LM1876 arduino mute - Page 2

dataplex · 12th January 2013, 07:16 PM

hey tauro

im worried the mute pin might draw to much power from the arduino. the I/O pins of the arduino are limited to 40mA / 20mA reccommended!

and for some reason i cannot get the mute pin to work anyway, using a 5v battery to mute pins and ground. weird huh?

plus i need a latency free mute switch, and im not sure if the LM1876 mute pin works instantly... does anyone have experience with this chips feature?

tauro0221 · 12th January 2013, 07:30 PM

Hi,
If you check the mute in the schematic Figure 6. LM1876 you can see that the mute goes to the base of a transistor so it would not required a lots current to enable or disable the mute using the output from the Arduino. I will use the output with no problem.

madtecchy · 13th January 2013, 08:36 AM

Fast muting/ unmuting will cause pops.. there must be a better way to get where you need to be .. Unfortunatley we do not know what that is so it makes it a little difficult to suggest any other potential options ..

Regards Mark

tauro0221 · 13th January 2013, 04:13 PM

Hi,
Just to let you know that I am using a NANO micro to control the speakers output and also the mute of my LM3886 amplifier. Since the mute in the LM3886 it is negative and for isolation I am using a solid state relay LH1546. It worked with no noisy whatsoever.Just clean in the ON/OFF.

dataplex · 14th January 2013, 12:34 AM

hey, thanks for all the replies!

maybe i can switch the signal on/off before the LM1876 - if i where to use this IC :: http://semicon.njr.co.jp/eng/PDF/NJM2521_E.pdf

can someone help me draw a schematic that flips a low power signal on/off with my arduinos digital pins?

thanks,
úlfur

Zero Cool · 14th January 2013, 12:58 AM

try a 10k resistor between the arduino and the LM chips. that should sufficiently limit the current.
you could always use some small signal transistors as switches connected to the arduino to mute the chips. plenty of examples on the arduino web forums for that!

counter culture · 14th January 2013, 01:13 AM

Quote:

Originally Posted by dataplex

and for some reason i cannot get the mute pin to work anyway, using a 5v battery to mute pins and ground. weird huh?

No, not weird, if you're using a single supply. In which case you need 1/2 the supply voltage +2.5V to achieve mute.

tauro0221 · 14th January 2013, 01:50 AM

Hi,
Attached is an schematic on to do the input selection switching. This is an idea how to do it. It use 2 I/O pins from the Arduino micro.

dataplex · 14th January 2013, 05:43 PM

thanks again tauro

how does this PCB look to you? (its a bottom layer, thus inverted for printing!)

tauro0221 · 14th January 2013, 06:26 PM

Hi,
At the beginning I was unable to follow the circuit since you over look that pin 1 it is the one with the square. You have to turn around the socket or leaving it like it is just cosmetic. Are you trying to switch audio no? I was thinking that you was trying to mute the LM1876. The NJM2521 what it does is to select one output from three inputs. I just want to verify that were are in the same track.

14th January 2013, 12:58 AM	#16
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	try a 10k resistor between the arduino and the LM chips. that should sufficiently limit the current. you could always use some small signal transistors as switches connected to the arduino to mute the chips. plenty of examples on the arduino web forums for that! __________________ It's not about what you can BUY...It's about what you can BUILD!

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12th January 2013, 07:16 PM	#11
dataplex diyAudio Member Join Date: Aug 2012	hey tauro im worried the mute pin might draw to much power from the arduino. the I/O pins of the arduino are limited to 40mA / 20mA reccommended! and for some reason i cannot get the mute pin to work anyway, using a 5v battery to mute pins and ground. weird huh? plus i need a latency free mute switch, and im not sure if the LM1876 mute pin works instantly... does anyone have experience with this chips feature?

12th January 2013, 07:30 PM	#12
tauro0221 diyAudio Member Join Date: Nov 2008 Location: Victoria,TX	Hi, If you check the mute in the schematic Figure 6. LM1876 you can see that the mute goes to the base of a transistor so it would not required a lots current to enable or disable the mute using the output from the Arduino. I will use the output with no problem.

13th January 2013, 08:36 AM	#13
madtecchy diyAudio Member Join Date: Dec 2010 Location: wigan	Fast muting/ unmuting will cause pops.. there must be a better way to get where you need to be .. Unfortunatley we do not know what that is so it makes it a little difficult to suggest any other potential options .. Regards Mark

13th January 2013, 04:13 PM	#14
tauro0221 diyAudio Member Join Date: Nov 2008 Location: Victoria,TX	Hi, Just to let you know that I am using a NANO micro to control the speakers output and also the mute of my LM3886 amplifier. Since the mute in the LM3886 it is negative and for isolation I am using a solid state relay LH1546. It worked with no noisy whatsoever.Just clean in the ON/OFF.

14th January 2013, 12:34 AM	#15
dataplex diyAudio Member Join Date: Aug 2012	hey, thanks for all the replies! maybe i can switch the signal on/off before the LM1876 - if i where to use this IC :: http://semicon.njr.co.jp/eng/PDF/NJM2521_E.pdf can someone help me draw a schematic that flips a low power signal on/off with my arduinos digital pins? thanks, úlfur

14th January 2013, 05:43 PM	#19
dataplex diyAudio Member Join Date: Aug 2012	thanks again tauro how does this PCB look to you? (its a bottom layer, thus inverted for printing!)

14th January 2013, 06:26 PM	#20
tauro0221 diyAudio Member Join Date: Nov 2008 Location: Victoria,TX	Hi, At the beginning I was unable to follow the circuit since you over look that pin 1 it is the one with the square. You have to turn around the socket or leaving it like it is just cosmetic. Are you trying to switch audio no? I was thinking that you was trying to mute the LM1876. The NJM2521 what it does is to select one output from three inputs. I just want to verify that were are in the same track.