Shahriar Posted April 9, 2006 Report Share Posted April 9, 2006 HiI 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 advanceSahriar Quote Link to comment Share on other sites More sharing options...
windoze killa Posted April 10, 2006 Report Share Posted April 10, 2006 Can you supply a schematic. Quote Link to comment Share on other sites More sharing options...
Shahriar Posted April 11, 2006 Author Report Share Posted April 11, 2006 HiThese two schematics are similar to the Ones I mean.One is a Single Supply Amp and the other is a double supply.ThanX in advanceShahriarMute.zip Quote Link to comment Share on other sites More sharing options...
windoze killa Posted April 11, 2006 Report Share Posted April 11, 2006 I think the easiest method would be a switch on the O/P. just open cct the O/P Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 11, 2006 Report Share Posted April 11, 2006 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. Quote Link to comment Share on other sites More sharing options...
Shahriar Posted April 11, 2006 Author Report Share Posted April 11, 2006 Dear windoze killa Can you write the full Dictation of CCT? I don't know what does it mean.Dear AudioguruFading with a ramp was very tricky. But I didn't understood where you put that Resistor anf FET? ::) ::) to mute the systemThanXShahriar Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 11, 2006 Report Share Posted April 11, 2006 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 AudioguruFading with a ramp was very Quote Link to comment Share on other sites More sharing options...
windoze killa Posted April 12, 2006 Report Share Posted April 12, 2006 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. Quote Link to comment Share on other sites More sharing options...
Shahriar Posted April 12, 2006 Author Report Share Posted April 12, 2006 Dear windoze killa Thank you very much, Strange Abbreviation :)Dear AudioguruI 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?ThanXShahriar Quote Link to comment Share on other sites More sharing options...
Shahriar Posted April 12, 2006 Author Report Share Posted April 12, 2006 Here the CCT ;DShahriarmsmicsch.zip Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 12, 2006 Report Share Posted April 12, 2006 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. Quote Link to comment Share on other sites More sharing options...
Shahriar Posted April 13, 2006 Author Report Share Posted April 13, 2006 Dear AudioguruThank you very much...But do you have any oponion about The Transistor in the noninverting Pin.Have I explained it clear?ThanXShahriar Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 13, 2006 Report Share Posted April 13, 2006 Dear AudioguruThank 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. Quote Link to comment Share on other sites More sharing options...
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