Paul, Perfect analogy..For me it would be a waste to buy an Amp that wasn't high current. Glad to see you a man who commands his lawn. i am one of only 2 people in my whole neighborhood that still cuts his on lawn. like listening to music it's therapeutic especially when it's done..☺
That was a simple and to the point explanation. A power amplifier is a power supply modulator using the input and voltage gain stages to drive the output stage that take DC power from the two voltage sources (V+, V-) and drive the loudspeakers. Ratings, given for non inductive 8 ohm and 4 ohm resistances (not really inductances) can be very misleading both because the loudspeakers unfortunately don't hold a stable value. But even these, can really show the unsuitable ones, as said, unless the 4 ohm power is double that of 8 ohms, the amplifier is not full of juice. And because loudspeakers don't present a resistive load to the power amplifier. When a loudspeaker has a dip in impedance to 1-3 ohm values and becomes inductive, it can almost kill the amplifier. Unless the amplifier has ample reserves in the transformer and filter capacitors, thick cables going to the output stage, hefty transistors taking the load and large heatsinks to take the heat. Such an amplifier is no one made to a price. Having said all that, I really don't know why some loudspeakers are made so hard to drive. If not anything else, it's not ... polite.
The Sunfire signature series 2 channel amplifier is one of the only amplifiers I know of that is rated at 2400 watts into 1 ohm impedance. Starts at 300 8 ohm, 600 4 ohm, 1200 2 ohm and 2400 1 ohm they can be found on Ebay occasionally
@behexen250 you cant drive a 1ohm load with most amps without them melting down. Been a fan of Carver for a long time. And the sunfire were what he originally envisioned but the technology wasn't there yet. That's why people still buy used Carver amps. What did that Krell run you probably a lot more than the sunfire. It wasn't the sub I was talking about.
what equipment you use to make educational videos like these??? love all your videos... one more questions what do you mean when the protection circuit doesn't turn on??
Automotive nowadays often use 1 Ohm woofers and class D amps to get maximum power out of the 12V power rail of the car battery. You need thicker speaker cables when driving lower impedance for avoiding insertion loss and damping factor drop. An amp driving 1 Ohm speakers obviously need to be designed for the much higher currents. It’s not really a good fix, for example, to use an amp that can do 2 Ohms and add a 1 Ohms in series to the 1 Ohms speaker to get 1+1 = 2 Ohms of load impedance as you just ruin the damping factor (especially poor bass decays) and lose half the power in the resistor doing so.
What annoys me is that too many manufactures messure watts with 1ch driven, 6ohm, 1kHz @ 1% or maybe even 10% THD to make it look more powerful on paper. It can say i.e that it has 200watts while another amp that is messured the correct way; with all ch driven, 8ohm, 20-20.000Hz @ 0.005% THD can say it is "only" 100watts and still be quite a bit more powerful than the so called 200watt amp.
There has been a shift from the complex impedance of the speaker on an amplifier trying to maintain a given voltage at wide current demands. This shift in the commercial audio space is in what used to be termed a servo amplifier. Instead of a fixed voltage gain, the input voltage commands a current from the amp while ignoring the voltage. For example a voltage input peak of 5 volts into the amp would put out a current peak of 5 amps while ignoring the voltage. This removes the damping factor completely. Zero voltage in = zero current, even if the cone is moving. The damping is taken care of by the enclosure. Servo amps, are a mix of voltage to current and a mix of voltage to voltage. The design is not very common. It does take quite a few design fundamental changes to get it to work well. One thing this does do well is reduce the distortion at long throw from the speaker suspension. A voltage driven amplifier when driving a speaker cone into mechanical limits get less EMF feedback which results in HIGHER current at the peaks of speaker cone extension. Ideally, the current should remain the same, when the cone reaches the mechanical limits. This reduces heating of the voice coil, less power draw, and softer landing at the end of mechanical movement because current is not ramped up to compensate for the reduced cone movement. This servo design is most often seen in powered subwoofers to keep the sound cleaner when driven hard. Over current limits prevent slamming the cone into the stops extending the life of the speaker. Not sure if PS audio used any integrated amplifiers with a voltage to current built in amplifier. I am not familiar with their product line. For heat and power efficiency, most of the designs are switch mode amps, not linear. They are built to put out the thump without destroying themselves..
For linear coil B.E.M.F. over the entire range of " speaker xcursion " , the coil must be of embedded type..i.e. there is no coil overhang beyond the magnet.
@@analoghardwaretops3976 Actually the motor portion of the voice coil is the part in the air gap between the end of one pole and the pole piece. Coil can extend past this high flux density zone with no ill effects. A short coil that exits the gap just before the spider limits movement is soft clipping. This image shows a cut away. The pole piece from the rear wraps inside. The other pole piece makes a gap between the pole pieces. You can see at rest, the voice coil is centered in the gap. Longer throw speakers require longer voice coils. I am not aware of this "Embedded type" you refer to.This is a large subwoofer voice coil. i.ebayimg.com/images/i/271889340221-0-1/s-l1000.jpg
@@isettech ..by embedded , I meant ..for any../ full cone travel.. upto the " X " max ..the coil is ALWAYS "IN " the magnetic field... i.e. the coil is designed with no overhang..
@@analoghardwaretops3976 That makes sense. This long voice coil design is less common as the force on the voice coil is still strong at the end of cone travel resulting in higher stress when the cone reaches mechanical limits. Due to the longer voice coil length, relative to the mechanical throw, the center portion of the throw has higher relative impedance and less force for the current. A short voice coil has higher compliance in the linear range of cone movement and a rapid drop in force at mechanical limits. To achieve this, edge wound, and/or double layer voice coils are used. Longer voice coils have lower current density in the gap because it it extended beyond the physical come travel. I prefer the voice coil to begin to exit the gap near the end of cone maximum travel for softer clipping and less mechanical force at hard cone movement limits. This results in higher compliance in the linear range with better damping and less destructive mechanical limit forces when driven into the mechanical limits. Most subwoofer designs have the voicecoil length designed to exit the magnet gap at the end of mechanical travel. EG, a speaker with a +/- 1.125 inch travel will have a 2 inch long coil, or just under. For subs, I prefer the edge wound voice coils. They have high current density in the gap, high compliance at lower power levels, and less severe distortion at mechanical limits.
I use an Ego self propelled electric lawn mower. I heard (and saw the lights) on a Carver 1.5T amp with I think 350 watts per channel go nuts trying to drive a pair of Kappa 9's. I think you need an amp with real current capability to drive those speakers.
It all comes down to the output impedance of the amp. Ideally it should be zero, in order to drive low Z surrenders, but practically that's impossible. The o/p importance of the amp is inversely related to its damping factor, so a high DF is desirable. But, trying to drive complex loads down to 1 ohm requires an amp that's designed like an arc welder!
To oversimplify things for William of Illinois, the picture is like this: The differences in amplifiers is dependant of the output devices (transistors) they use. There's out there some very powerful output transistors, capable of high current delivery, but they themselves need high current to function properly. And so, it all comes down to the *power supply* of the amplifier in question. Is it 'beefy' enough (transformer, rectification diodes etc), to deliver the excessive current the output transistors demand? That's the bottom line and, no amplifier designer can escape from it!
My background is with car audio , and Mosfet amplifiers are usually rated for use with speakers down to 2 ohms , if you had a 1 ohm subwoofer you would use a Class D amp , i know high-end Audio is starting to see some 0-20khz Class d Amps , so why not use one of them.
When a speaker impedance curve dips to 2 ohms or thereabouts it means the XO network is shunting the amplifier current AWAY from the speaker ! This scenario occurs when the speaker designer wants to tame an unwanted peak OR to provide a steep roll off in the XO. This isn't good ! It plays havoc with any amplifier if played loud .. peaks should be tamed by series LRC networks .. I aim to provide an impedance curve no less than 6 ohms for a nominal 8 ohm system .. the phase response will be far better too .
That is one possibility, but that is not the case for the Kappas. They use a very large series capacitor at the input (conducts all current to the woofer and remainder of its crossover) and an inductor in parallel with the rest of the crossover. That LC is tuned to around 35Hz, depending on model, and draws high current but uses that to cause a high voltage step-up to the downstream crossover and driver.
I have a Cerwin Vega CXA-10 power amp. It's rated at 600w 8ohms. 900w 4ohms and 1400w 2ohms both channels driven stereo. I bought i because my speakers are hard to drive. 87dB sensitivity.
In fact, the power amplifiers are not so different in this point as the loudspeakers are. The difference between the speakers is just the amount of wattage they have. 10 W at 8 Ohms and 100 W or even 1000 W at 8 Ohms make the difference. If you have efficient speakers which are dominated by their dc-resistance it is usually not a problem to use a 10 W amplifier to fill a normal living room with sufficient amout of good sound reproduction. But the speakers are the issue. Speakers are in general not very efficient (so I really don't understand the class D guys with their efficiency argument vs. the class AB guys). The coefficient of perfomance of an efficient speaker is usually not better than 3 to 5 per cent (horn speaker can achieve up to 30 per cent). But there are some very problematic high end speakers which sound great but have efficiencies of less than 1 per cent at some regions of the audible spectrum. Furthermore their impedance is sometimes very much dominated by inductive or even capacitive parts which can even kill an amplifiers. I think, some of the loudspeaker designers should keep their products more strictly in the specification range of a resistively dominated device and avoid components which require several 100 W to drive them or even can send amplifiers to hell.
What you might want to try..Put a 1 ohm (10 or 20 watt, non-inductive ) resistor "in series" between the amp + output and the pos. speaker wire line. Although the resistor will absorb a bit a bit of power the amp will be more stable relative to the "reactive" speaker load. It may even improve the sound.
A 1 Ohm resistor in series with your speaker will cause the damping factor to drop dramatically. This means more ringing/decay time and especially less precise bass.
Toroidal: Cheaper, lighter, more efficient, but with less surge headroom. They are less tolerant of residual core magnetization that can be left at turn-off, or arising from DC in the power source. In normal operation they do not need the shielding that E-I core transformers do, but if you exceed their VA capacity, they do produce strong interference fields. E-I core transformers are more straightforward to wind. Mass production of toroidal transformers requires special equipment, but once that investment is made, the cost to produce each unit is not excessive.
For a given output voltage the load impedance will determine the load current. Period. An amplifier that cannot drive a load properly has ONE cause, ONE. The amp's output impedance is too high. When this happens, the output signal will drop across the amp's internal impedance rather than being delivered to the load(in this case, the speaker). Ohm's law... works every time! Maximum signal amplitude is delivered when load impedance is much higher than that of the output. Maximum transfer of power takes place when output and load impedances are matched.
I'm guessing you have not worked on too many amplifiers lately. Damping factor is the inverse of the impedance. An amp with an damping factor of 20 has an output impedance of 0.05 ohms. To prevent burning up the amp, overcurrent protection is often in two stages. One is with reduced gain limiting current on the peaks, and if driven with too low, impedance, the protection relay will operate. How low the amp is stable is often in the specification for higher quality amplifiers. Eg, stable to 2 ohms. Note 2 ohms is a long way from 0.05 ohms. The amps are not able to supply excessively high current. The power supply sags first reducing the heat and available damaging current. Feel free to ask Paul about amplifier protections in power supply design, current limiting, and overcurrent shutdown. A complex impedance load with high reactive currents needs an amp designed to handle high out of phase currents. Not all amps do this well.
@@N00B283 It has several names. Damping factor is the inverse of resistance. A source damping factor has an equivalent resistance of 1/20th ohm at the terminal. Admittance is used for complex reactive impedance. This is used when the resistance is frequency variable such as the admittance of a tuned LC circuit. The admittance includes the reactive as well as the resistivity component. en.wikipedia.org/wiki/Admittanceen.wikipedia.org/wiki/Admittance
@@isettech Wouldn't damping factor be a ratio between source and load impedance? Also when talking impedance aren't we talking in complex numbers since impedance [ Z ] contains a real number: resistance [ R ] and the imaginary number: reactance[ ±jX ] Z = R±jX? While the inverse of Impedance is Admittance [ Y ] with the real number being conductance [ G ] and the imaginary: susceptance [ ±jB ] 1/Z = Y given in the unit Siemens instead of Ohms. Also the imaginary part of the complex number is the one that is frequency dependent and denotes wether we are dealing with a capactive reactance or an inductive reactance based on the number being negative or positive. Inductive Reactance + jX is known as XL XL = ωL wheres ω(omega) is unit for 2πf. And L is Inductance in the unit H (Henry) Capacitive Reactance - jX is known as XC XC = 1/ωC = 1/2*π*f*C Where C is the Capacitance F (Farad) You can then rewrite the formular however you want wether you want to know what the reactance at a given frequency is or the by including the real number: cut-off frequency or phase shift. You can also cancel out the imaginary part of the impedance meaning Z = R making it purely resistive. Which will rid you of internal reflections in the cable that would otherwise cause power loses in the wire other than what the purely resistive part caused, but that is mostly used in transmission line theory so it isn't as much applicable to audio frequencies & cables. At least that's what my professor told me.
@@N00B283 Damping factor as rated by amplifier manufactures disregards load impedance both resistive and reactive. Sorry professor, reactive impedance is not imaginary. The proper term in the power generation and transmission is the VAR (Volt Amps Reactive) sometimes referred to as wattless power. The reactive current is real in loads on the amp, current in the wire, and resistance loss in the wire. A damping factor as published by an amplifier manufacture is the equivalent source resistance inverted to the load. An amplifier with a published damping factor has an apparent source resistance to damp the speaker movement. An amplifier output terminal change in voltage with 1 amp applied load for example producing 10milivolts on the terminal would be an apparent resistance at the terminal of 0.01 ohms. This would be an amplifier damping factor of 100. This is apparent damping as this is the result of active negative feedback of the amplifier, not the actual output transistor resistances, protection relay, and associated wiring. If you do the math, the amount of capacitive reactance and inductive reactance in a speaker cable is negligible at audio frequencies. The capacitance of pF per foot has very little current in a 20 foot speaker cable in parallel with an 8 ohm speaker. Same for inductance. Most reactive current from speakers is both the crossover which in contrast to maybe 1nF of speaker cable capacitance, has crossoveor capacitors of several mF, and active come movement with EMFgenerating current. This is more than 5 orders of magnitude larger. Yes it exists, no it is not significant. Keep studying my friend. Knowing the formulas is important for an engineer. Actually doing the math with real world numbers shows what is below measurement. You can see the travel time on a speaker wire, but you need less than 1nS rise times to see it in common speaker cable lengths in the home. Most homes use speaker cables less than 20 feet and frequencies under 20KHZ so you won't see the effect of speaker cable capacitance as the current is insignificant. Try it. Feed a 1 KHZ signal into a 20 foot speaker cable and measure how many amps the open end cable draws in reactive power. It is measurable with sensitive AC current meters. You could engineer it too and calculate it too. Say 30 Pf per foot, 20 foot cable is 600 pF. 1 KHZ at 20 Volts into 600pF is a capactive reactance of 265 ohms for a reactive current of 75mA in parallel with the 8 ohm speaker drawing 2.5 Amps. The cable reactive power is 1.5 Watts while the speaker draws 50 watts. This is why it is recommended to keep speaker cables short. A few hundred feet of cable is a significant increase.
To William needing to drive those low impedance Infinity Kappa speakers check out this amplifier www.bobcarvercorp.com/crimson-raven if that is too expensive look on the used market for this amplifier stereotimes.com/amp010500.shtml it's a Sunfire LOAD INVARIANT 600 watt amplifier capable of 4000 watts into 1 ohm ( that's a LOT of current) on a time limited basis , and bass notes are time limited.
150 or more or less is a relative term only you and other household members who listen.. can decide... room size..room acoustics.. distance from unit...your own audible sensitivity...may at one time tell you even 50 W from 150 is enough. another time. 100W from 150 is not enough...
Gadgetdad it depends how big the room is? What kind of speakers bookshelf or floorstanders? Sensitivity of the speakers? My new high quality performance class D power amplifier is 100w 4ohms, 60w 8ohms. And my 8ohms bookshelf speakers are a pretty good for bookshelfs 90db sensitivity. Plus my room is small with a low ceiling. The 60w 8ohms from my amplifier is more than enough to drive my bookshelf speakers to very loud volume (but still crystal clear) in my listening space 🔊🎶
I have kappa 9's also Pushing em with 4 x 300 watts Emotiva mono blocks out of their seven channel monster old school amp impedance can dip down 1/2 no problem, infinity's can sing. Mac was faild, onkyo 506 and 508 biamp puked, tried Aragon 4004 nope only Emotiva doing the job.
When the driver is rated @ 0.5 OHMs @ 200Watts RMS.... W= V×I won't give you the correct information.. Should apply the (I sq. × R) = W ....so for grounded loads...( not bridge mode )... the amp should be able to DELIVER 20 amps RMS with 10 volts RMS across the driver .. so figure out the maths required for a class AB.... approximately +/- 30-35Vdc @ (20-22)A.... approximately..+/- 20-22Vdc @ (20-22)A ...for class D amps.... And that's for ONE CHANNEL.. and more than double it for 2 Channels.... Here one is better off with an SMPS...
Infinty kappa 9 are not great speakers for the fact that the require so much of the amp, it will be cheaper to replace the speakers and get better sound in the process, and besides geting an amp that can go down to 1 ohm is not cheap, most speakers today dosent go much Below 3 ohm thats a much better speaker
@Fat Rat Then why are cheap Audio Technica's that are 38ohm easy to drive with a phone when my Sennheiser HD6XX's that are 600ohm don't even come close to the same volume? I resorted to a desktop Schiit Magni to use them.
Trust me, you don't want an amplifier that can handle a more flexible load. The amplifiers that usually do that are not very natural in sound, meaning that they usually have an extended circuitry. More flexibility usually means more manipulated/polite/restrictive sound because of more filtering, which usually also makes it more linear and boring in detail. (stuff like Mcintosh) A solution that is better is to get a speaker like the new Jbl l100 classic, cheap and works with almost all amps. (you sell your speaker and get this for about the same price which sound better) But if you absolutely want to keep your speaker, then take the bob carver 180 mono blocks and pair it with an audio note m3 preamp, that solves the problem at a high level. The best amps in the world are usually the less flexible ones, because you get direct feedback from the components inside of it. The flexible stuff is usually sound that is emotionally dead and flat in dimension, with detail staying at the top and not going fully through. (like mcintosh) The hifi community have for years been teaching people to care about watts and ohms. They only run these SPECS to take attention away from the cheap components inside. Versatility is the killer of the best sound, and you will always have to compromise compared to the highest possible standard. At least if you have to play this type of game, then do it properly with stuff like D'agostini and Gryphon, they are some of the very best.
well that's not necessarily true! you can have an amplifier 70 Watts and a amplifier at 250 watt what can't power a hard to drive speaker better than the lower watt amplifier
@@Tacet137 depends where you're taking your Watts from, most manufacturers use consumption, if it was 2000 watts amplifier as an example you break this down to 4 ohms it would be about 400 watts peak power at the most and can be a lot lower in most circumstances in real-world scenario, if you have a amplifier producing 120 Watts at 4 ohmsRMS it is more powerful. So saying 250 Watts 4 ohms peak power is not as powerful as a 70 Watts RMS amplifier , manufacturers do this all the time to mislead people. And the representation I was using it is actually a PS audio amp at abouts 250 watts compared to a naim 70 watts amplifier. You need to look at SPL figures at 4 ohms that gives you the true representation of the power per channel, say 4 ohms you want to look at something like 109 dB SPL in stereo I think is about 112 dB spl, to give you a sense of how loud a chainsaw is about 110 dB spl having that in a room you know how loud it is.
@@johnsweda2999 good inkling on spl comparison.... but something other than / additional to the chainsaw example.....my reasoning being the chainsaw db level is in the mid..to hf range..ok..partly but how to compare that spl at 40-200 Hz. that the spkr can produce... thunder..as in thunderstorms....
@@analoghardwaretops3976 never looked at the SPL thunderstorm I would have thought it's a lot higher than 110 db when overhead definitely give you that bass lol
DC does not have power factor in the power formula. V times I = P in DC. V times I TIMES PF equals P in AC. The VA that is not P in ac is the VAR. Sigh, Another audiophile unaware of Ohm's laws. If you have a very reactive speaker load, what does the amplifier do with the regenerated power returning? It is fine if the load is purely resistivity. Connect a 20mH coil in parallel with a 40uF non polar cap, and test that on the output of your amp in parallel with a 4 ohm speaker..
I guarantee you that I can put together a setup using JL Amps (RIPPS) in a house environment that you would never be able to tell the difference blind. Maybe with lab / test equipment but that's about it. Sigh, another person that thinks specs and formulas on paper = real life application.
@@Audiojunkabus Yes, many amplifiers are able to be stable into a reactive load. I have no data on that amp. There are just too many on the market past and present to test each one. Most QSC amplifiers can do the task just fine, along with JBL, Crown, Yamaha, and Peavey.
@@Audiojunkabus Looked to see if they were independently tested. They were. Looks to be more a company into car thumpers than home stereo. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2mmx07rzB9s.html Yes they are 2 ohm stable.
This is how I understand it: Car speakers were driven by amplifiers built into the in-dash radio. Not having much room to work with, amplifier circuits needed to be small, and therefore have meager output (10 watts maybe (at 8 ohm)). So, an easy way to gain loudness was to drop the speaker resistance to 4 ohm allowing for a realized output of 20 watts.
@@shanecabbage2187 actually its more about the power the speakers can draw. In a car the amp draws power from your battery wich is actually a good source of power for amplifiers. In a stereo system it all depends on the power transformer that's inside the amplifier. Usually the more power the amp is able to put out the bigger and more expensive the transformer is.
@behexen250 most vehicle battery stacks are 12 or 24 V rated...so is the car audio gear. being solid-state equipment... it is inherently low impedance devices..thes work well when used with low impedance speakers / drivers... ..to give the best performance...
@behexen250 ..well..I tried to give my reasoning on WHY normally low z spkr. for car audio is better....and no other COMPARISON... reasoning... justification...about anything else....
@behexen250 here I will say in your comparison of car amp & spkr. and the home setup are of same impedance..is not enough to compare.. Both amps must have same input sensitivity and equal power rating.. Both car and home speaker must also have the same power rating...come size/type and db. Spl . sensitivity... comparing both with similar enclosures or swapping them is when one can conclude something realistic..... & not just 4 ohms vs 4 ohms..
Infinity Kappa 8 and Kappa 9: Great examples of how NOT to design speakers. Instead of using drivers and cabinets that are capable of the low end directly, they skimp in that area and compensate by putting a Giant LC Tank Circuit in front of the woofer section, using its resonance to draw more power from the amplifier in an attempt to extend the low end. The ridiculously low impedance that results, is no accident or side-effect of an otherwise sound concept. It's plain irresponsible and impractical design, an example of how things can go seriously awry when you turn a physicist loose in the parts bin, who has nothing in mind but a performance goal, and no concern for potential consequences. Mind you, Paul has commented at length, recommending against using EQ to extend a speaker's bass response. Buy better speakers instead, he says. But what are the Kappas? They are electrical EQ built into the speaker, and in the worst possible way. Any owner of these beasts would fare better to tame them by removing the tank circuit and adding a parametric EQ unit or separate subwoofer, to achieve the same end result in a manner that is compatible with most amplifiers. And then one gains much better control than is offered by the 2-position switch.
From my understanding... lowest impedance at resonance is bad for most amps.. so should be tackled... When we say a " TANK CIRCUIT " usually it's L & C in parallel....this produces MAXIMUM IMPEDANCE @ RESONANCE..so minimum current through it... so if the tank ckt. is IN SERIES WITH the driver..it offers HIGHEST IMPEDANCE when itts tuned to the same Freq. as the spkr. resonance frequency...
not to my knowledge....but if these drivers do have Really good quality & designed powerful RARE EARTH magnets mounted as opposed to the heavier & cheaper ferrite magnets..they definitely would require that high current for optimum performance..yet staying cooler.. mmf..& it's maths equated to do justice...
@@analoghardwaretops3976 No, a tank circuit is either parallel or series, and the one used in the Kappas is series, with the rest of the crossover in parallel with the inductor (the huge capacitor is in series with the input and passes *all* woofer current). Impedance of a conventional (no tank circuit) speaker at resonance is the *peak* value, not the minima.
