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| how to isloate audio ground from the amplifier |
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| Audioguru:
I live in North America so I buy Canadian and American things here, not in India. Can't you look for Indian things and buy them there? |
| Adhith:
--- Quote from: Audioguru on March 28, 2018, 02:36:44 pm ---I live in North America so I buy Canadian and American things here, not in India. Can't you look for Indian things and buy them there? --- End quote --- yes sir, I normally do buy things that are commonly avaliable here. The place where i'm coming from have very limited options in electronics sir. when I went to look for darlington today I understood that the shopkeepers haven't seen those type of transistors, even the buck boost modules was available only since last year. Things are tough here and we dont even have hobby shops, radioshack and things like that. just a few small electronic shops thats all .So the case is that if i look for an alternate component also it wont be available here sometimes. I have a good contact with a shop, where they take orders from shenzhen, china so they are usually helping me out to find the unavailable components with very cheap price due to my interest in electronics. I dont mind struggling, i just somehow need to learn electronics ,thats why sir, what about the 100k and 200k resistors at the pin 5 of the VU meter that I mentioned in my previous post?? i dont need those right?? just feed pin 5 dirlectly from the peak detector output right?? |
| Audioguru:
Disconnect everything from the pin 5 input of the LM3915 and connect it to the output of my peak detector circuit. Many cheap electronic parts from China are fakes or manufacturer's rejects. There are many videos on You Tube showing garbage put inside cheap fake lithium batteries from China. I buy genuine North American or European parts that are inexpensive and in stock from a reputable local parts supplier. |
| Adhith:
--- Quote from: Audioguru on March 28, 2018, 10:43:27 pm ---Disconnect everything from the pin 5 input of the LM3915 and connect it to the output of my peak detector circuit. Many cheap electronic parts from China are fakes or manufacturer's rejects. There are many videos on You Tube showing garbage put inside cheap fake lithium batteries from China. I buy genuine North American or European parts that are inexpensive and in stock from a reputable local parts supplier. --- End quote --- Ok sir I'll disconnect everything from pin 5 and connect to the output of the peak detector. yes I admit that there are lots of fakes here and is a serious problem. Most of the time the shops sells two variants of IC , a cheap variant and other costs a couple of bucks extra. I always buy the good one but I know that extra money is not a surety for the original product but it seems to have a good casing when compared with the lower cost variant and thus move on with it. But the batteries sold here especially 18650s have lot of fakes with different labelled capacities than the company actually produces. In my previous post I mentioned that I got a 6.3V between the left channel positive output and the ground near the DC jack just after switching on the amp, what is this voltage actually??. I know that we are taping from a bridged amplifier so half of supply voltage (12v/2 = 6v) is seen,but it could be seen even without a music playing so makes me little confusing that I'm i using the wrong terminals or not. Also this peak detector could block this signal right?? |
| Audioguru:
All audio amplifiers that use a single positive power supply voltage bias the input so that the output is at half the supply voltage so that it can swing equally up to near the supply voltage and down to near 0V. The peak detector has an input coupling capacitor that passes the audio but blocks the DC. Audio amplifiers that use a positive and negative supply bias the input so that the output is at 0V and can swing equally up to near the positive supply voltage and down to near the negative supply voltage. An ordinary amplifier with a single positive supply has DC on its output that causes trouble if it feeds a speaker so it has a coupling capacitor to feed audio to the speaker but block the DC. A bridged amplifier has two amplifiers, each one feeds one speaker wire. Since both amplifiers in your bridged amplifier have a single positive supply then both have their outputs at half the supply voltage so a coupling capacitor is not needed to feed the speaker. |
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