Check out these other great forumsSoundSolutionsAudio.comAudioAddicts.netCarAudio-Forum.comCarAudioResources.comHomeAudioForum.net

Jump to content

SSA Tax Refund Sale

Anatomy of the Power Amplifier, By Robert Zeff

- - - - -

  • You cannot reply to this topic
46 replies to this topic

#1
Aaron Clinton

Aaron Clinton

    CA-F.com Steady

  • Admin
  • PipPipPipPipPip
  • 10,832 posts
  • Gender:Male
  • Location:CA-F HQ East
  • Interests:German performance auto's, American Speakers, rare or collectible amplifiers.

*
POPULAR

Another great read that I felt was worth having here also:

Anatomy of the Power Amplifier
Dissecting the Modern Audio Power Amplifier and Power Supply
By Robert Zeff

With the Proliferation of Different Amp Types, Which is the One for You? In the past we had essentially two types of amplifiers to choose from: Class "AB" and class "A". Today we have AB, A, D, G, H, & T, in addition to some that do not have a class name. New technology brought down the size and price while improving performance and efficiency. We'll review the various topologies of the modern amplifier, spending extra time on the aspect of efficiency (as the quest for smaller, more efficient designs have spawned the class D, G, H, & T designs). We'll also try to dispel some of the misconceptions and folklore that seem to surround amp design.

Amplifiers require circuitry for short and thermal protection, fan control, turn on delay, and over voltage protection. In the past we littered the designs with dozens of components to handle these events. Today we can use a single microprocessor to handle all of this in addition to having many more features without additional cost. The microprocessor can monitor the battery voltage, internal voltages, temperature, control volume and crossovers, and drive external displays. These embedded computer chips also allow features like compression and power limiting with little added cost. Of course, what is an amplifier without a power supply? First we'll visit the power supply designs, as every amplifier needs one.

The Power Supply
The purpose of the supply is to convert the auto's battery voltage to a higher voltage. For example, if an amplifier is to produce 100 watts into a 4 ohm speaker, we need 20 volts RMS. This implies that we need about +/-28 volts. (20 volts R.M.S. = 28.28 volts peak). We call that the "rail" voltage. Since the amplifier's output transistors cannot pull all the way up to this rail, we actually need a slightly higher voltage.

The process is to convert the 12 volts DC into AC, feed it to a transformer and convert it back to DC again.

Converting the 12 volt battery voltage to AC is simple, a PWM (pulse width modulator) IC feeds a bank of MOSFETS (MOSFETs are switching transistors perfectly suited for this task).

The 12 volt power is switched at a very high frequency, somewhere between 40 and 150 kHz. Slower switching speeds require a larger transformer, but high speeds have more switching loss. Advanced transformer core materials, faster rectifiers, and clever winding methods have enabled us to utilize very high frequencies. Some of today's better amplifiers have very small power supplies that produce enormous amounts of power.

Regulated Power Supplies
Most early audio amplifiers contained unregulated power supplies. Regulated supplies require very high quality filter capacitors (called "low ESR" capacitors), output chokes, and an optically isolated voltage feedback circuit. Regulation occurs by controlling the switching pulse width from 0 - 100% to compensate for changes in the battery and rail voltage. The same action occurs when the audio level increases. As the amplifier draws more power from the supply, the rail voltage drops. Again, the regulator circuitry senses this drop and responds with an increased pulse width.

The high frequency PWM waveform is rectified (converted to DC) and applied to the output filter choke and capacitors. This output of this circuit is the + and - DC rails that feed the power amplifier.

Unregulated Power Supplies
Unregulated power supplies are less expensive than regulated supplies. They do not require an output choke, voltage sense or isolation circuitry. Because the duty cycle is nearly 100%, capacitor ripple current is much lower in unregulated supplies. Lower ripple current requires less expensive capacitors throughout.

Often we hear that unregulated designs have more "headroom". That means that the amplifier will produce extra power during transients. Most home audio amplifiers employ unregulated power supplies. The power supplies in these amplifiers run at 60 Hz, thus the filter capacitors must be 200-500 times larger than those used in high frequency switchers. The extra capacitance in home audio amplifiers results in extra headroom. Headroom for anything other than very short transients simply doesn't exist in the unregulated designs. The following is an example of specifications for an unregulated vs. regulated amplifiers.

Unregulated designs have a higher supply voltage at low power, causing higher voltage on the output transistors. This reduces the amplifier's efficiency.

Small amplifiers (less than 100 watts) cannot justify the extra cost of the regulation circuitry, so we often see unregulated supplies in these amplifiers.

Pros and Cons of Regulated / Unregulated SuppliesSome designers try to keep their supplies regulated down to battery voltages as low as 9.5 volts. The supply compensates by increasing the current. The following table shows voltage and currents for a 500 watt over-regulated amplifier operating at full power.

The current increases dramatically at the lower voltages. Because of higher currents at the lower voltages, the supply efficiency drops further, requiring even more current.

At higher voltages, the pulse width reduces, causing increased ripple current. This high current creates heat in the filter capacitors and can destroy the capacitor's electrolyte. Some manufacturers do not use capacitors of sufficient quality for this range of regulation. These amplifiers may not perform up to specification just one year after installation. Also, the extra current at low voltages is extra hard on a battery that is already suffering! So, we recommend that amplifiers stay in regulation down to about 11 - 11.5 volts. Any properly working charging system can easily keep the battery voltage well above this.

The Amplifier Section, Class AB and AClass AB and A amplifiers are similar, so we'll discuss both here. Class AB amplifiers have transistors that pull up to the positive rail and transistors that pull down to the negative rail. This corresponds to the action of pushing the speaker cone out and in.

Class AB means that the output transistors do not always have current on them. For example, when the upper transistors are pulling up towards the positive rail (pushing the speaker out), there is no current in the lower transistors. When the output signal swings through zero, towards the negative rail, the output transistor must go through a transition from zero current to a non-zero current. The best analogy that I can think of is driving an old car with too much slop in the steering. As you go from one side of the road's crown to the other, the steering crosses a "dead" zone, and you tend to over-steer. Special temperature compensated bias circuitry reduces this dead zone, known as notch distortion. The figure below shows the output of a class AB amplifier with too little bias and the resulting distortion. Notch distortion increases at higher frequencies and low volume levels. Some modern designs have reduced this type of distortion to very low levels.

Class A means that every transistor is always conducting current. They are very similar to class AB amplifiers, but the bias circuitry is set so that there are very high currents in the output transistors. Because these amplifiers do not have this "dead zone', less feedback is required to achieve low distortion.

A 100 watt amplifier may dissipate nearly 100 watts internally even when there is no audio output. This type of design is impractical in the harsh auto environment. Many class A amplifiers pedaled for the automotive market are not really class A. They are huge power wasters in the home as well.

Input and Driver Stages
The amplifier works this way: A small audio signal is presented to the amplifier's input. Transistors are not linear, which means that the input signal will distort somewhat as it passes through the various amplifier stages. To correct this distortion, a portion of the output is compared with the input. The difference creates a correction signal reducing this distortion. The input stage is a special type, called "differential". It has a + and a - input because it must accept both the audio input and the input from the feedback circuitry. Excess feedback can lower distortion dramatically, but cause instability. Careful design rules must be followed to avoid this instability.

The output of the input stage feeds into the driver stage. The driver stage may use one, two, or three devices. Often this circuitry is referred to "Darlington", or "Triple Darlington". The driver circuit feeds the output stage, which may have two, four, six, or more transistors. The more output transistors, the better. Multiple output devices reduce distortion (requiring less negative feedback) and improve reliability.

Bipolar or MOSFET?
We have seen both MOSFET (Metal Oxide Silicon Field Effect Transistor) and Bipolar transistors used in audio amplifiers. Claims have been made that each is superior. I have seen claims that MOSFETs have a tube ("Valve" for the Brits) sound. This is more folklore. The musicians and their instruments are supposed to have "the sound", not audio equipment! MOSFETs are tougher than Bipolars, and can pull closer to the supply rail. It takes more Bipolar transistors to achieve the same power as a MOSFET, therefore Bipolar amps tend to be more expensive. But, MOSFETs are very non-linear, compared to Bipolars and require much more feedback to achieve reasonable distortion numbers. They are a great choice for bass amps, as low frequency audio is not difficult for a MOSFET. The most expensive car and home amplifiers almost always use Bipolar transistors.

Efficiency
What makes an amplifier get hot? Both the power supply and the power amplifier generate heat. The maximum efficiency of the power supply is nearly 100%. Good power supply designs, with the highest quality components approach 85%. The class AB amplifier efficiency at full power can approach 75%. The total efficiency, including the power supply, can be about 65%. But, efficiency drops at lower power and can typically be under 20%. A class AB amplifier actually runs cooler at full power than it does at half power. Run this amplifier into clipping and it might run even cooler! Where is all this power going? The output transistor is basically a large variable resistor. If the instantaneous output voltage should be 40 volts and the power supply is 100 volts, then 60 volts must be "wasted" in the output transistors. Driving a reactive load (like a speaker) causes the efficiency to drop ever further. This brings us to the other audio classes designed to improve efficiency.

Class D
First, let's dispel another myth: Class D does not stand for digital. The input is converted to a two-state (binary) representation of the audio waveform. That's where the similarity ends. This distinction is important because class D doesn't provide the benefits normally associated with digital components.

That being said, class D designs dramatically improve efficiency. Instead of wasting power in the output transistor, the output is switched at a very high frequency between the positive and negative supply rails. If the output is to be zero, then the waveform is at a 50% duty cycle. If the output is to be a positive voltage, then the duty cycle would be greater than 50%. Because the output devices are either completely turned on (no wasted voltage) or completely turned off, theoretically efficiency is 100%. So the audio input must be converted to a pulse width modulated waveform (PWM). The yellow trace below is the output of the amplifier; the blue trace is the PWM waveform. The blue waveform is fed to an output filter, which results in the yellow output waveform. Notice that the output looks somewhat distorted. All of the switching noise and distortion cannot be removed and the result can be seen here. Because of this process of converting the input signal to PWM and converting back to analog, a good deal of distortion is introduced. Conventional feedback like that used in class AB designs is used in these amplifiers to reduce distortion.

MOSFETs are the only choice for class D designs. Most class D designs are useful only for bass amps as they can not switch fast enough to reproduce high frequencies. Some high quality, full range class D designs exist for pro audio, but they are complex with multi-phased outputs.

Class T
Class T (Tripath) is similar to class D with these exceptions: This class does not use analog feed back like its class D cousin. The feedback is digital and is taken ahead of the output filter, avoiding the phase shift of this filter. Because class D or T amplifier distortion arises from timing errors, the class T amplifier feeds back timing information. The other distinction is that this amplifier uses a digital signal processor to convert the analog input to a PWM signal and process the feedback information. The processor looks at the feedback information and makes timing adjustments. Because the feedback loop does not include the output filter, the class T amplifier is inherently more stable and can operate over the full audio band. Most listeners can not hear the difference between class T and good class AB designs. Both class D and T designs share one problem: they consume extra power at idle. Because the high frequency waveform is present at all times, even when there is no audio present, the amplifiers generate some residual heat. Some of these amplifiers actually turn off in the absence of music, and can be annoying if there is too much delay turning back on.

Class G
Class G improves efficiency in another way: an ordinary class AB amplifier is driven by a multi-rail power supply. A 500 watt amplifier might have three positive rails and three negative rails. The rail voltages might be 70 volts, 50 volts, and 25 volts. As the output of the amplifier moves close to 25 volts, the supply is switched the 50 volt rail. As the output moves close to the 50 volt rail, the supply is switched to the 70 volt rail. These designs are sometimes called "Rail Switchers". This design improves efficiency by reducing the "wasted" voltage on the output transistors. This voltage is the difference between the positive (red) supply and the audio output (blue). Class G can be as efficient as class D or T. While a class G design is more complex, it is based on a class AB amplifier and can have the same clean characteristics as well.

Class H
Class H is similar to class G, except the rail voltage is modulated by the input signal. The power supply rail is always just a bit higher than the output signal, keeping the voltage across the transistors small and the output transistors cool. The modulating power supply rail voltage is created by similar circuitry that you would find in a class D amplifier. In terms of complexity, this type of amplifier could be thought of as a class D amplifier driving a class AB amplifier and is therefore fairly complex.

How to Choose?
Regulated or unregulated? Class AB, D, or T?If you're really into a lot of bass, the class D or T may be for you as these amplifiers will produce the highest SPL with the smallest size. If you just want to wake the neighbors, blur your vision, or make a big splash in SPL contests, maybe you just need one of the inexpensive, powerful, & dirty class D designs. Want the cleanest high frequencies? Maybe a good class AB amp would be your selection. Whatever you choose, I hope this information helps you achieve the sound you're looking for!


>> Click here for images and diagrams too <<


#2
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View PostAaron, on 20 October 2009 - 10:07 AM, said:



The process is to convert the 12 volts DC into AC, feed it to a transformer and convert it back to DC again.![/i]

>> Click here for images and diagrams too <<



thank you for the awesome read aaron. this just prove me again that there are people out there that know about this that  ac does not come out of amps  people think this because they play a sine sweep that ac will come out not that way there are dc sine wave too. there just high and lows in dc but the amprage never reverse flow direction like in ac dc alway flows from plus to minus this is why it is a so awesome for speaker application. because the magnetic field does creates is pedictible were ac is not. any ways if you put ac to a speaker it will play in reverse buy useing the x max in reverse same as if you wired the plus / minus back wards.

#3
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male
i think they get all there learning from the Internet and www.bcae1.com is were they get it from and there are completely wrong on what they wrote


mainly #21
on this page at right


http://www.bcae1.com/

Edited by sadistic_customs, 20 October 2009 - 11:18 AM.


#4
Aaron Clinton

Aaron Clinton

    CA-F.com Steady

  • Admin
  • PipPipPipPipPip
  • 10,832 posts
  • Gender:Male
  • Location:CA-F HQ East
  • Interests:German performance auto's, American Speakers, rare or collectible amplifiers.
Robert Zeff is the originator of Zapco.  He is no longer there, he is part of Nikola who designs for others.

#5
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View PostAaron, on 20 October 2009 - 02:28 PM, said:

Robert Zeff is the originator of Zapco.  He is no longer there, he is part of Nikola who designs for others.


sure is you can tell

#6
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male
btw it a great read too

#7
Aaron Clinton

Aaron Clinton

    CA-F.com Steady

  • Admin
  • PipPipPipPipPip
  • 10,832 posts
  • Gender:Male
  • Location:CA-F HQ East
  • Interests:German performance auto's, American Speakers, rare or collectible amplifiers.

View Postsadistic_customs, on 20 October 2009 - 03:31 PM, said:

sure is you can tell
I consider Zeff, Mantz, and Kenny of Lunar to be some of the best American amplifier designers.

#8
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View PostAaron, on 20 October 2009 - 03:38 PM, said:

I consider Zeff, Mantz, and Kenny of Lunar to be some of the best American amplifier designers.

i hear ya

#9
thumper88

thumper88

    CA-F.com Newbie

  • CA-F Member
  • Pip
  • 9 posts
  • Location:Michigan

View Postsadistic_customs, on 20 October 2009 - 11:15 AM, said:

thank you for the awesome read aaron. this just prove me again that there are people out there that know about this that  ac does not come out of amps  people think this because they play a sine sweep that ac will come out not that way there are dc sine wave too. there just high and lows in dc but the amprage never reverse flow direction like in ac dc alway flows from plus to minus this is why it is a so awesome for speaker application. because the magnetic field does creates is pedictible were ac is not. any ways if you put ac to a speaker it will play in reverse buy useing the x max in reverse same as if you wired the plus / minus back wards.

ok...yikes...where to start.

DC Sine Wave? Do you happen to have an example of one? Maybe an article I could read about them? I'd like to see that on an oscilloscope... :blink:

http://www.pcguide.c...sicsACDC-c.html

A speaker needs to move in and out to make sound waves. AC pushes and pulls on the coil in a speaker...DC would only push or pull depending on the polarity.
Hook a car battery (direct current) up to a speaker...all that's going to happen is it will push out or pull in...eventually burn up the voice coil if connected long enough. Hook a speaker up to a wall outlet (alternating current) and it will move in and out, creating a 60Hz (USA) tone...of course eventually failing due to going over its thermal power handling (Pe) or its mechanical excursion limits (Xmech).

The sentence you quoted all happens in the power supply section of the amplifier. The audio output section of the amplifier takes these +-DC rail voltages and creates an amplified musical output...alternating current.

One feature some amplifiers have is DC Offset protection....to shutdown the amplifier before the speakers are damaged by a DC signal. Yes, the purpose of DC Offset protection is to block Direct Current from reaching the speakers.

DC Offset Protection

Hopefully that helps.

#10
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View Postthumper88, on 20 October 2009 - 06:26 PM, said:

ok...yikes...where to start.

DC Sine Wave? Do you happen to have an example of one? Maybe an article I could read about them? I'd like to see that on an oscilloscope... :blink:

http://www.pcguide.c...sicsACDC-c.html

A speaker needs to move in and out to make sound waves. AC pushes and pulls on the coil in a speaker...DC would only push or pull depending on the polarity.
Hook a car battery (direct current) up to a speaker...all that's going to happen is it will push out or pull in...eventually burn up the voice coil if connected long enough. Hook a speaker up to a wall outlet (alternating current) and it will move in and out, creating a 60Hz (USA) tone...of course eventually failing due to going over its thermal power handling (Pe) or its mechanical excursion limits (Xmech).

The sentence you quoted all happens in the power supply section of the amplifier. The audio output section of the amplifier takes these +-DC rail voltages and creates an amplified musical output...alternating current.

One feature some amplifiers have is DC Offset protection....to shutdown the amplifier before the speakers are damaged by a DC signal. Yes, the purpose of DC Offset protection is to block Direct Current from reaching the speakers.

DC Offset Protection

Hopefully that helps.

try to digest this slowly your mostly right there are just other parts to it


i can get you a isbn on my college text book maybe publish photo to the web if needed but i will try to explain the difference first. there is anode cathodend gate i think on diodes like the schockely diode.there are trigering the gate and basicaly the dc sit's behid the either the anode or the cathode like a water spigit waiting to be turned on when you turn the handle or trigger the gate it lets electricty or in the example water flow threw. see the trigging is done so fast as in pico and nano seconds. it create a look a like sine wave which never goes negtive like ac does by trigging i saying going 300,000 time in a second it can flicker on and off. so it may go to 5 volt one time then 2 volt another and back up to five volts again and never go negtive. see you can not use ac on a speaker. ac the curent is set moving back and forth in cycles like 60 hetz like a wall out let say by back and forth i mean negtive and postive switches directions so yourspeaker for a given frequeny like 60 hertz will pull in for half of the cycles. like you do for a clam shell configre like done for one of the subs in it. but yes you are right you give a sub non pulsated dc it will come unglued like giving it strit dc for like 5 -10 second is all it will take to fry one sub. the palsation is like turing a light switch on and off a bunch of time but under a 100,000,000.00 of a second or one millionth of a second.

got to remember a speaker has a stiffen suspenision system right because it's not meant to be pulled in the suspension system does it for it such as spider surround this is were voice coil tincel lead slap is very imporantant. a one way piston in other words of couse you can do it with ac pull it in it the magent working in reverse of what it should be sub are meant to go in only one direction hence the postive and negtive markings

sorry i had to fix it but the spell check is not working...

Edited by sadistic_customs, 20 October 2009 - 07:56 PM.


#11
thumper88

thumper88

    CA-F.com Newbie

  • CA-F Member
  • Pip
  • 9 posts
  • Location:Michigan
http://www.webervst....term.html#phase :blink:

#12
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View Postthumper88, on 20 October 2009 - 08:09 PM, said:



read number three of the link you gave why would you want to re lable it ???? if it's ac ???


You might find that some vintage speakers, particularly JBL and
   Jensens, were reverse-polarized. This means that a plus voltage
   on the plus-indicated terminal of the speaker will actually cause
   the speaker to move in rather than out.
   You will want to make a note of this or relabel it for your convenience

#13
thumper88

thumper88

    CA-F.com Newbie

  • CA-F Member
  • Pip
  • 9 posts
  • Location:Michigan
Did you read the last part of number 3?

"Again, the speaker is an AC device. The purpose of
   characterizing and marking them is for the convenience of the user to
   ensure they will be connected for proper acoustic phasing."

Keeping speakers in phase is a common term in car audio, surely you've heard of speakers being out of phase?

The purpose of the polarity markings is simply to have all the speakers moving in and out at the same time (in phase).

Edited by thumper88, 20 October 2009 - 08:22 PM.


#14
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View Postthumper88, on 20 October 2009 - 08:21 PM, said:

Did you read the last part of number 3?

"Again, the speaker is an AC device. The purpose of
   characterizing and marking them is for the convenience of the user to
   ensure they will be connected for proper acoustic phasing."

Keeping speakers in phase is a common term in car audio, surely you've heard of speakers being out of phase?

The purpose of the polarity markings is simply to have all the speakers moving in and out at the same time (in phase).

yes your right there if it is ac the phase will switch in side the wire if you notice the 2volt 5volt 2volt 5volt if you put them on a graph like in the first like you gave it look a lot like a sine wave ith out be comeing negtive five volts see you were most correct i will show the grap i am talking about you just got to play connect the dotts when you put the dotts on the graph

#15
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male
like the firist pic on at this lik of a grap of 12 volt dc plot it on this type of grap the 2 volt and the 5 volts it should make a sine wave


http://www.pcguide.c...sicsACDC-c.html

Edited by sadistic_customs, 20 October 2009 - 08:29 PM.


#16
thumper88

thumper88

    CA-F.com Newbie

  • CA-F Member
  • Pip
  • 9 posts
  • Location:Michigan
direct current is just that...direct...there is no such thing as a direct current sine wave... Look it up, find something that says different. Direct current has no phase, no frequency......if it did...it would be alternating current. :excl:

Look at this link...
http://www.kpsec.freeuk.com/acdc.htm

Notice the "varying" DC graph...in a sense what you seem to possibly be describing...which is not an audio signal (DC obtained by rectifying AC).

#17
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View Postthumper88, on 20 October 2009 - 08:46 PM, said:

direct current is just that...direct...there is no such thing as a direct current sine wave... Look it up, find something that says different. Direct current has no phase, no frequency......if it did...it would be alternating current. :excl:

Look at this link...
http://www.kpsec.freeuk.com/acdc.htm

Notice the "varying" DC graph...in a sense what you seem to possibly be describing...which is not an audio signal (DC obtained by rectifying AC).
your right there is no dc sine wave it is pulse width modulated dc also know as pwm circuitry this is why i termed it as strait dc for the unglued speaker in post above. but if you notice the ac graph at link suggested from you in this quote the ac sine wave dips below zero to negative this is were alternating current get it's name so if you hooked ac to a speaker it would be like switching the polarity every second this is why they hit so hard wired right and not wired in reverse this is were dc is predictable were ac is not i just term it as a dc sine wave because it never went negtive which is using dc to make a sign wave wich this is werte i can tell your a smart guy becuse dc has no frequency or phase but can be made to have it by pulse width modulation any ways very intresting topic thank you for bring it up.

#18
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male
have a look at page two at this link item b it's pulse width modulate dc versus a ac input versus dc out put of a pwm circuit


http://www.personal....axl17/242l9.pdf

#19
GX3

GX3

    CA-F.com Newbie

  • CA-F Member
  • Pip
  • 3 posts
  • Gender:Male
  • Location:Michigan
sadistic_customs   :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  you are an Idiot.


"so it may go to 5 volt one time then 2 volt another and back up to five volts again and never go negtive. see you can not use ac on a speaker. ac the curent is set moving back and forth in cycles like 60 hetz"


AC is the ONLY way speakers will produce sound!!!!! I wonder why ALL amps and speakers have a  frequency range. DC is like Thumper said Direct current. you CAN NOT pulse DC to a speaker all the will happen is the cone will max out in one direction. The fact the ac goes +/- is the way a speaker makes sound. But why am I wasting any time on this.  Go BACK to school and try again.............. DUMBASS

#20
bum

bum

    CA-F.com Steady

  • CA-F Member
  • PipPipPipPipPip
  • 2,893 posts
  • Gender:Male

View PostGX3, on 21 October 2009 - 03:56 PM, said:

sadistic_customs   :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  you are an Idiot.


"so it may go to 5 volt one time then 2 volt another and back up to five volts again and never go negtive. see you can not use ac on a speaker. ac the curent is set moving back and forth in cycles like 60 hetz"


AC is the ONLY way speakers will produce sound!!!!! I wonder why ALL amps and speakers have a  frequency range. DC is like Thumper said Direct current. you CAN NOT pulse DC to a speaker all the will happen is the cone will max out in one direction. The fact the ac goes +/- is the way a speaker makes sound. But why am I wasting any time on this.  Go BACK to school and try again.............. DUMBASS
btw your spelled every thing wrong  "hertz" is spelled with a r in it  negative is spelled negative  to so learn to spell before you play with the big boys





0 user(s) are reading this topic

members, guests, anonymous users