Could Class D really be that good?
I've heard statements praising modern class D amplifiers all the time but was sort of hesitant to try. Lately, one particular model caught my eye, the Fosi V3, which costs sub $100 but is praised for having refined sound like class A/B. To fulfill my curiosity, I quickly ordered one and tried it with my Burchardt S400II and Wharfedale Linton speakers. Basically, this is a neutral sounding amp but, to my surprise, the sound is clean, open, airy, with full mids, wide soundstage, good imaging/separation, with nearly null traces of the edginess, dryness, or lean sound that traditional class D amplifiers have. The background is just as quiet as my current systems. The core is the TPA 3255 chip from TI and comes with a 32v, 5A power block, which is supposed to deliver approximately 65 watts per channel (into 8 ohms). It drives the S400II/Linton without any hesitation, as well as my 130-watt-per-channel high-current Parasound A23. Very impressive.
Measurement is not everything. However, according to the lab test results, when operated under 10-60 watts, the distortion level (THD) is below 0.003%, better than a lot of high-end (price) gears. I am going to build around it for my fourth system with upgraded op-amp and LPS. I believe it will outperform my current mid-end (price) amplifiers.
I know, I know, quite a few Audiogoners' systems are above $100k, and mentioning this kind of little giant that costs a fraction could be rather embarrassing. But I thought this is just like gold digging with a lot of surprises and fun. Don't you think?
For those contemplating the question of this thread, you aren't the only ones: https://pmamagazine.org/is-class-d-amplification-now-better-than-class-a-b-and-class-a/
Yes. Not worth worrying about on weekends. |
@atmasphere Ralph, great post and thank you for sharing. I also enjoy your afternoon talk here, which helps me understand some of the intricacies of class D design. |
Class D amps have been getting better and better. You have the "all you need is more feedback to lower the distortion" people....Bruno, for instance....and you have the "all you need is a certain kind of distortion" people ......Ralph, for instance..... you have the "all you need is a tube buffer to sweeten it up" people....PS Audio, for instance, you have the "We are using the best Ganfets....all the rest use junk" people.....AGD for instance, etc. However, it is not just one thing.....this is what I say over and over. AGD has had two updates to their "tubey thang" and everyone agrees the latest is the best sounding.....they are still using the same "magic Ganfets" they used in the original version. Look at the Aavik amps that use the Pascal modules.....they have different versions of the basically same amp but they add more "active Tesla circuits"....more dither circuits, use a more damped and low hysteresis chassis (made from copper) and use more tweaky feet in their more expensive ones.....same Pascal module used in each one.....but all the reviews state the more expensive ones sound better. So, they are selling you more tweaked versions. This is exactly what I do to Purifi, Ncore, etc. amps......I tweak them to make them sound better. They will not measure any better.....just like the various more expensive Aaviks don't measure any better.....they just sound better. The new $10K Ganfet amp from Mytek has been promised for over 3 years......but supposedly is starting to ship soon?....he he. Like waiting for Godot. Laiv audio is said to be working on a GAN class d amp. Their new $2700 Harmony DAC is the latest rage. . It is interesting that Aavik now has a class A amp as their reference amp....so they think class a is still the best (well, for $70K, it better sound great!). However, they are using a stock? Pascal module in their class D amps. What if they used their own super class D circuit or one from AGD or Purifi or Ralph or whatever? Still much more evolution to be had here. Class A transistor amps really started to get tweaked back in the late 70s......class D really on has maybe10 years of serious tweaking. Here is a link to a post on Audio Circle where two people describe the difference between using the stock polyester Wima output filter caps and my modified Polypropylene Wima caps. The comments worth reading are on the first page and the last page......everything in between is mostly people arguing about nothing |
@jl35 glad can of some help. enjoy listening. |
