2. amps-preamps
  3. 189470-161121

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?

lanx0003

Showing 6 responses by eddnog

eddnog
48 posts
 

I currently run the following chain and love it:

Musician Draco -> Schiit Freya+ rolled with matched quad Psvane CV181-T MkII tubes ->  a pair of Fosi ZA3 power amplifiers with rolled op-amps (Burson V7 Vivid in the left channel gain, Sparkos SS3602 in the XLR input) run as monoblocs in stereo mode each with a 48V/10A power supply -> LS50 Metas and also an SVS SB-3000 hooked up to the single ended outputs on the Freya+.

This chain absolutely blows away the same chain with a PS Audio GCC-100 in place of the Fosi amps. I am hotly anticipating the release of their V3 Monos, and am considering putting in a preorder, but I’ve been in touch with them and it looks like in order to roll op-amps, you will need a pair of the same ones for each amplifier in gain section and I’m not sure if I’m willing to invest in an extra pair of Burson V7 Vivids (I would roll over the op-amps from my current amps except I currently only have one pair of the Bursons).

-Ed

eddnog
48 posts
 

@lanx0003 I am not sure if it will be detrimental to performance, and I imagine a lot of factors come into play (efficiency/sensitivity of your speakers, listening volume level, driving impedance/load of the speakers, etc.). I didn’t see any results from anywhere testing the V3 Mono specifically with a 5A power supply versus a 10A, making it even more difficult to say.

-Ed

eddnog
48 posts
 

@lanx0003 a little under 3 hours until the Kickstarter for V3 Mono opens up!!!

-Ed

eddnog
48 posts
 

@lanx0003 Yes, I am hoping to make that cut as well. I have a feeling first 200 will go FAST. I plan to get a pair without power supplies as I already have a pair of 48V/10A units that I currently use with my ZA3s. Once the V3 Monos arrive, I’ll roll over the op-amps to the new V3 Monos, put the stock op-amps back into the ZA3s and then sell them with the 48V/5A power supplies I have sitting around.

-Ed

eddnog
48 posts
 

@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

eddnog
48 posts
 

@lanx0003 well…guess I should be glad that I went with the dual 48V/5A option, then! Granted, I always believed that in the spirit of actually running separate monoblocs, it would imply powering them with actually separate power supplies as well. It should not be a huge surprise that there are actual benefits to doing it this way. The detriment is always to the wallet, yeah? But in the grand scheme of our beautiful hobby, this specific cost difference isn’t all that huge.

-Ed

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