Adapting PC Headset to Aviation Radio.. ( NEED HELP PLEASE )

[roland_xp_80]

Hi there,

As we know that PC Microphone is not Amplified, and Aviation Microphone is amplified.

I need to make an adapter from PC headset microphone to Aviation headset microphone.

I have the diagram for Aviation to PC headset, just I need to reverse this thing.

Thank you..

 

[(*steve*)]

You may get away with just a 22uF capacitor (or pair of them as shown).

I'm assuming that the Aviation mic is an electret. Not sure that the PC headset will have an appropriate output level though.

 

[roland_xp_80]

hi steve, thank you for your reply..

Could you explain me a little bit more about this, how can I do it, i have a basic only electronic knowledge.

if you can describe me by drawing(preferable), or by text

let say the Aviation Microphone as AM, and PC Microphone as PM

So I connect the AM ring direct to the 22uf do we need any battery anymore??

thank you very much for your answer it does really helps me..

 

[(*steve*)]

The naive suggestion is to use the same circuit, just without the battery and resistor.

It shouldn't be too hard to test.

 

[roland_xp_80]

ohh ok.. thank you... so just wire the sleeve directly,

just wire the PC microphone TIP to the same ciruit(2 22uf capacitor), then the output goes to the Aviation Microphone Ring.

If it is not right please advice.

Tank you once again..

 

[(*steve*)]

I would try that first. See what happens. Most particularly, see if the levels are acceptable.

 

[Resqueline]

Afaik both PC headsets and most aircraft headsets use electret mikes, so the only adaptation necessary should be to remove the PTT from the equation.
I just measured now that the mike input on my computer outputs some 3.5V DC so I don't see why that diagram was made like that in the first place.
I have seen some aircraft headsets with dynamic mikes though, and once made an amplifier to be able to run those on an electret input radio.

 

[roland_xp_80]

Hi steve,

It does work, but just the level is not enough.. I need 2x level from this current level..

I have tried the microphone direct without the circuit , but the level was way lower..

Please help me how to increase the level, can I just add one more pair of 22uf capacitor? Or is there is any smaller device that I can use?

Thank you for your assistant now sir..

 

[(*steve*)]

Adding more capacitors will not help.

You need some amplification.

If this is being used by operating crew on an aircraft, then I would stop right now and get the correct equipment.

 

[aiden]

我不太懂,但是我可以帮助你把帖子顶起来I do not know, but I can help you put together the top post

 

[roland_xp_80]

Hi steve,

Thank you for your help, I need this for an extra headset for backup only, and I just want to learn how to build the amplification..

I would really need your help to make a simple and small amplification for the microphone. Preferable without the 9v battery.

Regards,
Vince

 

[roland_xp_80]

Hi steve,

Thank you for your help, I need this for an extra headset for backup only, and I just want to learn how to build the amplification..

I did try it again to use it, and when I use it most of them can hear it, just they said that the level is quite low..

I would really need your help to make a simple and small amplification for the microphone. Preferable without the 9v battery.

Regards,
Vince

 

[roland_xp_80]

Hi steve,

Thank you again for your help.. I need to make a headset for amatuer to follow jump seat with my friend if he fly, it is not for the line.. and I really want to learn how to make this ampilification..

if you could explain me how can I make this ampification that would be awesome. preferable in small size..

thank you very much..

Regards,
Vince

 

[(*steve*)]

It may be possible to use the small amount of power available to drive the electret mic to power a small amplifier, but it would be tricky. You may need to have a battery to power the ampilifier.

 

[roland_xp_80]

That's fine boss..

I really appriciate it if you could draw me a sketch or explain me what should I do..

Waiting for your reply..

 

[roland_xp_80]

Dear Steve,

This is some specification of both microphone:

Aviation Microphone :
Element Type: Noise-canceling electret
Frequency Response: 150Hz to 5 kHz
Operating Voltage (supplied by aircraft): 8-32 Volts DC
Matching Impedance: 150-1000 ohms
Sensitivity: -33±4 dB
(Ref: 0dB SPL=20.0uPa at 1 kHz with 10 Vdc 150 ohms AC load)

PC Microphone :
Frequency response: 100 Hz – 10 KHz
Sensitivity: -42 dBV/Pa re: 0 dB = 1 Pa, 1 KHz
Test conditions: 3.0 V, 2.2 K ohm


Some Explaination :
There are 3 basic types of microphone used in aviation: Carbon, Dynamic and Electret.
Electret Microphones

A more recent development is the electret microphone. In an electret microphone the voice diaphragm is connected to two plates which sandwich a small piece of piezo crystal. As the pressure on the crystal varies, it produces a very small audio voltage which is picked up by the plates. This voltage requires considerable amplification to become useable and a small amplifier is directly connected to the piezo crystal. The amplifier requires a DC voltage to operate and in an aviation transceiver this is usually provided by the DC energising voltage present at the microphone input. The electret microphone, because of its small size and excellent frequency response, has become the commercial microphone of choice. However, in most electret applications, the output voltage level is designed to be much lower than that needed to fully drive aviation transceivers. In aviation applications, the electret mic is designed to have considerably more amplification to provide the 0.5 to 1.0 volts needed to drive an aviation transceiver.

please help me to finish my project, I don't have a clue how I do it, or where should I go to get the parts, i don't mind to buy the electret microphone with the specification.

Please reply..

Regards,
Vince

 

[roland_xp_80]

another aviation headset example :
DC Bias Supply: 8 to 16 volts, not polarity sensitive
Source Resistance: 220 to 2200 ohms
Output Voltage: 370 mV @ 114 dB spl re .0002 microbar
Noise Level: 120 dB spl re .002 microbar

 

[roland_xp_80]

Now I have opened what is inside my General Aviation Headset, I took a picture for it for you to look it up..

Is there is any easier parts to replace this small parts? cause this parts is extremely small to put together without a PCB.

Again, Thank you, and sorry for few posts.

 

[Resqueline]

I'm not very good at reading mike spec's but it could seem like the mike used in the aviation headset is 9 dB more sensitive than the one used in the PC headset.
They also seem to be made to run on different voltage levels. Proper impedance matching is vital in order to extract maximum signal levels from mikes.
Electret mikes have a FET transistor built right into them. I don't understand how you could get yours to work with a capacitor in series with it.

As far as I can tell you have two (or three) options:
1: Buy some microphones with the highest sensitivity value you can find and try them out.
2. Experiment with impedance levels.
3. Make an amplifier (/copy the circuit in the aviation mike)

Here's the circuit in the aviation mike (it's incomplete but as far as I'm able to make it out):

 

[roland_xp_80]

Hi Resqueline thank you for the reply.

A. Before I am going to make this, just want to verify that all the k means resistors right??

B. do you think that it will work without the blank component you drew?

C. Please let me know what do you mean by verify with impendance level? should I just add resistor to the mike?

Thanks one more time for your help and concern.

Regads,
Vince