What are the Differences Between Class A, AB, and D Amplifiers?

[@GunnyPhillips]

Just so you know, this video is still helping people today. Best objective explanation I've heard. Thanks Gene!

[@swizzy8735]

Agreed

[@LoganRST]

Helped me in 2024!

[@ryanwaege7251]

@@LoganRST me too 2024

[@trog69]

As a poor retiree I have settled for used gear. I lucked into winning an auction for the Adcom gfa-555 power amp and it made me realize that the Carver M-500 I'd been using for a couple of months desperately needed repair as it lacked both high and low freq. sound that the Adcom outputted quite well. Anyway, after getting my grubby mitts on a wonderful-sounding pair of ADS L810's, I thought about how their 94db efficiency would hold up with less power, so I hooked them up to the Emotiva a-100 Flex amp I'd been using for headphones, and the sound was every bit as good as the Adcom. All of this is in near-field so none of the amps were ever pushed very hard at all, but the 50wpc Emotiva has proven to be everything I could want for this desktop. Love the vids, Gene!

[@martyjewell5683]

Nicely explained and very lucid. I read somewhere that Hitachi had the licenses for class G, class H and magnetic field amps and licensed them to Soundcraftsmen and Carver respectively. I have a Hitachi class G receiver (SR-804) purchased in 1979 and still use it today. I keep it serviced and in good order. I find that it can be on for hours, sometimes eight hours and only gets barely warm to the touch. Sound is clean, clear almost crisp. I found the cost (in 1979) of this receiver very compatible with other similar powered brands. It cost me $340 in 1979.

[@ianforfun1]

Extremely well explained. I have a class A Tube EL34 2 x 12 Watts single-ended running in ultra-linear with a Tube preamp, a Technics 2 x 55 watts class A and a Sony 2 x 50 watts class AB and use a home built 1/4 wavelength 14feet transmission pipe floor standing enclosures running duel concentric 61/2 inch drivers with 25% of the spider removed for greater compliance and efficiency and at 8ohms with balanced passive crossover and Zobel network with 25-30Hz (dependant on room placement) to 20Khz response. By a long way, the Tube amp has far more control and with an HD source is breathtaking! So much more harmonic detail and presence and the image is stunning with depth and can 'feel' the music. I think the trade-off of less efficiency is worth the results. All achieved with a low budget in mind and 100s of hours of effort.

[@srijitkp3]

You got me chuckling on the "to be honest, if you're listeninig to it so loud, you don't have any hearing left to begin with" ...lol! Stellar one, as always. love the research there!

[@நக்மாசெல்]

Beautiful explanation for a beginner. People always crazy on 1000w 20000w kind of figures. This tutorial cracks down the myth

[@loudspeaker-solutions]

very good video killing the myth of audiophiles and bringing rationality into sound reproduction. that's the way i believe audio should be treated in marketing. thanks.

[@XX-121]

enjoy your class d. won't ever catch me running one. fool me once...

[@pimpmyskin]

I have always used A/B because I thought I paid more for less with A and that A was just old stuff for stubborn old guys. But now 20 years later I'm looking to get my next 2-chanel stereo after not having one the last 4 years I found Class A and have totally fallen in love. Nothing A/B sounds quite like Class A. I have listened to sooo many High End A/B amps and nothing is as smooth and powerfull at the same time. I also think that it's impossible to measure "Good Sound". You can have two cables made out of the same conducting material but put together different that will measure the same but sounds totally different. In my opinion the only quality test you can do on hifi is an old fashion listening session. Hifi is in the eye/ear of the beholder. It's like art, you can't measure art and say that's good or bad you can only look and make your mind up. Something you love I might not so who's right. Well that's all from me and have a blessed day

[@BojanBojovic]

I had a friend who was an audiophile. On the other hand I am a musician and our interests matched at some point. I learned so much from him, but the most important thing he told me is never to become an audiofool. Since then I simply love science and objectivity. Thanks for this great explanation.

[@Bluecrabsandsushi]

best source of reliable information in the entire audiophile world

[@michaelslocumbsr.2286]

Gene, What are your thoughts regarding the Crown XLS Amplifiers for Home Theater....

[@northern_moss]

Thanks Gene. This is one of the best videos I've seen from you guys, and watched quite a few. Really helping rooks plan well, save, and avoid pitfalls. Maybe even inspiring taking courses at uni. Thanks for doing this.

[@larry4802]

I changed from Class A and Class AB to Class D amp two years ago. First is that the heat is not a problem at all with Class D, esp since I live in Florida! The Class D sounds great! This presentation is excellent and would rec it to all for a good clear rep of the different types of amps available.

[@Phloored]

Going class d all the way. With the advent of GaN transistors is irresistible . For a stereo set up running a tube preamp with GaN class d is heaven

[@sadoxell5462]

Hey my man thabks for keeping this video up. Been looking at so Much of your old videos lately. Love you guys

[@buzzcrushtrendkill]

"..you're basically using a space heater." That is hilarious. Great video. I love your channel.

[@pimpmyskin]

I know a guy here in Sweden that help heat up the warm water in the house with his home built Nelson Pass Class A amp and the water also cools the amp so Win Win for everyone.

[@markrigg6623]

I literally used my A class Yamaha as a heater in my small bedroom.

[@stevengagnon4777]

@@pimpmyskin excellent solution good for all seasons because a space heater is generally not good in the summer unless you are in a cold basement.

[@NightAndDay247]

Hi Gene, I’m running a Pass Labs XA-30.8. It provides 61 Watts of pure class A regardless of impedance. After that it goes in class A/B. I use it with a pair of 100db efficient Klipsch towers. They were the top of the line Klipsch in 2006. Together they provide plenty of oomph. I’ve had the Pass for just over a year. The Klipsch never sounded so good!

[@Audioholics]

That sounds like a great combo. Congrats.

[@davidmbugua4765]

Hi Gene. Awesome video as always. Currently using Emotiva Gen 3, 3 channel. So far am impressed with the output. Usually listen to lots of stereo music for hours and when I touch it it's still cold to the touch. Makes me wonder sometimes if it's really working but am sure it is. Cheers. David.

[@allanwhittle3041]

Top class analysis of the various types of amps ..Thank you ! Audiophiles / Gene are on another level of understanding from 99% of reviewers . No bullshit , just facts , it makes it easier when you’re an expert in the subject matter ..and Audioholics def is 👍

[@foxpup]

I run four beautiful Onkyo M-504 power amplifiers with my 7.1 channel home theater system and they are the most wonderful sounding "space-heaters" I've ever known. I do most of my movie/tv watching in the winter so the extra heat is actually welcome. I'm not sure these are genuine Class-A or not, but these beauties heat the room like Class-A's. They sure have great audio quality specs and are dead silent when on. Any noise you get, if any, comes from external sources. :-)

[@dedskin1]

I am a producer , i work with sound forever , and let me tell you , why would you need more then 20W , i have 2x200W speakers , 8inch 2 way system , quad amped , every driver its own amp , 75W tweeters and 125W bass . That is a good system , clear as day , no distortion , i use about 20W of it usually even less . So whats the issue you ask ? The issue is music is not a perfect thing , perfectly clean speaker and amp , thats clinical , its not musical .. So that is what i use because im a producer , i have to have clean sound . But when im listening , Class A nothing else . No discussion . Its not a bout measurements , its how it sounds . I want that soft Clip , i want that less hten perfect dynamics . The Amp Sings and adds richness to the sound . So much that producers copy sounds of some machines , some Compressors and things . Hence let me tell you , if you are an experienced audio person, you dont need more then 20W , so Class A and that is it . Of cours you can have more then one amp for times when 20W is not enough .

[@nancy4don]

I currently use a Crown XLS1002 Class D amp - a professional amp. I heard many good things about it through the grapevine, especially about how "neutral" it sounds. I'm an old audio tweak who started in the 1970s. I've worked at Radio Shack and also Best Buy among my many retail audio experiences. The old "guiding principle" was straight-wire-with-gain. The best stuff was equipment that got out of the way, letting you get into the presence of the original recording. For years I used an SAE power amp that was reputed to be more neutral than any made at the time. (Mine was made in 1975.) I found that (after break-in!) the Crown was even more open and neutral. I use a Carver C-9 Sonic Hologram Generator with it, and I am getting imaging and presence that eliminates the need for surround or other multi-channel. Gene, if you haven't taken a couple of hours to listen to these Crown XLS DriveCore2 amps, you're missing out. Oh, and it's ice cold, even after 8+ hours of use - the fan has never turned on.

[@marknash7113]

Hey Gene, Egg cooker here. As an engineer and audiophile, I use a combination of internal amp channels and separates to power my 5.2.2 system. Class D is coming along but fails to provide the dynamic headroom therefore requiring over spec'd power requirements. Also the effect of switching noise coupling into source paths concerns me and I see no testing of it. I agree class A is bit much for anything high power and more than 2 channels, However, for my main channels I always use a good class A/B separate amp. Current system: 5.2.2- Legacy Whispers FL FR Center, Driven by Adcom 550's : Celestion F30 Surrounds, Just added height channels to front with cheap BIC bookshelves , Yamaha TSR-7810 AVR. Next Upgrade: 5 Channels of class A/B tube power amplification. Dynaco MkIII's fronts, Craftsmen monoblock center, Dynaco ST70 for Surrounds. All are being rebuilt/designed with upgraded power supply boards and caps. Distortion specs acknowledged, there is no power sag and the dynamic tonal quality of these amps in my opinion is better than all but very high end AVR and most separates. The All 5 channels run < 600 watts wide open and efficiency or not, these things still outperform most amps in any price range. They will sit atop my old school solid oak entertainment center for visibility of the tubes and near intake vents for my HVAC system in the walls. Listen well.

[@AFlyingCookieLOL]

How the heck does class d fail in dynamic headroom? =/

[@miltonrodriguez8923]

I had a pioneer sc 35. Beast of a amp. Very efficient and it drive all my 7 channels simultaneously with no problem. Amp didn't get as hot as other typical av receivers. Audio was in my experience superb. I use 8 to 4 ohms speakers with ease. Unfortunately its life ended because I had a bunch of toddlers who thought my amp was yogurt approve.

[@__jabird__2635]

Excellent explanation of the difference in amplifiers. I’ll keep listening 👂

[@Byeohazard]

I enjoy the no BS approach to this channel.

[@bphilbac]

As always, great info Gene, thanks for sharing. I never considered class D amps before now but maybe I"ll check them out due to your findings. Keep the great videos coming!

[@jasonrobertsutliff]

Been slamming a Fosgate T500-bdCP at 1-ohm for five years now. Love the constant power capabilities & being able to internally drop load. Two 12" two-ohm subs ... Wired in & it can auto-switch to 1-ohm. Car audio ... solid electrical. The new classes available to us, especially in car audio, has made all the difference. PS: Yeah, my Fi Audio subs are WAAAAAY underpowered.

[@isaacsykes3]

Thanks for the video, would please provide a recommendation of two amplifiers for each category that you mentioned. I think that would be extremely helpful.

[@daveb5041]

Crosley, Sherwood, realistic, RCA, oh wait those are all terrible brands unless you like distortion. Why don't you just look at the specs or the best way listen to them, your ears don't hear data printouts and specs.

[@martybrozek7973]

@@daveb5041 realistic haven't heard that brand in a long time brings back memories of the old RadioShack stores. 🙄

[@jackdaiter8245]

Great video! I have Rowland 925 monoblocks with Rowland Coherence II preamp, KEF Blades, Esoteric X03 SACD, Rega P10 table and Clear Audio Balance+ phono stage. An almost fully-balanced system. Audio heaven!

[@aegisofhonor]

one of the best multi-channel class D amplifiers ever made (at a reasonable price at least) was the Sherwood A-965, it was a 7 channel beast that pushed 7 channels at 100 watts each, and tests showed it was clean up to 120 watts, and driving two channels could push as high as 160 watts at 8-ohms. I wish I had one, they have become a rare find in recent years.

[@stephenwyatt7747]

Great video good explanation. My first amp was a Yamaha CA1010 integrated amp, it sounded great. Then i got a NAD 3020 that also sounded great sadly it went up in smoke one night. Now I have a NAD Viso1 bluetooth speaker and it sounds fantastic. I know what a good system sounds like I built my own speakers for one set i used Phillips drivers with a 12inch woofer mid and tweeter. For my 2nd set i used an Electro Voice 15inch woofer with a horn tweeter. I used to place the Phillips speakers on top of the EV speakers and drive all 4 speakers with that Yamaha amp it played very loud would blow your hair back. I don't listen at those levels these days but that NAD Viso1 speaker can play very loudly indeed it has PSB speakers in it and is very accurate and dynamic, if you have not heard one of these you should check them out. They have to be considered the best value in audiophile sound, you will be impressed.

[@TheaterAtReference]

truly thankful for everything you've done Gene ..your expertise , passion has been very helpful

[@webking185]

Well informed Gene. I always said amplifiers and sound are like a car and engine, a Chevrolet does what a Mercedes does. But, will it give you the prestige and name brand feeling like the other? Amplifiers were perfected in the 90's already, they are just becoming more efficient with newer technology and capacitators. For sound quality, there are many factors in getting that perfect sound from the source, room treatment, placement, etc... There are people who spend $100k for a perfect system and swear they sound better. than a $1k system. I've used my vintage amps and speakers, and I don't need anymore; I've show friends at a garage sale to get equipment for $1k and listen to it, and see how good it sounds. I think a company like Emotiva or Schiit gives you that quality vs. McIntosh or Accuphase. People are just spending money on brand recognition. Run two Emotiva HC-1 mono and bang, you have the best 2 channel stereo amplifier for the next 10 years. For movies any receiver will cut it.

[@xlostlovex]

After 6 minutes of viewing I realize my top right screen is moving.. (Full screen mode) Good explaination btw!

[@YoYo-uh3xj]

@@noemycabrera8686 ?

[@andyossie]

Very interesting, I was using my dad’s old Carver Amp and preamp but it needs taking into the repair shop to get it looked at. The preamp is a Carver Model C-1 High Fidelity Control Console Sonic Holography Preamplifier has sonic hologram processing technology for a 3D sound stage. The amp is a Carver Model M-1.5t Magnetic Field Power Amplifier High Headroom Low Feedback Power Amplifier with 350 watts per channel RMS Class A. It doesn’t have transformers in it and it’s smaller than a VHS/DVD combo player and weighs half as much and has not one switch or dial on the whole thing including an on off switch,you have to turn it on and off at the wall, it has an LED power indicator and 2 columns of LEDs to indicate the power output of the speakers once you turn the volume past half way on the preamp. The LEDs rise higher as you turn the volume up until the top 2 start flashing and if you leave it too high for too long it will trip out the speaker protection because they are being overheated, not because the amp is pushed too hard and there’s next to no distortion at that level either! You can hook up a lot of speakers to the one amp and it will just be adding more sound output to the listening room the more speakers you add until you blow the fuse at which stage you get a bigger fuse and you blow that fuse then you may want to turn it down a bit because your whole neighbourhood pushed out of their house lol! We used to have 4 large old school speakers hooked up 2 Realistic 160 watts each and 2 made up boxes adding to 230 watts each and with all 4 going they would be so loud but still clear.

[@marianneoelund2940]

The Carver M-1.5t is class H, not class A.

[@stevefoster6047]

My take away from this very nice video is that if my priority is the best possible sound, for instance to drive a 2 channel audiophile system, Class A amplification is the best possible choice with appropriate caveats regarding budget, listening space size, desired listening levels and speaker sensitivity. If those considerations demand more than about 20 watts, then Class AB may be a better choice. If those considerations demand more than about 200 watts, then Class D should also be considered and may prove the best compromise. If my priority is minimizing my electrical consumption (or $ outlay) and sound quality is secondary, such as multi-channel AV system, or a music system for casual uncritical listening, then well chosen Class D likely offers the best compromise. One concern I do have unique to Class D is that the output filter is a reactive LC circuit, and most amp testing simulates speakers with a simple resistive load. Speakers are not resistors, but rather are reactive LCR loads in their own right, which therefore will interact with the Class D output filter circuit quite differently than a simple resistive load. Hopefully that interaction doesn't result in audible distortion, but testing the amp with a resistive load will not reveal whether or not that is the case. The only test that can is to use the actual speakers chosen for the system as the test load, since each speaker design offers unique LCR circuit characteristics. This issue is well known, much studied, and I hope, largely solved.

[@paulsalongo4927]

100% agreement.

[@blueflame0003]

My pioneer sc55 is a class D3 amp and boy its great on 9.2 i never ever crank my volume maybe a little over halfway and its too load...i just bought a fan kit for it to keep cool cause i have it enclosed now for 10 year's and im afraid its going to go out,but thinking of finding a good amp to biamp it with and just use it for processing...good video keep up the good work.

[@dealzguyYT]

Have the next version SC65 and it is absolutely amazing. Never went about -25 volume level from reference 0

[@erictarbox]

I have class A across the front soundstage with class AB for all the other 8.2 channels. 200 Watts per channel minimum all around the theater room, Adcom, Kenwood, Yamaha, B&K and Carver to be specific. Okay so I have a lot of power available for sound quality and effects. It is worth it for me.

[@user-xg6zz8qs3q]

I am currently commissioning a guy to build a custom class A tube amp for me. The amp design is based on the Unison Research Simply Italy schematics. I save 700€ over buying the Unison Research amp. The custom amp will use bare wire for all components and will use better parts. So this amp should last a long time and be easy to service. I will pair this amplifier with wideband speaker towers (using 1 driver) based on the Audax AM 21 driver. I am stoked. Wideband drivers combined with tube amps sound so life-like. The speakers are so efficient, they only need 1~3 watts. So the modest 10W amp output is plenty.

[@rolandlickert2904]

I use NAD C- 388 integrated amplifier (D) used A and A&B power before but I made the Jump to D Power and I'm impressed plenty of power controls the speakers very well runs cool and has 90% efficiency never looked back

[@sonicyouth29]

Great amplifier. Surprised by how good it sounds.

[@manjsher3094]

Still loving my Krell KSA 50, just love it.

[@shaeradraghiem3044]

Thanks for such helpfull tutorial ... Specially at 2 AM (by looking at your desktop clock :D)

[@DanneM26]

I am running an Austrian AYON Crossfire iii tube amp. A single ended, class A amp. giving 2x30 W weighing about 95 pounds. I drive a pair of Martin Logan ESL Summit X. Yes, it gets warm in my man cave but the sound is silk smooth, warm (LOL) and just beautiful. The amp is actually very modern. It has internal digital control function but no digital circuits in the signal path.

[@garyc5245]

Thanks Gene, I am trying to absorb as much of this info to make the next and hopefully final system build to carry me through retirement. My current amp is ATI 6002 amp, with Anthem 720 mrx reciever and Martin Logan Theos. I am trying to get as much research under my belt to make good decisions, especially now looking at the discussions between tubes vs solid state and how tubes sound better (opinions vary). So I was kicking the idea around about Bob Carver's 350 Mono Tubes. All the articles and peoples opinion have not helped me make a decision. I really want to hear the RBH SVTS speakers and then build the system backwards from those speakers if they are as good as everyone says. Of course then the issue is mono block or 2-channel amp. I foresee myself purchasing some of your consulting time as I get closer. Many thanks for what you do and Happy New Year!

[@vcp93]

Great video. I've learned a ton from this. Thanks!

[@riffraff9000]

I have a Proton D1200...I *think* it uses a variation of a Class G amp. They called it "DPD," "Dynamic Power on Demand." Rated at a conservative 100W per channel, they typically had about 7.7 dB of headroom.

[@ChristianPinnock-r4s]

In the early years of class d people used to hate the sound of class d amplifiers but as technology advanced I think they've got so much better than they used to back in the early days

[@texasbuzzard4970]

Fantastic content gene. Exactly the video I was looking for

[@robertkeefer7791]

I have a Yamaha AX900U amplifier. It's a class A/B design. It can pump 320 Watts into a 2 ohm load. It utilizes 4 NPN and 4 PNP BJT's on the power rail with a large aluminum heat sink. It runs cool and powers my 4 ohm speakers with ease.

[@steveodian6008]

I have been using PS AUDIO M1200 class D amps for 3 months now and loving them.😄

[@XX-121]

did you get a ps audio powerplant with it? i hear you need one to get the full performance out of one of those.

[@steveodian6008]

@@XX-121 No, not a believer.

[@uscfroadie]

Gene, another great video! One question, please. Why have manufacturers not launched a multi-channel (5/7/9 or 11) Class D amp for hooking up to AVRs to get better power to their home theater speakers? Spending $1500 on a receiver to only get ~40-50 watts when all channels are driven is pretty pathetic.

[@Audioholics]

Yea the industry is slow to adopt Class D and to do it right, it's still costly. Thankfully most midpriced AVR's have preouts to add power down the road if you need it.

[@waltermolina7115]

Hi Gene. great video!! I have a Denon X3400 with Elac Unifi lineup as home theater. I was planning to get the Outlaw 5000. But after watching your video, it got me thinking about a 5 channel class D amplifier. Any suggestions??

[@masterchief8790]

Any of the Pioneers, regardless of generation, that are running the ICE Power amps will do. I saw a test done by an audio store owner where the Pioneer SC25, rated 140watts, held true to 140watts under 2ch load and roughly 90 - 100 watts under 7Ch load. This was put up against an equivalent Yamaha model, which, in that owners test, the Yamaha (rated 140 watt) output 180watts under 2Ch, but drastically fell down to 40 and even 25 watts at 5 - 7ch load. In his testing, the Yamaha ended up blowing out its power supply, and he sent it for RMA. Of course, I would always recommend using multiple 2 channel power amps and using a Receiver as the DAC/Switch. Most modern receivers support pre outs. What you save in not buying an over priced receiver, you spend in amps. At the very least, Power the FL FR with a 2 channel.

[@birgerolofsson2347]

I have two bridged Primare A34.2 to my 2 main-speakers and a Primare A30.7 to my center and surround channels and they are Class D amplifiers.

[@ChristianPinnock-r4s]

@birgerolofsson2347 I have a class d subwoofer made by sony and it sounds similar to a pa active subwoofer

[@hdtvkeith1604]

Love your videos and knowledge. I am trying to make the jump from AVRs to separates. I am looking at the ATI 527NC and then use my Denon X7200WA as a preamp for now.

[@irisfailsafe]

What about the new Lexicon class D amplifiers? Are there like Crown amps?

[@hometheaterguyusa8464]

Compare Lexicon, to Crown and QSC, slew rates and damping factors have better sound quality, with Lexicon.

[@AlexandreLollini]

I have gone from a heavy yamaha integrated amp to a smsl ad18, my power bill came down, and the sound is like removing another grill from the speakers, to me it's awesome. going from cinch to usb for the signal helped too i suppose.

[@silversurfer8283]

I would watch a video every couple of days if it was that frequent, 30 min might be a bit long but 20 is just fine

[@professorpickles1]

What do you think of the Emotiva DR line compared to the XPR series?

[@nbrown5907]

How about Crown class I have you looked at those yet? I have the XTI 2002 and love it.

[@MrShaggy789]

This information is so useful for beginners. Thank you.

[@MaZEEZaM]

Is it just me or do you also hear Oracle every time he says Article?

[@Woofy-tm8si]

I would love to see you test the new Emotiva PA-1 Mono Amps with the ICEmodules. At $300 apiece, they're a multichannel afficionado's dream come true and a budget audiophiles dream come true. Can you imagine? A pair of 300w monoblocks for $600! If they sound as good as promised, they're gonna sell tons of them. Well, and I was thinking about getting three for both the fronts and center channel, but I was hoping to see a reliable review before I jump in with both feet. Cheers!

[@TexasCorgiGun]

Same here also I'm between emotiva and red Dragon but red dragon is double the price

[@zaneslocombe8008]

Just doubled my knowledge on amps with this video.

[@captaincanuck7110]

My Krell KSA 250 is a egg fryer! Its also a b&lll buster to lift!

[@ford1546]

The quick answer is. Class-A full power on transistors for best sound. Class-B only power on transistors when there is sound in and it can create unfortunate audible things when transistors turn on. Class-AB. transistors are always on with a little power and never turn off completely. A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices (transistors, usually MOSFETs) operate as electronic switches, and not as linear gain devices as in other amplifiers. They operate by rapidly switching back and forth between the supply rails, being fed by a modulator using pulse width, pulse density, or related techniques to encode the audio input into a pulse train. The audio escapes through a simple low-pass filter into the loudspeaker. The high-frequency pulses are blocked. Since the pairs of output transistors are never conducting at the same time, there is no other path for current flow apart from the low-pass filter / loudspeaker. For this reason, efficiency can exceed 90%.

[@haircut2015]

I just bought a Adcom 5500 amp because it was so highly rated over the years. So what class is it??? I have no idea . Massive heat sinks and BIG round transformer....Great vid..!!

[@Bob.martens]

AB

[@michaelbeckerman7532]

It's very interesting now today that most amplifier manufacturers (at least the ones sold at retail) no longer disclose or even really want you to know what class they are. Why do you think that is? The trend now today is for manufacturers to either provide little to no detailed information on their spec sheets or simply no longer even publish a spec sheet of any kind at all for their products. The phrase you commonly hear now from them is, "We like to let our third-party partner sites out there on the web determine all of those details and publish that information instead." WHAT? Are you even kidding? Since when would ANY company let someone ELSE out there just basically guess at what their specs and internal components are? Why would anyone let something as important as that type of information be handed out to the public (the people actually BUYING your product) by random people out on the Internet? Is it because they want to reserve the right to completely change their specs and internal components square in the middle of a production run if needed and not have to be tied down to one particular architecture that was already laid out on a company provided spec sheet? That's the ONLY reason I can possibly think here for doing this. Can someone please explain this thinking to me and make it make sense? Because right now, it really doesn't.

[@bigdiffas]

Did buy sony str-va555es for running my hometheater. Quite sure it is A/B by the mass of it (24kg says on the box). Just loving how it sounds on stereo mode. Earlier I had some cheaper start of the line sony hometheater amp and the difference in the sound is like night and day.

[@Bulldog_DK]

calyx femti is GREEEEAT !!!got 2 in bridge 2x500watt class D and sounds is so clean and no noice or hum and no clip in high volume! :D

[@PremjitTalwar]

It would be great if you compare the consumer D amplifiers with professional D amplifiers from companies such as QSC, Crown, Powersoft, etc. These commercial level amps are extremely reliable. They drive multiple speakers and are designed to work for hours without a break.

[@larryhazelwood5491]

I have a 1988 Technics se-a5mk2 150 wpc power amp with new class a. It gets warm but not hot. Sounds great on my technics sb-m3 honeycomb disc monitors.

[@kennethsrensen7706]

Technically ´New class A´ is just a class AB with a ´fancy´name for marketing use. It´s a class AB amplifier also thats why it doesn´t get so hot.

[@agems56]

Very comprehensive! Thank you so much!

[@roocrew86]

Awesome video I realise how little I knew... I thought i liked audio 🤣

[@blasterman789]

I'm still running a Panasonic SA XR55 from 2005. I've compared it in sound tests alongside many newer non D amps in the sub $1000 range and sonically the XR55 keeps up fine in its power class, if not beating a few. I dont need convincing Class D is the way to go given how old the panny is.

[@igor1069]

hey Gene I have a 6 month old Cambridge Azur 851 A Integrated Amp it's fine. I have a PS Audio Stellar pre-amp/dac hooked to it. However, I gotten intrigued lately with Jeff Rowland amp have a chance to pick up a 525 Amp (class D) vs. the x/t(A/b ) in the Cambridge. Which to think is better and more importantly better sounding and clarity? Would it be worth the $2,400 or diminishing returns ?

[@KillerKev1961]

I stumbled on this video, and Im glad I did. I have a pair of Infinity Kappa 8s, from about 1989. I currently drive them with a Denon POA 2800, and yes, the amp turns into a heat radiator. What would be a proper alternative to the Denon amp? I love the speakers, they are outstanding for what they are.

[@nilabjasarkar]

I use a Sony proprietary S Master Digital amplifier, so am i using the best in class or is it just another technical jargon, as they claim with the S-Master digital amplifier, a simplified, full digital signal path, the S-Master amplifier reproduces digital audio signals without the multiple analogue stages required by conventional amplifiers. The result is not just more power, but significantly less distortion from heat build-up.

[@DiGiTaLdAzEDM]

I will soon be using a Yamaha AX-930 integrated amp. Where does that fall in the scheme of things re amp class? Thanks.

[@johncameron4172]

I’m about to buy a 4 channel amp for my F-150. I put component speakers in each door. So, I have 4 woofers, 4 crossovers and 4 tweeters. They’re rated at 125 watt rms each. I don’t have a lot of money. So, I can’t decide between the Rockville DB45 or the Taramps DS800x4. The Rockville is class a/b and the Taramps is class D. Each have enough power but which one will be clearer? Have you any knowledge of either? You obviously know exactly what you’re doing. Any advice for me?

[@MrsZambezi]

Once you have enough bias to eliminate crossover distortion that's enough. There are no gains in moving to class A biasing.

Could you guys do a head phone video? Like pre amps and how to match them?

[@ravichandran4589]

Very informative and good insights. Btw have you reviewd NAD masters 7 channel power amp class D yet. If so pl l share the link. Thanks a lot.

[@rb89509]

Love me some Class D amps. I have two Crown XLS-1500's running off my receivers preamp outs. One is set to High Pass for my Klipsch front speakers. The other one is set at Bridged / Low Pass for my Klipsch sub. These Crowns put out over 500 watts into 4 ohms in stereo, and over 1500 watts bridged into 4 ohms. Is this why I have tinnitus?

[@thepiecesfit5049]

Outlaw 2200's driving my Polk LSiM on Denon Pre-Outs. Sounds fantastic!

[@richardwheeler7821]

Hey, I've got a set of Atma-Sphere M60's and the transparency and clarity are second to none. I'm currently driving (breaking in) my ELAC series 6 monitors but I love hearing these amps on my rebuilt Scientific Fidelity Tesla I's. Honestly, I haven't hear ANYTHING modern that has the sweetness and musicality of my Atma-Spheres. I look forward to your comments.

[@C--A]

It's much more easy to make a amplifier sound smooth with warmth to the music. It may sound good but is unnatural artificial. Much harder to make a amplifier that's transparent, linear, low distortion. One that doesn't add or take away anything from the recording. No tube amplifier including the Atma schere M60 can be truely transparent to the recording. You will need a good non tube class A, AB, D amplifier for true transparency. 🎶

[@MrWkendwarrior]

Nice job in layman's terms.....i like u using real world brand and model examples and your added insight was extremely helpful, especially as technology improves. Than you!

[@johndope6183]

He used a receiver outside its rated impedance load, then critiqued it. ICE amps were not designed for 4ohm load. Home audio is typically 8 ohm. Notice the Pioneer with ICEamps had no issues at 8ohm ... Tech manual even explains what its rated for. Edit: Referring to a nominal load of course.

[@johnspencer4106]

I run the Rotel RMB1555 , what reviewing have you done on my amp?

[@jtmcfarland3512]

Thanks for going beyond manufacturers’ specs. I’d like to see a much higher impedance linearity test though. Your graph is centered at zero ohms and tops out at 8. It would be much more helpful to see it start at zero with the top somewhere around 30 ohms. (A “4 ohm” driver isn’t actually 4 ohms; that’s its minimum)

[@qua7771]

Glad to see class D technology evolving. That combined with the efficiency of a toroidal transformer would make for an efficient system.

[@hi-fidude6670]

Class D will never overtake class A or even AB in audio quality anyway.

[@qua7771]

@@hi-fidude6670 Not as of yet. If they could it may mean that the more demanding speakers could effectively be driven with a receiver.

[@hi-fidude6670]

@@qua7771 Speakers aren't even that demanding, I've had some in the 87-89db range not even that much power required at least with 1970s gear where everything is better and beefier. The best things are never the most efficient. A Toyota Yaris uses less fuel than a Plymouth Roadrunner, becuase it's a small economy turd and totally uninteresting.

[@qua7771]

@@hi-fidude6670 You may be correct as a general rule. My C5 Corvette with a tune gets 32mpg on the highway.

[@masterchief8790]

Class D cannot. Its how the Sine Wave works. Class AB will always sound better. But Class D has become good enough for the average audio enthusiast.

[@bs11100010]

I love geeking out. Thanks

[@jeffsloane8628]

I'm running a class A/B Denon AVR -2307CI and using it in a 2 Chanel system. I'm doing this because the amplifier is good, but a few of the digital inputs have gone out. I'd like to upgrade to a tube preamp (Schiit Saga) with a Crown XLS, XTI or XLI class d amplifier because of their reputation and you get so much power for the money, but I am not willing to sacrifice on sound quality. What do you recommend? Speakers are ELAC UB-5 Slims.

[@13thChip]

Hi Gene, I am planning to purchase an AVR and considering the Denon AVRX4500H or Marantz SR6013. I am setting up my new house for Dolby ATMOS (5.2.4) and would be using my AVR for Movies/Music. I have not in person heard the quality of their sound output as I couldn't find any demo showrooms in the place I currently live. So I am banking on the internet reviews and make the purchase online. That's how I mostly do shopping and It works for me. If I have to decide between the two brands, which one would be better purchase for sound quality? My living room is about 12x10 sqft and I wouldn't drive them too loud. If not between these two brands, do you suggest something better in the same price band? What type and brand of speakers to go for (bang for the buck vs no budget constrains)? Please share your thoughts. Thank you for putting out such a wonderful and informative video on sound engineering.

[@mark1953]

Hi, would love to know what your thoughts are on a Yamaha M80 amp ?.

[@i23intheplace2b]

Perfect explanation for beginners. Cheap, class d amps allowed me to explore better audio I've always been curious about.

[@nandiboyle9987]

HI There Gene and All, can you help me please? I am wanting to upgrade my system to something extremely good quality and powerful. Currently I am running a Sugden A21 class A amplifier with Celef three-way speakers (I believe that company became the modern day Proac) I am keen to get a really very good, Maybe a good modern Class D Amp, hopefully not the most expensive one on the planet; but one definitely up to the job of bringing the best out of the Arendal 1723 monitors or even the towers. Also of course happy to hear any other recommendations of reasonably priced good quality speakers? Thanks in advance Kestrel.

[@pingardilie7398]

Thanks Gene for your Explanation , we hope in the future we have a new Technology The sound like Class A but with the efficiency Class D , Because I am still like Krell power Amp

[@CanDoo321]

Thank you.

[@austintyler7991]

Wow what world of info. Wonder if my yamaha rvx890 is any good? Got it new in 1998-9. Thanks for the update of knowledge brother.

[@mrtim6]

Thanks very much for the reply and your excellent videos!

[@yogeshsakhare8299]

Hi, if there is no transformer used, can we say it's class D amp like in my LG BH 6340H blu ray home theatre when I opened to see what's inside in it. I also got SONY str dn1080 with wharfedale speakers & I like the sound of both. Thx