Amplifier Class Elitism??

[JMac]

As anyone who has seen any of my recent posts may know, I've been looking for a new amplifier. Having read numerous reviews and forums etc one thing thats become apparent is an apparant instant dismissal of anything Class D. Class A seems to be accepted as the best with a begrudging nod to A/B but then anything else is dismissed out of hand. My question is why?

I'm sure a class D done well can be just as good an amplifier as a class A/B. Arent cyrus class D and Bel Canto but they seem to get good reviews.

 

[Singslinger]

You're right JMac about Class D being just as good - I use an MBL Corona C51 integrated in one system which uses MBL's particular variation of class D and I find it very musical indeed. Before that I had a Jeff Rowland Continuum 500, which also operates in class D and was very detailed and warm, though IMO not as musically involving as the MBL.

I wouldn't let the class operation be a significant consideration, unless the heat generated by class A might be a problem.

 

[chebby]

As anyone who has seen any of my recent posts may know, I've been looking for a new amplifier. Having read numerous reviews and forums etc one thing thats become apparent is an apparant instant dismissal of anything Class D. Class A seems to be accepted as the best with a begrudging nod to A/B but then anything else is dismissed out of hand. My question is why?

I'm sure a class D done well can be just as good an amplifier as a class A/B. Arent cyrus class D and Bel Canto but they seem to get good reviews.

I've heard good examples of all three that you mentioned.

A/B is usually biased such that only the first very tiny fraction of the output is class A, so it's basically operating in class B for everything you can actually hear. My old Naim Nait was one such example. (But I have heard a couple of A/Bs where the amp is class A up to 20 Watts per channel or more. So, through efficient speakers at moderate volumes, it's all class A.)

I have heard valve class A, solid state class A and A/B 'hybrids' (valve pre and MOSFET power stages.)

I have lived with class D for three and a half years - so far - and it sounds great to me.

Class D is catching on more and more as manufacturers get to grips with implementing it properly. It is incredibly power efficient and never gets hot (or even warm) which is a bonus.

 

[plastic penguin]

As anyone who has seen any of my recent posts may know, I've been looking for a new amplifier. Having read numerous reviews and forums etc one thing thats become apparent is an apparant instant dismissal of anything Class D. Class A seems to be accepted as the best with a begrudging nod to A/B but then anything else is dismissed out of hand. My question is why?

I'm sure a class D done well can be just as good an amplifier as a class A/B. Arent cyrus class D and Bel Canto but they seem to get good reviews.

Personally don't read too much into different classes. Sure some classes such as 'A' is a little more draining on the National grid than say class 'D'. But really, all that matters is which make of amp has the right tonal quality for your needs.

 

[Al ears]

As anyone who has seen any of my recent posts may know, I've been looking for a new amplifier. Having read numerous reviews and forums etc one thing thats become apparent is an apparant instant dismissal of anything Class D. Class A seems to be accepted as the best with a begrudging nod to A/B but then anything else is dismissed out of hand. My question is why?

I'm sure a class D done well can be just as good an amplifier as a class A/B. Arent cyrus class D and Bel Canto but they seem to get good reviews.

I've heard good examples of all three that you mentioned.

A/B is usually biased such that only the first very tiny fraction of the output is class A, so it's basically operating in class B for everything you can actually hear. My old Naim Nait was one such example. (But I have heard a couple of A/Bs where the amp is class A up to 20 Watts per channel or more. So, through efficient speakers at moderate volumes, it's all class A.)

I have heard valve class A, solid state class A and A/B 'hybrids' (valve pre and MOSFET power stages.)

I have lived with class D for three and a half years - so far - and it sounds great to me.

Class D is catching on more and more as manufacturers get to grips with implementing it properly. It is incredibly power efficient and never gets hot (or even warm) which is a bonus.

I have boldened the very relevent section in chebbys reply. I think this says it all. Early attempts at Class D amps were a bit of a disaster and I think this is where the 'dismissal' comes from. Each to their own but I think anyone who has not yet experienced a modern Class D amp is missing out somewhat.

 

[Covenanter]

Class A was materially better than Class B in days of yore because the cross-over distortion was odd harmonic which is particularly grating to the human ear (or I should say some ears as lab tests in the early 1970s showed that some people couldn't hear it at all). With current day designs I think it's probably inaudible for nearly everybody and I wouldn't worry about it.

Chris

 

[Cypher]

I think the biggest advantage of class D is the low noisefloor. The sound is so incredibly clear..........haven't heard any A/B amplification accomplish that. It's a bit hard to describe but listen to the NAD D3020 for instance and you know what I mean. It sounds more pure and natural.

Also the upcoming Sprout amplifier from PS Audio has digital amplification.

 

[unsleepable]

There are more examples of top-class class D amplifiers, apart from those mentioned—such as Primare and Devialet.

What concerns me is that, in order to make them sound good, the preamp sections may be tailored to the power amps. So I don't know if a Primare power amp would match well with a non-Primare preamp.

 

[unsleepable]

The latest Cyrus Lyric seems to be. Also, the upcoming Naim Muso.

 

[CnoEvil]

There are a lot of differing opinions out there, which is why I like to encourage people to try each Class of amp and then make up their own mind as to which they prefer.....which was why I suggested that you try Bel Canto (as well as a Class A), in your other thread. (I don't think Cyrus is Class D, but could be wrong).

Generally though, people do not go to the effort of trying different topolgies, and just go for a mainstream 5* product (generally AB).

 

[matt49]

There are more examples of top-class class D amplifiers, apart from those mentioned—such as Primare and Devialet.

[Puts pedant's hat on.] Devialet isn't Class D. Technically it's a hybrid, with the signal generated by a low-power (1W) pure Class A amp and the current supplied by Class D modules. But in terms of the signal path it's pure Class A, as the Class D modules are fully slaved to the Class A amp and therefore functionally "invisible". This has two theoretical advantages: you get the near-perfect linearity of Class A, but because the Class A unit is so small, it generates relatively little heat, which means lower running costs and unmeasurably low thermal distortion. The overall distortion figures are AFAIK the lowest ever measured for any audio amp.

And it comes in a nice shiny box.

*dirol*

Matt

 

[spockfish]

I guess it's all about the implementation. Class D in itself is 'rather simple', but getting it right is 'rather complex'. What you (still) see is that a few companies use a standard component (B&O's Icepower, Hypex modules) and imho those amp's often 'fail'. Bel Canto for example uses Icepower. These amp modules are also heavely in use in the diy world. "In general" you could state that these off the shelf amp modules are reasonibly good, but they also have some serious drawbacks. Recently I listened to a Bel Canto (they look fabulous btw!) but I was not impressed.

Recently there's a 'new breed' of class D amps where manufacturers build a custom solution: Devialet comes to mind of course, but also Nuforce is one of them.

In 20 years I expect class D to become widely accepted (and deployed) in hifi. The energy efficiency being the biggest accelerator for this.

My 2 cts.

 

[Al ears]

Cyrus Lyric is indeed Class D although all of their integrated amps currently available are Class AB.

The efficiency and size of Class D amplifier modules mean they are becoming utilised by many manufacturers in their 'all in one' systems.

 

[chebby]

In 20 years I expect class D to become widely accepted (and deployed) in hifi.

5

 

[lindsayt]

I listened to a Bel Canto Evo 2 class D amplifier at a bake-off. It made pianos sound all wrong.

Listened to a matchbox sized class D amp at another bake-off. It was OK for rock and pop music, but again sounded all wrong with piano music.

Listened to another matchbox sized class D amp at another bake-off. We used some pop music to compare it against an A&R A60 (class A/B). The A60 sounded better. The sort of "Phew, that's a relief!" better when we put the A60 on after the class D.

 

[Cypher]

I hope to see more products like the NAD D3020 in the future. Including the small size...........a bit tired of why every hifi product has to be 43cm (width).

 

[andyjm]

There are more class D amps manufactured than any other class. Most portable devices (pads, pods, smartphones) use class D. Rather like the speaker manufacturers who can't see past their wood glue to embrace active designs, analogue amp designers seem determined to cook their output drivers and ignore the benefits of switching designs. It will happen eventually.