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 believe that at the same time wearing smart (communes) and a player - nonsense, and at least uncomfortable. Yes, and if I pipe for 400 bucks, then why the heck I am also a player to buy ?? We have to make smart to work so that the player did not have to. Once upon a time I was smart and I was SX1 forumchanin on Oslik.ru. There is such a topic about audio amplifiers. But then the music changes slightly interested and I did not give it much importance. After I changed Sx1 2 more Smart. But 2 smart stolen from me (Ngage). And because of the lack of funds had to buy SL45i and return to Oslik.ru. It was at that time I became interested in music. Soldered to the headset adapter for Sl45, KossThePlug took a long time enjoyed it a great sound. Then I changed Sl45 on I600. I will not talk about what a wonderful smart, but I sound a little after Sl45 untenable. Tihovat was, even in normal headphones. The situation was saved by a little time coming up SRS Wow Xt. With him the sound is much better and louder !! But certainly still did not reach the old Semyon :(. And here I thought of the strange theme of amplifiers !! With a soldering iron then I turned bad and decided to try to put it all !! And the result I was flabbergasted !! The sound super-duper! ! Nakonetstaki was found replacement SL45i. More than half a year I have improved circuitry and assembly options. and now I can say that gathered quite reliable and working with the headset amplifier and 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, prepolyusovki protection, low voltage and current consumption, the absolute simplicity of operation - a godsend for designers of portable radio equipment. The upper diagram is a stereo signal for amplification. The load connected modern stereo headphones. Bridging chip (see bottom chart) lets you get at the output of 150mW, which makes it possible to connect a small speaker. If the resistance is less in said circuit switch in series a resistor, dynamics and the total resistance of the resistor must be 64Om. Otherwise, there will be great distortion. Resistors R1 and R4 regulated volume. In the uppermost circuit is used to adjust the volume dual variable resistor.
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 ...)
Patriotic mikruhu I found could not, in this and going to TDA7050. I Tried 2 scheme. That the proposed AlexM412 and the one that gathered himself. In the scheme of AlexM412 at a very high volume began to appear strange "clatter" sound. Replacing mikruhi and Conder to nothing lead. Just increase the power to no avail. I was ready to throw the hell out of the whole structure. Suddenly I was told that the mono diagram (Fig ...) gives the best quality, maybe linear amplification. And I decided to put his scheme into 2 collection of amps. And it seems to reach a better sound on these mikruhi.
Question powered decided very simply. I knew right away that you can not feed from the phone. He will give very small voltage, and sit Akuma will be much faster. Initially fed amp 2 mikropalchikovyh batteries. The design was very cumbersome and inconvenient, and did not give the normal sound. Then he decided to use the phone Akuma has more power than the 2 batteries. Kostruktsii become much smaller and more convenient, but quickly sat Akuma and had to charge it constantly desoldering. The problem with charging I decided quickly. Chinese bought the charger from the phone (I do not remember what), soldered charging jack to Akuma, and hung a new charger plug for this jack. Now I charge safely from Akuma charge and it does not depend on the phone itself. A problem quickly discharge decided by Akuma nokii BL6c with 1100mah capacity. I think everything is clear on the pics.
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