wireless headphone system with aurel module txfmaudio and rxfmaudio

[ashefr10]

Hello, I wished carried out an audio connection without wire for my metal detector. I thus chose 2 modules from aurel: rxfmaudio and txfmaudio, I thus carried out 2 assemblies as on this site:

http://www.tavernier-c.com/microsansfilhifi.htm

that functions rather well only I did not have enough power at exit in the helmet I thus modified some value of components on the receiver. I have thus to modify the condenser of exit in series with high the speakers I put one at it 100 uf instead of the 220 nf envisaged the sound is really more intense and a little more serious and I have to modify the resistance of 22 K which is at the entrance of the aop by one 2.2 KB. As I did not have aop TLC272 I replaced it by a NE5532 I thus have a his nickel on the other hand there or I have small problems I have a breath in the loudspeaker. and more I assemble volume plus this breath is present. somebody could you it help me to solve this problem since it is necessary to completely changing the stage of exit which appears me to be the source of the problem. In addition on another site I saw that on the level of the stage of exit it was not a aop used but one filled up audio of type LM386, therefore are what it is necessary that I entirely remake the assembly with this amplifier or then are what I can replace the aop by 2 transistors in darlington to see whether this breath attenuates.

[Thomas]

I see the rx only has a OP amp driving the audio, that is not enough, you will need some power amp like the 386 to get enough Volume. Or you could use the other 272 OP amp like this it would double the current out.

[ashefr10]

ok thanks , should limit consumption because food is a 9 volt battery to the fullest. So 2 aop I think it will consume too. and such audio amp it must consume a lot. I have enough power that is annoying is the breath in the speaker.

[Thomas]

one other thing, R2 on the Mic amp, should be at least 10k. did you turn down the gain (P1) on the mic amp?

[ashefr10]

ok ,
for the transmitter I made a montage without aop, then it is at the receiver I think we intervene when I breath in the headphones

one other thing, R2 on the Mic amp, should be at least 10k. did you turn down the gain (P1) on the mic amp?

[Davor]

This solution seem too complicated. There are headphones like these: http://www.ebay.com/bhp/wireless-hea...-with-fm-radio that do the Rx part beautifully, and in my case less conspicuously.
The only component that may require development is Tx. One could make it very complex or very simple. A quick fix is this: http://www.ebay.com.au/sch/FM-Transm...-/73836/i.html

[Thomas]

yes, lots of already made and working better alternatives, and very inexpensive, and simple to modify.

[Thomas]

and in my case less conspicuously.

Going into Stealth mode?

[ashefr10]

modules do not cost much, and it works very well, however I still have breath in speakers to delete.

[Thomas]

Are you saying hiss or static when you write "breath"?

[ashefr10]

I have in fact a permanent audio bottom at exit of the receiver. I think that it must be possible aténuer by changing the assembly for example by using an audio amplifier instead of a op amplifier

Are you saying hiss or static when you write "breath"?

[Davor]

Going into Stealth mode?

Unfortunately I have to.