Hello,

I'd like to know if is it difficult to assemble a battery-powered circuit made up of two microphones, with adjustable gain and having as output headphones (each microphone having as output just one headphone), perhaps with a maximum sound intensity limiter in order to protect hearing but still allowing softer sounds.

Thank you

Allison

 

Everything is easy...right after you know how.
Google, "headphone amplifier".
Start with 2 mic pre-amps, feed that to the headphone amplifier, Viola. Done.

 

Hello,

I'd like to know if is it difficult to assemble a battery-powered circuit made up of two microphones, with adjustable gain and having as output headphones (each microphone having as output just one headphone), perhaps with a maximum sound intensity limiter in order to protect hearing but still allowing softer sounds.

Thank you

Allison

Make one of these for each ear...

https://www.eeweb.com/blog/extreme_circuits/spy-ear

 

Do you want to build a circuit from scratch, or assemble some ebay modules?

ak

 

I see, thank you all.
Would there be any problems to use relatively long wiring (40 cm/1.3 ft) connecting each microphone to the circuit?

Everything is easy...right after you know how.
Google, "headphone amplifier".
Start with 2 mic pre-amps, feed that to the headphone amplifier, Viola. Done.

Are there any specific low noise preams I should look for?

Make one of these for each ear...

https://www.eeweb.com/blog/extreme_circuits/spy-ear

I've checked, very nice but uses just 1 mic, while I'd like to use 2 and have each output to a separate channel (without mixing them) and doesn't have a maximum sound level limiter.

Do you want to build a circuit from scratch, or assemble some ebay modules?

ak

I'd like to assemble it from scratch.

Thank you,

Allison

 

I've checked, very nice but uses just 1 mic, while I'd like to use 2 and have each output to a separate channel (without mixing them) and doesn't have a maximum sound level limiter.

That is why my post said to make two of these circuits - so you have one for each ear. I can copy and paste a second circuit next to the first if that is more clear.

A maximum sound limiter can be a simple pair of diodes on the input, one in each direction. If that limits too much, use four diodes (one pair in series in each direction).

 

Are there any specific low noise preams I should look for?

Yes, microphone pre-amps.

 

Would there be any problems to use relatively long wiring (40 cm/1.3 ft) connecting each microphone to the circuit?

I wired a church with 85 feet of wire between the mics and the amplifier. Why is your mic so special that it can't survive 2 feet of wire?

 

That is why my post said to make two of these circuits - so you have one for each ear. I can copy and paste a second circuit next to the first if that is more clear.

A maximum sound limiter can be a simple pair of diodes on the input, one in each direction. If that limits too much, use four diodes (one pair in series in each direction).

I see thank you, I feel like I'm not experienced enough to modify this. Is there any thread/forum section in which I can ask about hiring somebody to draw this kind of circuit for me?

Yes, microphone pre-amps.

Are there any superior to LM386N in the < $20 price range but still with a large low-noise gain?

I wired a church with 85 feet of wire between the mics and the amplifier. Why is your mic so special that it can't survive 2 feet of wire?

You're right, I may have got too concerned about harmonics and the kind of wire to be used. Thank you

 

Are there any superior to LM386N in the < $20 price range but still with a large low-noise gain?

The LM386 is not a pre-amplifier. It's a noisy pig of a power amp.
My preference is a single j-fet or a TL-071

 

I see thank you, I feel like I'm not experienced enough to modify this. Is there any thread/forum section in which I can ask about hiring somebody to draw this kind of circuit for me?



Are there any superior to LM386N in the < $20 price range but still with a large low-noise gain?



You're right, I may have got too concerned about harmonics and the kind of wire to be used. Thank you

What is your goal?

What kind of sounds?

What distance?

What other noises present (even refrigerator motors, flowing water, heater vents, ...)?

What kind of microphone do you want to use?

What type of power (

Any size limitations.?

Do you plan to make this on a circuitboard vs strip board vs breadboard?

If battery, how long do you expect them to last?

 

Thank you again for your patience.

The LM386 is not a pre-amplifier. It's a noisy pig of a power amp.
My preference is a single j-fet or a TL-071

You're right, thanks for correcting me. TL-071 are still within <$0.50 each, is there anything better I should be looking for but still under $15-$20, or are transistors and IC more or less the same within this price range?

What is your goal?
I'd like to have enhanced hearing, I've always been fond of birdwatching and hiking, nature sounds can't really be approached closely so while I am at it, I'd like to have even better hearing capabilities than before.

What kind of sounds?
Mostly chirping, bellowing, hooting, crickets singing.

What distance?
As far as technically possible (with each circuit element within <$15-20, I wouldn't mind to have adjustable hearing up to extremely enhanced bionic levels.

What other noises present (even refrigerator motors, flowing water, heater vents, ...)?
Just walking and the human sounds that came with it, hence I looked for a safe-limiter too since

What kind of microphone do you want to use?
I don't have any specific in mind, been uncertain between capsule or MEMS due to the (possible) high humidity (or even relatively rainproof) capability of the latters.

What type of power.
Battery powered, I don't mind any rechargeable batteries such as 1.2v AA or 3.7v 18650 Lithium (as used in flashlights).

Any size limitations.?
Possibly within 1 kg/2.2 lbs since I'm not that strong and would already carry a backpack with water, food, tripod and binoculars.

Do you plan to make this on a circuitboard vs strip board vs breadboard?
I'd solder this on a generic PCB or even one to another as close as possible and then put it in a plastic box (except microphones which I'd attach to the outside of my jacket, since in my very limited experience breadboards can be noisy and pick up harmonics, or at least the one I'm using have this problem with LM386's and untwisted wiring.

If battery, how long do you expect them to last?
It'd be nice if it'd last 24 hours for ever battery charge, so that even in cold weather or holidays I shouldn't bring loads of spare batteries.

Thank you very much

Allison

 

Thank you again for your patience.



You're right, thanks for correcting me. TL-071 are still within <$0.50 each, is there anything better I should be looking for but still under $15-$20, or are transistors and IC more or less the same within this price range?



Thank you very much

Allison

You can get even lower noise op amps but start with the TL-071 series and get the device working. Then a better JFET op amp will be a drop-in replacement if you need lower noise. The burr brown OPA2134 / OPA2132 are just two examples of what you can look at. The prices will change a lot depending on what you are looking at. Also, are you looking for low noise, low power, low total harmonic distortion, low off-set voltage, low ... what? You never get everything, no matter how much you are willing to pay. Share your goals now so we know (any reason you quoted my question but provided no answers?)

Also, OP amp are much lower noise than audio amps (like the 386 chip mentioned above).

 

is there anything better I should be looking for

Looking for to do what?
Not answering questions gets you not receiving replies.
C'mon, it's a two way conversation.

 

You can get even lower noise op amps but start with the TL-071 series and get the device working. Then a better JFET op amp will be a drop-in replacement if you need lower noise. The burr brown OPA2134 / OPA2132 are just two examples of what you can look at. The prices will change a lot depending on what you are looking at. Also, are you looking for low noise, low power, low total harmonic distortion, low off-set voltage, low ... what? You never get everything, no matter how much you are willing to pay. Share your goals now so we know (any reason you quoted my question but provided no answers?)

Also, OP amp are much lower noise than audio amps (like the 386 chip mentioned above).

I thought to have answered each question under yours inside the quote, check above reply, if it doesn't work for some reason, I'm pasting them here:

What is your goal?
I'd like to have enhanced hearing, I've always been fond of birdwatching and hiking, nature sounds can't really be approached closely so while I am at it, I'd like to have even better hearing capabilities than before.

What kind of sounds?
Mostly chirping, bellowing, hooting, crickets singing.

What distance?
As far as technically possible (with each circuit element within <$15-20, I wouldn't mind to have adjustable hearing up to extremely enhanced bionic levels.

What other noises present (even refrigerator motors, flowing water, heater vents, ...)?
Just walking and the human sounds that came with it, hence I looked for a safe-limiter too since

What kind of microphone do you want to use?
I don't have any specific in mind, been uncertain between capsule or MEMS due to the (possible) high humidity (or even relatively rainproof) capability of the latters.

What type of power.
Battery powered, I don't mind any rechargeable batteries such as 1.2v AA or 3.7v 18650 Lithium (as used in flashlights).

Any size limitations.?
Possibly within 1 kg/2.2 lbs since I'm not that strong and would already carry a backpack with water, food, tripod and binoculars.

Do you plan to make this on a circuitboard vs strip board vs breadboard?
I'd solder this on a generic PCB or even one to another as close as possible and then put it in a plastic box (except microphones which I'd attach to the outside of my jacket, since in my very limited experience breadboards can be noisy and pick up harmonics, or at least the one I'm using have this problem with LM386's and untwisted wiring.

If battery, how long do you expect them to last?
It'd be nice if it'd last 24 hours for ever battery charge, so that even in cold weather or holidays I shouldn't bring loads of spare batteries.

Looking for to do what?
Not answering questions gets you not receiving replies.
C'mon, it's a two way conversation.

Sorry, thought I did answer to all questions in the above reply, inside GopherT's quote.

I'd like to have a portable, battery powered low-noise (since I'd enjoy listening to them and have reasonable fidelty instead of just being able to guess a nightingale is around) and adjustable gain (possibly capable of high gain too) hearing enhancer able to pick up low and distant sounds/songs/calls (within 50-20000 Hz) but protecting my ears with a maximum sound limiter against the usual brushes from clothes/vegetation or wind that mics may pick up.

Thank you all

 

Pick a microphone. Nothing moves until we know what the input is because one can not design an amplifier for an unknown input.

 

Pick a microphone. Nothing moves until we know what the input is because one can not design an amplifier for an unknown input.

I'd leave that choice to you experts too, since I'm not that knowledgeable to understand what could be a reasonable choice complying to the high humidity (or possibly rain too) resistance and relatively low price, good sensibility and availability.

 

@allisonr

Which state (country) do you live in?

 

I'm tired of playing 20 questions just so we can design something that is already available on the retail market.
Number Twelve, out.

 

@allisonr

Which state (country) do you live in?

Switzerland.

I'm tired of playing 20 questions just so we can design something that is already available on the retail market.
Number Twelve, out.

How can I hire somebody on this forum to draw this kind of circuit for me?

Thank you