Class D got better.
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?
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My nearfield desktop audio system is very crowded and had no space for an A/B or A amp of any kind when I switched to passive monitors ~6 years ago. Thus I was pushed into the alien (to me) world of class D amps. I did a ton of research, looking in particular for any class D amps described even occasionally as "musical" and pleasing to the ear. All that research led me to a gently used ICEPower design, the Wyred 4 Sound ST-500, which I sited standing on one side on my desk (w/the mfr’s OK). That cool running amp immediately worked well for me. It sounded great, had none of the obnoxious brightness and thin harmonics some ascribe to class Ds. Until a month ago I wasn’t tempted to change. I never really stopped following class D, and had become curious about NCore modules used by various amp makers. The one other (to me, somewhat affordable) class D brand I read positive things about is Bel Canto. I looked for their stereo NCore amp, but instead found a cherry pair of 600M monos. After installing them IMS, I can verify that they, too, sound quite musical. They have somewhat more resolution and better soundstaging than the ST-500, which is nice to have. I got pushed into class D by space considerations but must say I’m quite impressed with the sound of the 3 examples I’ve used in my system. I've had 4 pairs of studio monitors here with these amps (ATCs, KEFs, Aerial Acoustics, Harbeths) and all worked extremely well with these amps. |
@eddnog I got in and pledged for two Monos with two 48v/5a PSUs. I felt fortunate making the last-minute decision and went with two independent PSUs because later today I saw this https://www.youtube.com/watch?v=wjWVSFCR5MI where the host experienced noise/interference issues using one block. |
@phd believe it or not, there are people out there who simply write off Class D and some even Class AB right off the bat without so much as a blink. -Ed |
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