Do ClassDAudio Amps Have Proper Decay Of Notes?
As I’ve mentioned hear and on other threads, to me Class-D is still in it’s infancy with problems of having class-d switching noise filter effecting the phase in the audio band right down to 5khz, Technics with their SE-R1 have raised this switching noise filter more than double the frequency with special much faster semiconductors with far less effects into the audio band, Absolute Sounds and Stereophile seamed to enjoy this amp very much.
"Conclusion: Absolute Sounds: The Technics R1 is exciting on many levels. On a technical level, it points the way to a future where digital signal paths are much simpler and more direct—and therefore more like analog—and solid-state overcomes the last hurdle separating it from tube-like holography. On a sonic level, Technics has managed to create a system that does virtually everything right, including self-effacement in service of the music. Value is another cause for excitement. True, the price point of the R1 system puts it out of range for audio acolytes. However, this system will—and in my listening room did—satisfy some of the most finicky, hard-core audiophiles, used to listening to far more expensive gear. The Technics value proposition remains strong, even in this price range. Finally, the R1 system is exciting in that it heralds the return of Technics, a brand that once paved the way for new audiophiles to enter the fold, and for numerous technical advancements that eventually became standard practice. Today, with the R1 system and lower-cost variants that incorporate much of its technology, the company is serving the same twin roles. Technics is back, and its return is most welcome." "Conclusion: Stereophile. Although the SE-R1’s huge twin output meters and beautiful anodized-aluminum finish were visually distracting, the marketing of a class-D amplifier as a separate high-end component was important. This amplifier delivered some of the best reproduced sound at CES 2017. I persuaded Bill Voss to rip the contents of my copy of Rutter’s Requiem to his media server’s solid-state drive. The broad and deep soundstage, imaging, upper midrange detail, and bass extension were thrilling during the system’s rendition of "Lord, make me an instrument of thy peace" and "Pie Jesu." I appreciated the work done by the Technics staff to prepare their exhibit suite with recessed sound-absorbing panels. I left wanting to hear more. Cheers George |
Ancient thread here, but I have to chime in. I recently did a DIY Hypex nc500 implementation with one of their switch mode power supplies, and the amp, which is connected directly to a DAC (in this case Teac UD-503 with variable output and remote) that serves as a pre-amp. I've also used several other DACs including PS Audio Digital Stream III, various Cambridge Audio (both Azure series DACs) and an ebay Sabre 9038PRO DAC, also with remote and volume control. My previous amplifiers Krell, a Musical Paradise SET tube amp, Marantz separates, various Onkyo integrated and separates, "vintage" Technics, and others. The Hypex kit deserves every bit of "hyp" it gets. Seriously I can't imagine anyone who has ever listened to one (including with swapping op amps and stuff) could say that the sound quality suffers from the switching frequency or that decay is a problem. In fact I built this little kit as an experiment and because a friend basically 'forced' me to buy them off of him, which cost me about $1400 total, including a chassis/case. In the end, I sold my Krell KAV-400xi because it just didn't sound as good (and my tastes veer toward neutral and no emphasis on any particular frequency range) with any of the music types I listen to, not to mention that, as others have noted about Class A or AB transistor amps or even tubes, the Hypex runs cool to the touch even after hours of play. There is never any fatigue and there is always sufficient power for even previously very challenging transients. As one example, on William Orbit's electronic classic, "Water From a Vine Leaf" - streaming and played on my CD transport/DAC combo - there is one moment where all the bass, chorus and rhythm comes in at once after a prolonged quiet passage. This is hardly a great track to test the typical "audiophile" criteria like soundstage and precision, but in terms of the ability to convey pure power and energy into a room at every frequency equally, there is no comparison between any of the previous amps I mentioned and the Hypex. Just amazing, really. Before I come off as some kind of Hypex fanboy, I do not listen to much challenging classical and my tastes in sound profile lean toward power, impact and clarity. So I haven't run every type of music through this system and my speakers aren't really "high end" - for example the best ones I've tested are the KEF LS50, JBL Studio 590s (amazing, BTW - totally underrated), Wharfedale Jade series, B&W 600 equivalents, Elac UB5 (the ones that DO NOT deserve all the hype). But I challenge, or suggest anyway, anyone to put a good class D amp like the Hypex to the test for a few days in your own system. The only reason I can think of that anyone would hate the sound is if you're looking for "sweetness" or other unnatural coloration. That said, the Hypex gives my tube amp a real run for its money on midrange clarity and puts out a holographic soundstage (without super wide extension to the sides tho) with no emphasis on any particular sounds/frequencies. With the JBL Studio series compression drivers, voices are surreal and there is an intimacy that I have never heard from any other setup, including at hi-fi consumer shows or in showrooms. If you're interested in what you are or are not missing, it's 2018 and you really should give a solid Class D amp a try. BTW, someone said that Class D is not "digital" which is partly true, but PWM is a digital signal processing technique, so it's understandable for those amps to be called "digital" especially from a marketing angle. |
BTW, someone said that Class D is not "digital" which is partly true, but PWM is a digital signal processing technique, so it's understandable for those amps to be called "digital" especially from a marketing angle.Just had to put that in there.... that 'someone' being me... Class D was first demonstrated during the vacuum tube era. The reason it is called 'class D' is that class C came before it and so was already taken. PWM (Pulse Width Modulation) is an analog technique. Just ask any keyboard player with an analog synthesizer (by varying the pulse width, a string sound can be obtained from a square wave). From the Wikipedia page (https://en.wikipedia.org/wiki/Class-D_amplifier): The term "class D" is sometimes misunderstood as meaning a "digital" amplifier. While some class-D amps may indeed be controlled by digital circuits or include digital signal processing devices, the power stage deals with voltage and current as a function of non-quantized time. The smallest amount of noise, timing uncertainty, voltage ripple or any other non-ideality immediately results in an irreversible change of the output signal. The same errors in a digital system will only lead to incorrect results when they become so large that a signal representing a digit is distorted beyond recognition. Up to that point, non-idealities have no impact on the transmitted signal. Generally, digital signals are quantized in both amplitude and wavelength, while analog signals are quantized in one (e.g. PWM) or (usually) neither quantity. |
