explain please
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From: bryan ohio
Car: 1986 camaro, 1993 nissan altima(winter beater, 1992 mustang (summer daily driver)
Engine: 350tpi
Transmission: 700r4 with shift kit
explain please
The diffrent classification of amplifiers, I know diff between 2 chnl and 4 chnl but not the mono or d class amps
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im not sure it stands for digital, but yea.. class d only produces subwoofer frequencies, but the up side is that it puts out way more power for way less current..
as a side note, i always love when people ask this question.. cause usually jim responds with his twelve paragraph switching transitor essay that only about 4 people on the board actually understand
ahh this board is great 
as a side note, i always love when people ask this question.. cause usually jim responds with his twelve paragraph switching transitor essay that only about 4 people on the board actually understand
ahh this board is great 
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Originally posted by mudaholic
im not sure it stands for digital, but yea.. class d only produces subwoofer frequencies, but the up side is that it puts out way more power for way less current..
as a side note, i always love when people ask this question.. cause usually jim responds with his twelve paragraph switching transitor essay that only about 4 people on the board actually understand ahh this board is great
im not sure it stands for digital, but yea.. class d only produces subwoofer frequencies, but the up side is that it puts out way more power for way less current..
as a side note, i always love when people ask this question.. cause usually jim responds with his twelve paragraph switching transitor essay that only about 4 people on the board actually understand
ahh this board is great and...
Originally posted by Jim85IROC
A class "D" amp is what's called a "digital" amp, although that isn't really all that accurate.
A class "A" amp is the simplest (and best sounding) amp you can use, but it's very inefficient. With a class "A" amp, the amplifier produces the whole sine wave. Because there's always current passing through a FET even when it's not amplifying anything, a class A amp tends to suck a lot of power and get hot even when you're not using it. It's inefficient because there's always a voltage potential across the FETs, and there's always a current flow. When you have voltage and current present, you have power consumption. In this case, it's wasted as heat.
A class "B" amp basically uses 2 FETs instead of 1 like a Class A uses. With a class B amp, each FET amplifies half of the sine wave, one for the positive half and one for the negative half. This makes the amp more efficient because you can shut the FET off while you're not using it. The problem with this amp is that because a FET has a .7 volt turn-on window, you get a distorted sine wave every time the amp switches FETs. A simple capactior circuit can smooth it out, but it never gets 100% perfect. With this amp, because the rail voltage is 1/2 as big on each FET compared to a class A amp (because each FET only does 1/2 the sine wave, the voltage can be halved for a given output), you have less wasted power.
Most car audio amps are class AB. This type of amp is basically a class B amp, but they bias the FETs so that there's a little current flow at all times. This eliminates most of the crossover distortion, and it behaves like a class A amp at low power levels.
Anyway... on to class D. It's called class D (or digital) because the transistors are either on or off... there's no inbetween; sorta like a digital signal vs. an analog. The way this works is that the amp switches the FETs on and off at a high rate of speed. This results in a square-wave type of output, but when it's filtered it represents a regular sine wave. To produce more power, the amp just stays switched on longer. This means that when the transistors are conducting (switched on) there is basically no voltage across the transistor and when there is full voltage across the transistor (switched off), there is no current flowing through the transistor. This is basically how a switching power supply works too. Anyway, what you wind up with is a choppy representation of the sine wave that gets turned on and off a bunch of times, but once you filter it, you more or less get the intended sine wave. These amps are extremely efficient, but due to their switching nature, they can only be used for low frequency reproduction. They don't switch fast enough to be able to cleanly reproduce high frequency signals. But, since bass is what takes all the power, it's not really necessary.
Hopefully I didn't confuse the hell out of you. If you don't understand how a switching power supply works, you're probably not going to grasp the Class D idea. But the long and the short of it is that the class D amp is a very, very efficient amp that doesn't have good enough fidelity to operate anything except subwoofers.
A class "D" amp is what's called a "digital" amp, although that isn't really all that accurate.
A class "A" amp is the simplest (and best sounding) amp you can use, but it's very inefficient. With a class "A" amp, the amplifier produces the whole sine wave. Because there's always current passing through a FET even when it's not amplifying anything, a class A amp tends to suck a lot of power and get hot even when you're not using it. It's inefficient because there's always a voltage potential across the FETs, and there's always a current flow. When you have voltage and current present, you have power consumption. In this case, it's wasted as heat.
A class "B" amp basically uses 2 FETs instead of 1 like a Class A uses. With a class B amp, each FET amplifies half of the sine wave, one for the positive half and one for the negative half. This makes the amp more efficient because you can shut the FET off while you're not using it. The problem with this amp is that because a FET has a .7 volt turn-on window, you get a distorted sine wave every time the amp switches FETs. A simple capactior circuit can smooth it out, but it never gets 100% perfect. With this amp, because the rail voltage is 1/2 as big on each FET compared to a class A amp (because each FET only does 1/2 the sine wave, the voltage can be halved for a given output), you have less wasted power.
Most car audio amps are class AB. This type of amp is basically a class B amp, but they bias the FETs so that there's a little current flow at all times. This eliminates most of the crossover distortion, and it behaves like a class A amp at low power levels.
Anyway... on to class D. It's called class D (or digital) because the transistors are either on or off... there's no inbetween; sorta like a digital signal vs. an analog. The way this works is that the amp switches the FETs on and off at a high rate of speed. This results in a square-wave type of output, but when it's filtered it represents a regular sine wave. To produce more power, the amp just stays switched on longer. This means that when the transistors are conducting (switched on) there is basically no voltage across the transistor and when there is full voltage across the transistor (switched off), there is no current flowing through the transistor. This is basically how a switching power supply works too. Anyway, what you wind up with is a choppy representation of the sine wave that gets turned on and off a bunch of times, but once you filter it, you more or less get the intended sine wave. These amps are extremely efficient, but due to their switching nature, they can only be used for low frequency reproduction. They don't switch fast enough to be able to cleanly reproduce high frequency signals. But, since bass is what takes all the power, it's not really necessary.
Hopefully I didn't confuse the hell out of you. If you don't understand how a switching power supply works, you're probably not going to grasp the Class D idea. But the long and the short of it is that the class D amp is a very, very efficient amp that doesn't have good enough fidelity to operate anything except subwoofers.
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Originally posted by 89blackGTA
Well actually I said that it was a digital amp because of a reply that I read from Jim here https://www.thirdgen.org/techbb2/sho...ht=class+d+amp
and...
Brian
Well actually I said that it was a digital amp because of a reply that I read from Jim here https://www.thirdgen.org/techbb2/sho...ht=class+d+amp
and...
Brian
Owned....
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Joined: Jan 2002
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From: bryan ohio
Car: 1986 camaro, 1993 nissan altima(winter beater, 1992 mustang (summer daily driver)
Engine: 350tpi
Transmission: 700r4 with shift kit
cool, thanx guys I think I got ya. I aksed because Im thinking of switching from y current setup, too 2 power hx2 10's and not sure on what to push them with
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