What is Class AA amplification?

Anthony

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I am currently using my old Technics integrated amp,model SU-A700, whilst my Primaluna is getting sorted out. see here for specs: http://www.vintagetechnics.com/integrated.htm

recently i've realised that it really is very musical and enjoyable,which is obviously the reason i bought it in the first place. it is lacking if you analyse it from a hi-fi point of view and it's deficiencies are highlighted if you turn it up alot, but i've found that I don't analyse it I just enjoy the music -which is always a good sign.

i am wondering if this presentation that i quite likeis to do with the amplification type, which is stated as AA. What is this? Can't find anything on the internet about it.

 

Leonard Smalls

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I used to have an SU-V5 back in the early 80s. Very toe-tapping it was too.

And from what I remember "Class AA" was a Technics marketing term to make it sound better than a class A amp.. I don't think it meant anything particularly novel in amp design, just a pretty logo and the usual "first few watts are pure class A".

I always enjoyed the flashing lights though!

 

Biscuit

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there was something they stated as being different about class AA - can't remember what it was though. In the power amps, one section ran in pure Class A and the power section in B IIRC - it was in the manual of the 3000 series amps that Istari Knight is selling, maybe he can post up the info? I seem to remember it supposedly provided more power whilst limiting A/B distortion.

 

meninblack

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I found this:

Class AA Similar to Class AB, Class AA is not generally recognized as a proper amplifier classification, but as a variation on Class AB. In a proper Class AB amplifier, at some signal level, the amp operates in Class B with only one output leg active. In Class AA, the inactive leg never completely shuts off, but stays in Class A, but with a significantly lower idling current.

 

TIU

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4_aa_batteries.jpg


It's the power supply.
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:TheBird:
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:TheBird:

 

Anthony

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thanks people. must investigate Class A amps further. I must quite like the sound (even my cdp has a Class A output stage), and as I have more recently discovered I alsoseem to preferthe sound of valves to solid state amps I've heard.

Seems like I will have to get a listen to that Bewitched amp next year which has valves and Class A operation.

 

dudywoxer

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While your sorting that, have a listen to the sugden class A amps- run warm, but probably no warmer than valves.

 

Boxer

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Anthony, the Wigwam's pet Krell is heavily biased into Class A (that's why I had to leave it to cool down for so long at the end of the Edinburgh Rumpus!), so when we played it at slightly lower volumes, ie when I wrested control of the volume from Umberto, you did hear pretty much Class A at times.

I suspect this is part of why I preferred the Krell to the Expo 3010, which is a more typical Class AB circuit.

Boxer

 

Anthony

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dudywoxer wrote:

While your sorting that, have a listen to the sugden class A amps- run warm, but probably no warmer than valves.
have wanted to hear one of these for a while, but can't at a dealers if i'm not in the market to buy one. one day though.

 

Anthony

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boxer wrote:

Anthony, the Wigwam's pet Krell is heavily biased into Class A (that's why I had to leave it to cool down for so long at the end of the Edinburgh Rumpus!), so when we played it at slightly lower volumes, ie when I wrested control of the volume from Umberto, you did hear pretty much Class A at times. I suspect this is part of why I preferred the Krell to the Expo 3010, which is a more typical Class AB circuit.

Boxer
aah, of course - it had got pretty warm if I remember correctly.

sonic assault volumes are all well and good if you always listen at that volume, but I find it moreinformative to listen to kit at the volumes I normally use. If I like it and can get engaged at those volumes then I know it's good enough for me. If it still sounds as good when really loud then that's an added bonus in my book.

 

istari knight

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Ive got a despcription in the manaul to my power amp - will post it when home....

IIRC it says it offers the quality of class a with the none of the drawbacks....

James.

 

Anthony

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istari knight wrote:

Ive got a despcription in the manaul to my power amp - will post it when home....IIRC it says it offers the quality of class a with the none of the drawbacks....

James.
cool, thanks. my manual has long since been misplaced.

 

Davewhityetagain

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istari knight wrote:

Ive got a despcription in the manaul to my power amp - will post it when home....IIRC it says it offers the quality of class a with the none of the drawbacks....

James.
shock.gif.7732780fe7e208b945ce79ca96402fca.gif
:shock:
shock.gif.7732780fe7e208b945ce79ca96402fca.gif
There are no drawbacks to "Class" A
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Boxer

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Not if you like a toaster/ frying pan/auxilliary heaterin your living room and keeping a power station running by yourself, with associated `leccie bills:D.

Have noticed electricity consumption has gone up since I got the Krell (low starting point, which is how I can tell)
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.

Boxer

 

notaclue

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Anthony wrote:

I am currently using my old Technics integrated amp,model SU-A700, whilst my Primaluna is getting sorted out. see here for specs: http://www.vintagetechnics.com/integrated.htmrecently i've realised that it really is very musical and enjoyable,which is obviously the reason i bought it in the first place. it is lacking if you analyse it from a hi-fi point of view and it's deficiencies are highlighted if you turn it up alot, but i've found that I don't analyse it I just enjoy the music -which is always a good sign.

i am wondering if this presentation that i quite likeis to do with the amplification type, which is stated as AA. What is this? Can't find anything on the internet about it.
I suspect that MosClassAA (to give it its full name) is more a Technics marketing thang. Technics were always coming up with technobabble like this.

I also have a SU-A700. Not exactly a battleship but a lovely looking amp. A Hi-Fi Choice tech' test showed that the Technics actually put out almost 80 watts so pretty powerful too.

Interestingly, I also have a Pioneer Precision amp. Both were reviewed in the same Hi-Fi Choice.

The Pioneer was a 5 star 'best buy' classic and said to be the best amp on test. The Technics got a lousy two stars. I used to think the Pioneer was much better (in my audiophile days) but now I find they actually sound pretty much alike... Very similar indeed...

 

istari knight

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Davewhityetagain wrote:

istari knight wrote:
Ive got a despcription in the manaul to my power amp - will post it when home....IIRC it says it offers the quality of class a with the none of the drawbacks....

James.
shock.gif.7732780fe7e208b945ce79ca96402fca.gif
:shock:
shock.gif.7732780fe7e208b945ce79ca96402fca.gif
There are no drawbacks to "Class" A
wink.png
I think they meant from a design standpoint Dave
wink.png
(no massive heat sinks - high power consumption etc...)

from the manual :

Since developing it in 1985 , Technics has used the Class AA circuit in many amplifiers. Conventional Amplifiers had one amplifier to carry out two functions; Voltage amplification & driving the current to the speakers. The Class AA Amplifier combines two separate amplifiers that perform these functions separately.

The two amplifiers are the Class A voltage Control amplifier , which Controls the entire amplifier , and the class B current drive amplifier , which makes the drive current to the speakers. This combination means you get the great sound of Class A and the driving power of Class B.

The MOS Class AA usesa MOS-FET , which has outstanding input & output linearityin the voltage Control amp and a bipolar transistor in the current drive amplifier for its High current drive ability. The result is that no unwanted sound is added , separation & positioning are good , and that the sound source is expressed with a high degree of precision.

There you have it !
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:cool:
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