How to add a mute system to an OpAmp

[Shahriar]

Hi
I have an OpAMp (NE5532) which is driving a Headphone.
I want to add a Mute System to this circuit.
How is it possible whether it has a Dual Supply or single Supply. (If it differs)

ThanX in advance
Sahriar

[windoze killa]

Can you supply a schematic.

[Shahriar]

Hi

These two schematics are similar to the Ones I mean.

One is a Single Supply Amp and the other is a double supply.

ThanX in advance
Shahriar

Mute.zip

[windoze killa]

I think the easiest method would be a switch on the O/P. just open cct the O/P

[audioguru]

I muted the background music in a huge intercom system with a series resistor and a jFET to ground. Half of the input signal was fed to the gate of the JFET for very low distortion and the muting was made with a ramp for fading the music down then fading back up to avoid clicks.

[Shahriar]

Dear windoze killa
Can you write the full Dictation of CCT? I don't know what does it mean.


Dear Audioguru
Fading with a ramp was very  tricky. But I didn't understood where you put that Resistor anf FET?  ::)  ::) to mute the system

ThanX
Shahriar

[audioguru]

Dear windoze killa
Can you write the full Dictation of CCT? I don't know what does it mean.

A switch on the output.

Dear Audioguru
Fading with a ramp was very

[windoze killa]

Dear windoze killa
Can you write the full Dictation of CCT? I don't know what does it mean.

Sorry. CCT is just and abreviation for circuit.

[Shahriar]

Dear windoze killa
Thank you very much, Strange Abbreviation  :)

Dear Audioguru

I Had the same oponion to mute the signal in the same manner as you said, Of course with a BJT. I thought if the signal has a DC (i.e. 3V) then it works but when there is no DC I didn't have any oponion for Negative Cycles of Signal. Because in this condition, the Base-Collector Junction would go in Forward bias.
what would happen with a FET?

2- what I tested yesterday, In the Non-Inverting PAiA ciruit I attached, I put a NPN Transistor Between the 100k Resistor (R11) on the Noninverting pin of IC1:B and GND. When the Transistor was ON everything would work fine, when it goes Off, The Output would saturates gradually, but I didn't test it with a Sound Signal to see if It affect quality in Normal Condition.
What do you think?

ThanX
Shahriar

[Shahriar]

Here the CCT  ;D

Shahriar

msmicsch.zip

[audioguru]

Hi Shahriar,
The ordinary transistor has very reduced current gain when the signal ihas reversed polarity so the muting will be a little rectified.
Use a jFET like I said. It is a voltage-variable resistor and with the low level from the mic it will have low distortion even if you ramp the muting.
Wien bridge oscillators frequently use a jFET for amplitude control.

[Shahriar]

Dear Audioguru

Thank you very much...

But do you have any oponion about The Transistor in the noninverting Pin.
Have I explained it clear?

ThanX
Shahriar

[audioguru]

Dear Audioguru

Thank you very much...

But do you have any oponion about The Transistor in the noninverting Pin.
Have I explained it clear?

Like I said, an ordinary transistor would probably rectify the signal when it is turned on which would make low-level distortion. JFETs have been used for muting frequently.