Please Naim make a Class A amplifier

An interesting discussion on the topic from a thread here four years ago ....

What Class Are Naim Amps?

ClassA/B

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

I assume you mean 50W RMS output per channel, so 110W+ per channel heat dissipation, 250W+ electrical consumption and heat output - constantly.

Is the heating in your house insufficient?  Hang on a minute, what about summer time?

Also, you couldn't put a 50W + 50W class A into anything like a standard Naim chassis.  Purely size wise it's possible, but it would look completely different, have much more stringent ventilation requirements and may, quite possibly, need a fan running 24x7!

Seriously, why?
What advantage do you think it has?
What do you think is wrong with Naim's class A/B designs?

Christopher_M posted:

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

I own horn speakers.

AussieSteve posted:

Christopher_M posted:

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

I own horn speakers.

Try AudioNote SET.

Christopher_M posted:

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

Hi Chris, class A amps to tend to have quite a distinctive and attractive sound... and somewhat different character from the majority class AB Naim use... one of my favourite class A amps is the Sugden A21, quite sublime and infectious timing with the right (efficient) speaker, but not really suited to my ATCs and rather inefficient.....

A huge "for gods sake why?" from me...

Moderated Post: Jon, I've edited out your second paragraph. You will know why.

AussieSteve posted:

Christopher_M posted:

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

I own horn speakers.

OK, and... ?

Is there something odd about their impedance (electrical, yes I'm aware that their acoustic impedance is radically different and frequency dependant)?
What is it that makes them impossible to drive with a 80W Class A/B that will be sorted with a 50W pure Class A?

OK, as has been raised by others some Class A amps have a particular sound signature, but that's far from Naim's amp voicing, and has nothing to do with the type of speaker in use.

I still don't see where you're coming from on this.  If you want a Class A amp, as S-i-S says buy a Sugden A21 (or a Masterclass).  Classic class A style electronics classic class A style of sound, and an exceptional amp; but certainly not a Naim style amp (and like most class A amps, nowhere near 50W per channel - there's a reason for that!).

Huge posted:

I assume you mean 50W RMS output per channel, so 110W+ per channel heat dissipation, 250W+ electrical consumption and heat output - constantly.

Is the heating in your house insufficient?  Hang on a minute, what about summer time?

Also, you couldn't put a 50W + 50W class A into anything like a standard Naim chassis.  Purely size wise it's possible, but it would look completely different, have much more stringent ventilation requirements and may, quite possibly, need a fan running 24x7!

Seriously, why?
What advantage do you think it has?
What do you think is wrong with Naim's class A/B designs?

I have an old Musical Fidelity P270, which claimed to be strongly biased into class A. I can't remember the power available in class A - I know its not the full 150W rated output into 8Ω, maybe only quarter of full output or less. but that does mean most of the time it is in class A, with only the loudest transients not in class A. However, it consumes about 250W continuously (scarcely any change even when playing loud), which is enough to heat the large heatsinks on either side (about 12" long by 7" tall with a 1.5" fins) so they are too hot to touch.

However, I think it is common practice with class A amps to switch them off when not in use, as they only take about half an hour for the temperature to stabilise after turning on.

Horn speakers, with their much greater electroacoustic efficiency, need far less power, so an amp that is in class A for only the first few watts would similarly be in class A most of the time, but would run much cooler.

however, I just get the impression that is somply not Naim's scene - and if it were, the Statement power amp would need water cooling (doubling as central heating boiler, perhaps)?

Simon-in-Suffolk posted:

Christopher_M posted:

AussieSteve, Why do you ask? What is it that Naim amps aren't giving you?

Hi Chris, class A amps to tend to have quite a distinctive and attractive sound... and somewhat different character from the majority class AB Naim use...

I know that. You know that. But does AussieSteve?

While appreciating the purism associated with Class A,  there are common downsides, notably the monumental wastage of electricity and the concomitant amount of heat they generate. They require extensive dissipation/cooling. They also have a tendency to hum as the 'spare' electricity is dumped.

So all in all, not ideal.

However, there might be a case to be made for Class A on the tweeters only. It is also possible to design a Class A/B amp to operate as Class A for signals below a certain thresh-hold, providing some of the benefits without all of the downsides. 

My personal view is that Naim is better off doing further development of their existing A/B amps, as Class A would be a niche market at best.

Solid Air posted:

While appreciating the purism associated with Class A,  there are common downsides, notably the monumental wastage of electricity and the concomitant amount of heat they generate. They require extensive dissipation/cooling. They also have a tendency to hum as the 'spare' electricity is dumped.

So all in all, not ideal.

However, there might be a case to be made for Class A on the tweeters only. It is also possible to design a Class A/B amp to operate as Class A for signals below a certain thresh-hold, providing some of the benefits without all of the downsides. 

My personal view is that Naim is better off doing further development of their existing A/B amps, as Class A would be a niche market at best.

Not sure what basis there is for the statement about humming while dumping electricity? The only humming in a decent product is as with other amp classes, including Naim: the torroidal transformer, particularly if the electricity supply  contains a DC component.

regarfpding electricity usage, if compared with an amp on for the same tine period, then yes, but if a class A amp turned off when not in use (bearing in mind the short warm-up and stabilisation time) is compared to a class B or AB design left on continuously, the dirinction is less obvious (depending on usage).

Class A amps are subject to AC 'ripple' on the DC rails - much more so than A/B - which can emerge as hum. There are ways around that - eg capacitance/regulation - but some of the purity is compromised, and the requirement for heat management increases.

I'm not saying these are insurmountable problems, nor that Class A amps aren't good, just that the design has some characteristics that make them unsuited to most needs. There's a reason they're uncommon.

I am not sure a class a is any necessarily more susceptible to ac ripple on the powerline lines compared to class ab.... when you consider the amp as a whole, both can be mitigated ... I think the real issue is that they tend to be quite expensive as poweramp transistor designs, because they are inefficient generating a lot of heat that needs to be dissipated. Preamps  and front buffer stages on amps  tend to be class a because of the inherent quality class a designs can have by biasing into the linear part of the transistors transfer function, it’s just poweramp driver stages class a is less common because of the dissipation, powerhandling and efficiency issues.(For transistors)

well if it helps all Naim preamps are actually class A.

I found as Richard Dane reported many years ago, that the amplifier performance can only be as good as the source driving it.... (and that includes the source to preamp cable)

not really excited about amplifiers hierarchy or performance anymore, as I am with source improvements.

why not think of an LP12 turntable or NDS/555DR instead?

AussieSteve posted:

Please Naim make a Class A amplifier up to say 50w a side, in a standard component chassis size. I will buy one instantly.

Get a 252 and pretend the power supply is a 250. Hide the class A amp somewhere. 

I am not sure Naim is going to make one of a kind for good customers, but I may be wrong. If Naim had thought Class A was the optimal amp design Statement would have been the obvious Class A project.

Claus

Statement in class A would need water cooling with the radiators outside, or just divert the mill stream.

yeti42 posted:

Statement in class A would need water cooling with the radiators outside, or just divert the mill stream.

Fit with those silvery top covers and a couple of doors at the front... and call it an AGA.

yeti42 posted:

Statement in class A would need water cooling with the radiators outside, or just divert the mill stream.

and might not even be possible with current transistors suitable for audio

It's worth remembering that with true Class A power amps there's a large amount of waste heat.  This isn't just inefficient, it can have an impact on reliability and longevity of the components. I learned that the hard way some years ago with a well known UK class A amp that got really hot then broke down - too often for comfort.  The biggest problem was that every time it came back from the manufacturer it sounded totally different to before (not in a good way).  I got rid of it pretty quickly.

It may be possible to improve reliability...

Why not just go out and buy the Audio Note Gaku-On. Should quell your desire for Class A