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Arcam Class G amps ...

beammeup

beammeup

pfm Member
... has anyone had any experience of these newer Class G amps?

I have a few amps kicking around and was going to sell my A29 because it had very little use with my Croft being the main centre piece - but I must admit the A29 is a grower.

From my understanding the A29 runs in 'pure Class A' up to about 20 Watts.

The A29 has a smooth, engaging non-fatiguing sound, but it does seem to need some running in where evidently the sound quality does improve over time. I'm a terrible hoarder of good things without giving them a good listen!

There are mixed reviews on the net but it's certainly not a bad amp in my opinion. Perhaps Class G is another marketing ploy - or perhaps it is a good idea after all so you can have your cake and eat it in the sense you get pure Class A without the inefficiencies and excess heat of a regular Class A amp?
 
i had a class G creek evo 100A and its a lovely thing - there is no noticeable change from class a to g...i only moved it on as wanted to get back into naim.
 
nice , would like to hear the a29 , as i really love my a75 which has tone controls i like and seems to gel with the impulse . the sugden a21se was much better sonically but too much for my ears !! the gentle arcam does me just fine at the moment

i heard a few moans about hum on the a29 , have you had that problem ?
 
Class G is a class AB amp but in order to cut costs such as large heat sinks/casing it is made more efficient by using switchable power rails. Thus with low output the output stage uses a lower voltage = less power and then as the output goes up switches to a higher voltage rail. I just wonder what effect this will have on fast transients? Maybe O.K. for some PA equipment but HiFi?

Cheers,

DV
 
hifinutt said:
nice , would like to hear the a29 , as i really love my a75 which has tone controls i like and seems to gel with the impulse . the sugden a21se was much better sonically but too much for my ears !! the gentle arcam does me just fine at the moment

i heard a few moans about hum on the a29 , have you had that problem ?
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I hadn't noticed - however out of curiosity I just put my head close to the amp and yes there a small sort of light minor buzz - but nothing that's audible away from the amp. Similar I suppose to the Croft in that respect.
 
/\ it can be class A before switching rails, as said up thread. A good way of keeping costs down and yet giving class A most of the time with higher power available for peaks. Doug Self published such a design in WW.
It is most often used in PA amps for efficiency reasons but it has other uses;)
 
I've had a good listening session this afternoon and it really is a good sound - big boned, good presence, with sweetness mixed in - nothing at all harsh that's for sure.

The more you turn the volume up - the more the music expands rather than sounding strained - not bad at all!

Needs running in I'm sure. You've gotta give these things time.

I have a feeling this may not be an Arcam fan club site but the A29 is presenting itself well. I use good speakers that tell me how it is!
 
Arkless Electronics said:
/\ it can be class A before switching rails, as said up thread. A good way of keeping costs down and yet giving class A most of the time with higher power available for peaks. Doug Self published such a design in WW.
It is most often used in PA amps for efficiency reasons but it has other uses;)
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Is this how Krell do their special power supply? Or was it Carver that did this in one of their big amps?
 
stevec67 said:
Is this how Krell do their special power supply? Or was it Carver that did this in one of their big amps?
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That would be Carver with their Cube and other related amps. Three tier Class G but more importantly used a "magnetic field amplifier", as they called it, PSU. Nothing to do with amplifying in fact (though there are magnetic amplifiers...) and used a triac controlled saturable reactor transformer to modulate the output of the PSU with signal demand. It could be said to be both class G and class H in fact! Not that brilliant sounding and prone to regular releases of the magic smoke! It's claim to fame was that it gave something like 300WPC from a very small and light weight cube and did it back in the late '70's ish....
 
I'm impressed so far with the A29 - I'm going to give this an extensive listen and then compare with the other amps in my possession of similar price (Yamaha AS-801 and Musical Fidelity M3si) - the best stays the other two get sold.

It may be that I require the best for driving ability - thinking Maggies in the future - again all three amps are powerful enough with the Arcam more than doubling the power from 8 ohm to 4 ohms.

All three amps have a reputation of being excellent - so it's going to be tough. But an extensive listening session is called for so could take Months.
 
I’ve had the Arcam A39 and thought the class G was really good. Smooth but very powerful and quite punchy. Eventually sold it on though as I use an Arcam irDAC which together were a touch too rich for some music.

It’s interesting u have a Musical Fidelity M3si to play with as I now use the M2si which I really like. Quite different presentation to the Arcam but very powerful and fun.
 
MarkC274 said:
I’ve had the Arcam A39 and thought the class G was really good. Smooth but very powerful and quite punchy. Eventually sold it on though as I use an Arcam irDAC which together were a touch too rich for some music.

It’s interesting u have a Musical Fidelity M3si to play with as I now use the M2si which I really like. Quite different presentation to the Arcam but very powerful and fun.
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Yes all three amps are no doubt excellent - but as you say in your experience it's all about matching the equipment. Er, I too have the Arcam irDAC (hoarding confession goes on) so - guess I could hook that up too with the A29 and see if it's too rich as you say.

Reading between the lines I guess you are using your irDAC with the M2si now.
 
hifinutt said:
nice , would like to hear the a29 , as i really love my a75 which has tone controls i like and seems to gel with the impulse . the sugden a21se was much better sonically but too much for my ears !! the gentle arcam does me just fine at the moment

i heard a few moans about hum on the a29 , have you had that problem ?
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Have you ever heard a Delta 290/Alpha 9 (same amp different exterior casework)? If you can find one with the input selector sorted, it’s a real high point for Arcam in my opinion, more transparent and more drive than the smaller Arcam models of the time (and later) but without sacrificing the warmth and smoothness. I gave one to my cousin but only because it was too large for my desktop system where I now have a Linn Majik instead. It was a superb amp,
 
beammeup said:
Yes all three amps are no doubt excellent - but as you say in your experience it's all about matching the equipment. Er, I too have the Arcam irDAC (hoarding confession goes on) so - guess I could hook that up too with the A29 and see if it's too rich as you say.

Reading between the lines I guess you are using your irDAC with the M2si now.
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Yes I am using the irDAC with the MF M2si and really enjoying the combination with my Dali Oberon speakers. I found the irDAC is unusually rhythmic and has great timing and dynamics for an Arcam product and it’s refinement works well with the MF amplifier which is in itself very transparent (but not bright).
 
beammeup said:
The Alpha 10 sounded fantastic when I briefly owned one! I think the A29 pips it though.
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I’ve never owned one, but I did really like it when I heard one at my local HIFI dealership back in the day, I pitched it against the Musical fidelity XA1, Meridian 551, Naim Nait3 and the Linn Majik, I ultimately preferred the Majik overall but it was a close run thing with the Naim and the Arcam, each amp was different but excellent in their own way. I had to audition between two dealerships to try all of them but used the same partnering kit... and I have spent money at both so didn’t waste anyone’s time.:)
 
My Exposure 18S is Class A up to 10 watts, then runs Class AB. I don’t think I ever get out of Class A as I rarely listen over 85db and I use it with high efficiency loudspeakers, 94db/1w.
 
next week i hope to compare my humble arcam to a rather nice 11k hybrid integrated valve amp . we shall see how it goes
 
John said:
My Exposure 18S is Class A up to 10 watts, then runs Class AB. I don’t think I ever get out of Class A as I rarely listen over 85db and I use it with high efficiency loudspeakers, 94db/1w.
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No, it is not. Exposure amps are standard class A/B and will make probably more like 10mW in class A.
 
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