What's the difference between amplifier classes? | Crutchfield

[@makstaz79]

Finally someone explaining the amplifier classes in a way that everyone can understand.Great job!

[@crutchfield]

Thanks, DJ!

[@West3rror]

And failed to mention key details and not all correct info.

[@lennartgosman3640]

He did not.

[@EdBenji]

@@West3rror Details like price!

[@cgreenfield6655]

Crutchfield is such a great company. Always quality info, reviews and products. Glad to see they survived the Amazon invasion.

[@crutchfield]

Thanks for the kind words! 🙂

[@aegisofhonor]

class D uses a 'constantly switching" PWM (pulse width modulation) to maintain the output stage of signal while allowing as much of the input power to be converted to sound. In practice, you will never get 90% efficiency out of even the best Class D amps as the efficiency comes from the output levels matching what power is required to keep the output stage running at all times, which happens between 40% and 100% of maximum output power mattering on the type of amplifier and it's max power rating and still use a good chunk of power even at idle (NOT standby, idle; it's on, just playing music). Class A for instance will often use more then 25% (sometimes 50% for smaller amps) of it's max power input even on idle and never gets above 50% efficiency even at maximum output. AB is slightly better at about 20% input power at idle and gets to about 70% efficiency at around 80% of it's output power rating or higher. Class D often uses about 10-15% of it's input power at idle and hits it's maximum efficiency at around 40% power. Because most people rarely "push" their amplifiers anywhere close to their limits, their amp's effency is never as good as it's "max efficency" because you have to output enough power and use that power to really measure any respectable amount of "efficiency".

[@Skarfar90]

Depending on the load resistance, some Class D amplifiers can reach up to 95% efficiency when kept within

[@nighttow8780]

One thing I can say about a/b amps from reputable manufacturers, they certainly last a long time. I have an old Kenwood kac-7201. This amp in combination with some Fosgate Subs, have been in service in my various Vehicles since I was 19. I'm 41 years old now. And just like when I was 19, I pushed these things hard every single day. The amp is underrated as well as the subs. The amp is supposed to be stable with 4-ohm load only, and I've been driving a 2 ohm load in excess of 20 years. I have yet to own a class-d amp. I have an Optimus 4-channel Class AB that I purchased at RadioShack some 22 years ago driving 4 full-range speakers. This amp is capable of driving Subs, but its built-in, non-adjustable subsonic filter starts cutting off at 32Hz. Which is absolutely unacceptable for driving Subs. But it does pretty darn good for 6 by 9 coaxials and six and a half inch components. I do have to be careful though, at Full Tilt, this setups current draw exceeds alternator output. Edit: actually now that I think about it, this Kenwood amp that I'm so fond of came from Crutchfield all those years ago. I miss the days when a phonebook sized Crutchfield catalog would arrive at my door. For you kids that don't know what a phone book is, ask mom or dad

[@dandeson9723]

i still have few old amps, one being Alpine MRV-F407 that works like a charm, no use for it but is shows how good it was built "back in the days", i also use class A/B(Magnat The Rock 800) for speakers but for subwoofer i have class D because i see no reason to dissipate many kilowatts as heat or use alot of space for it.

[@AlmondCiderUs]

I wish I was in that era 😅

[@dougmurray7684]

A breakdown of how each of these classes work, how each reduces or increases distortion, etc., would be appreciated.

[@crutchfield]

Our article on the amp classes does go into these details here: www.crutchfield.com/I-rYALc921/learn/which-amplifier-class-is-best.html

[@ToppBossLuisito]

@@crutchfield do a video tho

[@askjayk]

@@crutchfield do a video its 2022

[@Zapgod]

@@ToppBossLuisito it delves deep into how the transistors are biased, the output waveforms in relation to the input and how class D uses pulse width module. Class A has constant on transistor which passes on as heat but there is almost no distortion. Class B has transistors turning on and off, but due to the required .3 to .6 volts required to bias the transistor when the input sinewave meets 0v both transistors are off until that knee voltage region of .3 or .6 is reached, the transistors conduct at 180degrees, so you have a less clean sinewave in the output. Thats where class AB comes in, the sinewaves are crossed over at the knee voltage of the transistors because they conduct for more than 180 degrees but less than 360 degrees of the sinewave so they are never turned off at the same time. With class C the transistors conduction region is less than 180 degrees. More like 90 degrees. So it is on for that 90 degrees and off or idle for the remainder of the 270 degrees. Remember this all happenes in a split second so if 1hz is a sinewave of 360 degrees, the transistor is only on for 25% of that time. Thus less conduction more distortion less heat more efficient. Class D amps use pulse width modulation in which instead of a sinewave the output is in pulses of "on" state or off state. These pulses are more evident at the positive peak and negative peak of a sinewave input. And less evident towards the center, these pulses create noise or distortion. Thats where low pass frequency comes in to cut off these noises.

[@zoroluva]

Very good quick educational video. Thank you! A couple of things to note:: 1. The claimed efficiency of A/B design is realized at over 85% output... Meaning your ears would be bleeding before you get anywhere close to it's peak efficiency. 2. Class D hits peak efficiency quickly. 30-40% of output you'll almost be at max efficiency. I think most people live in this range majority of the time and this is why Class D is the future.

[@patthewoodboy]

that would depend on the power output of the Class AB amp , if it was a 15 watt amp your ears wont be bleeding at all at 85% output

[@zoroluva]

@@patthewoodboy how about a 1W tube amp?

[@westelaudio943]

In home audio, most of the time, people only use around .5 - 2 Watts depending on the speakers. Assuming the amps you compare both are rated 100 Watts RMS, you would arrive at 35 or 80 Watts, that would only be a few dB difference and you would very rarely turn up the volume that loud at home. Also class D isn't "the future", it's been in HiFi for 45 years now and probably won't get any better or cheaper. Anything where Class-D makes sense has it incorporated already, like car amps, high-power miniature amps, PA amps, portable speakers etc. Anything else doesn't benefit from the additional complexity of Class-D.

[@zoroluva]

@@westelaudio943 totally agree.

[@thewoodlife3]

This is the first time I understood what different class amplifiers are. Nice explanation. Thank you

[@crutchfield]

Glad we could help!

[@jeffreystroman2811]

You still don't understand if this video is your reference.

[@thewoodlife3]

@@jeffreystroman2811 which one would you recommend?

[@RA-uj3nm]

Straight to the point. Easy to understand. Thanks 👍

[@crutchfield]

You got it! If we can ever help, feel free to reach out.

[@hahaahah7214]

This is an absolutely amazing explanation, I wish I watched this when I first dug my head into this HUGE rabbit hole

[@crutchfield]

Thanks! 🙂

[@OmarSharif-mi3ql]

Dear Sir, you have described the topic very efficiently ❤.

[@crutchfield]

You're welcome! We are glad that it helped!!

[@sandozdelysid]

I have bought alot from crutchfield. Also because of crutchfield, i have found a lot of work arounds from -forget crossover networks- to just get the expensive amp and the cheap subwoofer Props to you and all

[@itisjustacomment]

I remember building a mosfet amp some 600w single output at college 28 years ago . I still have it , but not the 15" guitar bass speaker and larger box I had set up to my stereo with I was young . Back then, I built with a normal stereo amp , mulplie crossover , plus 3 class D's one for bass and two for normal full range and the regular amp for highs only. The sound was unmatched to what I even had two, which costs 3k new just for speakers and pre plus power amp . It's amazing what building class D's yourself can achieve or trying out different chips in Morden versions at low cost. The only issue with building is the boxes, which cost more than all the components plus buying an external power supply. Luckily, I had already had multiple outputs . I wish some 30 years ago we had class D's to these days with such quality , controls, and power at around £100 pound, which can get you a 150-watt at 8ohms easily. It's kind of perfect for recond decks or phone jack to input to play KZbin music or other apps.

[@crutchfield]

That is awesome! Class D has certainly come a very long way, that is a fact.

[@toyotafan1234]

Great video crutchfield. Another great video would be to explain the differences between half bridge and full bridge amplifiers and how they work.

[@crutchfield]

Thanks. We'll pass this idea along to the video team.

[@tomkocur]

Anyone calling a basic class D amp "digital" should go to jail. Thank you for calling things the right way.

[@talibe801]

🤗😁

[@talibe801]

Yes sir.

[@henrikpersson4698]

Nothing can be digital in the end, or we wouldn't hear it. Ears are analog

[@tomkocur]

@@henrikpersson4698 If the device is doing some digital processing, it can be called digital. For example DSPs are definitely digital, they take analog input, convert it to digital form, do some maths on that signal and convert the result back into analog. This is digital. Class D amplifiers are in no point digital, they take analog signal, use it to modulate PWM or PDM signal to generate amplified output. This might be called discrete signal (before output filtration), but discrete is not an equivalent of digital. I think the presence of a discrete signal is where the "digital" comes from, but there's a ton of analog devices utilizing discrete signals - for example power supplies, which no one in their right mind would ever call digital.

[@AT-wl9yq]

@@tomkocur "Nothing can be digital in the end, or we wouldn't hear it. Ears are analog" That's a factually true statement. "If the device is doing some digital processing, it can be called digital. For example DSPs are definitely digital, they take analog input, convert it to digital form, do some maths on that signal and convert the result back into analog. This is digital." So what you're saying here a signal can be processed when its digital but then gets converted to analog in the end so we can listen to it.

[@CoolDudeClem]

I built a powered speaker with class B amplifier (yes, class B). It uses negative feedback to provide a "corrected" waveform to the output transistors (opposite to how they would distort) and it sounds pretty decent.

[@dab9742]

I've noticed that with class A amps, you don't have to wait long for it to reach operating temperature, and "sound" its best ! 😉

[@adrianbennett9322]

Still love the sound of my 18 year old Panasonic (Technics) Class H+ AV receiver. Have tried replacing it but I always come back to it. Can't find any info on the modules inside it, but can see two distinct voltage rails feeding them.

[@West3rror]

I had a Technics "Class H+" surround reciver once. It must be 20 years ago now.. Decent thing as a first reciver🤷‍♂️ But those fake "5x100w" was a litteraly joke compared to 5x45 (2x55 in stereo) real messured Harman/Kardon (class AB) watts I got later. H/K had twice the power supply, delivered much more actual power to the speakers and beat the Technics in absolutely every way. Technics had some good stereo recivers but nothing I would choose over others.

[@ML-rm3vk]

Wow thank you for the info on the classes of amp terrific video and the presenter did a wonderful job great speaking voice.peace to you

[@pavan1000]

really great explanation. loved it thank you.

[@crutchfield]

Thanks! We're glad to hear that you found it helpful! 🙂

[@bluesunflower2007]

Thanks for the nice and clear videos. I am from electronics background, so I know exactly how each amplifier circuits work, their pros and cons. What I don't know, however, is if a class A, class AB and class D amplifiers sound different or not, say for a typical price range. It would be great if you can post some samples or maybe fourier spectrum that shows the harmonic distortions?

[@crutchfield]

Thanks. We'll pass this along to our video team, and perhaps we can include this in a future video.

[@DarkSim712]

The old-school MTX 1004 and 502 are class A car audio amplifiers. I have several of them and they sound amazing. I'm never letting them go. Even though I have to keep four computer fans on max speed at all times on my MTX 1004 just so it won't overheat. lol

[@crutchfield]

Nice! What are you powering with it?

[@BrandonBuckaudioanarchy]

Amplifiers convert input POWER to output POWER. ALL electrical circuits are comprised of voltage and current, the combination of which is where we derive power. Saying amps convert input voltage to output power makes no sense. You could say they convert input voltage to output voltage but that's only half the equation. They also convert current... which again, is the second component of power. To measure efficiency you can't compare input voltage and output power... you have to compare input power to output power. Hope that helps clear this up.

[@jaysonmartinez2830]

I love your explaining how A (25%), B (more efficient), & A/B (60%) are different from D...& how much more sound you get from a D (90%) But than saying that people "Don't need to worry about what class amp you get!" Is.......WRONG!!! If you're adding an amp to your home....the A, B, or A/B would be fine. But in Car Audio....a Class D is 100 times better!

[@timtim4664]

Sound Stream made a class A amplifier that was 1/4 ohm stable... it was rated at like 12 watts in audio comps but could power so many highs/mids. It's been 30 years since I last saw it.... so my facts may be wrong. I loved the Sound Stream Reference series.

[@crutchfield]

They did have some Class A amps they rated down to 1/4 ohm! What is your go-to car amp brand these days?

[@olvinyldude]

Have your NAD C375 BEE that you recommended several years ago, & enjoy so much, to this day ! ( Running Polk RTi-A9 speakers, Technics 1200GLD with Ortofon 2M Black cartridge... Keep up the great work Crutchfield ! ( Bought your Salamander Cherrie Wood Stereo Cabinet few years back, it is GREAT !

[@crutchfield]

Thank you for shopping with us and for your kind words! Sounds like you have picked up some top-notch components over the years. Are you listening mainly to vinyl these days?

[@Ricardo-ge1yl]

@@crutchfield Yes indeed ! We have 46,000 + Records, is all we listen to, when want music ! ( Besides, vinyl has best sound! Best, R.

[@talibe801]

Good information,simple,not to tecnical and the way most people understand.

[@TemujinScott80]

Thank you for this!! My Sonos Five has 6 class D amps inside.

[@HanifBarnwell]

Gross

[@TemujinScott80]

@@HanifBarnwellshhhhhhhhhhh… no one asked you

[@jesusgavemeaids]

I travel through Harrisonburg VA every month & never knew there was a crutchfield store there until a couple weeks ago!!!! (Yes I know there's one in Charlottesville too.) That's awesome & I never even knew. FINALLY got to actually demo some of the speakers I've been looking into getting for the last few years but wasn't sure what to do since I had never heard those particular speakers!! Just too bad y'all don't let store customers make payments like online customers can. So I have to save up some money now....but at least now I know what I'm gonna get

[@crutchfield]

Typically, the speakers sold in our retail stores are also offered online on our web site so you can get the financing. Which speakers are you interested in?

[@conradmaceo]

Starting to see a lot more class D 4-channel amplifiers, that’s actually what brought me to this video. I’ve always had class-AB for my 4-channel amps, and class D for my subs. So would class AB still have better sound quality than D for highs amp, just less efficient?

[@capezyo]

Thank you Tomas

[@ShawnX]

You explain very clearly!

[@catherineescol7852]

I like this guy great Review! A blind person who enjoys great music does not know what sort of class of amps he listens, A nerdy Deep pockets audiphole would disagree though

[@davidcobra1735]

He didn't review anything. Are suggesting that knowing what kind of class amplifier you've got or plan to purchase is a bad thing? It's usually written on the box or in the spec sheet of any quality amplifier so you truly would have to be blind to not know.

[@timothyfreeseha4056]

Well done! Concise.

[@crutchfield]

Thanks, Timothy.

[@rowencasanova]

how I wish we had a Crutchfield store here in the Philippines!!!

[@crutchfield]

Hi Rowen! Wish we did too!

[@davidmaclennan5925]

Very good breakdown and super simple yet informative explanation, from now on I will just send this link to my clients whenever they ask the question, I tend to tired rehashing the same answers, especially when they get that glazed look in their eyes like a Cheech and Chong movie 😊😂😳

[@crutchfield]

Thank you for the kind words, I am happy you found the video useful and enjoyable! JR's videos are fantastic and us Advisors love them also😍🥰.

[@dlloyd6300]

Nice video Crutch!

[@emmaarcher]

fascinating & very informative keep up the channel

[@crutchfield]

Thank you for the kind words!!!

[@nanocash89]

Quick question, would it help showing showing a car audio tech thru headphones/earbuds , what kind of sound you want in your car by showing them what type of music you listen to ?

[@crutchfield]

Letting them know what kind of music you listen to should definitely help, as well as communicating the level of bass, volume, clarity, etc. you hope for.

[@nanocash89]

@@crutchfield thank you guys do you guys have people here in nyc

[@nanocash89]

@@crutchfield i wanna take car audio lessons and get my license/permit/certificate for it

[@crutchfield]

Nice! We don't have installers nationally but here's a great tool to find other install shops local to your zip: www.crutchfield.com/I-rFBKc384/LocalInstaller/InstallerSearch.aspx?installType=0

[@jesusgavemeaids]

@@nanocash89 I just recently discovered that they have 2 stores. One in Charlottesville VA & one in Harrisonburg VA. I'm 2 hours from Harrisonburg & travel through there every month. I know that isn't the answer you were hoping for but it's exciting to me... I've been needing to upgrade my speakers for a few years now & it's hard decide what to do when you have never even heard some of them. I just wish I had known about that sooner...& also that they let in store customers make payments like online customers can because some of that stuff is expensive. But at least now I know what speakers I'm gonna get.

[@JF-em6hr]

It' be helpful if Crutchfield had Amp Class as a catagory on their Web Page.

[@crutchfield]

For car audio the majority will be class D amplifiers. While we do not have a filter feature, the amp class for integrated amps and power amplifiers for home use is listed in the details tab on the product page.

[@sleelakrishnan]

Very useful content really appreciate it 🦅

[@SSD99]

The Alpine 3558 was a 4-channel, 40W/ch Class-A amplifier. Best guess, it drew 160W at idle.

[@debankur007]

Excellent explanation ..........

[@crutchfield]

Thank you!

[@toysforboysrc]

Glad you offered help because I Need someone to explain what… “ADAPTIVE FEEDBACK GLOBAL MODULATION TOPOLOGY” In a car amplifier application is and what does it for for this D CLASS four channel Alpine … It’s the model number (R-A60F) and the manual does NOT get into those details and there is not one KZbinr talking about this technology and if this is what makes a D class suitable as an A/B class? I bought it bccs it’s the only ALPINE amp that is 100w @ 4ohm x4 stereo. AND THE ANP IS “HI RES”… BUT…. It’s a D class… So what am I missing here?

[@crutchfield]

Great amp! What are you using it to power? Alpine did use a class D build for this amp to make it super efficient; but it does have their built-in "Dual "Sierra" feedback circuitry to ensure cleaner sound than you'd expect from a class D. That tech decreases distortion by correcting the output using the original input signal.

[@Siddharth_Matada]

Hi sir, whether class AB amps drain car battery more quickly than compared to class D amps when we have stop the car for 1 or 2 week? Also whether we need to face car starting problem as battery gets older in case of class AB amps?

[@crutchfield]

Just so you wire the amp properly, it would come on with the vehicle so as not to drain the battery. You would not expect to have more or less battery issues using either amp class.

[@akeemjackman9582]

What’s the best set up for a motorcycle. 2008 Hayabussa. I’m thinking 2x 6x9 speakers and then either subwoofer under the tail. What are your thoughts?

[@crutchfield]

We don't have specific information on your motorcycle but we do know that space is limited on motorcycles more so that any other vehicle. Class D amps are typically smaller than the other amp classes and should help in this application.

[@bryanguest2807]

Bruh, get yourself a 7 channel atmos receiver and run the height channel on your mirrors

[@mafosa8519]

Seems like AB for the doors and D for the sub would be a good combo

[@crutchfield]

Yes, that's a very popular combo! Do you have specific amps in mind for your system?

[@miksumasterjbl8899]

What about Class A and Class D hybrids like Devialet Phantoms? I own one and I fell in love with the sound quality and the powerful bass. I am about to buy a Devialet Phantom 1 108dB version, but I am waiting for the next generation of Phantoms. Bluetooth 5.0 isn't enough anymore. I am waiting for Bluetooth 5.4 generation. I also asked Devialet, if they would use APTX Lossless Bluetooth codec and Wifi 7. Devialet answered to my question by saying noted. Next generation will come late 2024 or early 2025, hopefully.

[@crutchfield]

Devialet power and sound quality is amazing! We are not showing any date or specs on the Devialet Phantom I 108dB replacement; but should offer it as soon as it's available so please check back.

[@rexlysailas4215]

Real stunning accurate information

[@clc2112]

Leave it to Crutchfield for the win. Also, my last name. I bought my first amp in 1986. Yamaha M80. My friend said, yeah get it, it's class A. I had no clue until today what that meant. Still enjoyin g the M80!

[@crutchfield]

Amazing! (Great last name too!) Sounds like your friend helped you choose an excellent amp! What type of speakers are you powering with it these days?

[@clc2112]

@@crutchfield The same. Wharfedale E90 Pro. Had them since '87. Also, swap in some JBL L100's one occasion. I can't afford new stuff :). You know how many times I've said, "Yes. like the magazine." When asked how to spell it"

[@crutchfield]

😁Happy listening!

[@blackbeansmatter1280]

Killer amp. Thing will outlast you

[@Lannd84]

I think you should care. After you filtered out if it can power your speakers or not, it would be good to know if you had a choice of for a D class.

[@PaperBoat.]

Class D amplifiers are 'digital' only when it contains ADC.

[@crutchfield]

Class D as the amp designation class does not mean "Digital", that is correct.

[@felipechavez6672]

For some kenwood peak power 700watt 6x9 what amp do you guys recommend? What Brand and how many watts ?

[@crutchfield]

We are happy to help recommend an amp. RMS watts are used to help match an amp to speakers. What is the RMS watt rating for the Kenwood speakers? If you do not have that information, we may be able to find it using the Kenwood model number.

[@Yes_Piano]

Class AB is the winner in sound quality and fidelity aspect, class D is more compact, thus it need less power or has more efficiency but the sound is less realistic.

[@stighenningjohansen]

A well executed (soundwise) amplifier has nothing to do with the class, the class has mostly to do with power consumption and efficiency. And selecting class before sound quality is probably a stupid preference, :)

[@knowledgeOcean007]

Mosconi AS 100.4 vs genesis series 3 which one you suggest mate? Waiting for your reply

[@crutchfield]

Hi Suresh, these are not brands/models we carry. Would you like help choosing an amp we stock? If so, what is your exact setup?

[@saedamad]

Knowledgeable... Thank you

[@crutchfield]

You're welcome, Sa'ed.

[@McCullochMac6]

I own many proton amps 222, 250, d275...from late 80's early 90's I have never found a better sounding amplifier than these..in my opinion...

[@crutchfield]

Are you still using them in your current systems?

[@311superfly]

Great job!

[@crutchfield]

Thank you!

[@bunnatang2081]

Intro: here are different types of Amp Classes: Body: You dont need to know about those classes. Ending: please subscribe.

[@anonymoususer4356]

well done, thank you

[@crutchfield]

You're welcome. It's great to hear that you found it helpful! 🙂

[@jasonwilke2703]

I noticed both of the Sony MEX-XB120BT stereos we bought from crunch field don’t seem to have very good quality of sound they get loud but not an enjoyable loud probably the class D amp it says it has. Do most car stereos have these class D amps now because I really want to replace them with some thing that doesn’t and also the 10 band EQ is a pain to use.

[@crutchfield]

Receivers typically have a MOSFET amp. While this amp is not a class D amp, it is also not a class AB amp. Its like a hybrid amp that still focuses efficiency and would not be expected to sound any clearer than the amp in this Sony receiver. An external amp is needed to increase the clarity of the sound. We can recommend one that will. We need to know certain specs on the speakers. The watts RMS each can handle along with the ohms of each. If you do not have that handy and can supply the brand and model, we will check our amps for one that will give cleaner sound.

[@jrgumex]

hi, knowing class D amp full range are more eficient than AB in term of fidelity is D supeior than AB or AB is has more fidelity than D in car audio? I need to make a decision for my two pair component speaker system

[@crutchfield]

These days, there are high fidelity options in both. Would you like help choosing?

[@jrgumex]

@@crutchfieldYes, I need to right ampf for my 2 pair of focal PS 165 V1 (80 wats rms each) at the front and rear part. I have alpine ute 73BT which output is inly 2 volts. I would prefer based on your explanation with class D (understanding that now days class D full range D are giving the same fidelity like AB and more efficient) so what would it be the right power per channel to chose?. Equal or a little be lower than 80 watts per channel or one with 100 watts per channel lowering the gain? any brand suggested?

[@emiel333]

Great video. In the past I owned a Harman/Kardon stereo amp. It delivered 85 Watts of power on 2 ch driven, 20 Hz to 20 kHz with 0.07% THD. It also had a HCC built in with 80 amperes. I still don’t know what the latter one was good for. Do you have any idea?

[@crutchfield]

Its a slightly different way to stating just how low of a single moment ohm it can support. When the deepest bass notes hit, they can cause the impedance of the system to drop for that split second. Based on the specs you provided, it sounds like that HK stereo amp was able to support some intense audio with any speaker, even the ones known to be power hungry

[@emiel333]

@@crutchfield Thanks for the explanation! Even Harman/Kardon customer support couldn’t tell me what it was for, so my compliments! And what you say in the last sentence, that it could drive power hungry speakers easily, is true. I tested many different brands and models and the HK-980 had no problem whatsoever with anyone of them. I’ve tested large Magnat floor standing speakers, Bose 501 series V, Bose Acoustimass series 2, some high end Bowers & Wilkins, Teufel floor standing speakers, Eltac etcetera. There is of course a difference in sound quality with each set but what I found interesting is that the HK-980 amp had a warm colored sound with excellent bass response no matter which set of speakers I hooked up. Harman/Kardon doesn’t make amps like this anymore which is a pity. But on the used market you can find many HK amps and receivers for a reasonable price. I do this sometimes to check them out for any defects and so forth. Thanks again for the useful information on the question I asked. You’ve got a lot of knowledge!!

[@crutchfield]

Glad we could help! Let us know when we can help again

[@nc3419]

@@emiel333 Was that 80amps both channels or each channel, left and right? With many AB amps under a grand today you can expect about 10 amps per channel, give or take.

[@jj66c]

Can you explain how the H class amplifier works? And why only Bob Carver uses it and no one else? Thanks.

[@crutchfield]

The Class H is an AB variation that manipulates the amplifier's own power supply to get you more efficient power. While there have been several brands that did their own take on this design, it's not as popular as many other options due to the sophistication the monitoring and control requires.

[@jj66c]

@@crutchfield Thanks for the explanation 👍

[@crutchfield]

You're welcome!

[@raymondchapman5990]

So, an A/B amp is better for mids/highs than a D amp as far as sound quality ?

[@crutchfield]

Class D amplifiers have an excellent sound quality. A/B class amplifiers tend to have a warmer, more natural sound tone.

[@Arjun08ac]

Thanks

[@crutchfield]

You're welcome! 🙂

[@TonyDaTunafish]

Who says!!... I'm still running my Soundstream REFERENCE 705s Class A

[@QuintinLourens]

When I bought my pa active mixer it was so light I couldn't understand. At first I thought it will be a POS and very under powered but I can't believe how much sound is generated by it. My previous amp was a A or AB and that thing was heavy. So because of the weight of my new active mixer I assume it's a class D

[@crutchfield]

Awesome! There are some amazing amp designs out there for sure. What do you use your portable system for most often?

[@HRazmikify]

I wouldn’t call the sound of a good amplifier “fuzzy….”

[@evrico7]

He said warm and fuzzy. To him meaning warm and soft. Sounds like you’re in the room with the artist. Listening to them sing.

[@bryanguest2807]

Not bright or harsh. Better?

[@AntiDot70]

Correction: none of the current amplifier designs are actually amplifiers at all. It's a common mistake to think that they take the original signal and make it stronger. They don't. What they do is use the original weak input signal to modulate, in one way or another, a much stronger DC current to recreate the original waveform from their own power source. Does it matter at the end how it's done under the hood, no, not really, but it should be mentioned that these devices, in reality, don't really amplify anything at all. They modulate.

[@selpingos]

There are many Chinese made Class D amps like aiyima and fosi audio. But what I keep hearing is that the have a lot of power but lack warmth. Is that true?

[@crutchfield]

The sound signature can vary from brand to brand and even model to model. To be fair, we would just be able to comment on models we carry and have experience with. Are you looking for a warmer sounding amp specifically?

[@EmpireBosscali]

I bought jl amp class D for bass few years back ..hit so hard 😅😂 💪

[@crutchfield]

JL Audio gear absolutely hammers!🔨🔨How many subwoofers are you running in your setup?

[@PMantle]

I am now exclusively using apps like KZbin Music to a Chromecast Audio/AV receiver/4 way selector to patio and in celling speakers. How do I decide on a new amp?

[@crutchfield]

Ideally, the amp will not exceed the watts RMS of the speaker selector or any of the speakers connected to the selector. Are you down-sizing from the A/V system and only need the new amp to power the speakers connected to the selector?

[@PMantle]

@@crutchfield Correct. No other job.

[@crutchfield]

Have you found those specifications on the selector and speakers you want to use in this system? If you have not, we can try if you list them here. Also, which Chromecast device are you wanting to connect to the new amp?

[@turbomustang84]

Class G is my historic favorite but I have a fascination for class D at the moment

[@crutchfield]

Class D has gotten better and better.

[@TradingSens]

Can you tell me which audio ic is best

[@crutchfield]

We will be happy to give a recommendation. What is the brand and model of the drivers that the amp will be used to power?

[@ebarbie5016]

An amp's job s to amplify the signal, not to add it's "sound signature" described by jubjective meaningless terms, like "warm" or "fuzzy". While most class D amps are analoge in nature (PWM generated by analog carrier), some are natively digital (PWM is generated durectly from PCM). The best sounding (and measuring) classs D modules are the Hypex NC400 and the Purifi. I'm using the first.

[@goofyrambo2173]

But I couldn't understand, I have 2 4 Ohm speakers, if I go out, what should I see when buying an amplifier?

[@crutchfield]

Our ears can detect more changes in clarity from speakers than they can subwoofers. Class AB is typically the best for clarity these days and is the best class for you to seek out for your speakers.

[@michaeltoroshin3761]

Great review! Can anyone explain me, what class my Rotel 931 mk 2 is???

[@crutchfield]

Hi Michael. Thanks for reaching out. Rotel does not specify the amp class for this model via the manual. You may want to try them directly though at [e-mail] And, if you need anything further, please let us know.

[@michaeltoroshin3761]

@@crutchfield Thank you 🤝.

[@crutchfield]

You're welcome, Michael.

[@gouster4583]

Hello. im tryng to make diy 32 channel amplifier with per channel mono modules that would work independently and each of them will get separate audio input, audio output and 48VDC. Im looking for recommendation for Class D amplifier chip. It should accept 48VDC (single voltage without - 48V, just GND and plus). Possilbly shouldnt require very complex circuit around. Want most powerfull option (most possible RMS) with usable quality (for home use, doesnt need to be studio grade). Thanx.

[@crutchfield]

Thanks for reaching out. Sounds like a fun project! We do not carry amp chips. You may want to try an online parts store like parts-express.

[@domdecosa]

The vast majority guitar amplifiers use Class A/B power amps, not Class A. If you see one advertised as “Class A” it’s almost always referring to the preamp, not the power amp.

[@Jazzyexplorer]

Hello I have question, I a class T car amplifier so what do you think of class T amplifiers

[@crutchfield]

We do not have any experience with power amps using that design. Wish we had different news for you there. Searching online, it appears to be a version of the Class D and should share a lot of the same design traits

[@tomkocur]

Tripath's version of Class D. Lower distortion than basic Class D amps, noticeably better sounding. I have a couple of cheap class D and class T amp modules and while class D is "meh", class T amps are comparable to a decent AB.

[@AT-wl9yq]

Its very similar to class D. ARC used to use them back when class D was getting popular. Everyone thought class D was digital, so they went with class T because they didn't want people thinking their amps were in any way digital.

[@brunoraffo6726]

Do you have a rule of thumb when pairing power amp with speakers ?(power wise). I'm bass player and found out that that question have a zillion answers...

[@crutchfield]

We always advise pairing an amplifier with power that does not exceed the RMS rating of the speakers you are using. Depending on your specific speakers and warranty, you may want to even use a little less power than the max RMS ratings. We are always here to help you dial-in exactly the right paired setup that would sound great and perform reliably!

[@jasontyre5060]

I can't use a class d amplifier in my car. They cause too much rfi to even listen to the radio. I have tried cheap to expensive and the outcome is similar. Of course, higher quality class d amps are better, it is still an issue. I drive a Fiesta ST, and the only place to put amps is in the hatch. Of course what is directly above the hatch? The radio antenna. That mushroom cloud of rfi just kills radio signals unless they are really close and strong. I live in a thinly populated area so radio stations are far away. Even in the city, the HD channels will not work with a class d. So I swapped the amps with A/B amps and have no radio station issues.

[@akisxaniotakis6353]

Inefficient or not i will never change my class A Signat amp in my car for anything else. Audio quality above all ! ! ! Great guide though.

[@crutchfield]

Thanks!

[@edwardchance2543]

Thanks for the great video subscribed

[@crutchfield]

😄🙏

[@raidenralph8883]

Which type power I use to play only my subs?

[@crutchfield]

The best amp will depend on your exact subs and setup. We're glad to recommend one for you. What brand and model sub do you want to power. How many do you plan to use? What type of pre-amp will you be using?

[@johnnytheg]

Why did the letter C get skipped over when defining the classes?

[@procsico1599]

Class C it's not used for audio.

[@catherineescol7852]

Agreed Correct Class C for RF signal Amplification

[@tigerdefensesystems]

I thought a few old junk amps from Profile, Pyramid and Jensen some where class C?

[@craigdavidson2278]

I picked up an old (1990's, so not too old) pioneer A400, no idea what class it is but it syre sounds good. Would it be worth getting it "serviced" as guessiing they are basic home audio system....it just sounds really good (it came with denon DCD625 mkII)

[@crutchfield]

That would be a good idea. Even if it plays, the capacitors in them that help it have the dynamic sound can go out.

[@craigdavidson2278]

@@crutchfield do you know which "class" it is.....I am happy which ever, yet would be nice to know.

[@crutchfield]

Sadly, no. We do not know the amp class of your Pioneer A400.

[@maghamson]

Good explanation. What does class AA amps mean? Can you please explain.

[@crutchfield]

We do not have information on class AA amps to know how they compare. Wish we had different news for you there.

[@tomkocur]

AA uses class A voltage control and class B current drive. To put it simple - class A circuitry covers the switching gaps of class B stage.

[@Johndouglasphillips]

@@tomkocur thanks! Curious, my new headphone amp is a THX class AAA Linear. I get class A, and now AA. Is AAA just marketing mumbo-jumbo?

[@tomkocur]

@@Johndouglasphillips in this case, AAA is not referring to amp class, it's a marketing name (meaning Achromatic Audio Amplifier) tied to THX's special design, which they have patented. Patent itself says that the amp can be operated in class AB, B, G or H, however there's no proprietary IC for this, it uses comercially available opamps.

[@frigzy3748]

So, from a EE prospective, class A = LDO, class D = switching converter. Cool

[@Cliff117]

I have a Bose 1801 and need to get it repaired but all the good stereo repair shops have disappeared. What do I do? It weighs a ton!

[@crutchfield]

Cool amp! Your best bet will be to check with Bose directly at 800-367-4008 or support.bose.com/s/get-help-landing-page?language=en_US

[@jollygreen4662]

Do u guys veh speaker system upgrade service?

[@crutchfield]

It sounds like you are asking if we can help recommend speakers to upgrade an audio system. If that is what you are asking, then we sure can help! What is the year, make, and model of your vehicle? Did it come with an upgraded audio system from the factory?

[@jollygreen4662]

@@crutchfield sorry. Do u guys do speaker upgrades? Installation service

[@rchokelal]

Awesome!

[@crutchfield]

Thanks, Raymond! 🙂

[@West3rror]

Mostly true and not bad explained. But you forgot an very important thing..: Class A gets more efficient the more you turn the volume up.. It's only at idle and low volumes they have really low efficiency. Class D are only "digital" in the sense that they have switch-mode power supply. And a tip: If that Rotel and speaker setup was yours.. Move that Atmos speaker where it is supposed to be.. High on the wall or in the roof.. Reflecting sound from the roof is not even close as good amd requires even more perfect room to even so it properly as intended.

[@crutchfield]

Great points! We chose an overview approach to this video which definitely glosses over some finer details, especially a proper Atmos setup, which we just tried to give a visual sense of here. Makes us think maybe a deep dive on Atmos could be in our future.

[@strobaholic]

Class d also tend to cost less these days, compared to the less common AB class.

[@crutchfield]

We are seeing class D rule the roost as far as car audio, and even start to become more common in-home audio too due to the efficiency and great sound quality. There are still folks that prefer the warm AB or even class A sound from a nice tube amp or preamp. It is really about personal preference most of all.

[@hashimmusiqq6789]

For car class Ab or D is better?

[@crutchfield]

Both can work well. Most subwoofer amps are Class D mono amps these days. Class AB amp designs are still a popular solution for 2-channel and 4-channel amps, although there are good class D options for those now as well.

[@TareqASamra]

My Asus RoG Phone 5S dac/headphone-out is advertised as a source as Class-G? How does this get defined? "ESS Sabre ES9280AC Pro with HyperStream II QUAD DAC technology and a built-in Class G ESS Sabre Headphone amplifier with up to 2Vrms output for headphones with higher impedance."

[@crutchfield]

I have not been able to find information describing the build of their class G amp stage. If its it similar to other companies Class G, then its a combination of a Class A and AB amp. Class A for the first half of the volume scale when power is not too intense to cause heat issues. Then Class AB for the second half to help keep heat down when needing power.

[@harishbabu4278]

I am in deep search of 3 way car audio. I own McIntosh class AB AMP and GE Tower 1 I own PSB B6 Bool Shelf amd Creek Class D As you know there is no comparison EOD Class D are are so so Class A & AB rocks many years to come

[@ejohnson3837]

What class are the newer High Current amplifiers????????

[@crutchfield]

That can vary, depending on specific models. Do you have a specific amp/receiver in mind?

[@ejohnson3837]

@@crutchfield just doing some research. I have a par of B&W 802N and a McIntosh 2200, 200 watts a channel and the 802 are power hungry. They go down to 3 ohms and the mac is 8 ohm stable. I believe the High Current amps are AB,????

[@crutchfield]

Nice speakers and they do love power! The Anthem STR Power Amplifier is an ideal AB power match for you here: www.crutchfield.com/I-rYALc921/p_973STRAMPS/item.html

[@ejohnson3837]

@@crutchfieldthanks

[@crutchfield]

You're welcome. Keep us posted.

[@soundknight]

I can hear noise in class D amp circuits due to the low frequency square waves

[@luism8612]

No you can’t literally end your life I bet you also claim you can hear losless music