0
\$\begingroup\$

I need to build a basic attenuator and wonder if someone could help.

I have updated my post to try and make it clearer what my problem is:

One end of circuit is a WiFi headset unit. Mic output is 2.5 V eff., 600 Ω.

Twisted pair (screened) from WiFi headset box Mic OUT Hi & Lo to audio box Mic IN Hi & Lo.

Audio box spec: 0.25 Vrms into 300 Ω nominal. Dynamic range from 20 mVrms to 1.5 Vrms. DC bias 18 VDC @ 20-30 mV.

What is needed to make these two units compatible?

\$\endgroup\$

1 Answer 1

Reset to default
1
\$\begingroup\$

It sounds like you need to use a taper pad attenuator if you need to maintain those impedances: -

enter image description here

Image from my basic website.

Is it as simple as a resistor across the hi and lo (in parallel) to drop the voltage and another resistor in series to drop the resistance?

It's three resistors for sure (see circuit in image above). Make sure that if phantom power is involved, you properly isolate the DC from the attenuator using coupling capacitors rated at the correct voltage.

\$\endgroup\$
2
  • \$\begingroup\$ Sorry, can you help me again, please. If I have phantom power, where would the two capacitors go in the circuit. And I want to drop the voltage from 2.5 to .025 so would the capacitors be different values? \$\endgroup\$
    – Audio24
    Commented Sep 20, 2022 at 18:40
  • \$\begingroup\$ You need to show more details if you want help here. Show a circuit, explain what bandwidth you want to achieve also. You should also take the 2 minute tour to understand why folk give help for free. \$\endgroup\$
    – Andy aka
    Commented Sep 20, 2022 at 18:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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