Tsunami coming
High end Class D amps?
Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
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I'm a big fan of class D amps, however, I've noticed that they do tend to truncate the natural decay times on bass notes, which I believe is due to their very high damping factors. I find this a bit ironic, since class D is often dismissed as only good enough for sub amplification. I'm wondering if others have noticed this because I've never read about this unnatural class D shortening of decay times here or anywhere else. It's important to note that this class D bass note decay time truncation issue is not something that is easily and immediately discerned by listeners, mainly because it's more distinct on certain instruments, notes and types of music. When I listened to my first class D amp, a Class D Audio SDS-440-CS with a rated damping factor of over 1,000, driving my former Magnepan 2.7QR speakers, for example, I distinctly recall perceiving the bass performance as the best I had ever heard on them since I bought them used about 6 years earlier. I perceived the bass as clearly being more prominent, powerful and dynamic as well as tauter and, at least initially, seemingly more detailed through my new class D amp than through my prior class AB Aragon and McCormack amps. It wasn't until about 6 months later, after installing an Audio Kinesis Debra 4-sub distributed bass array (DBA) system with all subs driven by a separate class AB 1K watt amp with a DF about 300-500, that I first became aware of this class D decay time truncation issue on bass notes. I ran my Magnepan panel speakers full range knowing they only had a rated bass extension of 35 Hz. My main purpose for installing the AK DBA system in my room was to provide full bass extension down to 20 Hz and provide the bass power and dynamics that my Magnepans lacked between 20 and about 40 Hz. I clearly noticed the bass quality was much improved being reproduced through the AK DBA system. The bass was even more powerful and dynamic, as expected, but it was also smoother, faster and much more detailed. I believe it was this added detail that enabled me to notice the stark difference between how the AK DBA reproduced the decay times of bass notes in much finer articulation, without any truncations and with more natural sounding durations than the class D amp was able to reproduce them through just my main speakers. Of course, I realize there's likely more factors involved in achieving high quality bass performance in a system and room than the type of amp used and its rated damping factor. The truth is that, more than anything else, I was surprised by the truncation of bass notes through just the class D amp driving my mains and the vast improvement in their reproduction, along with other benefits, provided by the addition of multiple good quality subs driven by a class AB amp. Currently, it's just my theory that the DF of the amp(s) utilized in a system is an important factor in determining the quality of a system's ability to accurately reproduce the decays of bass notes. This is all based on my personal experiences, however, and I understand that I'm no expert and that we typically don't know what we don't know. Which suggests that there are likely other important factors involved. Tim |
Thank you for sharing your experience. And thank you for realizing that you are just guessing. You actually have no idea.....that your theory about damping factor and class D has any meaning. You would have to get every class A amp that exists and every class d amp that exists and drive your subs and also your main speakers and see what you hear. Then you MIGHT have some actual real information. Every class D amp sounds different....including in the bass (my direct experience). Maybe adding great subs to any system will always get you better decay.....everywhere. Just as adding a supertweeter can make the bass better. So, what are you hearing? Without doing extensive experiments we are just a bunch of guessers. There is very little real information shared anywhere about how audio actually works. It is basically every man for himself. There are SOOOOOOOOOOOO many things that change the sound. Unless you account for every variable.....you know very little. I have spent over 40 years doing listening tests......and I know some things.....but really what I know....is that I know NOTHING! It is infinite. In drag racing there are only 5 things that make for performance......horsepower, weight, drag, traction and gearing. And all this can be measured by the clock. This is why dragsters all look the same......like the same person built them all. Everything is known in drag racing. Audio is the opposite. Nothing is known. All brands of solder sound different.....you cannot measure it....you have to listen....every wire, every resistor brand, on and on into infinity. Most things that make a sonic difference cannot be measured. I brought a proto of an amp I sold last year to someones house and A/Bed the amp versus his. Both his and my amps used IceEdge 1200as modules in mono blocks. Mine was modded....his was not. Both had the same damping factor and power as I did not change the feedback or output stage. His amp sounded "tubey" in the bass.....my amp sounded way faster, and cleaner and preferable by him and me. Damping factor is just one of tons of things that can affect bass performance. I am not saying that we should not share our guesses.....it is fun. The trouble is, that most state things like what you said but leave out the part that you have limited knowledge and its a guess. So, it is stated as "class d amps have zero decay in the bass....they are overdamped".......Then the rest of us just repeat this on other forums till everyone thinks the same thing. The blind leading the blind. Words are very powerful. Thank you for your intelligent use of words. The best words are those that uplift us. For we all want to be happy. Share uplifting words and deeds with everyone....we all win that way. May you all be happy and joyful this season and always. |
For those that want to know, I believe "that experience" is more likely because many speakers have there lowest impedance in the bass and also their highest -phase angle. Combined, these two give’s you what’s called EPDR, (Equivalent Peak Dissipation Resistance) and that can give the amp a very nasty load impedance to look at. Good big current bi-polar amps don’t mind seeing this . Class-D tends to quickly drop off it’s current starting under 4ohms down to 2ohms, look at any Class-D "independently measured" spec and you will see that, they never come close to doubling wattage from 4 to 2 to 1ohm, many even go backwards, showing severe current limitations into low EPDR impedances, this is limiting bass performance and becoming like a tone control, rolling off the bass instead of staying flat to 20hz. https://www.audiosciencereview.com/forum/index.php?threads/stereophile-has-started-calculating-epdr.... This link also on EPDR on the second page: https://www.stereophile.com/reference/707heavy/index.html Cheers George |
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