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PostPosted: Sun Jan 08, 2017 1:42 pm 
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Because when class D originally came out, sub amplification was all they were good for. That was years ago, things change, with technology usually quickly, people are typically much slower to catch up. Lots of manufacturers make top notch class D products now, Nuprime does an excellent job.


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PostPosted: Sun Jan 08, 2017 1:45 pm 
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IMHO, Jared was on the right track. Yes, Class D is great for delivering huge amounts of current in sudden bursts - perfect for kick drums, explosions, and other sounds that require moving large amount of air at low frequencies.

However, I have a hunch that the distortion in the audible range that Jared mentioned may have to do with the way the circuits work. If I understand correctly (that's a big IF...lol), Class D amps are switching amps, which means that the production of any sound involves the switching on & off of the current going to the speaker coils. If the amp switches on & off at too slow of a frequency, it may be that sub-harmonics are produced that happen to be in the audible range. (if you have ever played an synthesizer, you know that you can hear both upper & sub harmonics from an oscillator producing a square wave, which is often a desired effect...quite the opposite of what audiophiles want!).

So, it may be that, in the past, Class D amps (perhaps Class H too?) were not switching at a high enough frequency to eliminate sub-harmonics in the audible range, and that deficiency produced sub-harmonics that showed up as distortion. However, that has changed, and amps from NuPrime, Plinius, Devialet, etc etc etc can switch at a frequency so high that their Class D amps & sound smooth & 'liquid'.

Now what about subwoofers? Well, since they only have to produce tones up to the cut-off frequency (plus a tiny bit above that because of the shape of the filter), it was relatively easy to filter out the audible subharmonics above the cut-off frequency in even the earliest Class D designs. Consequently, Class D subs sounded good almost right from the start. Of course, there are many other advantages to employing Class D amps in subwoofers, so the technology continues to be used, even after the early shortcomings of Class D amps were dealt with.

Of course, this is all IMHO, so you may wish to take my reasoning with a grain of salt. :)


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PostPosted: Sun Jan 08, 2017 1:58 pm 
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Crosscut100 wrote:
They simply don't make class D tube amps.


Check out Orion Audio for their hybrid class D tube amps


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PostPosted: Sun Jan 08, 2017 2:24 pm 
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Class D was originally adopted for sound reinforcement because it uses a lot less electricity than class A, AB or B. Also, it was important for manufacturers because class D and especially switching power supplies are much cheaper to manufacture than the old technologies.

This was soon combined with switching power supplies which further increased the efficiency of amplifier circuits and, very attractive for touring, greatly reduced amplifier weight.

Gradually, consumer audio started following suit. Consumers, too, are attracted to amplifiers than weigh 5 or 10 kg rather than 20 or 30 or even more.

Jeff Rowland, generally considered solidly "high end audio" was already using switching power supplies a decade or more ago.

Like any other technology, each year brought refinements to the original technology and wider adoption of that improving technology.

At present, class D (also class H, a variant of A/B, nor of D; class T), with and without switching power supplies (more often with), is like the traditional A, A/B technology more familiar to audiophiles, available at every quality—and price—level.

My First Watt F5 Turbo v3 mono amps are ultra-traditional: linear power supplies, class A and A/B circuitry.

So are the amps inside my powered standmount speakers (Tannoy AMS-12A).

But my best speakers use switching power supplies and class H output stages (which run in class A up to 40 W).

And the Lab-Grüppen amps I use for biapming another pair of speakers use switching power supplies and class T (IIRC) output stages.

Once again, it's more the implementation than the technology itself, although as others have already pointed out, as a technology class D and switching power supplies have come a long way in the past 10-15 years.


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PostPosted: Sun Jan 08, 2017 3:27 pm 
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amarquis wrote:
Spectron ! Had monoblocks for 6 yrs. Not looking for anything else !




Could not agree more. :D


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PostPosted: Sun Jan 08, 2017 5:22 pm 
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Thanks everyone for your thoughtful comments. I suspect Class D separates will continue to gain in popularity going forward given their numerous benefits.


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PostPosted: Sun Jan 08, 2017 6:39 pm 
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blueznjazz wrote:
........ However, that has changed, and amps from NuPrime, Plinius, Devialet, etc etc etc can switch at a frequency so high that their Class D amps & sound smooth & 'liquid'.


What? Plinius produces class D amps now? Rowland made the move à few years back, Levinson did too. But Plinius!?


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PostPosted: Sun Jan 08, 2017 9:44 pm 
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Using Channel Island class D 35 watts per channel mono blocks vmb-1, and no they are not for sale.Sound fantastic with a passive or tube pre.


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PostPosted: Mon Jan 09, 2017 6:12 am 
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Spectron ! Had monoblocks for 6 yrs. Not looking for anything else !

Two stereo bridged into monos

Me three!!!


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PostPosted: Mon Jan 09, 2017 7:58 am 
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buybye88 wrote:
That negative bias no longer really applies to Class D amps used in pro-audio. I can pick up a 500 watt per channel Class D amp with one hand.....
Cheers,
David Neice


There has alway been a psychological connection between weight & quality in the hifi amp world. I think that also led to some negative opines.
It was enough of a factor that one of the PS Audio ICEpower amps I had actually had a steel plate welded to the inside of chassis cover to add weight..


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PostPosted: Mon Jan 09, 2017 8:11 am 
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darcman wrote:
Crosscut100 wrote:
They simply don't make class D tube amps.


Check out Orion Audio for their hybrid class D tube amps

I was only speaking to the amp side as a stand alone not an integrated amp.


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PostPosted: Mon Jan 09, 2017 8:43 am 
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Hi,

rngange wrote: 'There has alway been a psychological connection between weight & quality in the hifi amp world.'

For sure. Look at the recent post by OBI56 on the new Moon Monoblocks. When Quad released the 405s, which were lighter than the 303s, they were met with critical skepticism. Heavy iron is like Wegu beef; if the cost per pound is high enough then it must be 'better'.

Cheers,
David Neice

_________________
Chinese Proverb: 'Man who waits for roast duck to fly into mouth, waits very, very long time'.


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PostPosted: Mon Jan 09, 2017 8:54 am 
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daren_p wrote:
Because when class D originally came out, sub amplification was all they were good for. That was years ago, things change, with technology usually quickly, people are typically much slower to catch up. Lots of manufacturers make top notch class D products now, Nuprime does an excellent job.


I once spent a pretty substantial sum to acquire a set of Bel Canto REF 1000 mono's. I wanted very much to like them as they were small, produced no heat at all, had great minimalist, clean design, and operated with almost no electricity. Used them with 3 different speakers sets, where one set was a very high-resolution Verity Audio product.

It happened to be the worst-sounding amplification I ever had, well, almost. Everything sounded like coming out of a tunnel, with excessive "echoing" and reverberation-like sonics. That was back in 2010, not that long ago.

I am certain that today's class D amps are much better.

But still, I just could not justify taking the plunge again today.

Live and learn I guess.


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PostPosted: Mon Jan 09, 2017 8:54 am 
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buybye88 wrote:
Hi,

rngange wrote: 'There has alway been a psychological connection between weight & quality in the hifi amp world.'

For sure. Look at the recent post by OBI56 on the new Moon Monoblocks. When Quad released the 405s, which were lighter than the 303s, they were met with critical skepticism. Heavy iron is like Wegu beef; if the cost per pound is high enough then it must be 'better'.

Cheers,
David Neice

Not the best comparison. Wagyu beef just is better. Its not even close.

Back on topic: The day someone makes a class D amp that sounds as good as a class A amp, I will gladly entertain the idea of buying one. Until then.....

Sent from my SM-G920W8 using Tapatalk

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PostPosted: Mon Jan 09, 2017 11:09 am 
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milag wrote:
daren_p wrote:

I once spent a pretty substantial sum to acquire a set of Bel Canto REF 1000 mono's. I wanted very much to like them as they were small, produced no heat at all, had great minimalist, clean design, and operated with almost no electricity. Used them with 3 different speakers sets, where one set was a very high-resolution Verity Audio product.

It happened to be the worst-sounding amplification I ever had, well, almost. Everything sounded like coming out of a tunnel, with excessive "echoing" and reverberation-like sonics. That was back in 2010, not that long ago.

I am certain that today's class D amps are much better.

But still, I just could not justify taking the plunge again today.

Live and learn I guess.


Interesting, back then the Bel Canto's used ICEpower ASP modules and I've had every one of that line of modules in various chassis and brands, (and still do in my D-Sonic amp which has the 1000ASP's), and how you describe them is absolutely opposite to my experience. I've used them predominantly with Paradigm Signatures and currently the S6 v.3's. I'm getting pin-point imaging, accurate controlled bass, incredibly well defined top end without being "bright", and huge soundstaging all on a dead quiet background.
Might have been a component miss-match or system sensitivity to their SMPS, or maybe even defective if they were that bad.


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