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| Fellow Posters, I've noticed a lot of questions lately asking what "high current" means and how it affects your overall sound quality. Needless to say, the greater amount of current and stability of that current makes all the difference in the world to your ears. Basically, watts per channel (which has little universal definition in the industry as manufacturers arrive at that number is many different ways) means very little indeed when it comes to the "quality" of your sound. Here goes: High-Current Amplification-- Power ratings (watts/ch) can be very confusing in that high-power amplifier ratings don't always mean that you are getting the best sound. Power, typically measured in Watts, is an equation of Voltage x Current. Both the voltage and current output of an amplifier will vary between manufacturers and models. High voltage amplifiers typically require smaller power supplies and provide very little current output (low-current). High current power amplifiers, on the other hand, provide forceful power (by implementing robust power supplies)using current as a driver with low voltage levels. Thus, high current amplifiers usually will provide better sound than high voltage amplifiers. In terms that may make better sense, when power is applied to an electric train (not a toy train), the locomotive is driven by the current. When power is supplied to a speaker, a high-current amplifier will more accurately and forcefully drive the larger speaker magnets, those of the woofers. The speaker's woofers are used for reproduction of the very difficult to power low frequencies. For this reason, when an identical pair of speakers are run on a low-end, low-current AV receiver and a higher-end high-current system (of equal or lessor power ratings), the speakers on the lower-current receiver will sound tinny while the speakers on the high-current System will sound more full and richer. Along with the higher current available in the high-current receives is the ability handle the requirements of lower-impedence speakers (nominal 4ohm loads versus the easier to push higher impedience speakers, nominal 8ohm load), or multiple pairs of speakers (critical for our multi-speaker AV systems). In short (and simply) the higher the current your recievers are able to produce (and maintain) the better your speakers will sound and the more flexible you will be able to be in speaker choice (the best speakers are almost exclusively low impedence 4ohm speakers). -h1pst3r |
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Phil Krewer | H1p, Hmmm, I'll buy what you say if you can explain to me how what you just said confines to Ohm's law which it from what I can see doesn't. First Ohm's law E(voltage) = I(current)*R(resistance)(ie speaker) or with a little algebra I=E/R Meaning that the only way you can get a higher current is to 1) increase the voltage or 2) decrease the resistance. So to say that a high current amp puts out greater current with less voltage at the same resistance can not be done. Now what you said about power(watts) Yes P(watts)=I*E but it also equals P=(I)2*R and P=(E)2/R So by Ohm's law for a give resistance, and the same number of watts (power) you have to put out the same current. Unless you can magically reduce the resistance So what happens when you use a 4 ohm speaker. The current per watt or voltage will increase. Now logically you'd think you could drive these speakers easier, but that's not really true. But, what the logic tells me is that the less expensive amps have components that can't handle the increased current and shut down to avoid dammage. Where as the better recievers have better components and can handle the increased current. So, what I'm trying to say is that its not that a high current amp produces more current but can tolerate more current because it has higher grade components. Phil |
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Anonymous | Phil, It appears you know the rudiments of Ohms law but not the details as it applies in this case. Take a battery for instance. You can have 2 batteries with the exact same voltage, lets says 12 volts, and they are both powering the same load (resistance) yet one battery last twice as long as the other. How can this be? If we use your logic it would be impossible. The reason is the battery that last longer has more plates and/or surface area which in turn increases the amp hour(Ah)capacity of the battery . The same thing applies with a high current amplifier. The amperage(capacity)is what actually influences the voice coils of the speakers to move in and out or stop. In an amp instead of more plates it is a higher capacity transformer. If you take two amps with the same wattage (IxE) the one with the higher current ,and by default lower voltage, will sound better because it can control the speakers better. |
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Phil Krewer | LMAO, You haven't said anything that remotely shows how any device can produce more current with a lower voltage and the same resistance. In you example of the battery, which if you knew what you were really saying you would realize, each battery puts out the same voltage and if attached to the same load the same current. yes one battery can last longer, but it has nothing to do with Ohm's law but more the internal chemistry of the battery. Sorry, You'll have to do better. A transformer simply steps up or steps down the voltage. Voltage is induced and not stored like a capacitor or a battery. which is why you'll never shock anyone with a transformer that has no voltage applied. Even with a better transfomer you simply get more voltage and thus more current through the same load. You may use less house wattage to get more sound, but thats not what we are talking about. you can't take P=IxE and ignor resistance because I is dependant on the resistance (speaker) that is there. You need to reread your basic electronic book. Phil Phil |
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| Phil, Your last sentence is the one that I most agree with BUT is also the one that is most open to subjectivity...at what point do we agree on "quality-grade components"? Does quality atart at handling a load of 20 amps, 30, 40, 50, 120? I wanted to *try* and explain the impact of "high-current" on *sound*. I couldn't agree with you more that, as you say, "So, what I'm trying to say is that its not that a high current amp produces more current but can tolerate more current because it has higher grade components." Specifically, we're talking about everything from the transformer design and storage capacitor size to discrete output circuitry and minimal use of negative feedback. Internals like power supplies (which are a great place to cut costs) have a huge impact on an amps ability to handle higher current. I also intentionally baited the group. My definition of high-current and the example I provided come directly from an enginnering document I have from the amplifier company ADA. Cheers, -h1pst3r *and go easy on the fellow posters ;-) |
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| The resistance isn't constant. A nominal 8ohm speaker may have appreciably lower resistance (impedance) at some frequencies. The voltage isn't just a function of the input voltage to the amp. I'm a little foggy about this, but I believe the amps in our receivers reduce the voltage they supply when they encounter low impedence loads, to protect themselves. So, an amp not capable of supplying high current will deliver an output that has reduced dynamics when the load impedance goes down. A way to estimate the current supplying capacity of an amp, I gather, is to compare it's wattage ratings with an 8ohm load to ratings with 6 or 4ohm loads, if these are given in the specs. The ratings for lower impedance loads should be considerably greater, if the amp has good current supplying ability. Greg |
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Phil Krewer | H1p, You're right I should have been nicer. The adult thing to do would to have just let slide his insult of my understanding, despite the fact that he hardly knew me. I'm not sure where you would draw the line. That would be an interesting question and on that would help determine what components to buy. I also agree that every component in a receiver makes a difference and specifically the power supply and its ability to deliver good clean power. It would be interesting to read the document that you mentioned. Cheers Greg. Good point that everyone should understand. The load is not constant, which is why it is called impedance and not resistance. I simplified it to not have all kinds of trig functions all over the place. But the overall concept remains the same. I'll try to answer your question about input voltage. A power supply has many functions and one is to step up the voltage that the receiver gets from the wall outlet. So the actual power that you get to the speaker terminals is dependant on more than just the imput voltage. yes, I there has to be some sort of protecting circuit to keep some amp from causing itself dammage as the current goes up under lower loads. But the receivers that are capabable of handling these loads have better components that allow it to continue producing what is needed to drive the speaker. You may be right about the specs as I haven't looked at that very closely. The HK receivers have very high grade components which is why they can handle the higher current under the lower impedance speakers. And 75 watts is more than enough power for most users. Yamahas are also good at this and my 80 watt 5490 was more than capable of handling whatever I needed. Cheers Phil |
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CT | Hipster et al: How does one measure "high current"? I know that several manufacturers claim this status, but maybe we can attempt to flesh out Greg's rule of thumb: "A way to estimate the current supplying capacity of an amp, I gather, is to compare it's wattage ratings with an 8ohm load to ratings with 6 or 4ohm loads, if these are given in the specs. The ratings for lower impedance loads should be considerably greater, if the amp has good current supplying ability" |
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Syscrusher | What has been missing here concerning higher quality components is the size of windings (gauge) in the transformer, the voltage ratings of capacitors,etc. Smaller gauge wires can't handle as much current, the higher voltage and larger capacity caps help filter the power better. A larger iron core in the transformer helps its AC storage capabilities which makes it a better filter component and able to more smoothly source AC power to the power supply. It is these things that dictate the current carrying capacity of a power supply and hence the amplifier in general. Yes, larger capacitors and inductors are needed to fully filter the AC current into DC current at a usable voltage for the ICs and/or power transistors. In order to produce good amplification these ICs themselves must be capable of great heat dissipation (used in conjuntion with massive heat sinks). These are the areas where the components needed for reliably sourcing high current amplification get expensive. Why is high current important? Because your speakers voice coil is current driven, as opposed to electrostatic speakers which are voltage driven. In the old old days, the final stage of amplication was produced by a step down transformer on the speaker itself, where a 70 volt signal would be stepped down to a lower voltage, but higher current, just prior to reaching the speaker voice coil in order to produce the current needed to drive the speaker. |
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Phil Krewer | Sys, Yes every component is important and you make very good points. Any component that is "weak" will cause problems. I would be supprised however, to find a transformer utilizing AC current, while it is possible to rectify it later I would think that The rectifier circuit would be the first stage. With the filters that you mentioned smoothing out any ripples in the DC current after passing through the diode bridge. Phil |
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syscrusher | Transformers look like an open circuit to DC current. I am not completely certain of the sage positioning of the transformer in the power supply circuit. I imagine it is used in stepping down the voltage prior to rectification. It is also necessary to provide separate power to the digital circuitry and the simplest and most effectively isolating way to do so is to tap a different set of secondary windings and then rectify that separately. The transformer decouples the rectification and filtering side from the line fluctuations. I believe that if this is done correctly, the transformer actually "energizes" the rectifiers at times when the line phase drops crossing zero. The better AC storage supplied by the transformer, the more effective it is at keeping the power supply continually "bolstered". However, without digging out some books that I haven't seen in some time, I will limit my contribution to saying that bigger stuff makes for better sound. Maybe someone else here can shed light on the state of the art in ultra clean power? |
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Phil Krewer | Sys, Without digging out some books I'd be about the same but while a coil, part of the transformer, is a straight wire to DC current, it does produce a magnetic field which induces a current in the other side of the transformer and the number of coils on each side determine if its a step up or step down transformer. Also you might want to check into the transformer you mention that old speakers had. As a 200 watt receiver would only put out about 40 volts accross an 8 ohm speaker, could it be a step up transformer, which would make more sense concidering that you want to increase current and voltage and current are directly related. Phil |
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syscrusher | Phil, You seem to continually be confusing your DC and AC characteristics. Again, you cannot step DC up or down with a transformer, the only means of transfer involves the breakdown (zero crossing) of the electric field on the feed side, which causes the voltage stored in the coil to discharge into the secondary. Without alternating current you have only an electromagnet of some sort. The power formula you have utilized zealously is alright for DC but is woefully inadequate for AC, since AC power calculations involving impedances must account for the reactive component of the total impedance, which is often far greater than the purely resistive component. Since reactance changes with frequency for LC circuits, impedance measurements are generally made at a nominal frequency of 1KHz, but may be specified by the certifying body as another frequency at the leisure of said body. Sometimes RMS values are used to offer some simplification in calculating power dissipation for things such as power distribution networks, etc. A 200 watt amplifier could be considered capable of dissipating 200 watts (a measure of heat actually) and therefore if it's output stage was matched to eight ohms for maximum power transfer to an eight ohm speaker, it could handle conducting up to 25 amperes for as long as the rated duration of conduction at the maximum rated wattage, provided that the eight ohms were purely resistive and the current was continuous. The amplification factor can be found by dividing the concerned output dynamic parameter by the likewise input parameter. Since input parameter levels are fairly standardized (ie. 1 v peak-to-peak), a 200 watt amplifier is loosely comparable with an amplifier of a different output power level, assuming an eight ohm load. Power curves for amplifiers exist because an amplifier's ability to deliver power will vary with frequency. The best amplifiers vary little throughout the usable frequency range, although it requires less power to produce loudness at higher frequencies than at lower frequencies (moving masses and work performed). That last part gets interesting when one considers that inductors (voice coils) become more reactive with increases in frequency, which is one of the reasons that everything works in the first place. As for the 70 volt line, I never said that the voice coil impedance was 8 ohms, that has become a fairly recent standard, the seventy volts was a peak-to-peak measure and this method worked well with tube amplifiers, modulating voltage levels. It was just commonly known as a seventy volt line, but of course there's more to it than seventy volts DC. This was in wide use for PA systems, etc. Radio Shack may still be able to show you a PA that employs these seventy volt outputs. After leaving the amplifier output stage the impedance matching transformer on the speaker steps down the voltage, stepping up the current in the voice coil in proportion to the signal. This current induces EMF in the voice coil, which changes the coil's dynamic in relation to the permanent magnet that the voice coil is suspended around. In response to the varying EMF dynamic, the voice coil moves, this movement vibrates the air and you hear sound. I am aware that class B push-pull amplifiers often employ a tranformer at the output for impedance matching and also TO BLOCK THE DC BIASING VOLTAGE from reaching the output (speakers). DC KILLS speakers. Don't let your speakers drive on DC! Step up or step down refers to the voltage when considering a transformer. Stepping up the voltage decreases the current. |
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Phil Krewer | Sys, First you are right about the transformer being the first stage I reviewed some of my electronics and admit to my confusion. But yes you can have a DC transformer but it is basically inpractical at the voltages and current being utilized. Yes I am completely aware that you have to account for impedance which changes with frequency. However, the output from the receiver whether it has a frequency is DC, AC changes direction, I doubt that would be desired. It is DC with a frequency. Second at a fixed point in time those equations have to hold and do hold even after taken into account for the change in impedance that occures during a change in freq. I only used them as not to confuse everyone with complicated formulas. As for a fairly recent standard well we'd have to go back more than 20 years as 8 ohm was a standard then. When you talk about EMF or electro motive force it is the same as voltage. Straight line DC may kill speakers but it is DC, with a freq, that reaches the speakers. The current does not change direction or you would have sound cut out and multiple other problems. Remember that any current that does not change direction is DC regardless of whether it pulsates or changes in amplitude or changes in freq. So your transformer in the speaker does step up or down DC voltage. Cheers Phil |
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Syscrusher | Phil, You've got to be baiting me. Read the manuals, ask someone else, etc. Any signal, ie. frequency IS AC and AC dynamics must be considered. I'm not refering to 60 cycle AC power, just AC dynamics. I know that I am not fully enlightened on cutting edge amplifier technology so I won't continue into areas where I may be confused. The statements you made in your previous post show a high degree of confusion, however. Eight ohms of impedance may go back for twenty years as somewhat of a standard, but I'm glad that the history of man extends a little farther back since I am more than twenty years old and that would be hard to explain if nothing existed prior to twenty years ago. If you were to allow ANY DC on your speaker inputs, the voice coil would move appropriately to balance the Electro Magnetic Field ( I was confused here, I used EMF as an acronym for the former ), this new postion would become the new zero or quiescent position of the voice coil. If the DC was sufficiently great, the new zero could leave your bass driver fully extended. If this were to happen, your bass driver would only move on the "pull" stroke and your resultant sound output would be a clipped waveform (it might look like the McDonalds archs, over and over again). It wouldn't sound very good and any manufacturer selling amplifiers that allowed DC on the outputs would go out of business quickly. If you have an old speaker that you don't care about you can pulse it using a battery. When you energize it, it will either extend or pull back, depending on the polarity. The voice coil will be held in this position until you open the circuit. This is what DC does to speakers. Where you refer to a DC transformer, there are two such cases where this may appear to be so that I can think of. One of these is in an inverter circuit, where DC is converted to AC by switching it and shaping the square wave using LC networks until a nice AC sine wave can be produced. Your portable fluorescent lantern does this. The other is the coil in your car. The coil is a step up transformer. It is allowed to charge to the battery voltage on the smaller primary side, but then the points (or your electronic ignition) open the circuit, causing the stored energy to be dumped into the far larger secondary windings, which step it up to a high voltage capable of traversing the spark gap of your spark plugs. I have only responded to your post in order to prevent the further proliferation of confusion, but I feel that you can't be serious about your statements. Have Fun. SysCRUSHER. |
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Phil Krewer | LMAO SYS, Sorry but not everthing with freq is AC. You need to read your manual. AC, alternating current has to change direction, that is the definition and its you who is poliferating confusion. Not everything that has a freqency is AC. It also has to change direction. What you are confusing is what is know as straight line DC and pulsating DC. Now there may be similarities to AC in how its calculated in circuits and how it appears to a coil or a transformer or a capacitor, but unless the current changes direction it is not AC. Sorry, that just a basic definition. Virtually nothing in your house functions on AC without converting it to DC first. This is why your receiver not only has a transformer but also has a rectifier. The rectifier changes the AC to DC. The DC that exits the rectifier will still have a frequency, but will be 120 cycles as the peaks that in AC that are negative and change direction are fliped positive. Just look at any basics electronics book. This is now considered DC but has a frequency and changes in amplitude. Why, becuase it only flows in one direction! Again this is basic definition. This DC is then smoothed out as not to introduce distortion and then used in a basic sense to amplify the signal from lets say your CD player which is very small. The signal from you CD player, after going through the DACS, is also DC. Why, because it doesn't change direction and never goes below zero. Again basic definition. I hope that I have stated this enough times so that you can shed your common misconception of AC as it does have different properties than pulsating DC. DC does not have to have a straight line. Please read your books before you try and insult me. It just makes you look bad. Cheers, Phil |
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SysCRUSHER | Phil, I quit. If you have ever been to school for electronics, try to contact one of your instructors and see if they can straighten you out on this. Every signal is AC, the pulsating DC as you talk about only exists in power supply circuits prior to fully filtering it. The signal produced by your CD player is a full waveform and does cross zero. The amplifier stages then use the input signal to modulate the smooth as silk straight line DC which is gated through the amplifier stage to follow the input signal. Once the modulation has been done the result is AC, although it may be superimposed upon a DC component due to amplifier biasing which MUST be filtered prior to being output to the speakers. Sorry if you thought that I was insulting, but now you are the one looking bad because you obviously don't know and are making things up. Do yourself a favor and talk to someone before posting again. An intelligent person is able to admit that they were missing some facts and does not continue to insist on a false concept because their ego can't handle being incorrect. Nobody wants to listen to music that has no zero crossing, forget about it, it is untrue, and you are looking foolish to anyone who knows this stuff. If what I have said here seems insulting, I did not really mean for it to be so. I am merely stating fact. |
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Phil Krewer | Sys, LOL, If you say the the waveform from my cd, after conversion with the DACS is a full wavefrom and crosses zero then I'll beleive you. And if it does cross zero then it is AC. My ego has nothing to do with this. But I will check it out and would ask my instructors but, all of my instructors in Electronics have probably retired by now. Thanks for the lession in audio equipment. Though all of the debate you've covered everything that any of us would need to know. Cheers, Phil |
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| Zzzzzzzzzzzzzzzzzzzz, -h1pst3r |
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Greg Lee | SysCRUSHER, have you ever heard of the difference between balanced preamplifier outputs, generally found on pro equipment, and unbalanced outputs, generally found on home equipment? If you can't understand the difference between AC and DC signals, how can you even define balanced versus unbalanced? Whether music "has no zero crossing" obviously depends on what voltage "zero" is considered to be. If zero is at ground, there need be no zero crossing. |
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Someone else, not Syscrusher | Greg, I stated before that I am not an expert in the state of the art. But you are incorrect as well. You have introduced balanced vs. unbalanced without stating what you beleive this has to do with anything? For the purpose of driving your speakers, even if you have "pro" equipment, your signals will cross zero since no DC level (offset) is desirable and should not be present. Music is a collection of different frequencies and as such, each crosses zero, even when your amplifier is clipping, since only the peaks are clipped. The wavelength of each of these frequencies is defined by the distance between one given point and the next occurance of that same point, moving in the same direction as it was originally moving when it passed that point previously. I fully understand the difference between AC and DC, well enough to recognize someone who doesn't and is just trying to jerk me around. I've spent many long hours calculating reactance, resonance, Q, amplifier gain, heat effects, etc. I've connected an oscilloscope to my stereo and watched the waveforms produced. I've found the integral of a sine wave and the limits of functions that approach infinity and where, but I 've got to learn to avoid being sucked into these sorts of discussions. I would be interested in hearing more about balanced vs. unbalanced? Why don't you define this difference for us now that you have introduced these terms? Also illustrate for me your view of what music looks like in terms of it's description using integral calculus. You must be one those techno people who think music is just a rapid series of pulses? I prefer mine to be more "musical" and I know what it looks like, collections of sine waves at various frequencies and amplitudes. |
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Phil Krewer | To the person formaly know as syscrusher, You must be very proud wow, calculus. Yes, I was jerking you around but it is this attitude which deserves it. Second you made several statements that give pause to your understanding. For example stating that you can't use ohm's law when you can an do. You just have to compensate for impedance as well as other issues, which I have calculated many times. Or that an EMF is something special other than just another name for a votage sorce. Or that anything with a frequecy is AC, which is not true, and at various stages in your amp it probably is not. Now, I'm not up on the new solid state devices and maybe there are newer transistors that will allow current to flow in both directions but the ones I know of do not. So if you took a simple NPN transitor and put an AC signal at its base and a DC votage accross the collector and emiter what type of signal do you think you would get. As soon as the signal got to zero the transistor would saturate and no curent would flow and that would also occur with any part of the signal that crossed zero. What you would end up with is amplification of the positive peaks only with the negative peaks missing. Now you could compensate for this by using two transistors with one inverted to the other so that one amplifies the positive peaks and the other amplifing the negative peaks and then combine the amplified signal and I'm sure there are amp circuits that do just that. But why not just bias the input signal so that it doesn't cross zero and then you could use one transitor to amplify the entire signal. Of course the input wound now be considered DC and so would the output. Now most of my electronics experience has been with computer so I'm no expert on audio, but I would think that there would have to be several stages of amplification. you could use a circuit like I described and continue to amplify the signal as AC and maybe that's what modern amps do, I really don't know. But, I could also see leaving the signal biased and in DC form and sending that through several stages of amplification and return it to AC when you are done. Now to your speakers. Well the voice coil is nothing more than an electromagnet and placing AC accross it would absolutely be more efficient as the reversal of polarity would give you the maximum movement of the cone. Any DC would limit excursion and probably distort the sound if you got true sound at all. This is how they are set up. I don't know anything about pro audio so I can't speak for Greg. Personally, the way you just wrote to Greg is just bad form and I'll take part of the blame for f**king with your head and getting you pissed in the first place. For this I appologize to Greg. To you I appologize for nothing. Personally, I think figuring out your music with calculus and an Oscope hardly would makes it more musical, but if you enjoy it then do it. And as far as math is concerned I've had more than I care to remember and scored the highest grade on the calc final that had been recorded in 10 years. Graduated with a 4.0 and was #5 in my class in med school. I also took several courses in EE, just because I liked it. Now, I'm as guilty as anyone on this board for insulting people but you really take the cake. Playing with your head was a pleasure. Greg I appologize for getting this guy all worked up. Phil |
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Smart enough now to know better | Phil, So you admit to being a troll. You've also admitted to actually making up most of the stuff that you said. I've tired with trying to educate you but you're partially correct about DC biasing. A signal with a DC component is not a DC signal however. I only want to know one thing at this point. When is trying to help a person to understand something bad form? Is it bad form to point out when I'm being jerked around? You've admitted to trolling this thread trying to bait someone with asinine BS but you feel able to point up "bad form"? I want to see your transcripts, I think you're still making things up. Should I be impressed at your claim of attending med school etc? Your behavior alone tells me that you are not who you say you are. An educated person would not make things up either to play a baiting game or to debate a topic they should defer to those who know. As for you personal attacks on me you haven't made your case. Playing with your head was a pleasure - grow up, make some attempt at a real life. I seem to have discovered a bad element on the web. As for the rest of the vultures, don't even bother, Syscrusher has left in search of intelligent life somewhere else. |
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| Hey Smart enough, Phil ain't so bad once you get to appreciate his unique, how shall I say, charm. I know this first hand from a thread that descended very quickly into pejorative pugilism. I have watched *this* whole thread (heck I started it) and helplessly watched Phil's more obstreporous side emerge (at one point I even asked you guys to go easy on one another). It's not that he's not smart (he is), not a Doctor (he is), not interested in helping people (he is, here and at other forums), but he defintely doesn't take well to being mischaraterized or being called, um, wrong...who among us does. Phil and I, I think, have come to a mutual understanding and mutual respect to agree when we agree and agree to disagree when we don't. It is a philosophy that has served us both well after pretty much baiting the hell out of each other. I guess my point is that you're both, OBVIOUSLY, smart and mature people when not on the defensive. You both made good points, write well, explain your positions, and on the whole your energy benefits everyone here. So, to both of you, ease up, thicken your skin, and let the petty stuff go in favor of enlightening and attracting many more viewers than divisiveness and name calling will annoy and alienate. I sympathize with any poster who feels like they have to check the board all day to see who slung mud at whom. c'mon...isn't Dub-ya pissing off enough people? Diplomatically and respectfully (to both of you), -h1pst3r |
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good luck | LMAO, To the person whos ego is so big that he thinks he's smart enough to know better. You are too funny. I could care less if you believe what I say or not and you can see my transcripts anytime. Hell, you can look up my name on the AAOS site. Personally, I think they are as meaningless as you stating you used calculus to calculate the limits of your waveform, which I'm sure was meant by you to impress upon us just how brilliant you think you are. For me, I'm just someone who worked my a$$ off to get a good education. I could care less about the calc thing, it was just a bet between me and my instructor on whether I could ace the final. I just happened to work hard enough to win the bet. I think we both have discoverd a bad element on the web. I don't think its bad form at all to help someone to understand a topic, but it is bad form, and guilty myself, to point it out in a way as to try and make them feel small, which if you really read your threads and have the social skills to see it, is exactly what you did. But, I suppose your ego needs that and I should be more sensitive to your insecurities and not get offended when when this happens. Personally, I found your comments more inflamitory than eductional, but have really nothing at this point to be proud of in this regard. As far as those who know, the only thing you have shown me is that you have read enough to calculate your formulas. As far as the bias issue, well you can call it biased AC, or AC riding on DC or whatever the convention is you read about. The bottom line is that everything with a freq is not AC and if it doesn't reveres itself in direction you really can't call it that. A rose by any other name is still the same. For me, I just need to chill and not let people like yourself get me all worked up. For some reason I get the feeling that you will have a hard time matching your obvious superiority to all that respond to what you say. |
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| Phil, Z3--top down--stereo cranked--drive fast--breeaathe. -h1pst3r *the sagely advice of a sleep-deprived father of a three-month old. |
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Phil Krewer | Hey H1p, You're right of course. We must have posted at the same time as I didn't see your thread. It is time to chill and just let this one go. Thanks for stepping in and restoring my sanity on this one. The baby should start sleeping all night in the next couple of months. I'd put the top down but its snowing here, lol. BTW, how's the sub search going. Phil |
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Who? | Most likely you beleive that if you say it's so, then it is so. That's ego. And it's "bad form". |
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Phil Krewer | Some how I new you couldn't resist. Just let it go. There's really nothing more to add. Have a good one Phil |
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Phil Krewer | Some how I knew you couldn't resist. Just let it go. There's really nothing more to add. Have a good one Phil |
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Beleive It, now let it go. | Only the truth, Phil. If you review the thread you treated me far worse than I treated you. I only mentioned the things that I had done with formulas, etc. so that you might stop in your self-rightousness and consider that maybe you were communicating with someone who knew what they were talking about. The problem I have seen with your posts from early on is that you're setting yourself up as an authority in spite of your lack of knowledge on the subject. You have a lot of this right I'll give you that. You may even be a pretty good saw bones, I don't know. I can't imagine that electronics were covered in much detail in med school though, it's not your fault, not knowing that is. As far as I'm concerned you started the somewhat nasty turn that things seemed to take. Chastizing me for what I wrote in response to the crap that Greg posted was arrogant and unfair, realize it. Oh, by the way, I'm not laughing at you. I'm not even claiming to do so, that's just plain rude. (additional examples of hubris omitted here) In the off chance that this thread isn't totally about making the autocrats feel better about themselves, I'll tell you about a conversation that I had with a couple of the Double Es that I work with. Your mention of "conventions" for representing the complexities of electronic reproduction of sound caused me to consider that possibly my education was not all that I thought that it was. I'm a software engineer, but my first degree was in electronics. I work at a high tech company offering wireless communications solutions to transportation industries. The person in the cubicle next to me is close to earning his masters in EE from Stanford through correspondence, a very special program. His first degree was in Electronics Engineering. He does a bit of programming, genetic algorithms to determine RF coverage analysis in overlapping radio networks using multiple carrier frequencies. The owners of the networks did not wish to have their data captured by the owners of the other networks in this physical area. Myriad of base stations, overlapping channel access, etc. You get the picture. Anyway, two things I know about Steve, if I ask him a question about something and he doesn't know, he says so. If he does give me an answer, I can trust it as being completely factual. Steve's answer: Any frequency bearing flow of electrical current is AC, There are no alternate models or conventions that hold for DC to possess any sort of waveform other than a flat line. If there is a frequency, it is AC even if it has a DC component (bias, offset, level, whatever you want to call it, it's separable from the frequency). I didn't necessarily want to be right about this, I was hoping that I would have my eyes opened to a whole new subset of electronics that I had not known before. But this is all there is to it. Kudos to H1pSt3r for his insightful post. I don't like being mischaracterized either. At some point I began feel like that was the whole intent of some in this thread. Bold statement about Dub-Ya, I didn't know we were still allowed to disharmonize with the "president". |
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Phil Krewer | Well, I wasn't going to do this but here's a link just look at the bottom of the page, but I suppose that the person who wrote this is just as ignorant as I am. We are both acting in a self-rightous manner. I admit to my poor communication with you but you absolutely treated Greg poorly. And you still are by calling what he said crap. Why not just politely say you think he is wrong or misinformed. There is no need to imply that he's not intellegent because he said something you disagreed with. Even, with you responses to me you implied that I must be playing around or an idiot otherwise I wouldn't have written what I wrote. No one is going to respond well to that. And you're still doing so in this thread. I don't mind being told I'm wrong as much as I dislike being told I'm an idiot because I may have said something that was not true. Neither of us are idiots and we treated each other badly and why don't we just agree to disagree. Honestly, its just semantics and convention. I worked in computers for 8 years working on PBXs, mini mainframes and finacial terminals and took several courses in EE before going back to school and took an couple of others in undergraduate just for fun. I may have to dust off a few cobwebs, as this was 20 yrs ago, but I do understand most of this very well. My teaching was one way, yours another. It depends on who your instructors were, whos text books you read and when you read them as convention changes with time. Same thing for your EE friends. I remember being taught that this was really DC and the only reason to call it anything with a AC name attached was to remind people working with the circuit that it has and AC component that can be separated. The person who wrote this primer was obviously taught the same way. So why not just let it go and agree to disagree on this point. Does it really matter. And honesly, whatever you want to call it it wouldn't open any new electronics. I've learned a lot you made me review a few circuits and I feel that I gained from this regardless. You can disharmonize with me anytime you like and hardly feel like I'm the president of anything. But, please do your best to remember that we are all intellegent even if we are mistaken and I'll try to do the same. http://wb0nni.dakotamade.com/basic.html Phil |
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Syscrusher | Thanks Phil. H1pst3r said you were a good guy. I can see that now. Greg's post was an apparent attack and thats why I responded the way I had, sorry I went off. I'll take a look at the link you attached, I'm always interested in new perspectives. Syscrusher is the title of a song on Neil Young's Trans album, the only major collection of synthesized music he's produced that I am aware of. Check it out, it's unique. Have Fun, Syscrusher |
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Phil Krewer | Hey SysCrusher, What would we do without H1pst3r. I agree with your feelings about Greg's post and appologize for going off myself. I love Neil Young and will try to check out your song. I'm glad to see the Syscrusher back you have a lot to offer this forum. Have a good one, Phil |
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| I may change my name to Kissinger... ;-) Glad everyone's back contributing!!! Thanks guys...the forum would definitely have suffered without your contribution. Now back to Saddam and W...ugh! -h1pst3r |
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Michael Meysarosh | i just thought that I may toss a little info that may help on the topic. First high current amps do have there place but not everyone needs them. There are many tube amps out there that are not capable of producing a generous amount of current yet are able to drive certian speakers admirably. Yet there are other speakers that are made that may take a preference to an amplifier using a high current design. So here is what I can shed on the subject. Lets take a look at V = IR. Okay so lets say a speaker at a certain frequency range was a desired volage output. We can easily see that from 8 ohms to 4 ohms the current requirement would double. I'll take that little piece of knowledge with the formula P = IV we know that if we did maintain the voltage at 8 ohms and at the 4 ohms level it would produce double the power in watts. So how does this all come to mean anything? It boils down to the operating parameters of the output device. Tubes tend to handle voltage operation better then current. So if I was to design a speaker that was to run well off tube amps I would look to make the impedence quite smooth and high effeciency since the current and power output of tubes amps tend to be smaller as well as there total operating output (I will not go into why people a so fond of these amps). Lets go the other way. I want to use a cone that is very stiff, low resonance, and lots of other favorable characteristics but its heavy. In order to achieve good sound out of it with I seem to need a good amount of power to move it well. Transisters can handle current very well especially when they use mutliple output devices in parralel. So when I need to get a large or very quick motion from the cone I might decide to drop the resisitance and allow for some current flow to achieve the desired power input to do the job. You would see on these speakers these demands are typically seen at the upperbass region down where the port operating frequecy. The port aids in this output so it is not all up to the cone to move all that air with the front surface of the cone. Some speakers such as Thiel have mechanical crossover designs which in themselves needs large power inputs and use high current ot other frequecy ranges other then the lower bass. Since there are so many designs the possibilities are in the hands the speaker designer. This is just light start onto the topic of speaker/amp selection and it goes father than I could properly explain (aka understand sometimes) but the above information would be a good start on how to make the speaker and the amp 'firends for life'. Thanks |
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Chad | Hello to all, I am not sure that I have anything new to add to the conversation, but I will say that I have learned a lot from reading all of your posts. I have two questions: When selecting speakers, are there any particluar specs for current handling or are they just rated for Watts? My second question: In the world of RF, impedance matching is extremely important as it has an effect on power forward versus power reflected. Where should I look to best match the input impedance of my speakers to the output impedance of my amp? Thanks Chad |
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| Is an amplifier that is Pure Class A with a rating of 50WRMS with a current rating of 80 amps continius and 120 amps peak, a good spec amp to run speakers with a 6 ohm (nominal) rating? What about the "loudness" issue? Where does that fit in with the above figures? Thanks--Ajit |
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| let me give it to you striaght, first of all it you want to achieve a high quality audio out you must have voltage current and spl db let me break the following down in a simple way in audio voltage= magnitude of the signal. current= strength of the signal. spl distance/intensity of the signal. consider voltage as is a potentail diffence were in this example you could substitue voltage for a tire on a car, the larger the tire the further it can travel in one complete turn for example a 10 in tire will travel twice the distance than a 5 in tire. needless to say that the more voltage you have the louder the the sound. now with current, taking the two wheels example consider wind resistance a load w, and with the 5 inches wheel rolling in the opposite position of the wind w depending on the force of the wind or the load of the speaker(s) the speed of the wheel or in this case the voltage will be degraded the same would be for th 10 inche wheel now this is where the current comes in the currnt is depenand of the voltage in this i mean the the current supports the voltage vise versa in this example the current would fight in the same direction as the voltage it would fight the load or in this case the wind resistance{vc---> <---wr as we all know a the wire in a speaker coil has electron in it that will move in the opposite direction heres a cheap equation recvolt+amps-(volts+amps/ohmsspk) |