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Post by Andrew Robinson on Dec 24, 2013 13:09:42 GMT -5
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Post by deltadube on Dec 24, 2013 13:27:46 GMT -5
Good Video Andrew like the background!
Merry Christmas
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Post by knucklehead on Dec 24, 2013 13:29:29 GMT -5
Since there is no audible difference between the audio in class 'A' vs 'A/B' why even do it? I know audiophiles claim that pure class 'A' is the very best but since there is no audible differences between them why do it? Because you can?
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Post by ludi on Dec 24, 2013 13:34:49 GMT -5
Nice video!
The sound level (of the video, not the amp) is a little low.
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Post by mshump on Dec 24, 2013 13:35:54 GMT -5
Andrew, As usual, Well Done !
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Post by paintedklown on Dec 24, 2013 13:46:02 GMT -5
Andrew, this video has a much blacker background than the ERC video. This allows every word of Lonnie's to cut through the mix in a way that is palpable, and more poignant than ever before.
J/K, I'm at work and can't watch the video yet. LOL!
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Post by garbulky on Dec 24, 2013 13:57:05 GMT -5
Clicking to see more of the ERC-3 video's sophistication!
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Post by garbulky on Dec 24, 2013 14:01:53 GMT -5
I wanted to sit back with a glass of Cognac, a monocle and a Cigar after watching that! Good job Andrew!!
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Post by audiobill on Dec 24, 2013 14:16:28 GMT -5
LOL, Gar.
Please send a pic of that!
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Post by PGT on Dec 24, 2013 14:51:51 GMT -5
You guys need some sound treatment in the video room....I can hear the echo. _____________________________________________________________________ - Sometimes the terseness of my reply can't be blamed on my phone.  |
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Post by pdaddy on Dec 24, 2013 16:04:44 GMT -5
Since there is no audible difference between the audio in class 'A' vs 'A/B' why even do it? I know audiophiles claim that pure class 'A' is the very best but since there is no audible differences between them why do it? Because you can? The lack of audible sound is when the amp switches from class A to Class A/B. Great video. Really liking the Andrew add to Emotiva. It's really classing up the brand. |
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Post by paintedklown on Dec 24, 2013 16:16:36 GMT -5
Since there is no audible difference between the audio in class 'A' vs 'A/B' why even do it? I know audiophiles claim that pure class 'A' is the very best but since there is no audible differences between them why do it? Because you can? The lack of audible sound is when the amp switches from class A to Class A/B. Great video. Really liking the Andrew add to Emotiva. It's really classing up the brand. If you are unaware, Andrew has a background in video/multimedia content, and has even directed some films. He is also a very respected reviewer in the audio industry, and (IMO) was instrumental in helping to catapult the much lauded Pendragon speakers into the audiophile limelight. He certainly is an asset to the Emo family IMO.  |
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KeithL
Administrator 
Posts: 9,919
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Post by KeithL on Dec 24, 2013 16:18:23 GMT -5
I think you're misunderstanding slightly... Even when you play music very loud, the vast majority of the time you're only using a few watts; when the XPA-1 Gen2 is in Class A mode, it will be operating in Class A for all of that time. Now, if a huge drumbeat or cymbal crash comes along, and several hundred watts is required to deliver it without clipping or compressing the dynamics, that extra power will be delivered in Class A/B. If that happens, it's only the loudest portions of the loud drumbeat that will be in Class A/B; not only is the difference subtle to begin with, but it will only be in Class A/B for a small fraction of a second - and it's the loud part - where the subtle distinction is least important. Basically, you're getting pure Class A quality almost all of the time, with only an occasional visit to (still very good) Class A/B operation. In comparison, you can spend five or ten times as much as the price of the XPA-1 Gen2 for a "real 60 watt Class A amp". Both will deliver 60 watts in pure Class A; but, if you play something with peaks that need more than 60 watts to play cleanly, the pure Class A amp will clip, while the XPA-1 Gen2 will just go on and on, and deliver whatever power you need to keep sounding good. With the XPA-1 Gen2, you get all the benefits of a real pure 60 watt Class A amp AND all the benefits of a 600 watt high quality Class A/B monoblock.... and all for far less than the price of just the 60 watt Class A amp. So, the choice is between a 60 watt Class A amp that clips after 60 watts, or one that becomes a 600 watt Class A/B amp after 60 watts.... (And, yes, even in Class A/B mode, the XPA-1 Gen2 sounds so good that not everybody can tell the difference between it and Class A; but we don't see any reason to apologize for that  Every audiophile who can hear a difference agrees that Class A sounds better - and, even if you don't, you really don't have anything to lose. ) Since there is no audible difference between the audio in class 'A' vs 'A/B' why even do it? I know audiophiles claim that pure class 'A' is the very best but since there is no audible differences between them why do it? Because you can? |
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Post by Gary Cook on Dec 24, 2013 17:39:46 GMT -5
Correct me if I'm wrong Keith but this is the way I see it.
I'm listening to some music using at my normal listing volume with the amp switch in the Class A position, that about, say, 15 to 20 watts. I then flick the switch to Class AB position and notice no change in sound. That's obvious as I'm still listing about about 15 to 20 watts, so the amp is still in Class A.
Next I turn the volume up rather loud, with the amp switch back in the Class A position, and I can hear tiny clipping. Obviously I'm now listing at volumes (peaks) that exceed the Class A limit, hence the clipping. I then flick the switch to the Class AB position and notice a change in sound in that there is no more clipping. Because the amp is using Class AB to handle the peaks. The non peak sounds will still be the same as they are still being produced in Class A.
Having read a lot of posts it appears to me as though many people think that flicking the switch changes the amp from Class a to Class AB, when in fact it does not. What the switch position does is determine whether or not the amp moves to Class AB if/when required, which may be never depending on the volume (and the peaks). Hence is quite logical that no sound difference should be heard.
Merry Xmas
Gary
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geebo
Emo VIPs 
"Too bad that all the people who know how to run the country are driving taxicabs and cutting hair"
Posts: 24,181
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Post by geebo on Dec 24, 2013 18:58:44 GMT -5
Correct me if I'm wrong Keith but this is the way I see it. I'm listening to some music using at my normal listing volume with the amp switch in the Class A position, that about, say, 15 to 20 watts. I then flick the switch to Class AB position and notice no change in sound. That's obvious as I'm still listing about about 15 to 20 watts, so the amp is still in Class A. Next I turn the volume up rather loud, with the amp switch back in the Class A position, and I can hear tiny clipping. Obviously I'm now listing at volumes (peaks) that exceed the Class A limit, hence the clipping. I then flick the switch to the Class AB position and notice a change in sound in that there is no more clipping. Because the amp is using Class AB to handle the peaks. The non peak sounds will still be the same as they are still being produced in Class A. Having read a lot of posts it appears to me as though many people think that flicking the switch changes the amp from Class a to Class AB, when in fact it does not. What the switch position does is determine whether or not the amp moves to Class AB if/when required, which may be never depending on the volume (and the peaks). Hence is quite logical that no sound difference should be heard. Merry Xmas Gary My understanding of the switch is that when in AB mode the amp is operating in class AB almost throughout it's entire range. With the switch in A mode, it will operate in class A until a certain threshold is met at which time it will automatically transition to class AB. From the manual: 1. Class A - Class A/B Mode Switch
When this switch is in the Class A/B position, the XPA-1 functions as a very high quality, low
distortion Class A/B amplifier (600 watts @ 8 ohms / 1000 watts @ 4 ohms).
When this switch is in the Class A position, the XPA-1 functions as a pure Class A amplifier for all
signals up to 60 watts. If the signal level exceeds 60 watts, the XPA-1 automatically transitions
seamlessly into Class A/B mode and delivers its full rated power.
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Post by Dark Ranger on Dec 24, 2013 22:35:23 GMT -5
The B&W speakers are suspiciously missing from behind Lonnie.  Great job Andrew, Lonnie, and everyone else involved. |
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Post by danny01 on Dec 25, 2013 0:30:46 GMT -5
The switch changes the bias, not class. Every class AB amp will run class A to a certain point. The only difference with these amps is that this point is can be adjusted using the switch. When it is switched to "AB" it still runs in class A, but to a much lower power threshold. This is to say that if you don't hear it clipping in AB mode, you shouldn't hear it in A mode either as the clipping point are exactly the same. The only thing you may be hearing is the amp switching from AB to A, which will happen much more frequently with the switch in AB.
Sent from my HTC6500LVW using proboards
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Dec 26, 2013 23:28:44 GMT -5
When not just come out with a 100% class A amp with 200 - 400 watts. You don't have to make it the size of a AC unit. You can use heat pipes with 120 fans (low speeds) to do the cooling.
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novisnick
EmoPhile
CEO Secret Monoblock Society
Posts: 27,222 
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Post by novisnick on Dec 26, 2013 23:31:27 GMT -5
When not just come out with a 100% class A amp with 200 - 400 watts. You don't have to make it the size of a AC unit. You can use heat pipes with 120 fans (low speeds) to do the cooling. So! We're talking about water cooled amps now..?? well!........that didn't take long,,,,,now did it?? Nick |
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Post by vcautokid on Dec 28, 2013 3:19:18 GMT -5
Nice Video Andrew and Lonnie. These are enjoyable to watch, and tells what it needs to tell. I wish I could hear one of these XPA-1 Gen2. Thanks for doing all the videos.
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