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Post by garbulky on Dec 15, 2017 11:47:15 GMT -5
Looks like they bumped up the power supply rating on the DR modules. It is now a 3 kwatt switching power supply! Though no mention of what ampere circuit it's supposed to hook up to. XPA DR-1  XPA-1 gen 2  I see that the DR-1 blade appears to be half as short. Does that mean there are less output devices? Does anybody know the specs between the two? I think the XPA=1 gen 2 has 24 output devices per channel. |
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Post by geebo on Dec 15, 2017 12:22:07 GMT -5
Looks like they bumped up the power supply rating on the DR modules. It is now a 3 kwatt switching power supply! Though no mention of what kind of amp circuit it's supposed to hook up to. XPA DR-1 The XPA Gen 3's also have a 3kW switching supply. "The new XPA Series utilizes a high-current switch mode power supply. It’s a power supply capable of delivering over 3Kw of continuous power with absolute reliability and extremely high efficiency. It shares the dynamic attributes of a classic transformer-based design with none of the downside. It’s lightweight, intelligent, and extremely powerful!"
And the DR's use class AB amp modules.
"A fully modular, fully differential, fully balanced audio power amplifier with a high-efficiency switch mode power supply (SMPS), independent, fully discrete, dual differential, high current, short signal path Class A/B amplifier modules, Optimized Class H™ power supply topology, and microprocessor-controlled fault protection." |
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Post by copperpipe on Dec 15, 2017 12:27:54 GMT -5
What effect does number of output channels have on sound? Can you educate a newbie here?  |
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Post by garbulky on Dec 15, 2017 13:00:43 GMT -5
Looks like they bumped up the power supply rating on the DR modules. It is now a 3 kwatt switching power supply! Though no mention of what kind of amp circuit it's supposed to hook up to. XPA DR-1 The XPA Gen 3's also have a 3kW switching supply. "The new XPA Series utilizes a high-current switch mode power supply. It’s a power supply capable of delivering over 3Kw of continuous power with absolute reliability and extremely high efficiency. It shares the dynamic attributes of a classic transformer-based design with none of the downside. It’s lightweight, intelligent, and extremely powerful!"
And the DR's use class AB amp modules.
"A fully modular, fully differential, fully balanced audio power amplifier with a high-efficiency switch mode power supply (SMPS), independent, fully discrete, dual differential, high current, short signal path Class A/B amplifier modules, Optimized Class H™ power supply topology, and microprocessor-controlled fault protection."I meant like amp plug 15 A, 20 A. Not amp circuit. |
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Post by garbulky on Dec 15, 2017 13:01:53 GMT -5
What effect does number of output channels have on sound? Can you educate a newbie here? I think they do have an effect, and it can also be negative I think with an increased number. You'll have to ask Keith or somebody for more of a detailed explanation. I can tell you in the older generations, the more beefier amps had more output devices. The XPA-2 had half the output devices of the XPA-1 per channel. |
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Post by geebo on Dec 15, 2017 13:07:16 GMT -5
The XPA Gen 3's also have a 3kW switching supply. "The new XPA Series utilizes a high-current switch mode power supply. It’s a power supply capable of delivering over 3Kw of continuous power with absolute reliability and extremely high efficiency. It shares the dynamic attributes of a classic transformer-based design with none of the downside. It’s lightweight, intelligent, and extremely powerful!"
And the DR's use class AB amp modules.
"A fully modular, fully differential, fully balanced audio power amplifier with a high-efficiency switch mode power supply (SMPS), independent, fully discrete, dual differential, high current, short signal path Class A/B amplifier modules, Optimized Class H™ power supply topology, and microprocessor-controlled fault protection."I meant like amp plug 15 A, 20 A. Not amp circuit. Looks like 15 amp IEC connectors on the back for the power cord. Same for the XPA-Gen3's. Remember, the DR can accept a max of 3 blades where the XPA's can accept up to 7 blades. I believe the difference in power supplies lies mainly in the current and voltage delivering capacity. The XPA supply having higher current capacity with the DR supply having higher voltage. That is if I understood Lonnie correctly at Emofest. Perhaps Lonnie or KeithL can clarify. |
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Post by routlaw on Dec 15, 2017 13:48:55 GMT -5
Hmm, its always been my understanding that Class D amps are more current driven, while Class A or A/B are more voltage driven including tube amps. Regardless one thing to consider here that has not been mentioned is the fact how much more efficient these new amps are compared to heat loss generated A/B or A. I have to assume that alone might require less demands on an AC circuit.
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Post by gsand on Dec 15, 2017 13:57:37 GMT -5
Pre ordered a XPA-DR2 and now the wait/anticipation begins... Me too. Looking forward to January 15th. I will be forced to turn in my Secret Monoblock Society card. They came to my house demanding I surrender my "Secret Monoblock Society card" after selling my pair of XPR-1's but they discovered I still own a pair of Carver M-1.0's amplifiers (for now)... |
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Post by novisnick on Dec 15, 2017 14:24:38 GMT -5
Me too. Looking forward to January 15th. I will be forced to turn in my Secret Monoblock Society card. They came to my house demanding I surrender my "Secret Monoblock Society card" after selling my pair of XPR-1's but they discovered I still own a pair of Carver M-1.0's amplifiers (for now)...  |
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bill48
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I have a pair of Nautilus 804s,with a Marantz A-S2000 amp,using a Marantz AV7702 mk11 re amp
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Post by bill48 on Dec 15, 2017 15:17:17 GMT -5
I thought I’d give my good friends on the Lounge a sneak peek at the new XPA Differential Reference Series amplifiers! These beautiful new amplifiers will be shipping the first week of January and we’ll be taking pre-orders next week. Look for them on the site by Wednesday of next week. The new XPA DR-1 will develop well over 600 watts RMS into 8 ohms. The XPA DR-2 will output well over 550 watts RMS into 8 ohms, two channels driven, and the XPA DR-3 will deliver over 450 RMS into 8 ohms with all three channels driven. These are all low distortion, full bandwidth power specs. Pricing from $1,199.00 to 1,999.00. DR-1:  DR-2:  DR-3:  Cheers, Big Dan. |
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Post by Gary Cook on Dec 15, 2017 15:46:09 GMT -5
Hmm, its always been my understanding that Class D amps are more current driven, while Class A or A/B are more voltage driven including tube amps. Regardless one thing to consider here that has not been mentioned is the fact how much more efficient these new amps are compared to heat loss generated A/B or A. I have to assume that alone might require less demands on an AC circuit. The DR's are still Class AB amplifiers, just with an SMPS power supply in lieu of a linear power supply (together called Class H) Heat wise I would expect the SMPS to emit more heat than the linear power supply (in XPA-1 Gen 1 or 2). Note the heat sinks on the power supply in the pictures. Merry Xmas to all Gary |
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KeithL
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Post by KeithL on Dec 15, 2017 16:04:07 GMT -5
Counting output devices is a losing battle..... because output devices come in a huge variety of shapes, sizes, and power ratings. If you're using a single particular type of device, then more of them will handle more power, be more difficult to damage, and offer a lower output impedance. However, because output devices do come in a wide range of power ratings, from a fraction of a watt, to thousands of watts, one powerful output device will often handle more power than several smaller ones. (Note that, in amps by some manufacturers, different models may designed to use the same output devices, with more powerful models using more of the same device per channel...) The justification for a monoblock is that, whenever you have multiple channels in a single amplifier, there is at least the potential for them to interact. (It's possible that signal will bleed directly from one channel to another; it's also possible that, when one channel draws power, it will modulate the power supply rails, which will, in turn, affect the other channels.) Because each monoblock has its own power supply, power cord, and chassis, chances of even the slightest interaction between channels are minimized. With most modern amplifier designs, this is a minimally important factor - but some people are convinced they notice the difference. It's even less of a factor with the regulated SMPS in our new XPA Gen3 and XPA-DR models...... because the regulation minimizes the effect any channel has on the power available to other channels. (Because the channels share one power supply, the total power available to each, when all are fully driven, will be slightly less - but the sound quality will remain pretty much the same.) Therefore, going to full monoblocks really qualifies as one of those things where you're spending almost twice as much to get "that last little bit". However, if you really want the best, and have the budget for it, then it should make at least a tiny difference. What effect does number of output channels have on sound? Can you educate a newbie here? I think they do have an effect, and it can also be negative I think with an increased number. You'll have to ask Keith or somebody for more of a detailed explanation. I can tell you in the older generations, the more beefier amps had more output devices. The XPA-2 had half the output devices of the XPA-1 per channel. |
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KeithL
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Post by KeithL on Dec 15, 2017 16:47:36 GMT -5
The XPA amps use a Class H topology.... which means that their output stage is Class A/B, but is powered by dual power supply rails. At very low power levels, their efficiency is very similar to Class A/B (a tiny bit better). And, at full power, their efficiency is also quite similar. However, at medium power levels, which is where most amplifiers operate most of the time, they are significantly more efficient. We can't really give you a number because it depends on the type of music you're playing, the impedance of your speakers, and how loudly you are playing them. Note, however, that they are still less efficient than a Class D amplifier..... Internally, solid state devices are "voltage operated devices" while transistors are "current operated devices". However, that really doesn't have much to do with how efficient the overall unit is. All Class A/B devices operate in a linear fashion, which means that, at certain output voltage levels, the output devices must "drop voltage while passing current" - which means that they're burning power. Class D devices are designed to switch current - and so are either "on" or "off" and so avoid "dropping power" or "burning power". This makes them more efficient. However, because a music waveform varies continuously rather than switching on and off, amplifying it is more easily suited to a Class A/B amplifier. For this reason, it can be more a more complicated and difficult task to "adapt" a Class D "switching" circuit to accurately amplify a continuously varying music waveform. This is why it's taken so long for Class D designs that actually sound good to be developed and marketed. Hmm, its always been my understanding that Class D amps are more current driven, while Class A or A/B are more voltage driven including tube amps. Regardless one thing to consider here that has not been mentioned is the fact how much more efficient these new amps are compared to heat loss generated A/B or A. I have to assume that alone might require less demands on an AC circuit. |
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klinemj
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Post by klinemj on Dec 15, 2017 16:47:49 GMT -5
Therefore, going to full monoblocks really qualifies as one of those things where you're spending almost twice as much to get "that last little bit". Yes, but that "last little bit" - especially the membership rights of the Secret Monoblock Society - is well worth the money. Those of us in the club know what I'm speaking about, but - of course - I swore a solemn oath to secrecy as I joined the club, as we all did. Suffice it to say, it makes benefits of being in AAA, AARP, and the Possum Lodge ("I'm a man...I can change...if I have to...I guess...") seem like mere child's play. Mark |
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Post by Gary Cook on Dec 15, 2017 17:21:38 GMT -5
The justification for a monoblock is that, whenever you have multiple channels in a single amplifier, there is at least the potential for them to interact. (It's possible that signal will bleed directly from one channel to another; it's also possible that, when one channel draws power, it will modulate the power supply rails, which will, in turn, affect the other channels.) Because each monoblock has its own power supply, power cord, and chassis, chances of even the slightest interaction between channels are minimized. With most modern amplifier designs, this is a minimally important factor - but some people are convinced they notice the difference. It's even less of a factor with the regulated SMPS in our new XPA Gen3 and XPA-DR models...... because the regulation minimizes the effect any channel has on the power available to other channels. (Because the channels share one power supply, the total power available to each, when all are fully driven, will be slightly less - but the sound quality will remain pretty much the same.) Therefore, going to full monoblocks really qualifies as one of those things where you're spending almost twice as much to get "that last little bit". However, if you really want the best, and have the budget for it, then it should make at least a tiny difference. I have a couple of other "justifications"; 1. Being single channel specific a monoblock can be located close by its respective speaker hence utilising a very short speaker cable. In my case this means a less than 1 metre cable replacing a more than 5 metre cable. 2. Emotiva monoblocks are typically fully balance, discrete, quad differential and as a result have the sound quality advantages of that specification over other multichannel amps. Merry Xmas to all Gary |
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Post by Gary Cook on Dec 15, 2017 17:27:53 GMT -5
Technical question for KeithL (or anyone else who might know the answer), I noticed the blurb on the XPA-DR1 says "fully differential" whereas the XPA-1 Gen 2 says "quad differential". Is "quad" meaning 4, more or less than "fully"? Or is it technically the same just a different way of stating it? Merry Xmas to all Gary |
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KeithL
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Post by KeithL on Dec 15, 2017 17:43:37 GMT -5
A Word About REGULATED Power Supplies
We've mentioned that the XPA Gen3 and our new XPA-DR amplifiers use a heavy-duty Switch Mode Power Supply (SMPS).
And we've also mentioned in passing that it's a REGULATED power supply.
However, it occurred to me that a lot of you may not understand exactly what that means - and what a big deal it really is.
Amplifier Power Supplies 101
You probably know that the purpose of a power supply is to convert the 120 VAC (or 230 VAC) coming out of the wall into the voltages needed to power your audio equipment.
Virtually all of the circuitry in audio equipment runs on DC - at a variety of different voltages and current requirements.
Because they don't use much power, but are really fussy about having clean power, devices like preamps usually have regulated power supplies.
What this means is that, after passing through the transformer, and the rectifiers that convert the AC into DC, and the capacitors that filter it, the power passes through an additional regulator stage.
A regulator is an active device that acts sort of like an amplifier - except that, instead of music, its output signal is clean DC power.
The regulator removes virtually all of the last little bit of noise and ripple, makes sure that the voltage is correct, and makes sure that the voltage doesn't change, and the noise doesn't increase, when the load changes.
The drawback to old-style linear regulators is that they're only about as efficient as amplifiers.
That's fine for low-powered devices like preamps - which use so little power that wasting a significant percentage of it is no big deal.
But, when it comes to power amps, running the output stage from a regulated power supply just hasn't been practical - even though it might improve the sound quality.
Adding a regulated power supply big enough to run the output stage of an amplifier would make the whole amplifier bigger, heavier, less efficient, more complicated, and a whole lot more expensive.
And, because using a regulated power supply on a power amplifier would be so difficult, and the gains in sound quality wouldn't be immediately obvious, almost nobody does it.
At least until now.
The 3 kW Switch Mode Power Supply that powers our new XPA Gen3 and XPA DR amplifiers is fully regulated.
It delivers the same sort of super-clean tightly-controlled power normally used by the precision circuitry in a good preamp....
And enables us to run ALL of the circuitry in our power amp modules from the good stuff - including the heavy duty output stage in each.
The result is a small but significant improvement in sound quality....
(And, in case you were wondering, our modern SMPS power supply is able to deliver all of those benefits WITHOUT the drawbacks of older designs.)
So, the next time you compare one of our new amps to one of our "competitors".....
Check to see if they're using a REGULATED power supply.
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KeithL
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Post by KeithL on Dec 15, 2017 17:52:13 GMT -5
That pretty much nails it. The industry terminology isn't very specific. We use a version of our proprietary differential input circuitry, which is both differential, and cross-connects portions of the circuitry to further reduce distortion. (Either description is perfectly correct.... and neither specifically explains all the details anyway.  ) The whole amplifier is made up of two identical modules, one handling the non-inverted waveform, and the other handling the inverted waveform. That makes it "fully differential" (which also means it has a bridged output topology.) Each of the individual modules also has a differential input section; but the output stage of each module, taken separately, is not differential. (Yeah, it's really hard to figure out the proper marketing term for some of this stuff..... engineers just look at the schematic and go "yeah, that looks cool".  ) Technical question for KeithL (or anyone else who might know the answer), I noticed the blurb on the XPA-DR1 says "fully differential" whereas the XPA-1 Gen 2 says "quad differential". Is "quad" meaning 4, more or less than "fully"? Or is it technically the same just a different way of stating it? Merry Xmas to all Gary |
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Post by routlaw on Dec 15, 2017 18:22:06 GMT -5
All good info Keith, thanks for all the explanations. Not sure why I had it in my head these were Class D designs.
This does beg at least one more question though. You did not address the use of negative feedback, which most SS amps implement or so I'm told, and its also my understanding that NOT using negative feedback makes for a a better sounding amp though very expensive and difficult to implement properly in SS designs. How have the engineers at Emotiva addressed this?
Correct me if I'm wrong, but I believe this is one of the advantages of tube amps in that are by nature a design without negative feedback.
Thanks
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Post by Casey Leedom on Dec 15, 2017 19:31:58 GMT -5
routlaw , I'd put it the other way: virtually no amplifiers of any type operate in Open Loop Mode with no Negative Feedback. Control Systems Theory is our friend. Open Loop Systems tend to be very Fragile. In order to use an Open Loop System to solve any particular problem you need to completely over-design the system and make sure that the Inputs and Loads on the system are 100% within a very small Linear Range of the Operating Parameters of the Control System. Probably the biggest proponent that you'll find of this Amplifier Design methodology is Nelson Pass. Now, that said, Bruno Putzeys, who's probably the biggest proponent of Negative Feedback in Audio Amplifiers Designs that you'll ever run across, has written papers[ 1, 2, 3] and interviews[ 4, 5] regarding the use of "not enough Negative Feedback" in Amplifier Designs. His commentary on the subject indicates that using only a small amount of Negative Feedback can in fact introduce. potentially audible Harmonic Distortion. His solution to this issue was to introduce even larger amounts of Negative Feedback. Casey
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