better (IMHO). A few versions of this amplifier were created, they all sound ... Divinely, I can't find other words.
Power presented scheme no more than 15 watts (plus minus), 2 amp consumption current (sometimes a little more). The output cascade transistors will be basked even without supplying the signal to the amplifier input. A strange phenomenon, isn't it? But for class amplifiers. A, this is a completely normal phenomenon, a threshold current - a business card of literally all known schemes of this class.
The roller presents the work of the amplifier itself connected to the speakers. Please note that the roller is removed on mobile phoneBut the quality of sound can be judged and so. To check any amplifier, it is worth only to listen to just one melody - Beethoven "To Elise". After switching on it becomes clear what kind of amplifier in front of you.
90% of microcircuit amplifiers will not withstand the test, the sound will be "broken" whetherrs and distortions can be observed at high frequencies. But the foregoing does not concern the John Linsley scheme, the ultrainosis of the circuit allows you to completely repeat the input signal shape, this is obtaining only a clean reinforcement and sinusoid at the output.
In my case, the sound amplifier diagram was implemented on male PlateWhile there is no possibility to collect the second channel, but in the future I will definitely make it all in the case.
Alexey, why not start asking questions more consciously? Then you can answer more precisely. This is me not because here I'm here such a guru is all in white, and he "wrung out" despicable there, I stretch-ka my face on Table - no, of course. But or "... Composite can be applied or not to enhance the capacity ...", or "... there is enough power ..." - here is something one, you will agree. And if you are interested in why the weekend transistors are warm - so I would immediately be asked about it.
And, again, in order. "The problem is heated in another output" - this is how to understand? The output of the amplifier is two wires, signal and general, they are in your presentation and warm?
OK, it's still talking about excessive, in your opinion, heating output transistors. You, you "warm all the 4 transistors on the radiator" - I will try to read this stream. They warm - what does "heated" mean, in some limits these transistors and should be warm. Warm at a signal on big power Or warm without a signal? To which temperature are heated - if approximately, then the finger suffers (this is 50-60 degrees) or can you boil the teapot on the radiator?
Not indicated.
"All 4 transistors on the radiator from the Comet magnetophone" - and what? Alexey, a variety of models of Comet tape recorders from the 50s and until the end of Soviet times were released a little more than before the fig, this is nothing about anything. What are the sizes of the radiator and what is the measured rated power of the amplifier at the load of which value?
Not indicated.
"Maybe a radiator is not enough" - and hell knows, maybe a little. Or maybe just right. And maybe the current of rest is. What is the rest of the rest? What is it when turned on, i.e. on a cold amplifier and what is the amplifier after the booster run without a signal within 20-30 minutes? Why is this value of this current chosen, and not more and no less?
Not indicated.
"At the CT 819 output" - again: and what? KT819 in plastic or KT819 in metal, - not specified - these species have a different area of \u200b\u200bcontact with the radiator, the plastic, with other things being equal, is basked a little more, nothing terrible.
You see, Alexey, you put questions in such a way that to answer in your situation with all the desire is hardly possible. Therefore, some reasons for overheating output transistors are pretty abstract:
It is so, on the move I was relieved. Maybe someone else will remember. And to put two in the parallel of the output transistor at such an output power there is no point in no way: on a normal load and in normal mode, single pulled without any problems. CT819 will definitely pull.
For good, it is necessary not to invent anything else to fasten, but measure the modes of transistors and see the oscilloscope, which happens in the scheme as without a signal and when working on sinus generators and impulse; What we have at idle, and what is under load or on its equivalent. Such a conversation will be subject, but so far everything reminds an attempt to describe today's weather based on the sensations on the outdoor of the shallow finger.
And the first thing - to be able to correctly formulate the task: what is observed that it does not suit what they strive for and what costs on this path will be considered acceptable.
And then, Alexey, you will be helped by more efficiently.