2. amps-preamps
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My NAD 3020 D proves your Class D tropes are wrong

I have a desktop integrated, the NAD 3020D which I use with custom near field monitors. It is being fed by Roon via a Squeezebox Touch and coaxial digital.

It is 5 years old and it sounds great. None of the standard myths of bad Class D sound exist here. It may lack the tube like liquid midrange of my Luxman, or the warmth of my prior Parasound but no one in this forum could hear it and go "aha, Class D!!" by itself, except maybe by the absolute lack of noise even when 3’ away from the speakers.

I’m not going to argue that this is the greatest amp ever, or that it is even a standout desktop integrated. All I am saying is that the stories about how bad Class D is compared to linear amps have been outdated for ages.

Great to see new development with GaN based Class D amps, great to see Technics using DSP feed-forward designs to overcome minor limitations in impedance matching and Atmasphere’s work on reducing measurable distortion as well but OMG stop with the "Class D was awful until just now" threads as it ignores about 30 years of steady research and innovation.
erik_squires
erik_squires OP
16,268 posts
 
Erik, if this is too much of a rabbit trail, please disregard. If you (or anyone else) are aware, how does the NAD SQ/design compare to Naim? I have an Uniti Atom on my desk, but considered the NAD.


Youd have to be more specific, and I haven’t heard that much NAD and almost no Naim at all.

NAD has been experimenting with Class D in their products. As far as I know, the hybrid Class D in the 3020D is in maybe 1 or 2 other products. The top end that NAD amps that I am aware of are pure Hypex modules without the hybrid components.
allenf1963
369 posts
 
Can someone direct me to a good source to get a better understanding of the differences in Class A, A/B, & D amplifiers?  I thank you in advance.
erik_squires OP
16,268 posts
 
Can someone direct me to a good source to get a better understanding of the differences in Class A, A/B, & D amplifiers? I thank you in advance.


Here you go, @allenf1963

https://en.wikipedia.org/wiki/Power_amplifier_classes
decooney
2,117 posts
 
@jwl244,
"@decooney I wish I could say I put a ton of time in. I may have listened here and there for less than 20 hours total in a few weeks. I did not switch speakers in or out."


Good to know. Barely scratching the surface of end-game potential, possibly. I won’t name the company, yet the owner of a different Co started wondering why they were getting more returns than ever anticipated on a solid sounding product. After some in-depth internal investigation ,something very telling surfaced for this Co. They instituted a (3x) much longer pre sale/shipping burn-in process to these particular class-D products and components. The customer returns dropped radically after this process was introduced. Then they tell the customer to give it another 100-200hrs for the final 5%. Not all, but some higher-end gear benefits from longer burn in cycles, finally reaching a set point, optimum specs, bias, and maybe the type of sound we all look for. Its definitely worth giving a try in the future, fwiw. Good luck.


erik_squires OP
16,268 posts
 
Going along with that, there is something about some Class D that requires DAYS to warm up.  Even after being used and on for months my ICEPower monoblocks sound like garbage after being left off for a weekend.

I have not run a binary search pattern to correlate time off vs. sound quality, but there have been about half a dozen other encounters with other audiophiles who have had this phenomenon. 
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