Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

[SOLVED] Microphone signal on long distance (200 meters)

Status
Not open for further replies.
D

dustie

Newbie level 6
Joined
Oct 2, 2009
Messages
11
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
Macedonia
Activity points
1,354
Hi,
I haven't work with audio amplifiers and I need help.
I need to connect a microphone to an audio amplifier (using cable), but the distance between the microphone and the amplifier is 200 meters long.
On such a long distance the signal will probably attenuate and fail.
Now I guess I need any preamplifier, any IC maybe.... Please help me about that.

Thanks in advance,
Dejan
 

Attenuation shouldn't be a problem but noise pick-up might be.
I would suggest inverting the microphone signal and send the normal and inverted signals down a balanced cable. At the amplifier end, re-invert the upside down signal and add it to the normal signal. It will cancel interference and give twice the microphone level. You can get the inversion using a transformer at each end or use an active amplifier.

Brian.
 
  • Like
Reactions: dustie

    D

    dustie

    Points: 2
    Helpful Answer Positive Rating
use a low impedance microphone with balanced (2 core) screened cable. Try to use the inner two cores as the mic. live and earth with the screen only connected at the amplifier end. If this does not work then you will need a proper pre-amplifier and as betwixt said it is better to go down the route of a differential signal then just loading a lot of gain on a one legged system. Professionals use 600 ohm balanced circuits all the time for this reason.
Frank
 
  • Like
Reactions: dustie

    D

    dustie

    Points: 2
    Helpful Answer Positive Rating
Thank you very much friends, you helped me a lot :)
I wasn't experienced with audio signals and equipment, so I spent several days experimenting with it. But I would have gone the wrong way if I didn't ask for help....
Thanks again,

Dejan
 

The FET condenser mic is in vogue presently which has wideband input freq. range used for Digital signal tx.However , this has high impedance 200Kohm-150Kohm and consequently inherent noise pickup.A two transistor impedance changer (feedback stabilized )is used to retain the 25KHz. band for the harmonics jingles in fifth order.
However ,we can think of using TL082 /FET input OPA with low gain and low output impedance to give wide freq. range of >1MHz. .As such all the harmonic music contents are retained even after the signal travels 500mtrs .to the audio amp/equalizers /modulator and transmitters .
 
  • Like
Reactions: dustie

    D

    dustie

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top