Hi All,
Firstly, lets assume cost is no object nor greenhouse emissions.
I do most of my listening at relatively low power levels, and currently get by quite well with a 50W gainclone amplifier. However, I am considering purchasing either Cambridge Audio Azur 840A or 840W. These are rated at 120x2 and 200Wx2 respectively and can be seen here:
http://www.cambridgeaudio.com/series.php?SID=35
Now my question is, which would be better for my usually quiet listening levels? I know I'm never going to need 200W for my purposes...but... both amplifiers offer a few good watts of pure class A before moving to class B, with the 840W obviously having more with its idle power consumption of 180 watts. I really like the relaxed, laid back sound of class A and this is my preferred amplifier mode (after building a few JLH/PASS LABS clones).
Now pros and cons I see for each are (excluding cost and power consumption):
840A Pros:
1) Fewer power transistors (and maybe smaller and faster devices). Less chance of poorly matched components and probably better intrinsic circuit performance.
2) Overall a smaller and potentially simpler (better?) driver circuit.
840A Cons:
1) Less class A capacity and therefore more likely to use some class b during my listening.
840W Pros:
1) More class a power, likely to never leave class a for my listening levels (I love class a sound).
2) More power overall. Never going to clip for my purposes. No clipping induced distortion.
840W Cons:
1) More output devices and therefore a greater chance of poorly matched parts and poor circuit linearity and speed.
2) Larger, more complicated and possibly slower circuit overall - does this equate to poorer performance?
So I guess what I'm wondering is do I get a more complicated, ridiculously overpowered and possibly slower amp that will run in class a at my listening levels, or do I go for a smaller, simpler amp that will run into class b? Which one would potentially provide the best sound quality at under 50W of power? Is bigger better?
Any advice you can provide on this matter would be most appreciated!
Regards,
Greg.
1)
Firstly, lets assume cost is no object nor greenhouse emissions.
I do most of my listening at relatively low power levels, and currently get by quite well with a 50W gainclone amplifier. However, I am considering purchasing either Cambridge Audio Azur 840A or 840W. These are rated at 120x2 and 200Wx2 respectively and can be seen here:
http://www.cambridgeaudio.com/series.php?SID=35
Now my question is, which would be better for my usually quiet listening levels? I know I'm never going to need 200W for my purposes...but... both amplifiers offer a few good watts of pure class A before moving to class B, with the 840W obviously having more with its idle power consumption of 180 watts. I really like the relaxed, laid back sound of class A and this is my preferred amplifier mode (after building a few JLH/PASS LABS clones).
Now pros and cons I see for each are (excluding cost and power consumption):
840A Pros:
1) Fewer power transistors (and maybe smaller and faster devices). Less chance of poorly matched components and probably better intrinsic circuit performance.
2) Overall a smaller and potentially simpler (better?) driver circuit.
840A Cons:
1) Less class A capacity and therefore more likely to use some class b during my listening.
840W Pros:
1) More class a power, likely to never leave class a for my listening levels (I love class a sound).
2) More power overall. Never going to clip for my purposes. No clipping induced distortion.
840W Cons:
1) More output devices and therefore a greater chance of poorly matched parts and poor circuit linearity and speed.
2) Larger, more complicated and possibly slower circuit overall - does this equate to poorer performance?
So I guess what I'm wondering is do I get a more complicated, ridiculously overpowered and possibly slower amp that will run in class a at my listening levels, or do I go for a smaller, simpler amp that will run into class b? Which one would potentially provide the best sound quality at under 50W of power? Is bigger better?
Any advice you can provide on this matter would be most appreciated!
Regards,
Greg.
1)
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When it comes to ss power I like to insist on a minimum of 12dB headroom because NOTHING is as bad as clipping ss amps. For any speaker of 90dB @1w/1m I recon 100w to be the absolute minimum.
My speakers (4way active) with a mean efficiency of 95dB (91dB woofer, 95 mids, 107 tweeter, 95 supertweeter) I use a total of just over 900w/ch.
Chances are my class ab amps will never leave class a in normal operation and they never sounded better, much more relaxed, less strained than with the 250w (albeit passive) I used before. Any hint of harshness is gone for good.
My speakers (4way active) with a mean efficiency of 95dB (91dB woofer, 95 mids, 107 tweeter, 95 supertweeter) I use a total of just over 900w/ch.
Chances are my class ab amps will never leave class a in normal operation and they never sounded better, much more relaxed, less strained than with the 250w (albeit passive) I used before. Any hint of harshness is gone for good.
Hi,
I suspect the cost of the pre/power combo versus the integrated version
makes the latter far more cost effective. Alternatively you could build the
designers (Douglas Self) full on class A amplifier or the related Trimodal.
Class XD is not strictly class A operation, it offsets the operating point.
😎 /Sreten,
I suspect the cost of the pre/power combo versus the integrated version
makes the latter far more cost effective. Alternatively you could build the
designers (Douglas Self) full on class A amplifier or the related Trimodal.
Class XD is not strictly class A operation, it offsets the operating point.
😎 /Sreten,
as this is diy audio site, I would advice you to build an amplifier, possibly class A like JLH or any of Nelsons designs
you will save money, preferebly to buy music, and you might end with better sounding sytem, plus the reward of diy
ed
you will save money, preferebly to buy music, and you might end with better sounding sytem, plus the reward of diy
ed
I wouldn't get hung up over class of operation... it's pretty irrelevant to how the amp actually sounds... sorry I know some will see red at that 🙂 It's a very personal choice and depends on what you are seeking.
If you are spending that sort of money on a ready built amp you owe it to yourself to hear several before commiting. A good amp encourages you to listen... it has to be compelling... and it should pull the trick off with most music, not a few selected recordings... and at all levels, even low.
Dougs designs show a truly remarkable grasp of the purely technical aspect of design, however IMO they fail (to me anyway) to really sing and make music.
Adasons advice is good... JLH's amps really do perform. It would give you an idea of where to go from here.
If you are spending that sort of money on a ready built amp you owe it to yourself to hear several before commiting. A good amp encourages you to listen... it has to be compelling... and it should pull the trick off with most music, not a few selected recordings... and at all levels, even low.
Dougs designs show a truly remarkable grasp of the purely technical aspect of design, however IMO they fail (to me anyway) to really sing and make music.
Adasons advice is good... JLH's amps really do perform. It would give you an idea of where to go from here.
Not to mention his design is an almost blatant rip-off from Nelson Pass, and he has the hide to apply for a patent.
I wish I had of known this earlier before encouraging a friend to buy an 840A. I was even considering one myself at one stage.
Yes the JLH is a design that is hard to beat.
I wish I had of known this earlier before encouraging a friend to buy an 840A. I was even considering one myself at one stage.
Yes the JLH is a design that is hard to beat.
I agree totally, my class AB amps perform very well with a great clean sound.
Unlike class A they do it without cooking and wasting loads of power.
Ok thanks all. I appreciate your comments but my questions have not really been answered except partially by Darwin.
I see that a lot of you did not read my statement that I have built a gainclone, JLH and an aleph 3. So, I do understand the advantages of DIY, but I have my own reasons for going commercial at this stage. I can no longer build amplifiers due to time and space restrictions. I loved my JLH, but it ran bloody hot, didn't look nice (for the wife) and I was in constant fear of it destroying my speakers. If I could get this sound from a commercial offering that is what I would take.
Ultimately I would love a commercial pass product, but it's just out of my price range.
I never said the 840W was class A, just that it offers a reasonable number of watts of class A operation before moving into class B, or at least that's my understanding. It is this few watts of class A that I hope to enjoy at my listening levels.
I was hoping to get an opinion about the relative technical merits of using a larger or smaller amplifier for quiet listening, and listed my perceived pros and cons of each.
Any thoughts on this matter? I asked it at this DIY site because I know you guys actually know about the technical ins and outs of amplifier construction and was hoping to avoid the subjective mumbo jumbo that comes from other hifi sites. Though the comments about the sound of self's amplifier are duly noted.
I see that a lot of you did not read my statement that I have built a gainclone, JLH and an aleph 3. So, I do understand the advantages of DIY, but I have my own reasons for going commercial at this stage. I can no longer build amplifiers due to time and space restrictions. I loved my JLH, but it ran bloody hot, didn't look nice (for the wife) and I was in constant fear of it destroying my speakers. If I could get this sound from a commercial offering that is what I would take.
Ultimately I would love a commercial pass product, but it's just out of my price range.
I never said the 840W was class A, just that it offers a reasonable number of watts of class A operation before moving into class B, or at least that's my understanding. It is this few watts of class A that I hope to enjoy at my listening levels.
I was hoping to get an opinion about the relative technical merits of using a larger or smaller amplifier for quiet listening, and listed my perceived pros and cons of each.
Any thoughts on this matter? I asked it at this DIY site because I know you guys actually know about the technical ins and outs of amplifier construction and was hoping to avoid the subjective mumbo jumbo that comes from other hifi sites. Though the comments about the sound of self's amplifier are duly noted.
I found with low power amplifiers i was getting clipped transients very quickly even on modest output levels.
I moved from +/-45 volt rails to +/-60 volt rails and found a big improvemnet.
I moved from +/-45 volt rails to +/-60 volt rails and found a big improvemnet.
Do you mean outperformed in sound or in measurements? I'd agree if its the latter but as far as I'm aware, Mr Self isn't particularly interested in listening to his designs.
It's a difficult question to answer because it is very dependent on the loudspeakers you are using, the music you listen to and how large you room is.
You may have one amplifier that can deliver 120 watts into 8 ohms, 160 into 4 ohms and crumble into a 2 ohm load.
Then you could have another amplifier that gives 100 watts into 8 ohms 180 watts into 4 ohms and 320 into 2 ohms.
The second amplifier might be far superior in your system if the loudspeakers are a pain to drive.
If we're looking at the amplifiers that you talked about the Azur 840W would, in my opinion, be the one to go for.
It outputs 200 watts into 8 ohms, then gives 350 watts into 4 ohms. It will also give 800 watts into a 4 ohm load when bridged, which implies that in stereo, it is 2 ohm stable and will give roughly 400 watts into a 2 ohm load. This isn't perfect, but it shows it should be decent with more demanding loads.
Going by what Self writes in his books, I'd expect both the 840A and W to share very similar input and VAS stages. Adding in a couple more pairs of output transistors shouldn't affect the linearity of the amplifier in a bad way. In fact adding in more can help keep distortion lower into more demanding loads, even before any clipping is observed.
You may have one amplifier that can deliver 120 watts into 8 ohms, 160 into 4 ohms and crumble into a 2 ohm load.
Then you could have another amplifier that gives 100 watts into 8 ohms 180 watts into 4 ohms and 320 into 2 ohms.
The second amplifier might be far superior in your system if the loudspeakers are a pain to drive.
If we're looking at the amplifiers that you talked about the Azur 840W would, in my opinion, be the one to go for.
It outputs 200 watts into 8 ohms, then gives 350 watts into 4 ohms. It will also give 800 watts into a 4 ohm load when bridged, which implies that in stereo, it is 2 ohm stable and will give roughly 400 watts into a 2 ohm load. This isn't perfect, but it shows it should be decent with more demanding loads.
Going by what Self writes in his books, I'd expect both the 840A and W to share very similar input and VAS stages. Adding in a couple more pairs of output transistors shouldn't affect the linearity of the amplifier in a bad way. In fact adding in more can help keep distortion lower into more demanding loads, even before any clipping is observed.
Now we're getting into the territory of subjectivism and I side with the measurements rather then how it 'sounds'. I also believe that the sonic signature of an amplifier is far out weighed by other more significant factors. IE if you're loudspeakers are too bright for your liking, sort out the loudspeakers, rather then try and compensate for it in some other way.
I do not wish to take this discussion further in this thread however as that wouldn't be particularly polite.
I agee with this. Its important that the amp gives a clean undistorted signal through the audio bandwidth.
If the user then wants to change the sound then they can tweak a tone control or equaliser.
One of the exceptions is the rock guitarist who wants lots of nice distortion to make his guitar sound good.
I've noted that you don't intend to take this discusson further. I'm sure though I'll be able to keep it polite on my side😀
'Subjectivism' is not where I was going in asking my question. I respect your choice to 'side' with measurements too; I myself no longer make that particular choice. I don't perceive there are two 'sides' here - good sound is the aim, good measurements do not detract from that in my own experience.
I respect your beliefs. I myself do not share those beliefs though I once did believe that brightness was the fault of poor transducers. I put that particular belief to the test quite recently and bought a very cheap (around $25) pair of active speakers which to me sounded way too bright, splashy. I had assumed that was because the tweeter was an obviously cheap one. But after modding the amplifiers (leaving the very cheap chipamps in place) I found the raspy brightness disappeared completely. I was surprised to say the least, that merely rewiring the amps made such a noticeable difference.
'Subjectivism' is not where I was going in asking my question. I respect your choice to 'side' with measurements too; I myself no longer make that particular choice. I don't perceive there are two 'sides' here - good sound is the aim, good measurements do not detract from that in my own experience.
I respect your beliefs. I myself do not share those beliefs though I once did believe that brightness was the fault of poor transducers. I put that particular belief to the test quite recently and bought a very cheap (around $25) pair of active speakers which to me sounded way too bright, splashy. I had assumed that was because the tweeter was an obviously cheap one. But after modding the amplifiers (leaving the very cheap chipamps in place) I found the raspy brightness disappeared completely. I was surprised to say the least, that merely rewiring the amps made such a noticeable difference.
That's probably because they were intended to be bright. 😉 Some people like that.
For example, today i went to someone's place to take a look at the broken TV and see what parts i need to buy to fix it. From the neighbor above you could hear the music turned up to 20% THD, and no bass, just an annoyingly harsh midrange and some tinny treble. Probably coming from some $10 PC speakers. Then i made the comment about these new buildings, they're built so flimsy that EVERY SOUND goes thru the walls... I mean i could easily hear the vocals and the distortion, and by the lack of bass it was obvious that those were small speakers.
In my place, when my neighbours turn the music up, i can only hear the bass, and when that happens, i compensate with some of my own. 😀 But really, the $25 speakers you modded were intended for that kind of people, where brighter = better. Because with the typical featherweight power supply in those things, brighter = more level before distortion (and even more level after distortion), so brighter = better.
Well of course, it was intentional. Just not consciously intended. It was a side effect of the designer's limited knowledge in electronics design. There are other ways to make the sound bright if that's your conscious intention which are more predictable in their outcome.
But really, the $25 speakers you modded were intended for that kind of people, where brighter = better. Because with the typical featherweight power supply in those things, brighter = more level before distortion (and even more level after distortion), so brighter = better.
I don't question some people's wish for brighter sounding speakers. I do though question your 'reasoning' about the reasons they're brighter. Brightness in this case very definitely was distortion.
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