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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
lanx0003 OP
856 posts
 

@hifinut51  There is a pre-out terminal on the back designed to bypass the amplifier's built-in power amplification stage.  SE only but, if you want xlr, go with Za3 which is supposed to similar SQ based on the review.

audioman58's avatar
audioman58
4,169 posts
 

Myself hear a Lot of gear and owned a Audio store for a decade.

Danish Audio Group  AAvic integrated amplifiers ,

and their  Great  Forte series that has integrated dac,and streamer the model 1 starting at $5500.  A bunch of trickle down technologies . Using multiples of different types of Active Tesla coils , better then anything  in its class.

just go out of your way to hear them. The Borresen X series Loudspeakers are true game  changers at their price point and above ,these guys are thinking way above the norm.

timlub
2,040 posts
 

I have bought 5 different TPA3255 amp boards and have built all 5.  I upgraded filtering on all of them.... I have found a reasonably small 10mfd cbb cap that I use on the inputs. I always upgrade the filter caps normally 63v caps, sometimes higher, but I switch them to the highest capacitance that I can get to fit.  I look at coil quality, occasionally replace those, but not always.  Outside of the input, I upgrade electrolytic to mkp/cbb where I can, If not, I upgrade the electrolytic and bypass with good caps (mkp or film & foil) on bottom of the board. Always make sure the 3255 chip is properly mounted and has decent heat distribution. I use 36 to 46v smps supplies that I add significant filtering between supply and board.  These amps have ranged anywhere from pretty good to flat out excellent.  I have 2 more in my sites.  I have enjoyed these amplifiers very much.  

mapman's avatar
mapman
22,300 posts
 

I marvel similarly about high res 4K video streams on a good modern 4K tv. So much better than 20th century TV technology. 

pindac's avatar
pindac
2,864 posts
 

Bear in mind a fully loaded PCP for a Purifi Design as a DIY Build / Commission Completion can be acquired for between £300 and £600.

I would think that if the casing is not OTT on the aesthetic, the end Amp will be close to the £1K pricing for the upper cost model, even with Pure Copper RCA / XLR used and PC Triple C used as Hook Up wiring.

When assembled in a Casing there is little to compete, unless another wad of £0000's is spent. 

I have also made known on this forum in another thread about a Import Chinese Origin, Four Box Modular Class D Power Amp compared to a £50K Soulution Power Amp on a £200K system, or £150 400 system with the Import Amp.

The system owner was completely bamboozled by the Import Amp being such a performer, the Soulution out performed it, but at £49 600 to attain the difference on offer. For the individual who was with the experience of the comparison, that becomes a very difficult decision to even consider.

Even more painful, is that on the same occasion, a Neurchrome 365 at approx' £2K built, at times with certain tracks  was much more attractive than the Soulution.   

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