The hardware section of Finally appeared (whoever read the topic before, he will understand the meaning of the record)
After six months of testing and improvement, I decided to tell everything what was happening and how
Background:
I personally think that wearing both a smart (commune) and a player is nonsense and at least inconvenient. And if I have a pipe for 400 bucks, then why the heck do I have to buy a player too ?? It is necessary to make smart work so that the player does not have to. Once upon a time I had a smart SX1 and I was a forum member at Oslik.ru. There is such a topic about sound amplifiers. But then the music interested me weakly and I did not attach much importance to it. After Sx1, I changed another 2 smarts. But 2 smart stolen from me (Ngage). And because of the lack of funds I had to buy SL45i and return to Oslik.ru. It was at that time that I was fascinated by music. I soldered the headset with an adapter on the Sl45, took KossThePlug and for a long time enjoyed its beautiful sound. Then I changed the Sl45 to the I600. I will not talk about what a wonderful smart it is, but the sound did not suit me a little after Sl45. Quiet was, even in normal headphones. The situation was saved a little on time by the approaching SRS Wow Xt. With it, the sound is much better and louder !! But I didn’t reach the old seed anyway :(. And here I remembered that strange topic about amplifiers !! I addressed the soldering iron quite well then and decided to try to collect all this !! And the Result Osharashil Me !! The sound became super! At last, the replacement of the Sl45i was found. For more than half a year I improved the circuit and the assembly options, and now I can already say that I have assembled a completely reliable and working headset with an amplifier and I can already talk about it.
When assembling this mega headset, I had to answer 2 questions:
1: Which one to take the amp.
2: How to collect all this so that it is convenient to use.
1: How to take the amp
Almost all the material on the schemes is taken from Oslik.ru (****: //forum.oslik.ru/viewtopic.php? T = 25675 & postdays = 0 & postorder = asc & start = 0)
Assembly instructions from Werefox with Oslik.ru:
1. All that the earth according to the scheme, put together, connect to the "-" external battery, and to the land of the headset.
2. in the first circuit there is a DC isolation, only the capacitance of capacitors should be increased to 1 ВµF, use Soviet km-6 or analogs.
There is no isolation in the second circuit, it is better to plug in capacitors. you never know
3. Both schemes can be easily connected to the headphone outputs of the device.
4. in the first circuit it is necessary to raise the supply voltage if you want to connect 32 Ohm headphones (4.7 volts like mine).
5. It is likely that there is simply no feedback inside the microcircuit. Those. It is necessary to look for switching on with external OOS, or stupidly select the supply voltage and the minimum distortion of both half-waves of the output signal. and stabilize.
First amplifier: Amplifier with 1.5 V power supply at 174UN23:
img-98939-audio6601.gif: The output power of each channel reaches 240 mW. Due to the low supply voltage, the amplifier can be used in a variety of portable devices. Variable resistor has a linear characteristic. Bandwidth 20-20000 Hz.
Second amplifier: Power amplifier on the TDA7050:
img-98939-audio6601.gif: TDA7050 - excellent frequency characteristics, protection against prepolarization, low supply voltage and current consumption, absolute unpretentiousness in the work - a find for developers of portable radio equipment. The upper circuit is designed for stereo signal amplification. As a load, modern stereo headphones are connected. Bridging the microcircuit (see the bottom diagram) allows you to get 150mW output, which makes it possible to connect a small speaker. If its resistance is less than that indicated in the diagram, connect a series resistor in series, the total resistance of the speaker and the resistor should be 64 Om. Otherwise there will be big distortions. Resistors R1 and R4 adjust the volume. On the uppermost circuit, a variable variable resistor is used to control the volume.
Specifications:
Rated output power 2x75mW
150mW in bridge mode
Nonlinear distortion factor no more than 1-6%
Input resistance 2mOm
Load resistance 32Om per stereo channel
64Om bridged
Current consumption not more than 6mA
1.8-6V power supply
The first mikruha eats quietly from one mezinchikovoy battery-battery, which is enough for quite a long time !!! The sound quality is parasitically good, unlike the TDA7050 (it produces a normal sound, only with 2 mizinchikovyh batteries).
But the volume and duration of the TDA7050 is much more, and the volume is such that it is already tearing the speakers. This allows you to set the output power of the device by 10%, which increases the life of the phone's battery !!!
Summing up:
On a domestic mikruh, you can assemble an amplifier that is small in size and with a crystal clear sound, but the phone / amplifier batteries last one or two days! The volume is quite sufficient, even in order to listen to the subway !!! But if you do not have perfect hearing, you need long-lasting battery life, a super loud sound, BUT YOU DON'T MATTER THE BIG AMPLIFIER SIZE AND ITS GREAT WEIGHT, then the amplifier will suit you TDA7050 !!!
THE MAIN PROBLEM OF THE DOMESTIC MICRUS IS CONCLUDED IN THAT ITS HERE WILL FIND !!!
Forum user AlexM412 with Oslik.ru offered his version of the scheme on the TDA7050
img-98940-TDA7050.GIF: The circuit works normally with a 32 ohm load (when powered 1.5 ... 6 V).
Optionally, the frequency response can be adjusted, for example, if you need to add "high" you can increase the capacitance of capacitors C3 and C4. If you need to "high" to remove, you can reduce their capacity or vypayat. If you need to filter the RF (well, like super bass and all that), rearrange the capacitors parallel to the resistors R3, R4.
You do not need to set the capacitors on the input, the volume is adjusted in the same way as on the diagram (on the first page). Powered by two AAA batteries. The maximum current consumption is 20 mA, the rest current is 2 mA.
And my latest design on the TDA7050:
img-98943-1.jpg: Here, as you can see, I used 2 amps, connected them in a Mono scheme and hung them on each channel. The loudness and quality of the steel are maximized, so the mikruha does not break into 2 channels. From this there is practically no loss of quality. And in order not to burn the headphones, put the volume control over the circuit (see pic ...)
I couldn’t find the mikruhu in my country, that's why I collected it on the TDA7050. I tried 2 schemes. The one that offered AlexM412 and the one that I collected myself. In the scheme from AlexM412 at a very high volume, incomprehensible "clicking sounds" began to appear. Replacing mikruhi and Conder did not lead to anything. Also, an increase in nutrition did not work. I was ready to throw the whole thing to hell. Suddenly I was told that the mono scheme (rice ...) gives the best quality, since the amplification is linear. And I decided to assemble my circuit on 2 amps. And it seems that he achieved the best sound on these mikruhs.
The issue of nutrition is solved very simply. I immediately realized that it was impossible to power the phone. He will give too small a voltage, and Akum will sit much faster. Initially powered amp from 2 microbalt batteries. The design was very bulky and inconvenient, and did not produce a normal sound. Then he decided to use the phone Akum which has more voltage than 2 batteries. The construction became much smaller and more convenient, but the Akum quickly got on and for charging it had to be constantly drank. The problem with charging, I decided quickly. I bought a Chinese charger from the phone (I don’t remember which one), soldered the charging socket to Akum, and hung up a new plug on the charger. Now I calmly charge Akum from charging and it does not depend on the phone itself. And the problem of fast discharge was solved by Akum from BL6c Nokia with a capacity of 1100mah. I think everything is clear from the pictures.
2: How does all this carry with you ??
Assembly options were only 2:
I will try to sketch them.
1:
Schematically1 -
img-98944-Shematicno1.JPG: Legend -
img-98945-Shematichno1oboznachenya.JPG: Switching modes is done so that you can talk on the headset. The amplifier will inevitably catch the noise from the phone during calls. Therefore, it must be disconnected from the circuit.
Disadvantages:
Too huge !! Akum is located next to the circuit and increases its size. Even if the buttons for switching on the circuit and the “bypass amp” mode are clamped at the same time, then there are terrible sounds from which you can go deaf!
2:
Schematically2 -
img-98946-Shematicno2.2.PG: Legend -
img-98947-Shematichno2oboznachenya.JPG: In this embodiment, I moved the Akum down the circuit, and the amp moved closer to the speakers. To realize all this, we needed a 9 core cable (7 cores - Samsung headset; 2 cores + and - Akum). I removed such cable from HS23 headset. Modes are now switched with the help of a lever that has 2 positions: amp, bypassing amp. This implementation has no visible defects.
Amp in any case will catch the interference from the phone and you can not talk to him. But so that he does not catch interference from other phones, I recommend wrapping the circuit itself in foil. Saves from interference a little.
As for the board on which to solder the whole scheme: I personally do not know how to poison them, so I did everything on the wiring. Yes, and as for me, in any case, the fee will only increase the size of the entire device, which is not good.
Headphones for this case fit any 32-64 ohms. And if hunting for 16 (small player), then KossThePlug, KossPortaPro, SennheizerCX300 and SennheizerCX400 are best suited. In order not to be confused in the heap of wires, I recommend rewiring the headphones to the postings from the Hpm70 sonerik’s headphones. Themselves Hpm70 - complete shit, but the wiring is cool and convenient. I did this with the Coxes and CX300 (rice ... and ...). And in the CX400 there is no such problem, since the postings there are already small and perfectly suited for this case.
Now recommendations for creating an amp:
1.If you do not use the PCB and do everything on the wiring, then you must glue the mikruhi to the case in which the amp will be located. The reliability of the scheme will increase dramatically.
2. I do not recommend power amp from 6 volts !! I burned 3 mikruhi. Although the datasheet has a maximum of 6 volts, but in my opinion there is a maximum of about 5 volts.
3.If you use a phone Akum, then you do not need to evaporate the controller, there is a risk of recharging and even blowing up Akum.
4. As the case you should not use paper or cardboard boxes. In any case, they can bend and spoil the scheme. It is best to use plastic shells. I now have for example the body of the switch from the lamp.
5. It is best to take a regulator from large headphones.
6. It is best to keep the power away from the phone so that it catches less noise
7. So that everything looks okay I recommend wrapping the case in a picture and covering it with tape on top.
That's all that I wanted to tell.
Additions and improvements are welcome !!
And the main thing !! I Do Not Bear Responsibility For Damage To Your Equipment Or Damage Caused. You Do Everything On Your Fear And Risk !! (but it's worth it)
Well, how it all looks in reality:
Pictures Huge in Size !!!!!Earliest implementation
img-98948-PIC_0242.JPG: Implementation number 2
img-98949-PIC_0234.JPG: The most modern implementation:
img-98950-P1010032.JPG: img-98951-P1010033.JPG: img-98952-P1010034.JPG: img-98953-P1010035.JPG: Post has been editedslaiferr - 15.04.09, 16:22