1
\$\begingroup\$

So I have a small amplifier that plugs into a 12V source and a standard 3.5mm headphone jack and plays pretty good sound to a 8ohm speaker. I am wondering if I can connect the 3.5mm headphone jack to an electret microphone and play the sound from the microphone out of the speaker. I guess I am wondering what kind of voltage the mp3 player outputs. Since that work great with the amp I guess I am wondering how to get an electret microphone to the leverl where I could input it into the same amplifier.

\$\endgroup\$
2
  • \$\begingroup\$ Microphone needs to be biased for proper operation. So you cannot directly connect a mic to your 3.5mm jack \$\endgroup\$
    – nidhin
    Jun 28, 2014 at 7:05
  • \$\begingroup\$ Related: I used it the other way around. I plugged headphones into a microphone jack. It worked, it wasn't perfect but it did the job as a maleshift solution. \$\endgroup\$
    – WalyKu
    Jun 28, 2014 at 11:39

2 Answers 2

1
\$\begingroup\$

The Op's question reminds of a tricky question paper :) . What I construde is;

  • 1) 3.5mm Jack= O/P (looks like an I/p).
  • 2) He wants to insert electret microphone into this jack .

But If he is listening to something with MP3 then the Jack is not an output device , he probably has an additional speaker somewhere ?? .If this is true then Jack is an I/P connector. The electret mic cannot be inserted directly, you need biasing as below . enter image description here

It would be better to add a pre-amplification stage as below;

enter image description here
from: here

When you plug into the microphone , slowly adjust the gain of your opamp and O/P volume of your amplifier such that feedback is eleminated.

\$\endgroup\$
4
  • \$\begingroup\$ What is R8 for? \$\endgroup\$
    – sherrellbc
    Jun 28, 2014 at 13:20
  • \$\begingroup\$ @sherrellbc, Thanks for pointing out that it probably might be a careless mistake . I have rectified it along with other site link. \$\endgroup\$
    – Adi
    Jun 28, 2014 at 13:34
  • \$\begingroup\$ Is it assumed that the mic in this schematic includes a decoupling capacitor at its output? Also, I have never seen a mic amplifier like this. Typically they are just common-emitted amplifiers. What is the purpose of C1 and `R3? It appears to be some kind of high-pass filter for the feedback loop? \$\endgroup\$
    – sherrellbc
    Jun 28, 2014 at 14:22
  • \$\begingroup\$ @sherrellbc, R3 and R4 sets the gain and C1 is there for providing ac ground to audio signal for this single supply preamp. \$\endgroup\$
    – Adi
    Jun 28, 2014 at 18:11
0
\$\begingroup\$

I am wondering if I can connect the 3.5mm headphone jack to an electret microphone and play the sound from the microphone out of the speaker.

No you can't. The headphone jack is an output; a microphone requires to be connected to an input so that it can be amplified.

\$\endgroup\$
2
  • \$\begingroup\$ While the wording of the question is not great, I think the OP may be referring to the 3.5mm headphone jack as being the input connector for an amplifier. \$\endgroup\$
    – PeterJ
    Jun 28, 2014 at 10:21
  • \$\begingroup\$ @PeterJ you may indeed be right. Time will tell. \$\endgroup\$
    – Andy aka
    Jun 28, 2014 at 10:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.