! Amplifier In Headset! | All inside



Rep: (183)
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: Attached Image

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:
Attached Image


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: Attached Image

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:
Attached Image

Legend -img-98945-Shematichno1oboznachenya.JPG: Attached Image

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:
Attached Image

Legend -img-98947-Shematichno2oboznachenya.JPG: Attached Image

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:
Attached Image

Implementation number 2
img-98949-PIC_0234.JPG:
Attached Image

The most modern implementation:
img-98950-P1010032.JPG:
Attached Image

img-98951-P1010033.JPG:
Attached Image

img-98952-P1010034.JPG:
Attached Image

img-98953-P1010035.JPG:
Attached Image


Post has been editedslaiferr - 15.04.09, 16:22



Rep: (50)
Cool, but cumbersome :) Count up on a bus, think about it, listen to Mouzon while you get it, people around you will just be stunned to think that the terrorist: lol:



Rep: (183)
Not so cumbersome !! I take out on the bus calmly and do not take for a terrorist



Rep: (1311)
slaiferr ,
Fighting dead links. We start onsavagemessiahzine.comPictures (post # 16912)



Rep: (183)
Edited 1 post. Now all the pictures are normally visible.



Rep: (4)
Soldered the amplifier according to the simplest scheme on the PCB. I found the circuit on some site, I didn’t look at the datasheet very much, so the condensers are on 100µF.
Power supply - three AAA batteries. I used not a dual resistor, but two separate ones for each channel.
Test on the SonyEricsson J230i by connecting a Walkman headset to it. I used the 3.5mm audio output available in it. And on ordinary cheap headphones (32Ohm).
Everything seems to be done fine.
So here. Problem. When applying only one channel (through a resistor), the device sounds like no amplifier at all. It seems to be mono, but on two channels (headphones sound fully). When you turn on both channels in different positions of the transfer sounds in any way and with cracking noises, with the same position sounds louder, but STRONGLY presses low frequencies (very much like the work of some devocalizer'a). Male voice disappears completely.
Soldered everything as it should.
But I guarantee nothing.
What could be the reasons?

Posted on 10/08/2008, 5:58 PM:

Yes, still. In mono mode, with the same transmission on both channels, the circuit almost completely presses ALL sound.



Rep: (4)
One more thing. I have direct power, without a condenser. Does it affect something?



Rep: (183)
This is due to the fact that these noises and pressure appear without a condenser. Stick Conder and then check.



Rep: (4)
Problem solved. It turns out that my basic audio channel just went around the amp, and it also had to be connected to the power supply minus as ground. I don't know how or why it matters. Amp Laboka as he himself is not. :-)
Now the question is different. How much better will the AlexM412 feedback scheme with Oslik.ru sound? And is it worth attention at all?
Does your circuit sound better, where each channel is amplified through its own microchip using a bridge circuit? And will it sound even better if you develop the scheme provided by AlexM412 for your version with two TDA?
You wrote that you did not find a domestic scheme? People wrote that she had a "crystal" sound .... Much better than TDA7050?
Then what is the need to filter the power supply?
One last thing: how much can the size of the device be reduced if:
1) Implement everything without a printed circuit board and find better and smaller regulators (I used the first thing that came across - some big imported ones);
2) Go from three AA or AAA to a phone battery? And by the way, what is enough for longer: batteries or phone batteries?
In my original (well, in the very first, in principle) version, everything is implemented in a case with dimensions of about 55x85x23 mm.
Thank you in advance.



Rep: (183)
First: Come on You.

Secondly:
The circuit from AlexM412 sounds much better than all other circuits, but the mikruha trip itself is not really intended for stereo. In his scheme, one channel plays very well and without distortion, even at a huge volume, and the second channel is clicking, creaking and making noise. My bridging scheme sounds better than stereo, but it has a lot of flaws in the form of high sensitivity (the phone does not digest the whole volume) and a huge power consumption. I am now going to remake the scheme from AlexM412, putting its scheme on 1 channel and applying 2 schemes. And feed each mikruhu separately.

Thirdly:
As I understand it, the difference in quality between the domestic mikruha and the TDA is visible only on the oscilloscope, but the quota is greater for the TDA.

Fourth:
I do not understand how you plow without capacitors. After all, one of them filters the bass, and the other high. If you remove it completely, the sound deteriorates sharply.

Fifth:
By schema definition:
1) I always did without a fee, because it really reduces the size of the device. And the regulator is better to remove anything from the headphones.
2) I'm going to give up the phone Akum, tk blowing up the first after six months of use and breaking the second with the burning of mikruh I doked !! Yes, and the batteries last longer than Akum. And to spend 4 UAH per week for them is not so expensive. And in the scheme that I am going to do now is enough and 2 batteries for each channel.
3) And of course, the best way to reduce the device is to make the amp separately and power separately.



Rep: (4)
All this, of course, not bad.
And what exactly is “crap” when using the scheme proposed by you for two chips? And what about the old / new laughter?

I do not know what kind of Conder you are talking about, but I asked about capacitors that cling to power. In my opinion, they have nothing to do with high / low frequencies.

Here it is. For now. We will see later.
After the weekend, I’ll probably go to Caras on Tuesday, buy stuff - and get to work. Che do something.

Yes, still. Have you checked whether the difference in power supply from three and two batteries has a significant effect on quality?

Posted 10/09/2008 02:27:

But the chip, along the way, is made as a stereo ... Not for nothing, even in the datasheet are two uses.
Here I disagree with you ...



Rep: (185)
HARD - mastaki.
However, there is a topic and reasonably move)



Rep: (183)
Yes no Amp requires a separate topic. One post in that topic just can not do.



Rep: (4)
Another thing that interests.
Can you know or tell me where you can plug in the pinout of the connector / lace headset SonyEricsson type K750?



Rep: (0)
if you still need pinout for k750, then herehttp://pinouts.ru/CellularPhones-P-W/se_k750i_pinout.shtml

cool topic! I also wanted to solder the amp on tda7050, but then I decided on the standard tsmy, which is on ad823.



Rep: (4)
Maybe someone knows the simplest amp circuit, like this one, but powered by 9 volts?

Thorian
Thanks for pinout. It helped.



Rep: (0)
Here is the aforementioned CMoyhttp://tangentsoft.net/audio/cmoy-tutorial/
I soldered it in a couple of hours, although I had never soldered anything before) two film condenders, two electrolytes, six resistors and an opamp. food he is one crown. Wash, for the first time is quite normal)



Rep: (183)
Something seems to me that this amp is more complicated and more cumbersome than mine.
Although in the scheme, I looked at how you can LED.



Rep: (0)
If you are talking about the complexity of execution, I wrote above that I saw the soldering iron for the first time :)) and my hands are like parabolas) And I have sizes — I have a tyap-mistake on the breadboard, the dimensions of the board are 40 * 40mm. And I put Conder on food 1000mkf * 16V. and at the entrance of 0.47 μF. if it were 220 / 0,1, it would be even less



Rep: (4)
Quite an interesting scheme. Subject to review. :-)


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