Advance in Class D amps?

[eras]

Thanks George, I've always wondered what Halcro does differently. I don't really understand the phase shifts, or if it can be measured, but I presume a higher switching frequency means reduced need for filtering and better sound quality. Just out of curiosity, do you think the Halcro will sound excellent - i.e., do the measurements imply that it would?

[Captain Crunch]

Who gives a flying toss about amplifier theory if a Class D amp delivers where it counts - sound quality! Just get hold of one and try it out in your own system. I've owned amps by ME and McIntosh and I've never once wished I still had them when I listen to my music being powered by my Wyred 4 Sound integrated. Great sounding amp and the financial savings are huge compared to those brands.

[Audionutz]

Who gives a flying toss about amplifier theory if a Class D amp delivers where it counts - sound quality! Just get hold of one and try it out in your own system. I've owned amps by ME and McIntosh and I've never once wished I still had them when I listen to my music being powered by my Wyred 4 Sound integrated. Great sounding amp and the financial savings are huge compared to those brands.

And I've discovered the exact opposite ! Having owned Nu Force, Mole, Channel Isl, etc, I have now gone back to "normal" Class A amplification. The financial savings are huge (the amps are actually worth something when it comes time to upgrade) and they sound far superior to me. I found Class D had a real "wow" factor to it at the beginning. But as time went by, the high freq "weirdness", for want of a better word, became to much for me. Great on bass though.,

[georgehifi]

Thanks George, I've always wondered what Halcro does differently. I don't really understand the phase shifts, or if it can be measured, but I presume a higher switching frequency means reduced need for filtering and better sound quality. Just out of curiosity, do you think the Halcro will sound excellent - i.e., do the measurements imply that it would?

I have a friend with the DM88's or 78's and hear them a few times a year, they are a very controlled sound, he had a pair of 27watt Cymer E81 tube monoblocks which when were on song I preferred, this is on Wilson 7 & then 8's speakers. Like I said above I'm not a fan of Mosfets outputs, and if that what the Halcro's have then I prefer bi-polar outputs on transistor poweramps. Mosfets to me have again a bit of a lifeless sound a bit like an over filtered Class D as explained above.

Phase shift Eras is when filtering of HF rubbish happens depending on types of filters it can have a negative effect quite a few octaves below the frequency that the filtering has been done at.

EG: remember when CD first came out? the brick wall filters used at 20khz should theoretically been ok, but they sounded hard and bright.

And the higher switching frequency, if it ever happens with Class D, means that the filtering of the switching noises can be done higher and phase shifts don't come down as far into the audio band, and stay out of ears reach.

Cheers George

Edited August 14, 2011 by georgehifi

[dart6]

I lived with the plinius sa250mk4 [2 yrs] then rogue audio m150 monoblocs [2 yrs] and loved them both. To my ears in my system the spectron amp is better.

Maybe it's the extra juice my speakers enjoy

[Amar Dhall]

Who gives a flying toss about amplifier theory if a Class D amp delivers where it counts - sound quality! Just get hold of one and try it out in your own system. I've owned amps by ME and McIntosh and I've never once wished I still had them when I listen to my music being powered by my Wyred 4 Sound integrated. Great sounding amp and the financial savings are huge compared to those brands.

Wise words.

I am very happy with my Bel Cantos and have not regreted the purchase ever.

[Orpheus]

Yes, the problem with these amps, let's leave the theory aside, is that they sound brittle, thin, and distorted, in the systems I have heard.

Other than that, they are fine :nana.

[georgehifi]

Wise words.

I am very happy with my Bel Cantos and have not regreted the purchase ever.

Funny you should mention the Belcanto's my friend with the Halcro's and Cymer 31E's also had the Belcanto 1000m monoblocks for a short time and Nuforce-9-V3se which he wants to sell but can't find a buyer for.

Yes, the problem with these amps, let's leave the theory aside, is that they sound brittle, thin, and distorted, in the systems I have heard.

Other than that, they are fine :nana.

They make for great bass amp though, just that they need to come of age for the upper mids and tops, and they will in the future you can bank on it, as technology for higher switching frequencies will advance and the "new" chips for it will be just around the corner, by then even I will say goodbye to my big heavy inefficient boat anchors.

Cheers George

[Captain Crunch]

And I've discovered the exact opposite ! Having owned Nu Force, Mole, Channel Isl, etc, I have now gone back to "normal" Class A amplification. The financial savings are huge (the amps are actually worth something when it comes time to upgrade) and they sound far superior to me. I found Class D had a real "wow" factor to it at the beginning. But as time went by, the high freq "weirdness", for want of a better word, became to much for me. Great on bass though.,

And this highlights why the most pointless question to ask on an audio forum is 'what amp will sound good with my speakers'?

[Guest Bodhisattva]

I thought this comment from an interview with Industry icon Dan D'Agostino said it all for me -

"Many companies are starting to use PWM class D amp's. What are your thoughts about it?"

"My thoughts are I hope I never have to do it."

[eras]

I thought this comment from an interview with Industry icon Dan D'Agostino said it all for me -

"Many companies are starting to use PWM class D amp's. What are your thoughts about it?"

"My thoughts are I hope I never have to do it."

Too difficult?

[Guest Muon]

Maybe too painful

oops!

I promised myself I wouldn't post in this thread, but I caved...sorry

A little tongue in cheek btw.

[Guest Bodhisattva]

Maybe too painful

oops!

I promised myself I wouldn't post in this thread, but I caved...sorry

A little tongue in cheek btw.

Lol Datafone

[georgehifi]

Too difficult?

I ask with the technology that's around at present why would Dan D'Agostino not build a Class D amp, that costs in materials less than half to make, has more watts per channel, weighs a quarter as much, sucks way less power, is better for the environment, and makes him loads more profit?

The man has a conscience and scruples, but even he will fold once the chips that do the switching frequencies in class D amps are developed to do them at double or triple speed.

Cheers George

[DoggieHowser]

I expect based on Rowland's precedence, not many people were buying his super marked up ICE based amps.

Bel Canto's mark ups are higher than say W4S but I think there's a subtle difference in how they sound and you see where the extra costs go into.

Dan's new amp is nice and sounds the business. But with bespoke parts, there's less chance to make an apples to apples comparison.

Wait. Scratch that. You can make an apples to apples comparison it's actually almost half the price of his last amp for the last company he worked for. So that makes it really good bang for the buck.

[tktran]

I guess until a "traditional" high-end company makes a class D amplifier, it will be more difficult for review folk to pooh-pooh class D as "OK for midrange stuff". If one of the guys who already own the "stratosphere" (like Krell, Classe, McIntosh) comes out with as saying look boys this is the proverbial ****, it no longer becomes a tenable position to claim that class D can't reach all the way to the top.

Did you know your mobile phone synchronises it's time with the network time server? When you change time zones it automatically does this? It is more accurate and less fiddly than a luxury analogue mechanical watch, but people are always going to lust for the latter.

Performance isn't the whole thing with amplifiers, or anything else.

[Orpheus]

I guess until a "traditional" high-end company makes a class D amplifier, it will be more difficult for review folk to pooh-pooh class D as "OK for midrange stuff". If one of the guys who already own the "stratosphere" (like Krell, Classe, McIntosh) comes out with as saying look boys this is the proverbial ****, it no longer becomes a tenable position to claim that class D can't reach all the way to the top.

Did you know your mobile phone synchronises it's time with the network time server? When you change time zones it automatically does this? It is more accurate and less fiddly than a luxury analogue mechanical watch, but people are always going to lust for the latter.

Performance isn't the whole thing with amplifiers, or anything else.

I don't want a mechanical watch. I don't want a watch, full-stop. My phone is fine.

I avoided valve amps for years, because I thought they were too much trouble. I don't buy machinery for machinery's sake. However, the two that I live with daily, a McIntosh MC275 and an AR ref 110, both sound right with my system. I found they weren't much trouble at all.

Equally, I avoided turntables for year as too much trouble. Now that I have basically set-up my SP10 II reasonably well, it sounds great, and I understand the fuss. Again, it's not because I like machinery. It's because it sounds good.

Performance is the thing with the class D amps I have heard, unfortunately. Not up to scratch.

[Antripodean]

I ask with the technology that's around at present why would Dan D'Agostino not build a Class D amp, that costs in materials less than half to make, has more watts per channel, weighs a quarter as much, sucks way less power, is better for the environment, and makes him loads more profit?

Because it still doesn't sound as good as a linear amp, that's why. Sure, technology moves forward but is the driver for class D better sound? Most talk about reduced weight and power efficiency. Bruno P doesn't say his N-Core is as good as a linear amp, just better than his hypex UCD series. That's what he is measuring against. Bruno P is moving to improve sound quality but not all are. And if this step up suits most of his market then he can stop there and work on other aspects, like the power supply.

One thing to also look at is where Class D in audio is measured - 20Hz to 20KHz. Some Class D pro amps are now measuring to 10Hz but there is a conscious need to design to acheive lower frequencies. Well designed old school Class AB amps could always deliver under 20Hz but if you think about what's needed in pro audio its actually 30Hz and up. So you need to see actual measurements for FR and distortion to really compare apples and apples. Once that is sorted then we can start listening

[tktran]

Bruno P doesn't say his N-Core is as good as a linear amp, just better than his hypex UCD series. That's what he is measuring against

How do you conclude that?

Actually,

Ncore® is the first class D amplifier not just to nudge the best linear amplifiers, but to surpass them in every aspect relevant to sound quality.

Reference:

http://www.hypex.nl/index.php?option=com_content&view=article&id=89

The other error people are making is generalisation of Class "x" amplifiers. There are good, and bad examples of Class A, A/B, G, H, D or any other type of amplifier. The class is not important, it's the implementation.

The only thing PWM (or Class D) amplifiers have in common is efficiency. And that's it.

Edited August 20, 2011 by tktran

[Orpheus]

How do you conclude that?

Actually,

[/b]

Reference:

http://www.hypex.nl/index.php?option=com_content&view=article&id=89

The other error people are making is generalisation of Class "x" amplifiers. There are good, and bad examples of Class A, A/B, G, H, D or any other type of amplifier. The class is not important, it's the implementation.

The only thing PWM (or Class D) amplifiers have in common is efficiency. And that's it.

If you read this thread carefully, you will see that that is not all they have in common. They use a technology which provides certain challenges with respect to upper frequency response. Some may overcome those problems more successfully than others.

[tktran]

No I haven't been following this thread closely.

I've only been following Hypex's developments for the past decade, and it's latest NCore, which I thought was the initial poster's topic for discussion.

I haven't been following other Class D amplifiers as closely, because in all honesty, a lot of other implementations exhibit all kinds of funky behaviour in the midrange and top octave, which can sometimes be heard, but always measured.

Edited August 20, 2011 by tktran

[Antripodean]

How do you conclude that?

Actually, [/b]Reference:http://www.hypex.nl/index.php?option=com_content&view=article&id=89

The other error people are making is generalisation of Class "x" amplifiers. There are good, and bad examples of Class A, A/B, G, H, D or any other type of amplifier. The class is not important, it's the implementation.

I certainly agree about good and bad implementations of all amps, no matter what class. The quote you cited is pure marketing spiel. What else is an amp manufacurer going to say about their new amp? It's not so good??? So when Bruno P is questioned about NCore on DIY audio the facts are that measurements are made against the UCD and opinions are proferred against linear amps. It's a really interesting thread and well worth reading. Hypex licensed their power supply design from the beginning so there are perhaps many more similarities in some Class D amps. I don't question whether the NCore is better than the UCD. I just question hyperbolic marketing claims.

[Captain Crunch]

I ask with the technology that's around at present why would Dan D'Agostino not build a Class D amp, that costs in materials less than half to make, has more watts per channel, weighs a quarter as much, sucks way less power, is better for the environment, and makes him loads more profit?

The man has a conscience and scruples, but even he will fold once the chips that do the switching frequencies in class D amps are developed to do them at double or triple speed.

Cheers George

Dan D'Agastino wont build a Class D amp until he can get it to sound cold and clinical like his Krell's!

[Zaphod Beeblebrox]

Dan D'Agastino wont build a Class D amp until he can get it to sound cold and clinical like his Krell's!

I have not heard all the Krell amps ever made, but I've heard a few. I would generally characterise them as 'accurate', rather than 'cold'. OTOH, ALL the Class D amps I've listened to sound odd in the high frequency area. Every single one. Some are reasonable and easy to live with (due to a rolled-ff HF). Some are shockers. None can equal the best linear amps. Yet. None can match the better Krell models. IMO. Dunno about the cheaper Krells.

YMMV

[rantan]

i very much doubt he would even need to bother.

Class D amplifiers already sound natively cold and clinical.

Krell amplifiers are the epitome of lean,clean and fast.

Dan D'Agastino wont build a Class D amp until he can get it to sound cold and clinical like his Krell's!