PS Audio throws in the towel on Class D

OzarkTom · « **on:** 17 Mar 2014, 09:25 am »

Another amp company is giving up on Class D and that is PS Audio.

BEWARE OF PERFECTIONISTS-Paul's Posts — 17 March 2014
By Paul McGowan

I have officially thrown the towel in on the Class D output stage for the promised new reference amp.

In all honesty, it still sounds terrific and most people would absolutely love what it does and sounds like (I still do). Why give up on Class D? I just can’t get over the bandwidth restrictions inherent in the design, not after hearing what amps that go beyond 80kHz sound like. Not after realizing how much more is actually on our discs through DirectStream. I know it makes no sense. CDs are inherently bandwidth limited to 20kHz, just like class D amps. But play a CD on DirectStream through an amp with no bandwidth restrictions and you’ll never consider going back. I certainly won’t.

The reference amp that we want to build has to be of the same caliber as the DirectStream DAC. And that means it’s as close to the best in the world as we can achieve and stand alongside the few great amps of today without any regrets.

This will mark the third course correction so far, on this sea of change for the amp project, but with a speaker system as resolving as the IRS, a DAC as open and definitive as DirectStream, there can be no choice if perfection is the goal. And perfection IS the goal.

Maybe it’s just my age, but I don’t want to waste any more time on something that doesn’t offer the same level of musical discovery as DirectStream does. Not for the Reference design. Not for the main amp in Music Room One. Not for the amp in my home. Not for the amp I want to hang our hats on and suggest you do the same.

I am currently listening to a prototype of just such an amp. It is a remarkable design from an old friend, someone I respect greatly and someone who has far better design chops than I. Bascom King.

Yes it sets things back yet again. But I am not going to be apologetic. I’ve beaten myself up enough over this already. Our controller and GM have waved enough fingers in my face about the cost of changing directions so many times and now, to hire another outside designer …… start over ….. abandon most of what we’ve done.

Welcome to my world of being a perfectionist on a mission.

cab · « **Reply #1 on:** 17 Mar 2014, 12:43 pm »

More like a marketer with a budget.

He raved about ncore then tried to get the same performance out of the UcD because the ncore was too expensive to meet their "price point". If he was really sincere about creating the "best amp", he wouldn't be worried about a price point, he would simply use the best technology available.

OzarkTom · « **Reply #2 on:** 17 Mar 2014, 01:00 pm »

I doubt if he is worried about the price since he developed the $6K Directstream Dac. But Paul is right about the limited bandwidth on Class D amps.

Last year another Paul of TRL gave up on making the NC1200's sound right. His amps are not cheap, nor is the Dude preamp that some AC'ers own here.

To see the limited banwidth on Class D amps, just look at Soundstage's amp tests through Bascom King. All the Class D amps that he tested drops off at 20khz like a lead balloon.

http://www.soundstage.com/index.php?option=com_content&view=article&id=17&Itemid=141

hifial · « **Reply #3 on:** 17 Mar 2014, 02:30 pm »

But NOT ALL Class D amps were tested and NOT ALL Class D drop off at 20khz. All Class Amps bandwidth are dependent on their individualized design. I believe the NCore NC1200 goes to 50khz.

But it is not just bandwidth that makes an Amp sound great.

rollo · « **Reply #4 on:** 17 Mar 2014, 03:08 pm »

Something is fishy here. IMO politics with OEM vendors. There are some class "D" offering that make their own power supplies and class "D" modules. Guess PS Audio could not figure it out as well. Our Arion amps go from 5k to 70k. Disclaimer. We are dealers for Arion hybrid class "D" amps.

charles

SoCalWJS · « **Reply #5 on:** 17 Mar 2014, 03:16 pm »

The Quote above says that they got up to 80 khz - he just wants it to go higher

Shaman · « **Reply #6 on:** 17 Mar 2014, 03:30 pm »

Understandable, as I hear (pun intended) that bats and mice recently discovered HiFi and a new market is about to emerge.
NCores are relatively expensive, that's for sure. What is more, even if an OEM can accept that cost, it shouldn't be taken for granted that they'll manage to adequately differentiate their product without actually messing up the performance.

SoCalWJS · « **Reply #7 on:** 17 Mar 2014, 03:43 pm »

I will say that after listening to a Super Tweeter with response out to 200 khz that I did hear a difference, although what the upper limit was that actually made a difference I have now way of knowing. Would a super tweeter with response to 50 or 70 khz been the same? No clue.

HOWEVER,

How many speakers, even extremely high end ones, have a tweeter that responds to 80 khz or beyond? Very few I would imagine.

seadogs1 · « **Reply #8 on:** 17 Mar 2014, 03:46 pm »

Did anyone else notice that the Soundstage amp tests were from2001? As several people have noted there are several D amps that go out beyond 20k.

fredgarvin · « **Reply #9 on:** 17 Mar 2014, 04:08 pm »

Again, he's talking about an 80hz limit, not 20:

Quote

the bandwidth restrictions inherent in the design, not after hearing what amps that go beyond 80kHz sound like

To me it sounds like a promotion for the DAC as much as news on the amp...

OzarkTom · « **Reply #10 on:** 17 Mar 2014, 04:11 pm »

Quote from: seadogs1 on 17 Mar 2014, 03:46 pm

Did anyone else notice that the Soundstage amp tests were from2001? As several people have noted there are several D amps that go out beyond 20k.

The Roque Medusa amp is a recent model. So is the Eximus S1.

Folsom · « **Reply #11 on:** 17 Mar 2014, 10:58 pm »

Quote from: fredgarvin on 17 Mar 2014, 04:08 pm

Again, he's talking about an 80hz limit, not 20:

To me it sounds like a promotion for the DAC as much as news on the amp...

Ha!

The TPA3116 with corrected filters might achieve 80khz. It does produce out to 100khz, but suffers from some phase shifting with at least stock filters. On a T.I. questionnaire 40khz is said pretty easy to achieve by filter change. It's not as high power as the ncores. But the point being is class D isn't going to be limited forever.

cab · « **Reply #12 on:** 18 Mar 2014, 12:18 am »

He said in an earlier blog entry that he thought the ncores were amazing but too costly for them to use for their "ultimate amp". He said they thought they could get nearly there for much less with the UcD. Obviously, he is building to a price point despite his later claims to be building the best amp possible. It's all there in his blog entries.

fredgarvin · « **Reply #13 on:** 18 Mar 2014, 01:06 am »

Quote from: Salis Audio on 17 Mar 2014, 10:58 pm

Ha!

The TPA3116 with corrected filters might achieve 80khz. It does produce out to 100khz, but suffers from some phase shifting with at least stock filters. On a T.I. questionnaire 40khz is said pretty easy to achieve by filter change. It's not as high power as the ncores. But the point being is class D isn't going to be limited forever.

I agree, and cheaper too than the ncore.

OzarkTom · « **Reply #14 on:** 18 Mar 2014, 01:21 am »

Quote from: cab on 18 Mar 2014, 12:18 am

He said in an earlier blog entry that he thought the ncores were amazing but too costly for them to use for their "ultimate amp". He said they thought they could get nearly there for much less with the UcD. Obviously, he is building to a price point despite his later claims to be building the best amp possible. It's all there in his blog entries.

Paul said all of this before his IRS system was set up, guess he has changed his mind. I think we have all changed our minds one time or another. He never said the amp sounded bad, he just wants something better for his IRS's.

If you go to his website, you can ask him. I bet he has gotten a lot of flack today over his decision.

cab · « **Reply #15 on:** 18 Mar 2014, 01:40 am »

I really have little to no interest in what he is doing at this point.

DustyC · « **Reply #16 on:** 18 Mar 2014, 05:14 am »

Based on his bandwidth logic the best amps on the planet is the Spectral line. They extend out to approx 1M Hz and need special MIT cables to keep them from oscillating.
But he's not the first to jump into the class D pool and decide the water's too cold. Rowland dropped their line of class D amps also.
Marketing pressures play a big role in this too.

DaveC113 · « **Reply #17 on:** 18 Mar 2014, 05:22 am »

Yup, yup, we still haven't surpassed the 'ol vacuum tube....

firedog · « **Reply #18 on:** 18 Mar 2014, 09:00 am »

We should all note that Paul thought his ClassD amp sounded great. He dropped it because his goal is to make an ultimate statement amp, and he didn't think Class D would quite get him there today. In the future with speedier HW, it may.

GT Audio Works · « **Reply #19 on:** 20 Mar 2014, 11:41 am »

Funny, in my opinion, one of the attributes of the Arion class D hybrid amps was a very refined and transparent treble presentation.
Very pure and free of grain, unflappable at any volume.

Although the recipe is very important, the chef is just as much so.
Maybe they are just not Paul's cup of tea.
Jeff Rowland has adopted class d for his designs, I wonder how he feels about this? Greg