Good Class D amps ??

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11 minutes ago, esldude said:

For starters performance matters more than class of operation.  Each class of operation has its own areas of difficulty.  It really is a poor way to pick what equipment to use. 

 

Below are the graphs at moderate power from Stereophile testing of three well known brands of very powerful amps of class D, A and AB operation.  Which is which? The drive level is at 8 ohms, 4 ohms and 2 ohms with lower impedance giving higher distortion in each case.  We are looking at roughly 20 watts into the 8 ohm load and all amps are capable of well over 200 watts.  This graph is THD+N vs frequency. 

 

 

 

 

 

 

My wild guess is that the 1st is the class D...or maybe the 3rd...

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1 minute ago, esldude said:

Come on now, guess which is A and AB also. 

 

Ok, ok, my guess is that the 1st is A, the 2nd, AB, and third D...

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4 minutes ago, Kal Rubinson said:

The first is labeled Krell KSA-250.  Not a mystery.

 

Ha, I did not notice that...but I got it right!  Do I have "golden eyes" when it comes to THD?!?  

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12 hours ago, emcdade said:

I had a NAD M12/M22 combo that...Next day I was very excited to bring my NAD combo in and see how they sounded with the Sopras.  It was not good.  Dry, sterile, clinical, boring, etc. etc. etc.  Now it could've been partly to blame on the room being pretty damped, but the Sopras are pretty truthful to the electronics behind them

 

For what it is worth, I have never heard a NAD combo that I liked.  IMO, it must be NAD's "house sound" and not whatever circuit topology they are using...

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1 hour ago, sandyk said:

 According to prominent Audio designer and Author Douglas Self :

 

 

I don't get it, I don't think you are intending to affirm "All designs have areas that have to be handled." but you in fact did.  The area that Class A needs help is just another area (e.g. heat/power/efficiency, etc.).  "less linear" (your emphasis) is just one of those areas.  The audiophile personality you quote agrees.

 

What is a good class D design in your opinion (you know, the topic)?

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Just now, esldude said:

I think your fake post intended to compare to Soulution amps.  

 

I would say that GUTB's attitude about a host of things is fake Audiophilia, but sadly it is not...

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1 hour ago, GeneZ said:

 

 

FYI...   The S300 comes with an audiophile fuse. Found out its soldered in for best connection.  Learned that from PSA customer service. Its one more reason it sounds so good.  On the other hand,  I had to put an audiophile fuse in my ST-10.

 

Have you tried the balanced connections? 

 

A couple of years ago when I was researching NuPrime amps, I noticed a high amount (relative to the other amps I was considering) of user reports of strange amp/speaker interactions.  Don't recall much specific, but I would say that anyone considering a NuPrime amp, which is as you say is a unique/proprietary circuit design, do their best to make sure there are not known issues with their speakers/set up...

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1 minute ago, ShawnC said:

Could be, thus waiting on the new amp to arrive.  My emotiva and McIntosh amps I’ve had in this current system were able to recreate the highs I’d expect.  The McIntosh wasn’t powerfull enough, so that’s in a second system. 

 

Funny, I would consider the signature of an Emotiva amp to be almost the opposite of a McIntosh, even when factoring in that generally most folks overemphasise the signatures of amps (usually)..

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28 minutes ago, GeneZ said:

Strange speaker interactions?   Such as?    (sniff.. sniff)

 

Not motivated to document it for you (cough).  I recall  one forum where the (or perhaps "a") principal of NuPrime fielded these reports, and did not deny them...

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27 minutes ago, GeneZ said:

 

Do you have a 2 ohm speaker?  Know anyone that does?  Most people should not be so concerned....

 

On the contrary, they should be concerned.  Unfortunately manufacturers play a rating game (one reason I like Andrew Jones {Elac, etc.} - he does not play this game) where they rate their speakers at "8 ohm" when they dip below 4, 3 ohm, or more (see many KEF speakers for just one of many examples).

 

With many popular modern speakers, these NuPrime products are less than ideal for exactly the reasons we are talking about, and NuPrime even admits this.  For some strange reason you seem to be claiming the opposite.  This is not to say these products don't have other positive qualities, or that they work for you or many others, but this is an issue and no amount of denial is going to change it...

 

edit:  here is an example:

 

https://www.stereophile.com/content/kef-r700-loudspeaker-measurements

 

"The impedance magnitude (solid trace) remains between 4 and 6 ohms for almost all of the audioband....", and yet it is sold to the consumer as an "8 ohm" speaker.
 

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20 minutes ago, GeneZ said:

No problems here...  NuPrime was specific about no 2 Ohm speakers.  Not 8 Ohm speakers that may dip down lower.  That means a 2 Ohm speaker will dip lower than 2 Ohms.    Apparently some people with 2 Ohm speakers had a problem.   NuPrime also warns about certain amps with REL subwoofers, because REL has an unconventional way of hooking them up directly from your amp's outputs.   They are just trying to avoid certain audiophiles with rare problems.

 

I promise I will not drive my BMW in the back woods over the rocks and hillsides.

 

 

 

For those of us that have observed this for awhile (e.g. check out JA's measurements of the usual "audiophile" brands going back years) it is the norm that an "8 ohm" speaker is really a 6 ohm or 4 ohm speaker (that dips below 4, 3, or even lower).

 

Interesting what you say about REL (I run REL's).  REL's tap the amp's outputs with a high impedance (going from the top of my head, >10K) simply for a signal.  Can't think of a reason this would be a problem for an amp.  What's NuPrime's explanation as to why it is for their circuits?

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1 minute ago, GeneZ said:

 

Learn something before you storm the castle walls with your torches and pitchforks..

 

Its not about just Nuprime.   Class D design by default causes problems with REL Subwoofers.

 

Look at the REL page and look up about hooking up Class D amplifiers. https://relsupport.zendesk.com/hc/en-us/articles/115004486607-Class-D-Amp-Connection-Methods

 

Settle down Beavis, you appear to be overly defensive of Nuprime.  

 

I don't run class D so I did not know about REL's problems with them (and I don't remember this when I was looking into them).  Good thing I did not get to the point of purchasing as I do run REL's.

 

I like the fact that NuPrime pushes things with an unconventional design, but they are not for everyone...

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11 minutes ago, GeneZ said:

...
High output current drive capability for low impedance speakers.

...

 

Hum, interesting marketing claim.  "Normally" this claim is made around current delivery doubling down for each halving of load (e.g. if 100w at 8ohm, then 200w at 4ohm, and so on).  NuPrime does not do anything like this, so what is the basis and thinking around this claim I wonder. 

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6 minutes ago, esldude said:

Now something like a Maggie which is 4 ohm, and needs a bit of power, the Maggies are almost entirely resistive.  So the Nuprime type amps would likely be fine and dandy with those. 

 

Hah, we were responding at the same time.  I was thinking of Maggies and the like that NuPrime might be good with.  Dynamic speakers, at least the majority of all the usual suspects, would not appear to be the best fit for NuPrime.  Of course, this is Audiophiledom so as long as you like it then...  ?

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46 minutes ago, wgscott said:

I use a class D amp to power my pencil sharpener:

 

 

 

Yea, but it leaves the graphite grainy and the words come out soulless...

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22 minutes ago, GeneZ said:

 

Why is coloration having to always be bad?   This is an audio system that has glaring deficiencies in the light of what a real live performance sounds like. I have heard too many live performances that I wished I was hearing instead on a good stereo.  Today top bands travel with engineers who know how to better "color" their sound in a given room.  Coloration is the work of an artist. All mastering recording engineers find ways to better color the sound when they can improve what is heard. 

 

There is 'bad' coloration. There is 'good.'  All audio systems color the sound. Every time I recorded my drums what I heard in play back was not what I heard while playing.   Everything gets colored in some way.

 

Now?   Where were we? ?

 

17 minutes ago, jmpsmash said:

I was careful to not say that coloring is bad. That's pretty much why we add preamps. Otherwise, everyone will be running attenuated DACs directly into power amp.

 

 

Coloring maybe a necessary evil but that does not make it a good thing.  Art and Wine audiophiledom certainly supports it (and more importantly, sells it) but an older High Fidelity wanted transparency instead or rather as much as you could get given limitations in tech.

 

All that said I have a tube preamp in my headphone rig just so I can play with tuby coolering....

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3 minutes ago, GeneZ said:

 

 

That's how I came across?    I was speaking of speakers rated at 2 Ohms. (which is how the premise was worded).  Not speakers that simply dip into 2 Ohms.  Meaning,  some speakers dip near to zero ohms.

 

Like here!  https://www.audiocircle.com/index.php?topic=18325.0

 

Not disagreeing with you on the back and forth, but the end user (consumer) of speakers is better served by looking at the "dip" as opposed to the rating.  Since there is a rating game going on, the rating is as often as not not informative.  So the "dip" becomes a more useful data point.  Often, the "dip" is down around in the mid bass where there is alot of musical energy (particularly in modern genres) and so the consumer should be interested how the amp/speaker are going to perform there...

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3 hours ago, GeneZ said:

Why not cut to the chase? 

 

Someone ought to manufacture an amplifier and call it...   "The .00001 THD."

 

It would eventually gain the nickname...   "Are you Happy Now?  Amp."

 

Why not cut to the chase:

 

"...Just one power cord to my DAC transforms the entire system..."

 

its nickname would be...Audiophile!  Or would that be Audiophool?

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23 minutes ago, Matias said:

To be fair, even though I am curious to see THD measurements, truth is that big names like Nelson Pass and Dan D'Agostino do not care much about lowest THD. Instead they just design their amplifiers just sound good.

 

I don't know about Dan, but yes Pass does investigate and "builds in" 2nd order distortion and the like because folks like it.  This "coloring" is known (if not well understood) and part of the Audiophile world.  Its relationship to fidelity is controversial.  GeneZ point is the common art and wine radical subjectivism with the strawmen "how does it sound", etc. and is the usual trope.

 

On topic, THD and the like are relevant, correlated to the sound, etc.  It's not the end of the story, but it is part of it...

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22 hours ago, Matias said:

 

Hear it for yourself: 

 

 

Thanks.  A defensive of the artisan status quo, that an an advertisement for his company...

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8 minutes ago, GeneZ said:

  You're obviously missing the point.  The one he was making in spite of the fact that he is world renown at what he does.

 

Nope, the point is made again and again and again.  Anyone who has been in audiophiledom more than a day already understands that measurements such as THD are correlated with good sound quality, but are not the exact measurement of SQ, that a bit of 2nd and 3rd order distortion (but not too much) is liked by many (most?) and is why tubes have stuck around, etc. etc.  The video is just more of the same.  

 

The real point of the video is to sell Dan's "world renown" art in coming up with just the right amount of "mystery" (his word) distortion so that the sound is "musical".  Same old same old.

 

Your a happy customer however 😋

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4 minutes ago, GeneZ said:

  Do you enjoy your system?  Could it be better?  Have you already heard better? 

 

What are we looking for?  

 

2 minutes ago, GeneZ said:

Do you know how you sound?  How your response resonates?

 

Blah blah blah radical subjectivist trolling...your barking up the wrong tree.

 

Dan, Pass, and the like are the folks whom you want to discuss your feelings with, the "mystery" of the musical 😋

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2 minutes ago, Matias said:

Please move objective x subjective to another topic... My point was to compare their measurements, not the merits of such comparison. Let us keep talking Good class D here please.

 

The merits of measurement comparisons are exactly on topic in that they are related (if controversially) to what a "good" class D is.  The problem is that someone inevitably does not like measurements and how they question a purely art and wine evaluation (such as GeneZ).

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7 hours ago, Matias said:

Bruno has left Hypex a while ago and is now one of the owners of Purify Audio. He is finishing a next generation of class D amplifiers which are superior to nCore: the Eigentakt. More info here:

https://6moons.com/audioreview_articles/purifi/

 

Thanks.  At first I thought it was "just another project" but:

 

"...Hypex and I separated amicably a while ago so they're not involved in any of the new work. Measured and sonically, the Eigentakt circuit isquite a step up in performance from Ncore. So we're indeed looking to establish it as the new high-end standard. Purifi is actually three entities – one that does fundamental research into both loudspeaker driver units and amplifiers, then two subsidiaries to commercialize drivers and amplifiers respectively..."

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2 hours ago, firedog said:

Will be really interesting to hear (about) these when they debut. NAD has done some good things with their own implementation of NCore. If these are really an order of magnitude better, they could be game changers if at some point the price isn't in the stratosphere. 

 

In my opinion, unless they are not priced 'in the stratosphere' they can not be game changers.

 

At the risk of losing my objectivist credentials, once you push into the "high end" price range then everything should sound really good/great, have good features/implementation, etc.  NADs/PURIFI  THD/IMD numbers are past the point of meaning, as are most modern solid state amps (tubes have their own rules with their inherent characteristics).  So it comes down to that part of the sound that do not correlate with measurements, speaker interaction, etc...