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Class D Crown vs. Hypex nCore


richieb

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8 minutes ago, babadono said:

@DizRotus I have the receipts for my La Scalas that I bought there if you want the address, I'll dig'em out , hopefully they're not too faded. And yes they were on the east side of Woodward. I think between 12 mile and Catalpa.

 

That would be great.  A pic of one, with personal info redacted, would be even greater.  It's not important, but it does bug me trying to recall which storefront it was.

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4 minutes ago, babadono said:

Roger wilco. But not until later when I'm home, got this work thing getting in my way right now:)

 

Come on now - lets get your priorities straight! Work-forum --- work-forum --- work-forum.

I think the answer is clear and right in front of you --- and if you don't happen to be the Boss let me know.

I'll send him a note with your excuse for sub-par attention to the tasks at hand --

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10 hours ago, DizRotus said:

Hey @ClaudeJ1 do you know the street number of High-Fidelity Workshop from when it was on Woodward?  When I drive on Woodward I can't be certain where it was.  What Mile roads was it between?  I recall it being on the east side of Woodward.  What's in that space now?

Got my Khorns and mono LaScala center there back in 1977. The owners wanted to retire and the employees coudn't afford to buy the business, so they closed. IDK exactly where it was, but I do remember meeting Bob Moers there when I was barely 20. That was many moons, amps, and Klipsch speakers ago including 2 pairs of Khorns.

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8 hours ago, DrWho said:

The Rdson specs aren't the limiting factor when it comes to MOSFETs....switching losses typically dominate the heat generation.

 

I just wanted to mention that Class D designs that maximize efficiency 'usually' aren't maximizing the distortion capability of the system. It's a nice benefit that we don't need massive heatsinks, but the real benefit of Class D is that it has incredibly good performance at low signal levels. I think talking about the heat generation distracts from the true benefit of Class D, which sonically speaking, when implemented well, is going to be superior to Class A. I know some engineering friends that would cringe at that, but I think the numbers are defensible. The characteristics of a delta-sigma encoding are far better than a voltage encoding, but you have to be willing to accept a paradigm shift. We can encode signals in voltage, current, and time. Classical audio uses the voltage encoding because it's easy to wrap your head around, but is it the best medium? Why not encode in the current or time domains? Or why not encode across multiple domains? Delta-sigma encodes in the time/voltage domain, which is the easiest encoding to minimize errors in - especially for bandwidth limited signals. Class A is voltage domain only, and all of its distortions are related to the time domain, which require making tradeoffs. You can keep making delta-sigma better until you run out of electrons, and the parasitic effects of real parts can be designed in such a way that they just cancel themselves out entirely....

I agree about the switching losses dominating the heat as well as the capacitive parasitics in the MOSFET juncion.  I also agree that the real benefit is how much better than class AB they sound at 0.1 watts with efficient speakers. Every bit the equal of my single Ended Class A Pass Aleph J, which was the best I heard until I got the Hypex NC400. Now I have the best of both worlds WITHOUT the "space heater." This is truly all that matters to mine and other ears.

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Class D usually has problems at low levels due to the dead time required to prevent shoot-thru (which makes them overheat).

 

With low enough Rds-on specs, the DCR in the output inductors can generate more heat than the output stage (many pro designs have heatsinks on the output inductors).

 

I can show anyone wanting to do a commercial design how to eliminate dead time, even over temperature (for a fee of course).

 

(Burr Brown had a very complex design, my idea is simpler).

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16 hours ago, djk said:

Class D usually has problems at low levels due to the dead time required to prevent shoot-thru (which makes them overheat).

 

With low enough Rds-on specs, the DCR in the output inductors can generate more heat than the output stage (many pro designs have heatsinks on the output inductors).

 

I can show anyone wanting to do a commercial design how to eliminate dead time, even over temperature (for a fee of course).

 

(Burr Brown had a very complex design, my idea is simpler).

The dead time has zero effect at low signal levels if you design your modulation properly.

 

 

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The ATI amps (using hypex ncore modules) have excellent measurements at lower wattages, although I'd like to see the first watt expanded cause there looks like a dip thereafter: https://www.soundandvision.com/content/ati-at527nc-and-at524nc-amplifiers-review-test-bench

2017-08-02.png
 

But still, this beats most measurements I've seen except for the Benchmark AHB2.

https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier-measurements

 

Some more good looking measurements from the NAD M22 (scroll to bottom for IMD), I'm thinking they also use hypex ncores:

http://hometheaterhifi.com/reviews/amplifier/power-amplifier/nad-masters-series-m12-preamp-and-m22-stereo-power-amplifier-review/

 

3 hours ago, DrWho said:

The dead time has zero effect at low signal levels if you design your modulation properly.

 

 

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  • 5 months later...
On 7/31/2017 at 5:11 PM, DrWho said:

In college we set out to make our own Class D amplifier. We researched all the options on the market at that time and UcD was definitely the best. Those cheap T amps were close to the worst and limited by the power supply quality. We sat down to understand the limitations of the UcD architecture and came up with a design of our own (sitting on the shoulders of giants). A few years later the nCore series was announced, and it implemented all of the same things (and more) that we had identified in college. That's not to say we were doing anything incredible in college, but to say that the improvements of the nCore are quite dramatic and rather straightforward. I've never met Bruno, but based on his writings we see eye to eye on just about everything. I have the utmost respect for his engineering acuity, and yet he still respects the audiophile phenomenon and cranks out crazy stuff.

 

All that to say, the nCore amplifiers are without a doubt the best amps on the market. They're so good that you have to build special measurement equipment to even quantify the improvement. That's just crazy. Or rather, that's just testament to Bruno's quest for perfection.

 

I too am quite interested by the nCore powered products that Klipsch is coming out with. Are they available yet? Anyone heard one yet?

 

Do you know how the Hypex nCore compare to the best ICEpower amps or even ClassDAudio (brand) amps? The Hypex nCore is extremely expensive. I have not found a brand that offers them at what I would consider a price within my budget for the value they may offer.

 

I find your post very interesting about UcD vs. nCore though. The Klipsch amplifier uses UcD and so does the NAD amplifier around $500. A TEAC around $300 uses an ICEpower though is only rated something like 25watts. ICEpower ASX2 is supposed to be better and there are multiple tiers of ICEpower.

 

I think Nord is the cheapest around $800 for a 50 watt RMS per channel power amplifie using Hypex NCore NC252MP twin channel Module, so maybe I would consider that. I'd still need a preamp/DAC. It is Hypex nCore MP which is supposedly 85-90% as good quality (as the non-MP?) nCore lines. Not sure exactly.

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On 1/30/2018 at 10:45 PM, nicesound said:

Do you know how the Hypex nCore compare to the best ICEpower amps or even ClassDAudio (brand) amps? The Hypex nCore is extremely expensive. I have not found a brand that offers them at what I would consider a price within my budget for the value they may offer.

 

I find your post very interesting about UcD vs. nCore though. The Klipsch amplifier uses UcD and so does the NAD amplifier around $500. A TEAC around $300 uses an ICEpower though is only rated something like 25watts. ICEpower ASX2 is supposed to be better and there are multiple tiers of ICEpower.

 

I think Nord is the cheapest around $800 for a 50 watt RMS per channel power amplifie using Hypex NCore NC252MP twin channel Module, so maybe I would consider that. I'd still need a preamp/DAC. It is Hypex nCore MP which is supposedly 85-90% as good quality (as the non-MP?) nCore lines. Not sure exactly.

There are some shoot outs between amps made with these different implementations.  I have four different flavors if Ice up to the REF-1000s.  They sound great to me.  I also liked the NAD implementations with NCore.  It really is going to be a personal preference.

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I've had both nCore from Acoustic Imagery and now Ice module amps from Wyred, monos both. The nCore are currently being enjoyed by Cincy who seems to really like them. To be honest the sonic differences between the two module types and applications are 6 of one, half dozen of the other. I could tell little if any differences. But of course that's my ears, my room, my rig.

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8 hours ago, DizRotus said:

If I’m not mistaken, Claude, @ClaudeJ1, has both as well as a class D Texas Instruments 3255EVM board.  I’m certain about the TI3255 and Hypex nCore.

He’s in a good position to make comparisons.

Yes I am, but it won't happen until I build a power supply and chassis for the two TI 3255's, which will be used to drive a CF, LS, RS, and CR channels in a surround sound setup while the Hypex Monos will be on L and R Danley SH-50's with seemingly endless Headroom!

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9 hours ago, richieb said:

You are correct in that he built nCore kit amps bought from Hypex. I recall him being quite happy with them.

Yep. Also A/B compared to Audio Research Class D DS450M Monoblocs that a friend has (about $10,000 worth) and I could tell no difference with my Hypex NC-400's in his excellent room with all the custom treatment.

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I’ve read a lot of positive reviews and comments about the nCore Class D amps. I am curious how they compare to the TI TPA3255EVM Class D amps. I still have to piece together a linear power supply to run two TPA3255EVM in PBTL, but now I am thinking that I would like to build two monoblocs instead. 

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