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Class D

Thanks for the comments and advice, hifinutt and hairyderriere. I am using my Qdac as a pre as it has a variable control so I can play it all day at low volume to get the hours up.

NAD do some interesting stuff with their class D offerings and have achieved some high ratings on Audio Science Review. They are not keen on Valve amps though.
 
I've just been trying out some Nuforce Reference 18 v3 monoblocks and it's only after putting the Vitus power amp back in that I'm able to tell the hallmarks of the amp. I'd say the thing that lets me know it's 'class d', are when you hear hand claps and not much else - a slight digital splash sound maybe being the best description I can get to. Strings, voices and natural sounding instruments just sound exceptional though, and there's no giveaway I can tell.

Although I can (if I pay close attention) tell the difference, I think it's pretty clear (to me anyway) that the overall sound is exceptional, the mid-range is fluid, the noise floor is zero and there is none of this solid state grain you often hear (even with power amps like the Cambridge audio edge stuff) and the treble is essentially just transparent and very much there. I decided to give a fair bit of music a go and it was musical, great bass with excellent transients etc. I take it all back. I think you need to really get in to the very high end to compete and I think it stands in it's own right, just like tubes do or class A does etc.

How are you getting now with a bit more time? Friday getting closer....
 
One of the main differences I noticed with class D was that the character doesn’t change as you turn the volume up, the sound just gets bigger without any sense it’s going to run out of steam ( as with valves) or coarsening you can get with classAB. I had never experienced that before since I couldn’t afford high end muscle amps like Krell.
I thought it was a little drier in terms of harmonics, recording venue reverberation but that might have been my imagination.
 
Alas, alack and woe is me! The experiment finishes.

I have enjoyed the M22 and it has many great qualities. It is beyond doubt the quietest amp I have ever used. It has great detail and can sound lovely to the point of breathtaking.

BUT and you could see it coming it doesn't really gel with my KEF Reference 3.2's. On paper its should. It has massive power and 35 amps of current to drive the 3 and half way design (treble, upper mid, lower mid and bass for the pedants).

It was the 70's prog that did for it. On quieter tracks it was great. Roy Harper - Stormcock was brilliant. King Crimson - Cadence and Cascade was delightful but tracks either side were no longer epic but small scale and when power was needed it faded.

This happened on Dark Side of the Moon, ELP - Trilogy and Tarkus, Van de Graaf Generator. Fragile by Yes sounded good but Firth of Fifth by Genesis crumbled.

I am demoing a Musical Fidelity M6 PRX and my musical tastes and speakers it is more suited. Soundstage is deeper and projects forward of the speakers. The M22 in contrast is shallower and hangs back.

So sadly, the M22 is being collected tomorrow. Kudos to Sevenoaks they are a fab firm to deal with and their returns policy is excellent, quick and easy.

I think there is a lot that is great about class D and I am sure it will improve and progress but with my system and speakers it isn't weaning me off class AB just yet.
 
Good call, Bairnstorm.

As an interesting aside, Marantz noted this Class D effect on the gain structure of amps. One of the designers said he keeps both traditional Class AB amps to use with older recordings alongside their new 10.

I'm not sure how they account for it but their view is that newer production workflows depend almost exclusively on Class D gain chains and, as such, are better served by the 10.

For classic rock, jazz and older classical recordings, amps built in that era (when production and mastering workflows used more traditionally designed amps) seem better suited to the gain structure and reproduction of those recordings.

There's more on this discussion on phileweb (like me, you might need to use Google Translate) as the Marantz engineers and sound designers talk about the Reference 10 and why they designed it this way.

https://www.phileweb.com/interview/article/201703/30/440.html

https://www.phileweb.com/interview/article/201703/30/440_5.html <<< sound character discussion starts here.

"Mr. Sawada: A switching amplifier that uses a switching power supply like the PM-10 does not have a huge block capacitor like an analog power supply. A capacitor is a tank that stores electricity to drive a speaker, and you can think of a transformer as a tank that stores electricity here.
A condenser is a "suspicious substitute" with non-linear characteristics, and is an element that colors the sound. And it is the condenser that most influences the sound when tuning the amplifier. However, capacitors are indispensable for analog amplifiers, and how to organize them well is the highlight of your skill.

On the other hand, in some switching amplifiers, the cause of coloring, which is a large capacitor, does not exist for good or bad. That's why it sounds so brightly. Of course, there are conflicting factors, and it is not possible to tune the sound quality with a capacitor, and there are also problems that need to be solved unique to switching amplifiers, such as noise suppression."


"Mr. Ogata: Analog amplifiers are generally pyramid-balanced and have a solid low range, but for example, when combining PM-10 and 800 D3, the low range is clean and the texture of the entire band is complete. Also, the sound will be rather smart.

So, let alone acoustic recording, if you play music such as EDM [Electronic Dance Music] and programming, it will be easy to understand that it is PM-10. I used the SC-7 and MA-9 in combination with the previous generation B & W "802 Diamond" at home, but when I tried this and changed it to the PM-10, the sound of the 802 Diamond became completely different.

I also tried connecting the PM-10 to the pre-out of the AV amplifier, which was also very good. The sound of the movie is also a built-in sound, so I felt that it was a good match in that sense."


"Mr. Sawada: I think that it is suitable for contemporary software as a whole. Of course, it's not that the PM-10 isn't suitable for classical recordings and jazz that audiophiles will love. However, these works have a strong impression of being heard with classic speakers and amplifiers, and on the contrary, they may feel strange.

Some people say that the sound of PM-10 is very clear and good, but it's too refreshing and tasteless. ...Even if you don't have a character, it's not perfect enough to be heard through a transparent glass window. It may be frosted glass or it may be a little cloudy.

However, with analog amplifiers, the timbre changes slightly due to changes in frequency and dynamic range. This can be a factor in creating comfort. On the other hand, in a switching amplifier, the timbre is constant with changes in frequency and dynamic range.

...However, I have no intention of denying the nostalgic sound, and I am one of those who like it. At home, I also use B & W when playing modern recordings, but when I enjoy classical recordings, I use Tannoy's Autograph and tube amps. ...As long as switching amplifiers are used as monitors in the field of music production, audio playback cannot be the same as before. In that sense, the sound of the PM-10 will make a difference to the current audio."
 
TheDecameron said:
One of the main differences I noticed with class D was that the character doesn’t change as you turn the volume up, the sound just gets bigger without any sense it’s going to run out of steam ( as with valves) or coarsening you can get with classAB. I had never experienced that before since I couldn’t afford high end muscle amps like Krell.
I thought it was a little drier in terms of harmonics, recording venue reverberation but that might have been my imagination.
Click to expand...


Agreed. I sometimes don't realise quite how loud it is until someone talks to me. It's just effortless and clean.
 
My Class D twopenny's worth - I have two class D amps

Roksan Oxygene - Sexy small form factor. Warm occaisonally holographic sound. Excellent bluetooth streaming. Very very good.

Primare i35 - The scandanavian architect. Excellent soundstage and micro detail. Currently doing great things into my Stirling LS3/5a V2's (Falcon chose this amp to demo their LS£/5a's at recent shows). Excellent

The Primare is certainly up there I think with top SS amps (eg Leema Tucana ii)
 
Audited few class D in dealers comparing to traditional A/B , still does not convince me lacks the warmth... though it has shown much improvement in these years. The best class D so far I have heard was NAD master M32 seems based on nCore, wonder if their newer models or Lyngdorf Purifi models would be much better.
 
Mat C said:
Audited few class D in dealers comparing to traditional A/B , still does not convince me lacks the warmth... though it has shown much improvement in these years. The best class D so far I have heard was NAD master M32 seems based on nCore, wonder if their newer models or Lyngdorf Purifi models would be much better.
Click to expand...

Funnily enough I’m beginning to think the argument could as easily be that Class A and AB lack the control and precision, but then I also think SS lacks the holographic presentation compared with tubes, so in the end I think you only ever really choose your favourite compromise based on your preferences and biases and then from there the best you’re willing to pay for.

I will say that comparing an entry level class D amp I use for my subwoofers vs a high end pair of class D monoblocks did a lot to bridge the differences and the mids were exceptionally sweet and treble was very Class AB sounding to me, but with no loss of expertise in the bass department which is (as far as I can tell) common in class D even at entry level.

I haven’t tried all the amps (obvs), but they were my observations!

Edit - I’d really like to hear some of the newest and best Bel Canto stuff to see where that fits.
 
but then I also think SS lacks the holographic presentation compared with tubes,

I use bel canto pre 3 vbs with a sean jacobs into 2 class A monoblocks . the holographic presentation is IMMENSE . absolutely stunning . without a doubt these monoblocks are one of the best at imaging i have had . the class D monoblocks are good but the class A goes further [ with tannoys ]
 
Interesting to see this thread revived, as I have very recently moved away from class D amps (Hypex NC500 based from Acoustic Imagery) and back to class A/B.

I don't think that one can lump all class D amps together as having a certain class D sound. When I bought the Hypex based amps they replaced a Naim NAP 250 and, to my ears, gave a significantly more detailed and accurate sound. I have just replaced the class Ds with a Bryston 4B3 (4B cubed), which significantly out performs them; greater detail, less of a hard edge and way more powerful and accurate bass. Instruments just sound so much more real. The Bryston will also go a lot louder without the sound becoming compressed. Maybe this is because the Hypex units, despite being sold as 400W amps are actually only rated at 100W continuous, whereas the Bryston is rated at 300W continuous.

From this, I can only conclude that the differences between power amps are not necessarily all down to their class, but more to how they match with the speakers they are driving and their fidelity (i.e., how much they distort the input signal and the nature of this distortion; for example, how much does this increase with output power).

One other thing I have learned is that, if my experience is representative, class D amps might be inexpensive, but they are not reliable. I have used five Hypex based mono block amps over the last few years and all of them have suffered from power supply failures. They were all repaired by having the PSU boards replaced. I have sold two of them and, out the remainder, only one is still working correctly. In contrast, my Naim amps never failed and were easily serviced and the Bryston has a 20 year warranty. So if you want reliability, stick with class A/B.
 
From this, I can only conclude that the differences between power amps are not necessarily all down to their class, but more to how they match with the speakers they are driving and their fidelity (i.e., how much they distort the input signal and the nature of this distortion; for example, how much does this increase with output power).

yes agree with this a lot . having had quite a few class D amps over past 15 years , never had one fail but they were all icepower units .
 
I’ve heard lots of claims about this or that being like tubes, but it never quite seems to be. That said, class D (that I’ve heard) has something closer to it than SS class AB so far - it’s all academic though as I’ve not heard everything and as has already been said, it’s easy to think an amp sounds like it does because of its topology type.
 
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Sibbers said:
Funnily enough I’m beginning to think the argument could as easily be that Class A and AB lack the control and precision, but then I also think SS lacks the holographic presentation compared with tubes, so in the end I think you only ever really choose your favourite compromise based on your preferences and biases and then from there the best you’re willing to pay for.

I will say that comparing an entry level class D amp I use for my subwoofers vs a high end pair of class D monoblocks did a lot to bridge the differences and the mids were exceptionally sweet and treble was very Class AB sounding to me, but with no loss of expertise in the bass department which is (as far as I can tell) common in class D even at entry level.

I haven’t tried all the amps (obvs), but they were my observations!

Edit - I’d really like to hear some of the newest and best Bel Canto stuff to see where that fits.
Click to expand...

I onced owned a class D ten years ago, the Esoteric RZ-1 AIO SACD+DAC+Amplifier.... and I sold it shortly. I audited Wyred separated and Teac AP505 Class D in dealers showroom which supposed setup with matched gears but that experience was not really enjoying... You know it is rare cases , as most of the time we would find the sound is not same after brought them home...:)
 
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