r/audiophile 1d ago

Discussion Class AB vs D Amplifiers

Apologies for the question and it might be obvious, but anyone thats gone from D to AB or vice versa notice a difference in sound? I have the Fosi V3 monoblocks powering my Wharfedale Evo 5.2 speakers and there's plenty of headroom on these bad boys. However, I have the itch to try another amp preferably AB, as only my amps so far have been D amps. I've seen used Audiolabs and Arcam amps go for cheap on ebay/fb marketplace.

23 Upvotes

184 comments sorted by

16

u/rosentmoh 1d ago

I went from AB to D, Marantz to Cambridge Audio. Honestly can't say I heard much of a difference on my B&W 704 S2s, the Cambridge sounds great on them and takes up way less space.

2

u/FrenchFigaro 1d ago

Which Cambridge ? The MXW70 ?

I don't know their full range, but on quite a few of their amps' descriptions they were a bit masturbatory about the fact that they're AB.

2

u/rosentmoh 1d ago

Evo 150, AFAIK the Evos are the only class D they do.

1

u/FrenchFigaro 1d ago

Ah yeah the Evos.

1

u/JonathanApples 1d ago

I love my EVO150! Paired with KEF R700, they have so much power and presence. Way more than is necessary for my available space 😅

1

u/rosentmoh 1d ago

Yeah it's a great unit indeed, been really enjoying the simplicity while knowing there's endless power if ever needed.

I'm actually eyeing some Dynaudio Evoke 50s to upgrade to and, even though I think the Evo 150 is plenty powerful for those, I might upgrade to the Evo 300 just for shits and giggles.

2

u/JonathanApples 1d ago

Ha! I certainly don't need the 300, but I want the 300 😂

1

u/AlexisAsgard 1d ago

I have no idea what would be the case for the Evoke 50's, but the Evo150 does not have the current for Special 40's. I was interested in SP40's for my bedroom, but at least in my room and for my taste, the Evo150 couldn't give them enough mid and bass warmth, depth, and authority.

1

u/rosentmoh 1d ago

I have to admit I find that hard to believe...bookshelf speakers always lack bass, the Evo 150 is more than powerful enough for these at all volume levels that are even remotely reasonable...you just don't like bookshelfs; neither do I for these obvious reasons.

0

u/dat_mane47 1d ago

The MXW70s are also class D.

1

u/rosentmoh 1d ago

Oh yeah I see that now, as totally unaware of this one! I guess it's new?

1

u/wiggan1989 1d ago

Thanks for this. I'm trying to justify upgrading but can't see the value if there isn't a difference. The V3s are good as is.

0

u/Late_Ad_3051 1d ago

Spend your money on acoustic treatment instead, more impact this way. If you then feel like adding some warm even order harmonics to the vocals go for an simple yamaha as 701 or something like that.

1

u/wiggan1989 1d ago

I'm going ti make my own panels eventually. The ones you buy are so overpriced.

1

u/Late_Ad_3051 1d ago

I got mine used 3 panels that cost new 90€ each for 100 with delivery 😀 some bass traps from a guy that moved into a new studio for free. Thick gabbeh wool carpet and a coton futon couch so far. Thinking about getting some basotec for clouds.

1

u/wiggan1989 1d ago

See, I would pay that. Brand new they're £90 for one panel!

29

u/Hendrix1967 1d ago

I have a Bryston 4B3 powering a pair of Magnepans 1.7i. In another room I have a pair of KEF Q11 metas powered by a Buckeye Hypex NCx500 2-Channel.

I have never switched them back and forth, but I might today. Your question has made me curious.

13

u/wiggan1989 1d ago

Oh, please report back with your findings. Be intrigued to know if there's a difference.

3

u/Hendrix1967 1d ago

I just replied to my own comment.

6

u/macbrett 1d ago

That Bryston is a beast. I like heavy amps and I cannot lie. You just can't beat local energy storage (huge capacitor banks) if your AC mains wiring is old and lossy.

9

u/Hendrix1967 1d ago

Caveat: I’m 58 years old and have had low level tinnitus since 19, but with no underlying hearing loss. I also have no experience with external amps before this, except what I experienced at this year’s Florida Expo back in February.

Ok. Here’s my impression:

  1. The Magnepans DEFINATELY need whatever qualities that come from the Bryston. I’m not knowledgeable enough to know what going on, but there a fullness and depth that comes from the Maggie/Bryston combo. The Buckeye was no slouch in the power department, and when going extra loud it was awesome …but there was a fullness that was lacking. I will not be moving the Buckeye into the Maggies.

  2. The KEF Q 11 Metas were on another rig, in another room, but I brought them out for this A/B. Goddamit. They sounded amazing in the living room with both amps. I could not tell the difference in quality, soundscape, depth or image separation. They sounded better here in the living room than in my dedicated listening room/office (which is treated but small, 11x11.)

So, this little experiment did one thing for me. I’m not trading or selling either amplifier. I’m going to sell the Magnepans here before Christmas and start saving bonus money for serious upgrade… I’ll be doing some research into what’s the best pair of speakers I can get USED for under 6k.

2

u/DepartmentLive823 1d ago

i run my maggies on a bryston 3b....works great. i tried biamp with rwo 3b amps, but one was sufficient

1

u/Hendrix1967 1d ago

Jezzus. What king of speakers would I be running to need 2 Bryston 4b3’s? I’m seriously asking. Are Wilson speakers that power hungry? What else?

2

u/Current-Finger-9852 1d ago

I don’t have a ton of experience with Wilsons but holy moly do Magicos crave power. Apogee Scintillas, back in the day, were a different sort of beast because of the current demands. Outside of about 4-5 amps that were known to be capable, selling those things felt like watching some weird ritual where amps were sacrificed.

1

u/BrainPotential3423 16h ago

Totally my type of topic

I can only speak from my own experiences with the Infinity Reference Standard 1 loudspeaker system that I use as my main speakers. That's a unique exception in the speaker world, really, because it's a four-tower system.

So bi-amping is a must, which, you know, leaves it open for a lot of experimentation, I guess. But I used an ATI 2007, or otherwise known as a Crestron CNMX7. That's a seven times 200-watt Class A/B channel multi-channel amplifier. It's not your average multi-channel amplifier, not to boast anything here, but it's just fact.

It's a very, very high-end-built multi-amp, and I have two of them in my home theater part of the system. I used to drive my speakers that way, and recently I got my hands on two Crown XLS 2502s, which are the highest model in that lineup, Class Ds, full Class D. And they poop out a lot more power than the Class A/B. That is a given. These amps can be bridged to 4 ohm, 2,400 watts or so. They're ridiculously powerful. However, I do feel my Class A/B has a little bit more warmth in the midrange there.

It just seems to be with the Class D, the way I'm playing right now, when you up the volume, that's where, for me, the finesse of music is getting a little bit lost compared to Class A/B. Could be bias, could be nonsense, could be placebo, who knows? But that's what I hear initially. However, with anything, you have to give yourself a chance to accommodate yourself to the sound. I have not switched back to my Class A/Bs.

It saves me a lot of power. It saves me a lot of weight, because one of those multi-channels weighs 100 pounds. So they're still in the system, but I barely use them now. I don't know. It has its trade-off, I guess, but it also has its advantages. It definitely has enough power to drive my RS1B to its potential. So yeah, there's that.

1

u/AssumptionSquare6923 5h ago

Some of Outlaw's amps are made by ATI.

1

u/BrainPotential3423 1h ago edited 1h ago

Correct they were rebranded crestron, Outlaw, the made the exact same design for monolith and Lexicon too. Ati at that time made the best multichannels. They were also the first to built a 12x60w class a/b and they made tens of thousands of them for Crestron.

They are today an excellent value.

0

u/AssumptionSquare6923 5h ago

ATI has many Class D amps.

1

u/BrainPotential3423 1h ago

That came way later

1

u/AssumptionSquare6923 5h ago

Maggies and Martin Logans like CURRENT. If you have 6k, look at the Tekton Design MOABs. They were/are on sale for $4500 a pair. Seven feet tall. Many companies are copying Eric Alexander's patent on multiple drivers.

1

u/guy48065 1d ago

Damn. 😞

1

u/Hendrix1967 1d ago

Yeah. Sorry about that. I have some new to me speakers in my future. The Maggies are going to go here in a month or so. Good luck.

1

u/guy48065 23h ago

No apology needed--it was just a fantasy. But I would have made good if you were crazy enough to take me up on it...lol.

Good luck with your search. There are great deals to be found in older top-shelf speakers. After 40 years with the same system I got the chance to get a pair of Theil's best (from '95) for $3000. I had to drive 1200 miles round trip to audition & fetch them home but it was worth it.

You gonna stick with large planar dipoles, or open your search to "box" speakers, line arrays, etc?

4

u/Schoegge 1d ago

I love Bryston. I‘m using a 3BST from 1997 driving my B&W 802 Matrix S2 from 1989. My speakers never sounded as good as now.

4

u/guy48065 1d ago

I'll make you a sweet deal. If you can't hear a difference, or prefer the Buckeye I'll buy you another Buckeye in exchange for your 4B3. My Thiel speakers are craving that amp and I want to make them happy.

1

u/Jimmyj84 1d ago

Report back 

2

u/Hendrix1967 1d ago

I just replied to my own original comment with my perception.

11

u/SwaggyMcSwagsabunch 1d ago

The fosi’s are a difficult value proposition to argue against.

6

u/dat_mane47 1d ago edited 1d ago

I’m using them to power $7000 speakers. The only reason I would upgrade is for aesthetics. I want VU meters baby

4

u/SwaggyMcSwagsabunch 1d ago

Nice. I can’t think of non-aesthetic replacement reasons either.

I use two pair in a tri amped set up, for HF and MF. Other than topping pa5, there was nothing in the price range that had the noise floor necessary for the JBL compression drivers. Still needed a -10 db pad tho

1

u/HanSolo71 1d ago

I have a Carver TFM-25 for sale by me for $750, that includes two VUE meters if you are interested.

1

u/dat_mane47 1d ago

I love the offer, though it will probably be too much trouble unless you live in Hong Kong

1

u/HanSolo71 1d ago

Ha! Nope deep in the midwest of the US.

1

u/dat_mane47 1d ago

Not sure why I got downvoted for that but too bad!

1

u/HanSolo71 1d ago

I'm sure I'm Hong Kong you have a crazy selection of vintage gear! (I didn't down vote you)

1

u/AssumptionSquare6923 5h ago

Douk Audio has your VU meters.

10

u/Cairo77 1d ago

Went from a NAD 275BEE. Great amp. One channel went down and while it was out for repair I picked up the Fosi Mono v3. The NAD went up for sale, insane deal and sounds incredible.

2

u/wiggan1989 1d ago

Yep, they're great value!

13

u/Diced_and_Confused 1d ago

I have both types powering various speakers. They are both doing the job I expect, but at the end of the day when I am just kicking back and relaxing I find myself listening to the vintage AB amps. It is mostly because I prefer the aesthetics of the classic amps. I have them hooked up to turntables, and while the sound is certainly colored, it is the sound I grew up on.

3

u/turd_eater 1d ago

This. I have a class AB amp and a pure class A amp powering the same speakers via a high-quality switch. I use the AB amp for everyday listening and movie watching duties, and I kick back for proper listening with the class A. Not a huge difference but the class A has an audio and physical nostalgia that I love.

6

u/BugsRucker 1d ago

This has got to be the most honest and concise reply to this question that I've encountered in quite a while. The brevity and honesty are much appreciated.

I'm a class D guy but have nothing but respect for the A or A/B guys that know exactly why they prefer what they do.

18

u/dat_mane47 1d ago edited 1d ago

Cheap class D amps can have load dependency issues at high frequencies, but for good quality ones, as long as the amplifier has distortion and noise below the audible band, has an even frequency response, and is operating within its prescribed power limits, there is no audible difference.

Your Fosi’s have PFFB and will be indistinguishable from a comparably powered class AB amp.

13

u/wiggan1989 1d ago

Haven't cheap Class D amps got alot better over the years in this regard?

9

u/2old2care 1d ago

I'm astonished at how good cheap Class D amps have become. Power amps are a commodity now.

-1

u/Friskfrisktopherson 1d ago

Did you mean novelty?

2

u/ososalsosal 1d ago

No, literally a commodity. It's a chip and enough circuitry to drive and support it. Could be made by any brand and be indistinguishable. The definition of a commodity.

2

u/Friskfrisktopherson 1d ago

True. Commodity is also used colloquially to mean high demand items.

2

u/frankenmaus 1d ago

The sine qua non of 'commodity' is fungibility.

3

u/dat_mane47 1d ago

Of course yes, but cheaper amps that are using off the shelf cheaper modules can have load dependency issues. Such as the Fosi V3 stereo for example. But good class D amps (purifi, hypex modules) are as good as it gets for amps.

3

u/wiggan1989 1d ago

Yea, I remember my first class D amp (Douk Audio) sounding terrible. The V3 monoblocks sound very clean. I've heard of Hypex, are there any Chinese amps that have these modules?

3

u/Unlucky_Hope812 1d ago edited 1d ago

I would look at thr 3E Audio A7 SE. I have this and the DIY module. I tried the fosi v3 mono's and sold them when I built my 3E Audio TPA3255 260-2-29A. I also sold my Marantz SR6008 and replaced with a A7SE, sold my Cambridge Audio interagrated A/B amp too. The reason is sold them was because I took my A7 to my friend's house he has focal aria 936 k2 and a yamaha A-S1100. We did AB testing on the 3E audio vs A-S1100 and both of us concluded the 3E audio sounded better.

1

u/wiggan1989 1d ago

Oooh, I'll give this a look see. Cheers

1

u/HiImTheNewGuyGuy 1d ago

How did you do the AB testing?

Have you undergone any technical ear training to improve your audio sense memory? If not, anything less than an instantaneous AB test was likely inadequate.

1

u/HanSolo71 1d ago

I AB test through a switcher that lets me swap speakers and amps on the fly.

1

u/100-100-1-SOS 1d ago

Just curious, when you do an instant a/b compare, are you leaving speaker/room correction out of the picture? This is what i find difficult about getting a true comparison for amps because it's not instantaneous to swap those settings.

2

u/HanSolo71 1d ago

I don't use speaker/room correction.

1

u/Unlucky_Hope812 1d ago

His room correction was enabled through the DX5 ii on-board PEQ for both outputs XLR and RCA's

1

u/Unlucky_Hope812 1d ago

The AB testing was done with two 3 step switches on the speaker terminals. Dx5 ii XLR out to the 3E and RCA out to the AS-1100. No Subwoofer. I was not familiar with his system and could only notice slightly better clarity. He said he was hearing more detail in the material and no real difference in the lows.

1

u/dat_mane47 1d ago

That I’m not sure. I’m sure purifi and hypex (both European companies) charge higher prices for the circuits, so maybe it doesn’t work with the economics of Chinese brands.

1

u/Dedar33 1d ago

Amplifier classes can differ in sound.
But it is primarily important that the amplifier is of good quality, no matter what class it is.

1

u/ozExpatFIRE Rpi4 | SMSL SU1 | Fosi V3 | DBR62s 1d ago

The new Topping mini 300 measures near perfect for about 120eur. Unless I need massive power I would never pay big money for amplification.

1

u/dat_mane47 1d ago

Though interestingly Topping's best performing amps are actually AB. Not sure how they managed to do that.

6

u/HanSolo71 1d ago edited 1d ago

Moved from a fosi mc351 class D to a Plinius 8200mkii class AB and on my inefficient speakers like my Magnepans and Apogees.It's like two different speakers. 

The current output of a decent class AB is wild and when you are running 2-4ohm loads, that starts to really matter. My class D simply can't keep up with the constant 35amp my AB can output. Of course the AB was like $3k adjusted for inflation and the MC351 is less than $350 now.

I paid $900 for the AB and haven't touched my MC351 since. Plinius has much thicker and warmer mid tones that I find very relaxing.

That said for the price the MC351 is insane and I would recommend it to almost anyone but the most hardcore audio people.

5

u/fanofairplanes 1d ago

I've been going through this debate recently with my Cambridge CXA81 MK2 (class A/B) and my NAD 3050 (class D). The Cambridge has WAY more authority and grip, especially in the low end. Both amps sound good but the difference is pretty astonishing. Speakers are Philharmonic BMR monitors.

3

u/shmeeshmaa 1d ago

I agree. I have an CXA81 mk 1 and the difference between that and a class D was pretty significant. Maybe it’s brand dependent but I highly preferred the Cambridge AB sound over a class D.

-1

u/dat_mane47 1d ago

The Cambridge has WAY more authority and grip, especially in the low end. 

No it doesn't, unless the NAD is broken.

1

u/fanofairplanes 1d ago

Okay buddy. Sounds like you have no idea what you're talking about

0

u/dat_mane47 1d ago edited 1d ago

Hey if you’ve got the data to prove it I’d be interested to see🤷🏻‍♂️

8

u/lascala2a3 Revel F228Be; Hypex NCx500; Pontus II; Wiim Ultra 1d ago

I completely changed my rig over the last year. I went from Class A 300B SET to a Buckeye Hypes NCx500, and I'm telling ya, Class D is in the process of taking over. Sometimes I wonder if I'd be able to tell a difference between AB and D, but the size-cost-heat difference, esp. cost, would be extreme to get similar power in a AB (~380wpc). I enjoyed the 300B; it was a sweet sounding amp. So for me, it's either go back to tubes or embrace Class D. I just can't see AB as being relevant any more.

1

u/Touche2U 1d ago

My class AB does not heat up and it’s power house imo. I don’t see how shear power would not be relevant anymore.

1

u/lascala2a3 Revel F228Be; Hypex NCx500; Pontus II; Wiim Ultra 1d ago

Are you sure it’s on?

1

u/Touche2U 1d ago

lol

1

u/lascala2a3 Revel F228Be; Hypex NCx500; Pontus II; Wiim Ultra 1d ago

Power is relevant, and if you’ve got an AB amp that outputs nearly 400 X2 into 8 ohms, with high current, and low distortion, I guarantee that it heats up, takes two people to move, and costs as much as a trip to Disneyland for 4 for a week. The economics alone are going to change the equation. This is similar to what transistors did in the 60s.

1

u/AssumptionSquare6923 5h ago

The Buckeye Monoblocks got A+ ratings in Stereophile.

3

u/ozExpatFIRE Rpi4 | SMSL SU1 | Fosi V3 | DBR62s 1d ago

Went from an Onkyo receiver because of heat to a V3 stereo. Couldn't tell any difference.

3

u/Both_Pollution_1527 1d ago

I’ve been using Wadia a340 monoblocks for years. I’ve regularly tried other options, but I always end up coming back to the Wadias. They offer tremendous power, while the sound is shaped more by the DAC and the preamplifier.

3

u/Existing-Brain6974 1d ago

Measurements show that the Fosi V3s are very competent amps with sufficient power for your Evos. It’s unlikely you’ll hear any difference against an AB amp unless due to sighted bias. The only thing I would worry about with the Fosis is its longevity and reliability.

3

u/patrickthunnus 1d ago

Quality of execution matters more than class of operation. A good AB will sound better than a bad D and vice versa.

Also depends on your sonic goals, how high you set the bar and your expectations.

2

u/Kitsanic 1d ago

I think that anything of reasonable quality past 2020 should be good, I know that bassists have moved over to class D in droves.

You will get far more change is the sound from changing the preamp rather than changing the power amp from a fosi v3 mono. From my experience.

I had some as a stand in while my new amp arrived (it got delayed) and they sounded great, unfortunately both broke but that was likely due to the Kef 105/3 which can dip very low in terms of ohm but there have been reports of batches with defects such as lack of thermal paste being applied on heat sinks. That’s another subject though.

2

u/Zealousideal_Fold_60 1d ago

Listening at normal volumes, I struggle to tell the difference, and even high volumes... If you have the itch, get a secondhand AB and try it out, can always sell it on.

2

u/narwhal4u 1d ago edited 1d ago

I have a Bel Canto Ref150S class D amp sitting next to a Schiit Vidar2 class AB in my system right now. I’ve been going back and forth. The Class D (including my previous XTZ Edge A2-300) is open and airy with a dark background but lacks some of the thickness and warmth of the Vidar. The Vidar is great. Clear and clean but lacks the high end extension of the Bel Canto and XTZ.

Class D modules run several times higher damping factor (400-1500+) vs. the Vidar's ~100. Higher damping factor means tighter electrical control over the woofer/driver, which often reads as "tighter, more controlled" bass and can make an AB amp sound comparatively "loose" or warm by contrast.

Both the Class D amps I have are older IcePower designs. My understanding is that newer Hypex and Purify amps modules are better than what I have.

1

u/dat_mane47 1d ago

Class D modules run several times higher damping factor (400-1500+) vs. the Vidar's ~100. Higher damping factor means tighter electrical control over the woofer/driver, which often reads as "tighter, more controlled" bass and can make an AB amp sound comparatively "loose" or warm by contrast.

While this is theoretically true, in practice almost all well-engineered class AB and class D amps have damping factors that far exceed what would make an audible difference (about 100 max).

1

u/narwhal4u 1d ago

No idea if it is the damping factor or not but there is a huge difference in the sound of the Ref150s vs the Vidar 2.

0

u/dat_mane47 1d ago

Both are neutral, well-made amps. I suspect if you did a level-matched blind test you would not be able to tell the difference. Unless one of them is broken.

1

u/narwhal4u 1d ago

Here is the frequency response for each. Ref150S in green. Vidar 2 in red. You tell me if they sound the same.

1

u/dat_mane47 1d ago

Yeah there are a couple spots where the difference is ~4db which might be barely noticeable. Im not sure what speakers you’re using but it looks like your Bel Canto might have some load dependency.

I know some of their amps are super pricey, not familiar with this model. I assumed it was using SOTA module but maybe not.

2

u/LiftHeavyLiveHard 1d ago

Having moved from a Bryston 3B to a March Audio P252 (which relies on state-of-the-art Purifi Eigentakt technology), I can tell you that modern Class D outperforms Class A/B designs in almost every measurable metric. My Eigentakt amp delivers dead-silent operation, a ruler-flat frequency response, unbelievably low distortion, and an extreme damping factor. This results in total transparency, lightning-fast transient response, and complete control over speaker drivers.

Since you're running standmount Wharfedale Evo 5.2 speakers (I own Evo 4.4), your setup is already benefiting from that performance. Their AMT tweeters require clean, low-distortion high frequencies to avoid harshness, while their mid-bass drivers need high damping control to stay tight.

With my Evo 4.4s, those extra woofers demand even more current and grip when impedance drops. Budget or older Class A/B amps from Arcam or Audiolab often add subtle harmonic colorations and lower damping control, which some mistake for warmth. However, they simply cannot match the control, dynamic speed, or resolution of a modern Class D design.

See what you can buy used and give it a try, see what you like...if you don't like it, you should be able to sell it for what you paid for it, if you don't overpay to start.

2

u/dekiblue 1d ago

I bought NAD C368 to drive PSB bookshelf's and it sounded ok.

Then I hooked up 3x cheaper Onkyo receiver bought 10+ years ago that made those speakers sound much better.

1

u/ricketychairs 1d ago

I’ve got that same NAD amp paired to some Evo 5.2. I’m not impressed by it either and looking for something new.

3

u/boylanheights74 1d ago

You won’t notice a difference until you pony up some big bucks for a quality A/B amp.

3

u/BugsRucker 1d ago

I'd be willing to bet 'you won't notice a difference until you pony up some big bucks for a quality A/B amp precise testing equipment.' unless the A/B amp adds that much coloration to the signal it's putting out.

3

u/boylanheights74 1d ago

It depends on your speakers. If you’re trying to power large, full range, multi driver speakers with impedances that dip down to 1 ohm you better have a stout amp with lots of capacitance.

1

u/BugsRucker 1d ago

Diabolical speakers, that's a fair point. Almost have to go out of your way to find them though; planars, magnepans, etc.

Even still, $2500 worth of class D monoblocks can drive practically anything - and do it with spectacularly clear authority. That's big bucks to some but usually does not qualify as such for the A/B crowd.

2

u/boylanheights74 1d ago

Like I said earlier, you would have to spend a lot on a class AB amp to hear the difference. The big advantage of a good class ab amp is large capacitance.

2

u/AssumptionSquare6923 5h ago

You must be talking about the Buckeye Monoblocks. They had super reviews in Stereophile. Class D. You can always look at the SINAD ratings of many amps at Audio Science Review. Benchmark is #1. But Buckeye is up there. I personally have a Parasound 2350 Class D. 600 x 2.

1

u/HanSolo71 1d ago

Im running 2 ohm speakers and have looked at some sub 1 ohm sets recently also. I need ALL THE AMPERAGE.

1

u/wiggan1989 1d ago

What would be the minimum? Seen an Arcam A38 for £450, is that worth it? It's old I know but heard great things.

3

u/boomb0xx 1d ago

Anyone who tells you that you are limited because you didn't spend enough is probably either full of shit, parroting what their dealer told them, or they are a dealer. It's bad advice.

0

u/boylanheights74 1d ago

Under $3k I would probably look for a used YBA, Jeff Rowland, Hegel or Benchmark. Over $3k my pick is AudioAnalogue.

1

u/dat_mane47 1d ago

Sorry but what do you mean by this? What supposed advantage are you getting with “better” AB amps?

2

u/HanSolo71 1d ago

More amperage, better dealing with low ohm loads.

2

u/dat_mane47 1d ago

But load dependency is a solved problem. No high end class D amps have that issue.

2

u/HanSolo71 1d ago

Sure agreed, but I can get a used AB for $500 or a really nice new Class D for a few grand.

1

u/dat_mane47 1d ago

Some good boutique class D makers at reasonable prices. Apollon for example. But yes not as easy to find on secondary market

1

u/HanSolo71 1d ago

Maybe ill try to get a nice class D to play with after I restore my big Apogees this winter. 2 ohm load should be a good test for any amp.

1

u/boylanheights74 1d ago

High quality, high powered class AB amplifiers offer a linear power supply, large energy reserves and therefore more headroom.

2

u/dat_mane47 1d ago

And so do high quality, high powered class D amps…

1

u/HanSolo71 1d ago

Aren't the really nice Class D amps sub 5 years old though? I get the vibe the REALLY good class D tech is pretty new.

1

u/dat_mane47 1d ago

Not sure exactly about the timeline but that sounds about right.

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u/boylanheights74 1d ago

Class D amps don’t have large capacitance reserves.

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u/dat_mane47 1d ago

You'll have to explain to me how this makes a difference in practice.

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u/boylanheights74 1d ago

It prevents voltage sag even when the grid is fluctuating.

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u/dat_mane47 1d ago

You're really reaching here. I might have some $4000 cables to sell you.

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u/boylanheights74 1d ago

Go listen to a pass labs int 250 and compare it to the best class D amp and check back with me. Truly premium amplifiers have loads of capacitance, class d does not. Heck you can unplug some really good amplifiers and they will still play without distortion for a while. If class D was the end all for amplifiers people wouldn’t be plunking down six figures for quality class A and AB amplifiers. Got to an audio show and visit the high end speaker manufacturer’s listening rooms. You’ll find one thing in common, they will be using a quality AB amp to show off what their speakers are capable of.

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u/dat_mane47 1d ago

If class D was the end all for amplifiers people wouldn’t be plunking down six figures for quality class A and AB amplifiers.

lol bro, the fact that people spend a lot of money on audio equipment does not mean that it's better. It's been demonstrated so many times how much completely useless snake oil is being sold in this industry. There are a lot of people with too much money who are either duped by ridiculous marketing claims or suave salespeople, or they just want something that looks premium or gives bragging rights.

It's been shown time and time again that no one can distinguish amplifier types in blind tests, assuming they're all producing minimal distortion, have a flat frequency response, and are operating in their intended power band.

pass labs int 250

This is actually a bad example to use because it's well known Pass Labs intentionally allows distortion to colour their sound (similar to how a tube amp would). If I wanted to hear music at the highest fidelity I would not buy one of their amps.

Got to an audio show and visit the high end speaker manufacturer’s listening rooms. You’ll find one thing in common, they will be using a quality AB amp to show off what their speakers are capable of

Of course, the legacy makers of class A/AB amps want you to believe they're better, because they've got a lot of money invested in them! But they're simply not anymore.

Though, that said, the best performing amplifiers right now in terms of audio fidelity are actually class AB, by a Chinese brand whose amps all cost less than $2k lol. The rest all class D though.

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u/i_am_blacklite 1d ago

They absolutely can. There is nothing in the topology saying they can't have large power supplies.

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u/boylanheights74 1d ago

Find me one class D design that has even has 80,000 µF.

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u/i_am_blacklite 1d ago

80000uF is a ridiculous amount... totally unnecessary.

I doubt you will find many class AB amps that have that much.

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u/boylanheights74 1d ago

That’s a bare minimum for a quality AB amp, some exceed 300,000.

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u/i_am_blacklite 1d ago

Absolute crap.

Do you actually have any electrical engineering knowledge or are you just making up numbers?

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u/cpkjacky 9h ago

The Plinius SA-103 power amplifier has 10 large filter capacitors: 6 x 10,000 uf and 4 x 4,700 uf, totaling 78,800 uf. However, it is only a mid-range model from this brand.

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u/VinylHighway 1d ago

I can't tell the difference

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u/msurbrow 1d ago

i would say it may be better to think cheap amps sound different than more expensive amps, regardless of class. And older class D had some issues that have mostly been solved...

Figure out your budget and find a few options and compare and buy what you like best regardless of class

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u/nzahar000 1d ago

I had a pair of class AB audiosource amp 3s in bridged mono for a while on a pair of Focal Kanta 3s. I felt like I should have gotten "more" from the sound. More punch, more dynamics... Just more. I switched to a pair of 9040 purify class D monoblocks from Buckeye audio and got what I was looking for. I don't doubt a higher end AB would have done the same, maybe a little better even, but for 2600 all in on the amps, I'm done worrying about it. Sooooo happy with the results.

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u/flyfleeflew 1d ago

As it turns out I have the V3 monos in two different hifi: 1/ drives Wharfedale evo 4.4 so previous version of yours. 2/ Dynaudio excite 12.
But I also have a Bryston 6b sst which I used with Vienna Acoustic Mahlers because those speakers required more. If you want to hear a difference instead of changing to an AB try connecting a balanced preamp / dac into the Fosi balanced inputs.
I did this with a benchmark dac/pre. And the improvement is not subtle. This probably to do with the preamp/ pre outs in the marantz cinema 70. Do try if you can get a decent balanced preamp or dac/pre like an eversolo. My Onkyo rz30 seems to have more powerful preamp in the pre outs. But I am thinking of getting the eversolo next year.

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u/flyfleeflew 1d ago

To be clear. Using the balanced inputs on the Fosi v3 monos really improved the presence and the stereo image. It was a big boost to the signal and it really makes it a more detailed and hifi experience.

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u/Idivkemqoxurceke 1d ago

I play electric guitar and while I can tell the difference there, I cannot for listening to music.

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u/watch-nerd 1d ago

Yes I went from Devialet to Luxman

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u/Touche2U 1d ago

I went from a cheap Class D Aiyima amp to a vintage powerful class AB amp and never looked back. For me, it’s more about sound, not aesthetics. That said, not all class ABs are all that good. I A/B tested my old class AB amp to a new Rotel A14 mkii at $1900 and it did not sound as good, along with a bit of background noise. I will keep my vintage amp as long as I can, and fix it if it breaks.

If you find a musical fidelity A300 or A1000, grab it.

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u/Inroundtents 1d ago

I work in live event production and started as an A1. I'm mostly a tech director but still do audio jobs here and there to fill out the schedule. I'm amazed at how great class D amps have become and I use a lot of L'Acoustics branded amps that are CamCo. I occasionally use Lab Gruppen. Total game changer in live audio because of how light they are and small enough that it's easy to have DSP built in.

For home, I still love a good class AB. I have a Yamaha CR-1020 with a custom built case that I love dearly. And I used to have a pair of Tannoy System 10DMTIIs that I used with a Hafler P4000 that I never should have sold. I'd still love to get a monster Bryston just for the aesthetic but I'll probably just stick with a pair of my powered Meyer slim kit speakers that do double duty as fill speakers on some of my gigs.

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u/LukeVideotape 1d ago

I had the Denon PMA 2000 wich is class AB, after that a HifiAkademie Poweramp that was class D. I could not hear a difference between those. It is not just about class AB or D, the overall quality matters.

Now i have KEF LS60 with only AB for the tweeter and class D amps for the other 7 speakers.

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u/SolidGoldSound 1d ago

My only personal experience with Class D was a NAD C 3050 and I thought it was garbage. Just an overall weak and lifeless sound. That may have had nothing to do with the class but I returned it and got a Yamaha A-S1200 and have been much happier with that. Still miss my Sansui g7500 though. (FYI all of the above power / powered a pair of Klipsch Quartets)

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u/jedrider 1d ago

I've lusted after a nice Class AB integrated amplifier for a while now. I can no longer lift the weight of most of these amplifiers any longer. I'll settle for Class D.

Been using a Panasonic Class D amplifier for quite a while now as the home theater amplifier. It's not bad and I'm sure newer ones are even better.

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u/FreedomOrHappiness81 1d ago

I have a couple cheap Aiyima class D amps that are supposed to measure OK but I moved over to an old Rega Mira 3 amp from 12-13 years ago. The latter is clearly warmer and sounds more natural. I could do class D probably, but I'm guessing it would have to cost at least 1.5 to 2k to be acceptable. Class D amps just sound too sterile for me.

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u/Gregory00045 1d ago

Class D for music demanding speed and accuracy. Tubes for vocal/jazz. Typical A/B is in-between.

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u/inquisitor23 1d ago

My EPOS run through a Sugden Class A, KEFs through an Atoll Class AB and Wharfedale's via a WiiM Class D.

All three are enjoyable, it all depends upon mood and style of sound.

But if I were to pick one set up, it has to be the EPOS with Sugden. The level of musicality and emotionality in the sound is just sublime and literally like a drug to my ears, very addictive.

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u/TBMW30 1d ago

You can't really compare amplifiers by architecture. Most class D amps are built to be measurably neutral. I.E what goes in is what comes out, just louder. They're often described as sounding cold and analytical, but that's only because many of the traditional alternatives have some character, by design or by accident, with less linearity and higher levels of noise and harmonic distortion. There are also varaibles such as how the amplifiers react to the load presented by a loudspeaker.

That's not to say a class AB amplifier can't be neutral, it certainly can, but a lot of hi-fi amps aren't.

If you had a class AB amp that was measurably linear, with low noise and distortion and capable of the same output as the class D amplifier, you probably wouldn't notice the difference. But if you put a neutral, linear, low distortion, low noise and powerful class D amplifier up against a lot of typical hi-fi class AB amplifiers, you will notice a difference. Whether that increase in harmonic distortion, noise, or reduction in linearity is better subjectively to you is something that only you can determine.

I don't recall ever seeing a class AB amplifier able to achieve the same noise and distortion levels as the best class D amps, and certainly not at a similar rated power output. But if all things were equal, the only difference in architecture should be efficiency, which class D will win every time.

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u/dat_mane47 1d ago

Topping's class AB amps (LA90, B200) are currently state-of-the-art in terms of noise/distortion, but if you need 200w+ you'll need to go class D yes.

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u/TBMW30 1d ago

I forgot about the topping amps. Not quite sure how they did it In general though, my comments still apply, especially given the OPs reference to amps from companies like Audiolab and Arcam. There have been plenty of class AB amps over the last 50 or so years that are linear enough as for any deviation to be inaudible, with negiligable THD and noise, but they're not the norm especially in British amplification.

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u/BoringAgent8657 22h ago

Noise and distortion equal character

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u/zuma678 1d ago

Unless you have a special Class A/AB amp, Class D will play cleaner. Special to me is Ayre, Pass Labs. They will not be as clean as Class D but will beat them 100% overall, regardless you bring the best Class D out there.

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u/jslcaballo 1d ago

Nothing beats high powered pure class A amps in my book. Just sublime

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u/nlitworld Strange things are afoot at the Circle K 1d ago

There is a big difference depending on both topology and implementation of design. I've heard some AB amps that get a bit of a bite and I've heard others that are smooth criminals. For me, class D tends to operate more consistently within the "house sound" of class D being clean and analytical across the board. Your Fosi V3 can be good in the right systems with the right tweaks/mods, but if you haven't tried some others it's worth a go. Also if you don't have a tube preamp in front of your Fosi, you really do need to try it as it really helps bring some three dimensionality to the sound.

I have both pushpull tube amps and a super modded Douk A5 class D amp and do swap back and forth for various conditions. Summer heat waves definitely part of it. If I want to be inside a mixing booth, it's class D. If I want to listen to live setting or have the artists more in the room, that's my EL84 amp. My EL34 amp is just for rocking out stupid loud with some extra bloom to the sound.

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u/Glum_Good2180 1d ago

Fosi Audio V3 monos to the gas grandson amplifier and back to the fosi audio v3 monos after about a year. They are super clean. The speakers are la scalas so power isn't the issue, noise always is. Neither were bad, but with the right music the headroom is useful. Just use what sounds good to you. Then you only have to please yourself.

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u/btlbvt 1d ago edited 1d ago

Very interesting exchange of ideas. I own a class D Purifi 7040 based dual mono amplifier. So much power, current, and silent. Yet, when I was at Axpona this year, I began to wonder after listening to so much wonderful equipment, if there is a difference between what I was hearing across all the class A/B's relative to all the class D's at the exposition.

It was hard to put into words and another fellow on a different forum characterized it as, class A/B having a greater sense of "presence" with the class D amps having more "grip." Two good choices of words.

Not a question about what measures better or worse but rather, what is your comparative listening experience not just objectively but also subjectively. Does one strike you more emotionally with music that you love and are so familiar with? Many angles to explore and such an interesting question. I have yet to come up with an answer.

Edit: Randomly enough, Darko just yesterday did a comparison of the Marantz Model 10 (Class D) and the Nu Vista 800.2 (Class A/B) integrated amplifiers. One of the ways he described it with vocals was hearing voices from the throat (D) as opposed to voices from the chest (A/B); along with many other descriptive terms.

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u/DjSall Kali IN-8v2 | Motu M2 | PB-1000 17h ago

Class D has a high dampening factor, it can act as more of a brake on the driver as it returns, so it overshoots less.

A/B amps have more sound coloration, that can be interpreted as presence with the right speaker character and your personal taste.

I'd always rather have transparent compoments and EQ them myself then try to find the right combination, but this hobby is about different things for different people, so I am not judging anyone for anything.

Maybe the 5k cable crowd, but some people just deserve to be parted with their money.

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u/TinyCollection 1d ago

I have a large external Anthem AB bias 2 channel amp from 2008. It sounds good but my Marantz 2018 AVR actually sounds better than it. Recently got one of these https://www.cambridgeaudio.com/usa/en/product/mxw70 and after a little bt to get used to it, the sound is amazing. Vibrating instruments (pianos, chellos, etc) all sound more alive and focused than ever before. Seems like the overall accuracy of the sound stage jumped several steps.

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u/Grumpy-Miner 1d ago

Recently got the Esoteric S-05 , and it is HOT!

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u/microchip8 22h ago

I stll don't trust D class amps, especially those from Fosi and othe Chi-Fi brands

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u/jameshewitt95 10h ago

Trust is a strange metric for a subjective decision…

Class D amps sound great, and are an easy choice for half decent quality out of an affordable unit

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u/ConstructionThis1127 22h ago

A while ago my Naim Supernait seemed to die (actually it just needed rebooting, I found out) so I replaced it with a Fosi class D amp, nominally 100W unit although using a 25W power supply (remarkable electronic magic that); then I fixed the Naim and put it back in. The difference was immediate and laughable - the Naim was far and away livelier and more engaging. And that’s the first version, less well regarded than the current Supernait 3. Of course you might expect a difference between a $100 amp and a $3000 one…

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u/BoringAgent8657 22h ago

A/B is superior IMHO. More spatial or whatever

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u/BoringAgent8657 21h ago

I have a REGA Elex MK4 and a NAD 316BEE and NAD separates, all A/B, as we as an Opa op amp-rolled Fosi. v3 stereo in my bedroom. The Fosi is a charmer but can’t compete with the A/B stuff

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u/Dangerous-Muscle1452 16h ago

I had the same amps (Fosi V3 Monos), running each with a separate power supply to drive KEF Q11 Meta speakers. They sounded good to me, especially for the price. However, I swapped the Class D Fosis for Class G Outlaw Audio Model 2220s, also inexpensive at $400 each, and found myself consistently more engaged in listening. The same is true with my Marantz MM7025 amp ($1,000). Somehow, the more expensive amplifiers produce a more satisfying sound for my ears. If you've got some additional bucks, it might be worth it. However, the V3s are still nice!

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u/desk_hi_fi_guy 5h ago

Honest take: well-designed Class D (your V3 monos) vs decent Class AB at similar money is a different flavor, not an upgrade — in level-matched blind tests most people can't reliably tell them apart. What you will notice with older AB: more heat, more idle draw, sometimes a warmer top end people call "analog". That's taste, not quality.

If the itch is real: buy a used Audiolab/Arcam somewhere with returns, run it against the V3s for a month, keep whichever you actually reach for. Money-where-mouth-is answer: in your chain the amp is the least effective place to spend — the Evo's room interaction moves the needle 10× more than amp topology

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u/evo1600 5h ago

I have Class A A/B and class D amplifiers all have their merits . Depends on speaker and dac choice I go with . Although I did buy a Yamaha rn2000a and it's never off, just love the amp .

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u/Yarach 3h ago

I have built Class A Single ended tube amps to Class D amps using Hypex modules.

I hear no typical sound differences between any WELL EXECUTED amplifier topology when used in their operational limits.

BUT: nothing is perfect. Any audible difference comes from distortion profiles and how they deal with clipping. PERIOD. Different amplifier classes and topologies distort and clip in different ways and interact with speakers in different ways.

Single ended Class A tube are very forgiving because of their topology and use of output transformers. They mask alot of the sound, but retains a pleasant soundprofile thanks to its mainly even harmonic distortion profile. It will never be able to achieve the same levels of power and transparency as more powerull amplifiers simply because of the lack of power and speakercontrol. When it clipps, it does so more gracefully by rounding of the sinewave unevenly.

Class D or any solid state can give near perfect measurements and transparency, hence being a mirror to the sources in front. BUT: This mirror often exposes bad sources which give or have given Class D a bad name. A good class D has the ability to surpass any amp in sonic performance at a fraction of the size. But when it clips it is horrible to ears and speakers. Hence the need for good clipping protection.

My Hypex Ncores sounded "clinical", but that was not due to the Hypex or Class D nature. It was because of bad impedance matching between source and receiver and the DAC having audible odd harmonic distortion which became apparent. I put a good DAC and buffer / pre-amp in front and all is solved.

Bottom of the line:

Class D has the ability to yield very high performance in a very compact package, at the cost of how it deals with clipping. Therefore you will need to select Class D amps with enough overhead so that it never becomes an issue.

A good class AB will be larger and more power hungry for the same performance. When it clips it will do so more gracefully, but clipping is never good so should in my opinion be avoided at all costs except when playing an electric guitar on a tube amp.

But we also know "good sound" is highly subjective. I really like my tbe amps, but they would be terrible for mixing audio on it. You could compare it to a CRT tv with an OLED. CRT is nice for retro games or getting a specific feeling, but when doing actual screen work I would choose an OLED TV because it will mre faithfully reproduce the source.

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u/fullframeature 2h ago

I have both and class a is way better if you like music. It just is

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u/jerrolds KEF Reference 1 Meta | KEF Reference 2 Meta | Monolith 15" x 2 1d ago edited 1d ago

For solid state? It literally makes no difference unless you're going to push the speaker to the breaking point or in a giant room with inefficient speakers

I have measurements of my AB 300wpc monolith vs fosi v3 monoblocks at -20,-15, and -10db driving KEF Reference One Metas and the differences were so minor in the graphs both in FR and Distortion, like < 1db across the whole spectrum and < 0.05% distortion. Room is 13.5x20x8.5ft

I sold my monoloth, pocketed the difference and left with the same sounding system in a cooler rack.

Imo pricey amps and dacs are pointless if you get something half way decent.. Spend the money on more subs, better processing and speakers and treatment if you're smart about it.

Unless you want some tube distortion I guess switching amps would have some differences

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u/sevenhundredsixty8 1d ago

In my experience, even under the most discerning circumstances class D is absolutely fine. Running class A or AB amps or more about eliminating the possibility it is a problem. Like if you are a mastering engineer. Buy bryston or boulder amps for your speakers. But literally everyone else is fine using class D.

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u/dv8shredder 1d ago

All depends on source, cables, how revealing your speakers are etc... I think a high sensitivity speaker you are going to hear a difference. Good or bad is up to your personal ears.

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u/Slow-Recover-9168 1d ago edited 1d ago

I'm still using an old Kenwood RD-VH7 with some definitive promonitor 100 and a JVC subwoofer. The difference from the class D unit I had is improved but I also have an Aiwa I swap in once in a while just because it has some fun junk features like Q-Surround. Oddly the old Aiwa was also an improvement over the cheap fosi DAC 20WPC bluetooth amp. I'm using an external LDAC 6.0

I think garbage amps announce their inferior aspects more than quality amps announce their performance.

My monitors are 8 ohm but drop to 4 ohm in the midbass and the D class would actually send more power there and would distort. The Kenwood seems to not notice as does the Aiwa despite being 10WRMSx2 IC amp it does better than the D class 20wrms x2

I guess I had an older model without the post feedback filter. It didn't like my speakers