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Good Class D amps ??


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10 hours ago, sandyk said:

Why should this be of concern for people who use say, 20W to 50W maximum Class A amplifiers, when Class D amplifiers used by many members at ear splitting levels into inefficient speakers STILL consume far more electricity overall ?

 Have you gone " Green"  and become a " Tree Hugger " too ? 

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

With my class d amplifier, which actually sounds a bit better, I leave it on 24/7 and it idles at ~10 watts.  Big difference.

 

But, I chose the class d amp because it sounds better, and the energy savings is just a bonus.

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10 hours ago, barrows said:

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

With my class d amplifier, which actually sounds a bit better, I leave it on 24/7 and it idles at ~10 watts.  Big difference.

 

But, I chose the class d amp because it sounds better, and the energy savings is just a bonus.

 

The Perreaux I used years ago was a cooker - the huge heat sinks were not for show, they were almost at burning your fingers temperature, at idle. But I only got the best sound after many hours conditioning, so it was 24/7 :o; when one is chasing for optimum, you make sacrifices ... ^_^.

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10 hours ago, barrows said:

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

 I imagine that someone like Nelson Pass has since found a way to overcome this problem ?

A well designed SS amplifier should sound very close to it's best within minutes of switch on.

 The main problem is with the front end devices fully stabilising.  The output stage transistor Bias can also take a little while to reach it's designed value. This can also be overcome by proper temperature compensation measures.

They tried to do this in some power transistors using an integral separate diode.(ThermalTrak)

With my DIY Class A Preamps and Power Amplifiers I use a method of temperature compensation in the Input Differential Pair , using a Silicon Diode with a similar temperature coefficient.

This was discussed in a DIY Audio thread from 2008.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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12 hours ago, barrows said:

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

With my class d amplifier, which actually sounds a bit better, I leave it on 24/7 and it idles at ~10 watts.  Big difference.

 

But, I chose the class d amp because it sounds better, and the energy savings is just a bonus.

I had a Passlabs too and I agree with your statement. Also because of the thermal stress their sound deteriorated over time; I guess as mostly the caps aged. Now my main amplifier is a Devialet D250 Pro which is a hybrid classA/D and for my woofers a DIY class D (Anatech). I have Kharma MP150 which are Hypex derived and they are sitting in the garage (beautiful little red things).

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Amps from the Digital Amplifier Company are not based on either NCore or ICE, but on a completely custom solution.

 

The Maraschinos get fabulous reviews from everyone that hears them. The least expensive version is less than $1K.

 

The newest Megaschino amp is better still. It uses a large transformer and 12 output devices per channel vs. the 4 used in the Maraschino. In my experience the highs on the DAC amps are superior to the ICE and NCore implementations I have heard. Designed and made in the USA.

 

A recent review:

http://www.jeremykipnis.com/MEGAschino_Review_-_03_18.html

 

 

 

 

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On 3/28/2018 at 1:59 PM, Ralf11 said:

from the other thread...

 

apparently anything based on NCore is good & maybe the new ICEPower models

 

 

 

I intended to mention this before now.  Class D amps do have output filtering to remove the switching wave they work upon.  This makes them a little touchy about which speaker they are partnered with and probably why the common complaints are about the treble.  So mine works great with my speakers, but may have some output treble anomalies with other speaker loads.  I tried mine with some nice Audio Physics speakers once and it was not pretty.  Sometimes hard to tell which speakers causes issues.  Early Tripath based class D had a fairly large problem with this.  Great on one speaker horrid on another.  Later IcePower modules were somewhat better, but different companies use their own modifications to the output filtering.  Bel Canto leaves more output impedance than most.  Others use what is stock configurations.  And everything in between.  Ncore has been least effected by this though again various makers may use various filtering schemes.  

 

Here is an example using an early IcePower Bel Canto.  Measurements done by Stereophile.

 

Black line is their simulated loudspeaker load.  Blue is 8 ohms, magneta is 4 ohms and red is 2 ohms.  Obviously they optimized their filter for 4 ohms. 

555Belfig1.jpg

 

Here is Bel Canto's recent Hypex Ncore based amp from 2016.  Colors refer to the same impedances. 

 

916BC600fig1.jpg

 

So if I were going to try an amp now in the price range the OP has mentioned I might try a Nord which uses the Hypex Ncore modules. 

 

 Do notice the upper graph has an expanded scale and the worst curve for the simulated loudspeaker has a maximum variation of about .4 db until you hit 20 khz.  Possibly audible, but not horridly off.  Certainly a variation of the lower graph of maybe .1 db is better.  

 

EDIT to add:

 

Here is a more recent IcePower based result.  Still more variation than Ncore, but less than previously. 

 

218PSM700fig01.jpg

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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1 minute ago, Ralf11 said:

kit components, or ??

DIY, using Hypex NC-400 modules and SMPS-600 modules.  See:

 

https://www.hypexshop.com

 

for details...  

SO/ROON/HQPe: DSD 512-Sonore opticalModuleDeluxe-Signature Rendu optical with Well Tempered Clock--DIY DSC-2 DAC with SC Pure Clock--DIY Purifi Amplifier-Focus Audio FS888 speakers-JL E 112 sub-Nordost Tyr USB, DIY EventHorizon AC cables, Iconoclast XLR & speaker cables, Synergistic Purple Fuses, Spacetime system clarifiers.  ISOAcoustics Oreas footers.                                                       

                                                                                           SONORE computer audio

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On 3/27/2018 at 9:24 AM, barrows said:

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

With my class d amplifier, which actually sounds a bit better, I leave it on 24/7 and it idles at ~10 watts.  Big difference.

 

But, I chose the class d amp because it sounds better, and the energy savings is just a bonus.

 

Class D sounding better than a Pass is fake news.

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2 hours ago, Ralf11 said:

kit components, or ??

 

Hi Ralf,

 

Nord Acoustics in the UK assemble hypex amps for around 1200 -2000 US. The owner, Colin, is a terrific fellow and is great to deal with. He offers a range of mono, stereo and multi channel amps. I'm in Sydney and had no issues with delivery.

 

https://www.nordacoustics.co.uk/nord-one-up-nc500-power-amplifiers

 

I purchased the Nord One UP NC500DM Stereo amplifier about 18 months ago and have been very happy with its performance driving a pair ATOHM GT1 bookshelf speakers (French). I have also driven pair of ATC SCM19 (UK). Neither speaker is particularly efficient and I have experienced none of the problems that GUTB dribbles on about. 

 

From their web site:

 

"The UP Stereo Block Power Amplifier in Black uses our own Nord designed Input Buffer Board delivering all the benefits of standard amp but with even better dynamics and a richer, warmer more musical tone. Twin Hypex NCore NC500’s, Twin Hypex SMPS1200A700 PSU’s and Twin Nord UP Input Buffer Boards Board in a true Dual Mono design incorporated in a single stereo case. Same sound quality as the Mono Blocks."

 

all the best,

 

Ajax

 

LOUNGE: Mac Mini - Audirvana - Devialet 200 - ATOHM GT1 Speakers

OFFICE : Mac Mini - Audirvana - Benchmark DAC1HDR - ADAM A7 Active Monitors

TRAVEL : MacBook Air - Dragonfly V1.2 DAC - Sennheiser HD 650

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3 minutes ago, Ajax said:

 

Hi Ralf,

 

Nord Acoustics in the UK assemble hypex amps for around 1200 -2000 US. The owner, Colin, is a terrific fellow and is great to deal with. He offers a range of mono, stereo and multi channel amps. I'm in Sydney and had no issues with delivery.

 

https://www.nordacoustics.co.uk/nord-one-up-nc500-power-amplifiers

 

I purchased the Nord One UP NC500DM Stereo amplifier about 18 months ago and have been very happy with its performance driving a pair ATOHM GT1 bookshelf speakers (French). I have also driven pair of ATC SCM19 (UK). Neither speaker is particularly efficient and I have experienced none of the problems that GUTB dribbles on about. 

 

From their web site:

 

"The UP Stereo Block Power Amplifier in Black uses our own Nord designed Input Buffer Board delivering all the benefits of standard amp but with even better dynamics and a richer, warmer more musical tone. Twin Hypex NCore NC500’s, Twin Hypex SMPS1200A700 PSU’s and Twin Nord UP Input Buffer Boards Board in a true Dual Mono design incorporated in a single stereo case. Same sound quality as the Mono Blocks."

 

all the best,

 

Ajax

 

 

Only you can say if you’re pretending to like the sound or not.

 

I’ll note that no one with high end systems prefers class D.

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7 hours ago, barrows said:

 I also find Herbies Tenderfoot soft/tall footers are a better match with this amp than the Stillpoint Minis I used to use.

 

Of course, you are undoubtedly referring to performance issues, not their looks.

 Not that some members will accept that things like this DO matter!

 A C.S.I.R.O (Au.) friend of mine is a big Herbies footers fan too.

 P.S.

 As expected, some very nice workmanship on your part.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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1 hour ago, GUTB said:

 

Class D sounding better than a Pass is fake news.

Nope, it is entirely true in my system.  It took a bit of work to get the amp right, but once it was I sold the Pass.  It was not a night and day difference, but ultimately the Ncore had a lower noise floor, better detail retrieval, bigger dynamic contrasts and a deeper soundstage.  At first the Pass had a bit of an edge in terms of body and timbre, but the changes I made to the Ncore's wiring pulled it even in that department.

I did not make any spot decisions on this, and kept both amps around for over a year before selling the Pass, switching back and forth, etc, as I was a bit unwilling to believe it myself, but the listening does not lie.

 

Clearly you have not had enough experience with the best that class D has to offer in the right systems.

SO/ROON/HQPe: DSD 512-Sonore opticalModuleDeluxe-Signature Rendu optical with Well Tempered Clock--DIY DSC-2 DAC with SC Pure Clock--DIY Purifi Amplifier-Focus Audio FS888 speakers-JL E 112 sub-Nordost Tyr USB, DIY EventHorizon AC cables, Iconoclast XLR & speaker cables, Synergistic Purple Fuses, Spacetime system clarifiers.  ISOAcoustics Oreas footers.                                                       

                                                                                           SONORE computer audio

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37 minutes ago, barrows said:

but ultimately the Ncore had a lower noise floor,

There is no valid reason why the Pass should not have had a lower noise floor unless it was a much earlier design, or it's main filter electros had partially dried out due to heat related issues.

The nCore obviously would need a huge amount of work done to eliminate the extremely high RF/EMI generated by the switching action at a very high power level, partly due to FCC requirements, whereas the Pass would not need this.

 Could it be that the nCore has a noise gating action in the absence of a valid signal ?

If so, I suppose something like this could also be done with a Linear amplifier to further improve S/N to ridiculously low levels for specification boasting purposes ?

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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16 minutes ago, monteverdi said:

Did you ever had a newer Hypex (or Anaview) derived amp next to a Passlabs?

 Just remember that many of you would be pitting the very latest technology against a much earlier design  Pass amplifier.

Linear Amplifier design has also further improved in recent years as evidenced by the extremely high S/N of the Benchmark design.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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27 minutes ago, barrows said:

Nope, it is entirely true in my system.  It took a bit of work to get the amp right, but once it was I sold the Pass.  It was not a night and day difference, but ultimately the Ncore had a lower noise floor, better detail retrieval, bigger dynamic contrasts and a deeper soundstage.  At first the Pass had a bit of an edge in terms of body and timbre, but the changes I made to the Ncore's wiring pulled it even in that department..

 

A good result - a 'clue' as to how I go about things, ^_^, what I'm always looking for in the beginning is "better detail retrieval, bigger dynamic contrasts" - "body and timbre" can come later; something that has that, and not much else, is going to be much more work to sort - not really worth it, IMO. Plenty of driving guts in the sound is an excellent signpost - if it's "rough and ready" that's not so important; can be sorted, over time.

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