Class D amplifiers and "ringing" (pre-purchase questions)

I don't know but before I switched to tube 150-Watt Rogue monoblocks I ran these with the 475-Watt Crown.

Since I was now running them with a 3.9-Watt amp, I image that I could create some serious SPL's with the Altec A7's and the Crown amp.



This passive horn loaded commercial sub, a Yorkville UCS-1 is rated at 133-dB. continuous program material with a 1,200-Watt amp and the Crown, running in bridged mono can deliver 1,600-Watts.





To the Crown's, driving these are effortless.

 

Well, back in the day, some Class D amps maybe didn't have the strongest bass, at least in autosound which is the field I was in.

Infinity kinda screwed things up for Class D for a looooooong time in a rush to be "first" and make a big impression about the compactness of Class D. Now, first understand that in automotive the amp needs a DC-DC converter which limits efficiency and size overall. So the Infinity product in an effort to be amazingly tiny had just not enough heat sinking and was not a robust performer. Fast forward to later, and a friend extended the feedback loop out past the physical output filter, big heatsinks, good design, good sound. Like transistors amps-and surely tubes decades earlier-Class D started as a new raw technology with sonic problems which then have been refined out over decades. BUT some practitioners still can deliver inferior products for reasons of price and/or poor design. Just like digital audio!

People argue WAY too much about technologies. Belt-drive vs direct-drive? PCM vs DSD? Vinyl vs CD? Class A vs AB vs D vs G/H? All of these by now can have great results, or could be not very good. Ignorant consumers want to find easy rules of thumb and so gravitate towards blanket statements, but the truth is that the DESIGN ENGINEERING and the IMPLEMENTATION (and manufacturing) of said design counts for more than the underlying technology. It's like recordings, the care and skill of the engineers and producers matters a lot more than whether they were recording to tape or PCM or DSD.

 

I just acquired my 2nd Class D integrated amp this week, the Sprout100, the previous being the PS Audio Trio amp a few years ago. If the Sprout turns out as well as the Trio I'll be satisfied. Never had any issue with sound quality with the Trio.

 

I wouldn't say any audible 'ringing' but the clarity is so good I detect a certain 'aspect ' to the top end which I call Hardness and put down to the switching.
Pairing it with the right input/preamp can be useful.

 

RE "louder than usual"

Here's what I found (Wyred 4Sound STI1000). I was initially experiencing the same thing, but found that I had the gain setting on my Phono Stage (PH1) at 40 vice 46 on my PV5. I then bumped the gain up to 50 and the sound from vinyl was fabulous. I will check my other source components tomorrow. But I think (from memory) that you are spot on in your observation.

M~

 

Class D amps are inherently non linear and were made for low power, low heat applications like portable electronics. I used to really not be a fan of high end class D amps. They take a lot of engineering just to overcome the problems, including ringing in high frequencies, the design brings to the table. However the newer class D stuff sounds pretty decent and I’ve really enjoyed a couple of Class D implementations, so I think the days of knocking all class D amps are over. The ones Dynaudio are using in their Xeo 30s sound great.

 

Well they're switch-mode or PWM, so they're non-linear in the same sense digital recordings are non-linear. In other words, if you're going to damn class-D amps for being "non-linear," you better get rid of all your digital content, too.

And yes some were made for low power, high-efficiency use.

But then there are the larger Crown units powering the JBL line arrays, or the ICEpower gear from B&O.

 

That sort of characteristic would certainly show up during bench testing, but I've never seen any sort of similar comment in any reviews, nor have I seen anything similar in all the technical data sheets I've read on class-D components.

 

I agree, they are all getting better.

None of them that I have heard sound better than my tube amps yet. All of them are still miles away from my single ended tube amps.

Still someday, just not today.

 

http://www.tom-morrow-land.com/tests/ampchall/index.htm?i=1

An interesting read on amplifier listening tests.

 

I wonder if this is the same guy that offered the huge prize to anyone that could tell the difference between speaker cables? Anyways equalizing amps to sound the same seems like a cop-out to me. Still it would be fun to compare my 5 watt SE EL84 amp to a 200 Class D amp over some revealing speakers.

Anyways I’d call BS about comparing any tube amp to any solid state amp for the simple reason of tube rush. This guy is saying that no Audiophile was smart enough to bring an amp with audible tube rush to compare to a quiet SS amp and pick up an easy 10K. Seems pretty sketchy to me.

 

No, this isn't the wire guy.

And EQ is only applied if an amp isn't flat. Otherwise someone could bring an amp that rolls-off at 12k and spot it every single time.

But the levels are precisely matched. That is fair, any difference in volume is going to be easy to spot.

I think an amp exhibiting tube rush would be disqualified from the test.

 

I had a couple brands yrs ago.
I tell you bass was overkill.It drove me nuts.
Plus it's very hard to explain.But quite frankly the amps had lots of power..But my listening is ,,,,I could care less about unlimited power and bass. It's how it sounds.and to me .It was unlistenable in the long run.

 

I'm not sure why you quoted that post.

See if you can still get in on the Richard Clark Amplifier Challenge, sounds like an easy $10k for you.

BTW, it is interesting to see the scatter of the complaints about class-D amps, from no bass to bass overkill to...

 

You can't objectively judge anything if you put any kind of EQ or signal processing into the loop.

 

The purpose of the EQ would only be to undo any sort of deviation from flat found in an amplifier a participant would want to use.

The vast majority of amplifiers wouldn't need this, because they're already flat.

So you show up for the test with an amplifier you built yourself, insisting you can hear the difference between it and any other.

They throw your amp on the bench and scope it and the response curve is far from flat. They EQ it, otherwise the test isn't fair, as a curvy amp is going to sound like a roller coaster.

Now let's say you show up with an amp you think is special and they find it measures flat. No need for EQ, now you're comparing just the two amps.

 

Fine and dandy, but you can't put ANY EQ or processing in an audio chain without also changing the sound characteristics of that chain.

Either you compare two amplifier's are they are or you don't. If one of them has an obvious roll off then it really can not be compared to one that does not.

Not that I see any purpose for a comparison like this to begin with.

 

I own a Class D Audio SDS470c; I haven't heard any "ringing" at all.
I'm not sure how that "ringing" anomaly was pushed on Class D.

What class D integrated are you thinking of getting?

 

I love my Crown CTs2000! It sounds Wonderful! Man it's got some "Shoulders" too!
NICE setup Sand!

 

I've always liked Mola Mola, NICE!

Channel Islands makes excellent Class D also!

 

The purpose is to demonstrate that amplifiers with flat outputs are indistinguishable from one another, provided they're used within their normal operating ranges. To dispel the notion that expensive watts sound any different from economical watts.

 

Fine.. then find two amps with flat outputs to compare. But you CAN'T add an equalizer and pretend you're comparing amps!

 

Yes, I understand that there are those who feel that amplifier's that measure alike sound alike.

I also believe that there's no place like home...

 

Guys, the article is talking about overshoot and ringing for the square-wave and the impulse response of these class D amplifiers.. How is it that so few of you are aware of what ringing and overshoot is on square-waves? This is electronics 101 stuff.

 

"All signal processing circuitry (e.g. bass boost, filters) must be turned off, and if the amplifier still exhibits nonlinear frequency response, an equalizer will be set by Richard Clark and inserted inline with one of the amps so that they both exhibit identical frequency response. The listener can choose which amplifier gets the equalizer ."

That seems more than fair to me.