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
hifinut51
22 posts
 

@lanx0003 does this integrated amp have a preamp bypass (HT) input?

Is it balanced or single -ended?

zuesman
37 posts
 

here's a PS to my comment The only thing I would change is I wouldn't get there wiring because OCC single crystal rectangular is far better and even the OCC single crystal round is better than anything OFC at any price

lanx0003 OP
676 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
3,909 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
2,039 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.  

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