Do ClassDAudio Amps Have Proper Decay Of Notes?


I'm interested in the ClassDAudio kits. Has anyone tried them? I had a tripath amp once and it had a liquid, detailed quality that I liked but it was too fast with the decay so ultimately sounded a bit fake, even with a tube pre. Full-bodied, lush, but too fast. I've heard the Hypex modules from Holland have nailed the decay issue but they're miles out of my price range. Just wondering if the ClassDAudio kits are close in terms of decay.
uberdine

Showing 2 responses by ostensible_constituency

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. 
" 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)."


Believe me I know exactly what "digital" and "class D" mean, and that class D is not "digital" - however, my point was that from the marketing perspective there ARE "digital amps" which almost all use class D but also include a DAC and purportedly the audio waveform never enters the analog domain, other than as a PWM signal, inside the amp - hence the amp itself gets the moniker "digital" amp and "class D" is conflated with "digital" when in fact the amplification itself an analog process controlled by digital microcontrollers.

However, would you agree that what you just excerpted about PWM describes a process whereby the waveform (square wave being the trigger for lack of proper terminology at the moment) is a combination of ON or OFF states in an array of switches (transistors or vacuum tubes) and that ON = 1, OFF = 0 which would easily lead people to assume that the process is "digital" even when it was a plain square wave and not a complex microcontroller dictating the ’sampling’ process?

Finally, would you agree or disagree then, that today's class D amps, with built in DACs and which use complex microcontrollers to sample the output and alter the switching algorithms can indeed be called "digital amps"?