Hi Everyone,

I am trying to build an amplifier for an electret mic( collar mic) which gives output to a headphone. I am using NE5532 ic for the amplification.

I am not getting any sound on headphone. I have made the circuit on breadboard.

Please check the attached schematic and products I am using.

what I am doing wrong here? please help me.

thanks

 

what I am doing wrong here? please help me.
thanks

Not telling us what supply voltage you are using.
A NE5532 needs between ±5V and ±18V. It doesn't work off a 9V battery.

 

Please check the attached schematic and products I am using.

What is the supply voltage?

 

Besides the supply voltage I would use 47uf caps for C7 and C8.
Also increase the gain and check connections on the mic connector.

 

Not telling us what supply voltage you are using.
A NE5532 needs between ±5V and ±18V. It doesn't work off a 9V battery.

the supply voltage is 12v 2amps through smps

 

the supply voltage is 12v 2amps through smps

I could understand if it was a bit tinny. 1uF coupling to a 32Ω load gives a high-pass filter at 5kHz, but I am surprised you are getting no output at all.
What are the DC voltages on pin 1 and pin 7?
Also, don't forget that the output is limited to 38mA, that's less than 1V rms into a 32Ω load, but that might be loud enough.

 

Hi Everyone,
I am trying to build an amplifier for an electret mic( collar mic) which gives output to a headphone. I am using NE5532 ic for the amplification.
I am not getting any sound on headphone. I have made the circuit on breadboard.
Please check the attached schematic and products I am using.
What I am doing wrong here? please help me.
thanks

.
You must have a Low-Impedance-Audio-Amplifier to drive the Headphones.

We need to know your reasons for building this project to
provide advise that will provide the results You are looking for.

Tinkering around, trying to teach yourself about Electronics ............
or,
A high-quality finished-product that will provide high-performance results ...........
.
.
.
.
.

 

You must have a Low-Impedance-Audio-Amplifier to drive the Headphones.

An op amp output is low impedance, it is the output current capability that is lacking.

 

What I noticed this time is that the headphone set uses a FOUR CIRCUIT connector, with the top circuit being the microphone connection. What I think I see is that the headphone connection to the amplifier outputs is a three circuit connector.
So my suggestion is try your amplifier with an earphones only set before making changes.
If that check is not easy or convenient, use the ohm meter function of your multimeter to see if your headphones are actually connected. Meter common to the amplifier common, meter positive to the C7R11 junction and the C8R12 junctions.
You should read a lower resistance if the headphones are actually connected.
My guess is that they are not connecting.

 

C5 and C6 are too small to do anything. Why are they there?

ak

 

I could understand if it was a bit tinny. 1uF coupling to a 32Ω load gives a high-pass filter at 5kHz, but I am surprised you are getting no output at all.
What are the DC voltages on pin 1 and pin 7?
Also, don't forget that the output is limited to 38mA, that's less than 1V rms into a 32Ω load, but that might be loud enough.

I am getting 1.4V at Pin 1

 

Should be half the supply voltage.
What are the voltages on pins 3 and 5?

 

Should be half the supply voltage.
What are the voltages on pins 3 and 5?

its 7.5 volts

 

7.5 sounds right for a 15 volt supply.

The output pin is 1.4 volts on both channels?
Is that with the headphones connected?

 

7.5 sounds right for a 15 volt supply.

The output pin is 1.4 volts on both channels?
Is that with the headphones connected?

yes, both channels. its without headphone connected

 

yes, both channels. its without headphone connected

What about the voltage on pin 2?
Do you have C3/C4 the right way round?

 

"" rahulb said:
Hi Everyone,
I am trying to build an amplifier for an electret mic( collar mic) which gives output to a headphone. ""

As BobTPH accurately pointed-out,
I neglected to state exactly how much Current the Amplifier should be able to produce.

Then MisterBill2 made the observation regarding the Headphone-Jack possibly being
intended to include a 4th Circuit for the Microphone.
But as of yet, no-one has actually verified that the picture supplied
is a picture of the actual part being used.

This got me to thinking.
Lots of very basic questions need to be answered first.

Like why does his picture of a Lapel-Microphone have a 4-Conductor- Plug,
and what is the function of each of these conductors.
And, what does the Headphone-Plug look like.
We haven't seen a picture of it yet.

Where are the Spec-Sheets and/or Instructions that should accompany these products ?

Both the Headphone, and Microphone connections
need to be verified independently from the proposed Pre-Amp-Circuit.
.
.
.

 

1.4 V sounds like the output is saturated low. What is the voltage across the mic element, from the left sides of C1/C2 to GND?

Another test: Remove C1/C2 from both circuits, so the non-inverting (+) inputs are floating at the 7.5 V bias. If the outputs still are at 1.4 V, remove C3 and C4, leaving R8 and R10 floating. Now the circuit is a simple unity gain voltage follower with a 1.5 V input. The outputs should be at 7.5 V.

ak

 

The sockets you are using for input and output appear to have spring loaded contacts which activate when the plug is inserted. Double check your wiring. If you are using the wrong terminals, you will not have continuity through them.

 

The microphone plug shows 4 contacts.
The jack shows 3 contacts.

How do you know which 2 contacts to use?