Hello,
I'm using a LM3886 based Clone with the mute circuit currently functional.
I'm planning some ongoing tinkering and wanted to disable the mute function,eliminating the extra caps,resistors and wire.
I have the data sheets and have spoken with NSC who say a jumper from the mute pin 8 to the V- pin would do the trick.
Just wanted to see if anybody has successfully done this as I don't have any extra chips to burn!
P.S I hope this question is intelligent enough to garner a response as my other inquiry re: power supply caps may have been judged too stupid for some of you geniuses
I'm using a LM3886 based Clone with the mute circuit currently functional.
I'm planning some ongoing tinkering and wanted to disable the mute function,eliminating the extra caps,resistors and wire.
I have the data sheets and have spoken with NSC who say a jumper from the mute pin 8 to the V- pin would do the trick.
Just wanted to see if anybody has successfully done this as I don't have any extra chips to burn!
P.S I hope this question is intelligent enough to garner a response as my other inquiry re: power supply caps may have been judged too stupid for some of you geniuses
I have used the LM3886 for a GainClone and to disable the mute function and jumpered with a 10K resistor to limmit current from mute pin direct to Vsupply. Very easy, no wires.
Regards,
Thijs
Regards,
Thijs
Same here...
But I used a 8k resistor. I think there is a wide range of values to use in this situation.
But I used a 8k resistor. I think there is a wide range of values to use in this situation.
Greetings,
I very much appreciate your help.Did you notice any change in your amps performance?
Mine actually sounds very good and after many trials with grounding schemes is also very quiet.
I certainly don't need the mute and can only surmise that the amp should sound better without the added circuitry.
Lastly I have some very nice 20k Richen Ohm resistors would that be too much?
I very much appreciate your help.Did you notice any change in your amps performance?
Mine actually sounds very good and after many trials with grounding schemes is also very quiet.
I certainly don't need the mute and can only surmise that the amp should sound better without the added circuitry.
Lastly I have some very nice 20k Richen Ohm resistors would that be too much?
Save the riken comp resistors...
All you are doing is disabling the mute function. The quality of the resistor will do nothing to performance. The value on the other hand I am not familar with. I have only used the 8k, nothing else. Goodluck
All you are doing is disabling the mute function. The quality of the resistor will do nothing to performance. The value on the other hand I am not familar with. I have only used the 8k, nothing else. Goodluck
For another reference, Siegfried Linkwitz uses the following variation of the National application schematic, with a 38k resistor to disable mute functionality:
-Nikhil
-Nikhil
The resistor value has a effect on the muting. There should flow some significant current through the resistor (1mA?): check the datasheet for the recommended current: then calculate the resistor needed with your Vsupply.
Regards,
Thijs
Regards,
Thijs
tschrama said:
This is true. You must draw more than 0.5mA out of the mute pin.
Resistor = (|Vee| - 2.6v)/I
"I" must be larger than 0.5mA.
For example, if your Vee is -25v , then:
R = (25 - 2.6)/0.5mA
R must be less than 44.8 Kohm.
Eureka!!
I went with the 10k resistor accross pin 8 and V- and it seems to work just fine.
All the vitals measure the same including vanishingly low DC offset at the output of 01.5 mv dead on for both channels.
I'll let in run in for a while and report back on any change in sound.
Thanks everyone for your input and the schematic I think Tallman included,most interesting.
Regards,
I went with the 10k resistor accross pin 8 and V- and it seems to work just fine.
All the vitals measure the same including vanishingly low DC offset at the output of 01.5 mv dead on for both channels.
I'll let in run in for a while and report back on any change in sound.
Thanks everyone for your input and the schematic I think Tallman included,most interesting.
Regards,
I spoke with an engineer at Nationals audio division. To disable mute all you need is a resistor to provide the necessary current between the proper pins, pin 8 and 4 I think for the 3876. The value of the resistor depends on the supply voltage, read the data sheet for the exact calculation. You need to have some thing like 0.5mA or more flowing out of pin 8. Too much current might damage the chip, so I would recommend keeping the resistor, Rm. The capactor, Cm, may be omitted, if mute will be permanently disabled.
i am making lm3886 amplifier i got the circuit & pcb file from http://http://www.eeweb.com/project/circuit_projects/lm3886-gainclone-2x68-watt-full-amplifier-project i made same to same as shown but on the other hand diy audio user's circuit are some different. so i am in confusion, plz help i am beginner in diy. plz check the circuit and pcb file that they are right or wrong.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
i ordered two LM3886TF chip but i found LM3886T chip so i mount them on different Pentium3 heatsink connected with wires. will this trick work? or not. plz comment
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Be sure a too low resistor will destroy your LM. I almost did that by miscalculating. Luckily the power supply shut down. But don't go below say 4K you should be fine.
I'd always use mica and grease, or what you are "saving" now will later complicate your mounting in a chassis.
And personally don't trust fans very much, prefer "real" heatsinks or at least a vertical aluminum plate, 20cm wide x 10cm high , 2 or 3 mm thick.
And personally don't trust fans very much, prefer "real" heatsinks or at least a vertical aluminum plate, 20cm wide x 10cm high , 2 or 3 mm thick.
thanks for your advise, can you check the pcb layout and schematic. I have a doubt something about circuit.
- Status
- Not open for further replies.