[DaveC113]

Dave, I am interested in your thoughts re cable design and pairing with Ncore amplifiers.  Because Class D amps all rely on L-C output filters, I would expect that any cables which which exhibit high levels of capacitance or inductance could change the RF profile getting through to the cables.  Additionally, I suspect that some cables which exhibit high levels of C or L may even create resonance when combined with the output filter.  It would seem wise to use a cable with a balanced level of L and C, and as little of both as possible.
Also, since the output filter on  Class D amp is never perfect, and high frequency noise does show up on the output, a cable with a geometry designed to limit the antenna effect (to reduce RF broadcast which may be picked up by components and other wires) would seem to be a wise choice for use with class D amplifiers.
I have quite a bit of experience with ICE, uCD, and Ncore amps, and I would suggest that anyone auditioning these amps make sure to have them powered up for at least a few hours, if not overnight, before doing any critical listening.  Without extended warm up, none of these amps sound their best-often I think quick listening to a cold class D amp is responsible for many negative first impressions.

It seems like the performance of cables paired with class D amps is less predictable vs tube or transistor amps. Cables also have more of an effect on the sound of a system with many class D amps. I'd agree with using cables that don't have excessive L or C , which should be the case with some rare exceptions. I'm really not sure why class D amps seem to react to cabling (and vibration) more than other amps. As far as RF noise on the amps outputs, I have heard it's possible but it should be at very low levels. If the speaker cables are broadcasting RF shielding them would prevent that, but I doubt it's necessary. D amps can be tweaky but they do have a lot of potential, and the digital manipulation of AC power to make music is an accomplishment, those Crown amps weigh around 10 lbs and are putting out a lot of power with super high efficiency and good sound quality for a few hundred bucks. I can't see them beating a good tube amp on high efficiency speakers though... at least not yet. 

[Folsom]

Dave, they use an oscillation to be shaped to the signal. Vibrations effect on a itty bitty oscillation? Yes, they do well with reduced vibrations.

Excessive L or C will always be bad. But even if you could have no L, you'd have new problems.

The relationship to "digital" is only that they switch on and off in a binary way on top of an AC signal. There's no 010101 sorts of data that is digital.

The PSU is another topic for class D....

[Steve]

Have not read the posts, so if I post something already posted, please forgive me.

A simple check of the specs from:

http://www.hypex.nl/docs/UcD180HG_datasheet.pdf

we see this stat:

Frequency Response 10 - 50k Hz +0/-3dB. All loads

Unless a super high pass filter, with high slope, is incorporated, the low frequency response will alter the perception into the upper bass and lower midrange, if not higher.
 
Thus we see one variation from accuracy right away from the manufacturers own specs.

Notice this spec:
http://www.hypex.nl/docs/NC400_datasheet.pdf

Frequency Response 0 50 kHz +0/-3dB. All loads.

Much better low frequency response, more accurate.

This is just one spec I quickly noticed. Again, if this has already been posted, please forgive me for reposting.

Cheers

Steve

[DS-21]

That was an incredibly rude personal attack DS-21.

How is a simple description of your post (someone who hawks mere wires promoting idiot mythology in support of his pecuniary interest) "an incredibly rude personal attack?

When salesman's not shilling I guess he has to be chagrined for being called out for shilling.

Sorry to be here sharing my experience with class D amps, what is it you're doing here exactly?

Hoping to read something about Class D amps, specifically to see if anyone has actually measured a Crown Drivecore to see if they're good class D (load invariant, like the Hypex, Icepower ASX2, and Anaview modules) or low-fi/sub-only class D (most everything else) not wade through some sales-hack's idiot myths about mere wires.

As for my experience with Class D amps, I recently bought a pair for my desktop system that have the potential for vastly superior sound than any discussed here so far, including the Ncores. (And the potential for vastly worse sound!)

They are the miniDSP PWR-ICE125.

The Class D amp part of them, admittedly, is as sonically transparent (competent amps have no sound at all, unless you strike them with a mallet or something, of course) as an Ncore or whatever. However, they also have a sophisticated DSP board that can be used to apply parametric EQ, and thus improve both the direct-field response (with appropriate EQ based on nearfield measurements) and modal region response (in a small area, with appropriate EQ based on listening position measurements). Another cool thing about them is that in my system they have no AD/DA loop, because they can take a digital in and share it. So it's digital from the computer to the mains plate, digital bridge from the mains plate to the sub plate. Now, Meyer and Moran pretty convincingly showed that a single AD/DA loop is not going to be audible in their AES-published study. However, it's certainly theoretically better NOT to have one.

Oh, and my digital wires are Monoprice's "3-pin DMX Lighting & AES/EBU Cable," which carry appropriate price tags for a commodity part such as a mere wire. They are at least equal to anything you sell, and possibly superior for this application because they meet ABS/EBU spec and who knows what spec the voodoo brew of some "audiophile" mere wire salesman meets.

[wushuliu]

I just picked up a used once 2000 off of Ebay for $300. I will compare it to my Job amp running my Zellatons and report back. The Job amp is actually the very first amp on my dirty AC to never me any problems, especially fatiguing headaches.

Look forward to hearing  your thoughts on it. I love the TPA but high/low pass features and extra power would open up a lot of options speaker wise...

[bummrush]

Class d grabs you at first but is unlistenable long term Had b c and red Dragon

[werd]

can anyone guess who has the most unlistenable Hifi on this thread?

[bummrush]

I really wanted to like them.But I was very surprised They were very clean souding.But unemotional

[wushuliu]

Class d grabs you at first but is unlistenable long term Had b c and red Dragon

The amps you listened to may be unemotional. Not all Class D are the same. Funny the Class D amps I think are great are based on chips that very few companies are using e.g. Classdaudio.com/IR and TPA311X. They are mainly diy. Even though there is now a large fanbase building them. Don't know why there aren't more retail offerings out there. Such a shame.

[DaveC113]

Ds21 there is no "mere part" of a system, the rest I will not address. I'm glad you found a system you enjoy

[jk@home]

I just picked up a used once 2000 off of Ebay for $300. I will compare it to my Job amp running my Zellatons and report back. The Job amp is actually the very first amp on my dirty AC to never me any problems, especially fatiguing headaches.

I would also be interested in how that turns out. I just ordered a Crown Drivecore 1500 to try with my KEF LS50s...and the Job amp is said to also play nice with the KEFs.

And I have a question regarding class D amps (and the Crowns in particular) and bridging them to mono. Is there a reduction in sound quality as would normally be on a Class A/B amp, or not? As cheap as the Crowns are, it would be easy to swing two mono amps. Not necessarily for more power, but just better channel separation, etc.

[barrows]

I really wanted to like them.But I was very surprised They were very clean souding.But unemotional

I would suggest that it is unhelpful to categorize all class D amplifiers together.  It is doubtful that anyone on this thread has heard every possible implementation, and, as has been noted on the thread, many class D amps are sensitive to different speaker loads, wires, and vibration control.  My own Ncore amps sound a lot better with some input wiring changes, for example.
No one would lump all class A/B or class A amplifiers together and characterize their sound one way.  And I would never want an "emotional" amplifier, the amplifier should be neutral to allow the feeling of the music itself to come through.  If the amplifier has emotion of its own, then it is coloring the sound and altering the music.

[jonbee]

  My own Ncore amps sound a lot better with some input wiring changes, for example.

Can you elaborate on your approach to this? I've been eyeing upgrading my input wires as well.
I've enjoyed my n-cores from the start, but I found upgrading the wima caps to the "nuded" polys supplied by Ric Schultz made them notably more relaxed sounding, while losing none of their strengths. They are about as dead neutral sounding as anything I've heard, yet also very transparent and dynamic.
I've owned at least 10 "class D" amps over the past 15 years or so (still own a modded PS Audio Icepower amp, and a Magellan Tripath), and they all do sound different, and steadily better, IMO.
My audio buddies own "conventional" amps, such as big Berning tube amps, Bakun SS, Shindo SEs, etc., and guess what? They all sound great, and also different. In an overall sense, I can't say I prefer any of them over my n-cores, but I've gone to great lengths to tune the system cabling, etc., to get the results I like.
Is chocolate, vanilla, or balsamic vinegar better tasting? Context, of course, is key.

[cab]

No one would lump all class A/B or class A amplifiers together and characterize their sound one way. 

Yet we see this all the time with class d. At this point, as soon as someone makes the all inclusive "class d amps are ________", I know immediately they haven't a clue and read no further.

[bummrush]

If your comment is for me I could care less I had two of good quality and they didnt stand extended listening. If u find different fine.
I could easily say the same to you because of yout liking them.But it seems you dont csre for others opins

[barrows]

If your comment is for me I could care less I had two of good quality and they didnt stand extended listening. If u find different fine.
I could easily say the same to you because of yout liking them.But it seems you dont csre for others opins

well, I did quote you after all.  There are opinions, and there are facts: the fact here is that if you want an amplifier which sounds "emotional", then you are looking for an amplifier which is adding color to the music, and not letting the actual intent of the music through.
An amplifier such as a well implemented Ncore build will reveal any flaws in the rest of the system, whereas a more forgiving amplifier may cover up flaws in the rest of the system.  Even my Pass X150.5 is less revealing of system problems than my Ncore, and the Pass is not exactly a low resolution amp.  Sometimes one may need to address problems when a higher resolution component is dropped in to an existing system.
Of course you are free to prefer whatever you might like, but making blanket statements referring to all class D amps based on hearing two specific amps is not a helpful opinion.  I could say that all tube amps absolutely suck if I based my opinion of tube amps on hearing only two examples of such, and I have heard plenty of tube which sounded great as well.

jon: I changed the signal input wiring on my Ncores to 21.5 gauge Cardas litz wire, I use this wire a lot for signal path applications.

[cab]

jon: I changed the signal input wiring on my Ncores to 21.5 gauge Cardas litz wire, I use this wire a lot for signal path applications.

try some occ silver, 28 gauge, in cotton, in a 8 conductor braid....best I have heard and I have tried a lot...

[Freo-1]

There are excellent, mediocre, and poor sounding amps of all classes.  So, for arguments sake of this thread, let’s stick to the amps that most audiophiles hold in high regard, and compare the merits and challenges of each.  For tube amps, would also include DIY, as some of the BEST sounding tube amps I have heard were custom made types.

For Class D, the best sounding unit I have heard was the Yamaha MX-D1.  The audiophiles I know who have heard it all have been very impressed with its sound.  Although it’s not the most recent design, it remains competitive with other more current Class D designs.  The MX-D1 has a number of propriety design aspects that makes it an excellent performer. 

What really gets difficult is how to capture the differences in sonic presentations between any two amps, regardless of operating class.  Most all modern amps measure pretty well, and show fairly flat frequency responses into a 8 or 4 ohm resistive load.  Yet, we all know that the amps DO sound different from one another.  With some speakers, the differences in sound between amps may not be very noticeable.  Yet with other speakers, the differences are more pronounced.  There have been several lengthy discussions about sound versus measurements over on another Audio website.  One of the engineers who participate in the threads stated that he personally did not think the current set of measurements offered up fully captured the sonic presentation from a given amplifier.  He thought that measurements could be developed to capture these details, but we currently do not have them available commercially. 

I have subjectively noticed that the Class D amps that I have owned or heard DO present the music slightly different to other topologies.  Some aspects seemed as good as or better than other topologies (such as a clear midrange and vocals), while other aspects were not quite as good (2D vs. 3D, high treble hardness, some listener fatigue).  ALL amps deviate (slightly) from absolute neutrality, and the speakers used with the amps have a far great effect on the sound than the amps.  Devices like the power cube can provide a better set of measurements of amp performance, but even that doesn’t quite capture the full story of what it is that is heard. 

[jonbee]

try some occ silver, 28 gauge, in cotton, in a 8 conductor braid....best I have heard and I have tried a lot...

Hmm, good ideas. Thanks, guys. How did you handle the connectors?

[G Georgopoulos]

There are excellent, mediocre, and poor sounding amps of all classes.  So, for arguments sake of this thread, let’s stick to the amps that most audiophiles hold in high regard, and compare the merits and challenges of each.  For tube amps, would also include DIY, as some of the BEST sounding tube amps I have heard were custom made types.

For Class D, the best sounding unit I have heard was the Yamaha MX-D1.  The audiophiles I know who have heard it all have been very impressed with its sound.  Although it’s not the most recent design, it remains competitive with other more current Class D designs.  The MX-D1 has a number of propriety design aspects that makes it an excellent performer. 

What really gets difficult is how to capture the differences in sonic presentations between any two amps, regardless of operating class.  Most all modern amps measure pretty well, and show fairly flat frequency responses into a 8 or 4 ohm resistive load.  Yet, we all know that the amps DO sound different from one another.  With some speakers, the differences in sound between amps may not be very noticeable.  Yet with other speakers, the differences are more pronounced.  There have been several lengthy discussions about sound versus measurements over on another Audio website.  One of the engineers who participate in the threads stated that he personally did not think the current set of measurements offered up fully captured the sonic presentation from a given amplifier.  He thought that measurements could be developed to capture these details, but we currently do not have them available commercially. 

I have subjectively noticed that the Class D amps that I have owned or heard DO present the music slightly different to other topologies.  Some aspects seemed as good as or better than other topologies (such as a clear midrange and vocals), while other aspects were not quite as good (2D vs. 3D, high treble hardness, some listener fatigue).  ALL amps deviate (slightly) from absolute neutrality, and the speakers used with the amps have a far great effect on the sound than the amps.  Devices like the power cube can provide a better set of measurements of amp performance, but even that doesn’t quite capture the full story of what it is that is heard.

 

class-d is relatively new type of amplifier,it hasnt been tested in the marketplace,many are eager to try them in high power,will see how they go in the future?