Is Class ‘D’ amplification a serious contender?

Discussion in 'Audio Hardware' started by Khorn, May 22, 2020.

  1. Khorn

    Khorn Forum Resident Thread Starter

    I’ve been looking at replacing my stereo amplifier for a while now. I’ve pretty well decided what I want but the emergence of new class D has me very intrigued.

    From what I’ve read class D provides the bottom end oomph and midrange clarity I desire but there seems to be a bit of question about the high frequency SQ.

    A few new class D amplifiers have come out recently and wonder if anyone has had some in depth experience listening to any. I realize many are new and haven’t been around for long.

    I’m looking in the max 10k Canadian retail range but would prefer a bit lower. Power range approximately 300w-500w. Speakers: Klipschorns.

    Is class D a serious contender at this point in time?
  2. caracallac

    caracallac Forum Resident

    I’ve heard several class D amps over the last few years including some pretty high end contenders and in my personal opinion, I’ve yet to hear one that I could live with long term. There always seems to be a touch of coldness to the sound that reminds my of the reaction I had to early digital, yes it’s really good, but that special something that keeps you listening is missing.
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  3. thomaskong

    thomaskong Forum Resident

    Washington State
    Yes I had been impressed with Crown XLS 2502 with speed and fast transient.

    But it will be better to have tube pre amp in front of it to add some warmth.
  4. Khorn

    Khorn Forum Resident Thread Starter

    I’ve had great luck in the past with tube pre and SS amplifiers. Trouble is I have an SS preamp I really like.
  5. spartree

    spartree Forum Resident

    300-500W for a 105 dB speaker? Is that necessary?

    Give Peter from AudioSector a shout. He’s in Ontario and makes some nice chip amps, and he is willing to work with you on custom requests. Audiosector

    Edit: I should also mention that he is working on a couple of things for me right now and has been super flexible.
  6. head_unit

    head_unit Forum Resident

    Los Angeles CA USA
    YES says the guy who used to crank 120+ dB in my dorm room (with earmuffs on of course) :D:yikes:
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  7. macster

    macster Forum Resident

    San Diego, Ca. USA
    No one anywhere can provide you an answer for your situation. You are simply going to have to listen for yourself and only then will you "know" whether it's a contender or not. You may be able to come in much cheaper than $10K. For me, it worked, but I have Vandersteen speakers and you really have to work to make them suck. I love my class D integrated amp setup. I turn it on and listen that's that. I can also bench press the setup at least a 100 times, as for my old setup not even twice on a good day. As for high frequency, low frequency midrange, imaging and soundstage, heck we all hang out and enjoy each other's company some more than others.

    Good luck and try to get a demo, don't be like me, I just went for it.

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  8. thomaskong

    thomaskong Forum Resident

    Washington State
    If you have nice SS pre amp, then you shall go for tube power amp rather than D class power amp considering high efficiency of your speaker.
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  9. Khorn

    Khorn Forum Resident Thread Starter

    Thanks, I’ve done the tube amp thing in the past and it just didn’t work for me.
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  10. Kostas

    Kostas Forum Resident

    I use the Crown XLS 1502 or XTZ EDGE A2-300 with a VTL 2.5 pre. The VTL elevated both but they sound good without the preamp, just with the mediocre onboard sound card. I'm sure with a nice DAC they'll sound great, if I had just one digital source I wouldn't use a pre. Both have gain control to match different sources/preamps. I don't miss the Rotel, various M. Fidelity & Yamaha amps I had the past 20 years. If I had the money, I'd buy the top Nord model and call it a day. Or anything well designed with Hypex modules.

    One of the reasons for having a BIG pair of speakers. The extra power is a must for me, especially for a big speaker like the Klipschorn no matter the high sensitivity. No single ended amp can control the big drivers when you crank it up.
    unclefred likes this.
  11. The FRiNgE

    The FRiNgE Forum Resident

    That first watt will produce some impressive room spl's to the order of 100dB plus. (C weight at seated listening position both speakers driven) I wouldn't subject myself to that more than 30 minutes per 24 hrs, if at all. A 10 watt amp would give you +6 dB headroom , a 100 watt amp +12 dB (conservative as any good amp delivers at least another +2dB dynamic headroom above its RMS rating) Additionally a high power amp has more gain, which could add some hiss and noise to the signal... the noise remains constant even at lower volume settings on the pre-amp. High power and high efficiency are not the best match, and can sound harsh and grainy.

    A 50 watt amp would drive you out of the room, rattle some windows and walls... we are not filling an arena with people and flying tons of JBL's and huge bass bins here? (or are we?) :goodie:
    Last edited: May 22, 2020
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  12. head_unit

    head_unit Forum Resident

    Los Angeles CA USA
    Sure. Now, on this forum you can read all kinds of varied opinions about different Class AB (and A) amps. Whereas a thread like this will inevitably attract comments blanket-ly condemning all Class D as though they are all the same, which is silly.

    Decades in not all Class D amps are the same. Just like any other class there are wide variations in circuit design topology and implementation skill and parts quality. If someone like @caracallac hasn't heard any to like, that could also be true. It depends which Class D in which system AND let us not forget everyone's hearing is DIFFERENT. Plus unless someone is listening in their own system at home, there are so many other variables you simply cannot draw a scientific conclusion.

    To me, I have heard many amps that sound fine. Are some "better" than others? Well, I don't *think* they are all the same (haven't done enough direct comparison testing to make a scientific pronouncement)...but again, many sound quite fine, at which point who cares really. Someday we are going to compare a little battery powered Parts Express piece to my buddy's expensive Denon AVR. The little amp sounds quite nice running off an iPhone streaming KUSC into some nice Monoprice bookshelf speakers, and could actually pump out some Jay-Z as well. A comparison should be interesting!

    - Class D amps operate vaguely like an AM radio station-there's a carrier wave and the audio rides on top of that. Hmmm. Maybe that's not the best analogy. Anyway all Class D (AFAIK) have some kind of physical output filter to block the "carrier wave." This can cause variations in amplitude/time response at high frequencies. However, a coworker of mine cleverly extended the feedback loop out past this filter which rather mooted the issue.

    - Some designs (Tripath) vary the carrier frequency to avoid any consistent negative effect (I'm not phrasing that well).

    - Class D inevitably has some amount of ultrasonic noise. However the level is low at less than 0.1 watts so not enough to boil a tweeter and at a high enough frequency that in combination with the low level intermodulation distortions should not be a concern.

    - Class D purportedly has significant advantages of size and heat. That's another design "maybe." The first car unit from Infinity had a lot of failures and problems. Why? To capitalize on those advantages in a marketing and gee-whiz sense they shoved the amp into a very small size, which did not have enough heat sinking (there IS still heat generated! Just not as much). Also, the DC-DC converter needed in automotive applications limited the total efficiency and is its own significant source of heat. In home applications you can indeed get a smaller amp with less heat, and more power out before your circuit breaker pops, compared to AB.

    - There are also Class G/H/T which are basically running class AB but somehow tracking the output voltage rails to the signal for less waste heat. QSC has made some fantastic stuff via this method, and the BASH amps used in some home subwoofers.

    What are the Different Types of Audio Amplifier Classes?
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  13. Khorn

    Khorn Forum Resident Thread Starter

    You’re describing my small living room system in the 70s. McIntosh amps & JBL Pro bins, lenses and drivers. It was insane to say the least.
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  14. Tim Irvine

    Tim Irvine Forum Resident

    Austin, Texas
    I have a Rogue Sphinx, and I find it to be a good amp. I don't find it edgy or hard to listen to in my system.
  15. GoldprintAudio

    GoldprintAudio Forum Resident

    Lexington, NC
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  16. Luxmancl38

    Luxmancl38 Forum Resident

    Manchester NH
    My local dealer has the Gato Amps and Integrated's. Made in Denmark. Michael Kelly of Aerial initially brought them over and sponsored them.
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  17. Scott in DC

    Scott in DC Forum Resident

    Washington, DC
    My misgiving about many Class D amps is the price. If I'm going to spend serious dollars on a new solid state amp I would rather get a Pass Labs or Ayre.

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  18. caracallac

    caracallac Forum Resident

    Well it would be a dull old world if we all liked the same things, wouldn’t it?
    Khorn likes this.
  19. Khorn

    Khorn Forum Resident Thread Starter

    Thanks for the interesting info.
  20. Khorn

    Khorn Forum Resident Thread Starter

    My present choice is McIntosh but I’m really curious about class D.
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  21. Khorn

    Khorn Forum Resident Thread Starter

  22. JJ Cahill

    JJ Cahill Active Member

    Ojai, CA
    I set up a quick listening system while helping out my mom during these strange times. I went to my storage, which holds quite a few items from a production studio I closed down 4-5 years ago, and grabbed "small stuff." This included a pair of B&W 805's, some front end digital, and a lightweight Crown 2500 (used 3 for Klipsch/JBL "playback PA) fed by a wonderful tube preamp built for me by Grover Huffman almost 20 years ago. I do not miss the McIntosh MC 500 (beast) that drove them in my "B" room and am amazed at what an amp weighing less that 20 lbs can do!
    My way of dealing with his unprecedented time has been catching up on some great music listening, thanks to this lightweight Class D! :righton:
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  23. shug4476

    shug4476 Forum Resident

    The better designs I have encountered use a Class A pre-stage with a Class D power. I heard the Devialet - a beautiful bit of kit to hear and use. The soundstage was just vast.

    Something wasn't quite right though, but I only listened with Tidal, so could have been the source.

    I am told the Lyngdorf stuff is good (but I am very weary about room correction).
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  24. Helom

    Helom I'll take the monkey coffins

    If you have a budget of $10k, no need to settle for class D. You can get two Benchmark AHB2s and run them in mono. All the benefits of class D with none of the sonic sacrifices.
  25. ls35a

    ls35a Forum Resident

    Eagle, Idaho
    It's never my first choice.
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