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Post by davidl81 on Dec 4, 2019 21:26:34 GMT -5
How is a mono amp not "fully balanced". It's a darn mono amp lol Even if it has an XLR input, it is not fully balanced - it is only differential on the inputs. A fully balanced amp is also differential on the amp stages - meaning that there are two amps in there. Emotiva's code word for that is "quad-differential". Fully balanced requires nearly twice the circuitry so it is expensive to do. Also....a fully balanced monoblock amp sees the speaker load at half the impedance. So if it's driving a 4 ohm speaker, it's actually seeing a 2 ohm load (!!). If it drops to 2 ohms, it is seeing a 1 ohm load! What that means is that a proper fully balanced monoblock would be optimized to be able to run stable at very low impedances. The XPA-1 gen 1 and 2 are able to drive not just 4 ohm speakers but also (unoficially) 2 ohm speakers. This means it is seeing a 1 ohm load when driving a 2 ohm speaker and it is built hardy enough to handle it. A good example of a fully balanced monoblock amp that is NOT optimized for monoblock balanced operation is the Schiit Vidar. Hence it is ONLY rated for 8 ohm loads in monoblock configuration. Emotiva amps that are fully balanced are XPA-1 gen 1 and 2, XPA-1L gen 1 and 2, XPR-1, all models of the XPA gen 3 DR series (DR series only). Things that look fully balanced but are not are: The Emotiva UPA-1, The XPA gen 3 amp with one channel. The XPA HC-1. I don’t know the answer to this, but would the XPA-2 G2 be fully balanced when ran in mono block mode? Since you are bridging the amp and sending two channels (one + one -) to a single speaker. |
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Post by emofrmcgy on Dec 4, 2019 21:50:18 GMT -5
garbulkyYou forgot the pa1, it's also "fully balanced". What's the difference between dual differential and quad differential ?
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Post by rbk123 on Dec 4, 2019 21:56:16 GMT -5
Twice as much differential. Come on, everyone here knows more is better.
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Post by garbulky on Dec 4, 2019 22:20:58 GMT -5
Even if it has an XLR input, it is not fully balanced - it is only differential on the inputs. A fully balanced amp is also differential on the amp stages - meaning that there are two amps in there. Emotiva's code word for that is "quad-differential". Fully balanced requires nearly twice the circuitry so it is expensive to do. Also....a fully balanced monoblock amp sees the speaker load at half the impedance. So if it's driving a 4 ohm speaker, it's actually seeing a 2 ohm load (!!). If it drops to 2 ohms, it is seeing a 1 ohm load! What that means is that a proper fully balanced monoblock would be optimized to be able to run stable at very low impedances. The XPA-1 gen 1 and 2 are able to drive not just 4 ohm speakers but also (unoficially) 2 ohm speakers. This means it is seeing a 1 ohm load when driving a 2 ohm speaker and it is built hardy enough to handle it. A good example of a fully balanced monoblock amp that is NOT optimized for monoblock balanced operation is the Schiit Vidar. Hence it is ONLY rated for 8 ohm loads in monoblock configuration. Emotiva amps that are fully balanced are XPA-1 gen 1 and 2, XPA-1L gen 1 and 2, XPR-1, all models of the XPA gen 3 DR series (DR series only). Things that look fully balanced but are not are: The Emotiva UPA-1, The XPA gen 3 amp with one channel. The XPA HC-1. I don’t know the answer to this, but would the XPA-2 G2 be fully balanced when ran in mono block mode? Since you are bridging the amp and sending two channels (one + one -) to a single speaker. I believe YES the XPA-2 gen 2 is technically fully balanced in bridged monoblock configuration. But it is not optimized to run fully balanced. Therefore it's rated for 8 ohm speakers (not 4 ohms) in that mode. This is because 4 ohm speakers present a 2 ohm load and the XPA-2 is not optimized for loads that low. |
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Post by garbulky on Dec 4, 2019 22:26:03 GMT -5
garbulkyYou forgot the pa1, it's also "fully balanced". What's the difference between dual differential and quad differential ? Yes you are right! The Pa-1 is a balanced monoblock - the cheapest one Emotiva has ever made not to mention one of the best sounding. Quad differential is Emotiva terms. Dual differential is just talking about balanced inputs. This is not unusual and can be found on numerous dacs, amps and preamps that are not fully balanced but have XLR inputs. So before the signal gets to the actual AMP section of the amp it is differential/balanced. But not in the amp section. Here it is no longer differential. It is not considered a true balanced amp. Quad differential require the amps themselves to be balanced as well. This is much more expensive and complex for materials and build as they require two amps per channel. Here the signal is balanced from input to output. This is considered a true balanced amp. One that is optimized for fully balanced operation means that the amp is designed to handle very low loads and able to drive 4 ohm speakers - which results in the amp seeing a 2 ohm load and still being able to drive it. The advantage of fully balanced amps is that you can combine it with other fully balanced gear - like a fully balanced DAC (DC-1) or preamp (XSP-1/XMC-1). Then this preserves the fully balanced signal from the beginning of the chain to the end. |
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Post by Talley on Dec 5, 2019 7:42:44 GMT -5
So the Krell FPB250mc is a mono block and it runs 250w into 8, 500w into 4 and 1000w into 2
Does it mean that is "octo" differential?
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Post by AudioHTIT on Dec 5, 2019 10:47:10 GMT -5
So the Krell FPB250mc is a mono block and it runs 250w into 8, 500w into 4 and 1000w into 2 Does it mean that is "octo" differential? I think one of the points of the “fully balanced” discussion is that being a mono-block has no bearing on an amp’s balanced / differential design or status. It may be that due to the mono-blocks appeal to a more discriminate buyer (read ‘audiophile type’), that a larger percentage of mono-blocks are fully balanced, but that’s just conjecture. |
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KeithL
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Post by KeithL on Dec 5, 2019 11:33:26 GMT -5
Interestingly enough - no. In its bridged configuration, the XPA-2 (G1 and G2) has a balanced input, and a differential output, but the entire signal path is not fully differential. (At one point along the way the audio signal exists as a single non-balanced signal.)
In stereo mode the balanced input signal for each channel is converted into an unbalanced signal to be fed to the input of each amp channel. The input circuitry for each amplifier channel itself uses a dual differential circuit - but that circuit is driven from an unbalanced signal. In bridged mode, the unbalanced signal which would normally be used to drive one channel is converted back into a balanced signal by a phase splitter. And this balanced/differential signal is then used to drive the two output channels - as a "differential pair".
(It's all very clear on a schematic, if you read schematics, but it can get complicated to explain in words.)
In contrast, in a fully differential amp, like the XPA-1, or an XPA-DR, the overall signal does NOT pass through an "unbalanced stage".
Even if it has an XLR input, it is not fully balanced - it is only differential on the inputs. A fully balanced amp is also differential on the amp stages - meaning that there are two amps in there. Emotiva's code word for that is "quad-differential". Fully balanced requires nearly twice the circuitry so it is expensive to do. Also....a fully balanced monoblock amp sees the speaker load at half the impedance. So if it's driving a 4 ohm speaker, it's actually seeing a 2 ohm load (!!). If it drops to 2 ohms, it is seeing a 1 ohm load! What that means is that a proper fully balanced monoblock would be optimized to be able to run stable at very low impedances. The XPA-1 gen 1 and 2 are able to drive not just 4 ohm speakers but also (unoficially) 2 ohm speakers. This means it is seeing a 1 ohm load when driving a 2 ohm speaker and it is built hardy enough to handle it. A good example of a fully balanced monoblock amp that is NOT optimized for monoblock balanced operation is the Schiit Vidar. Hence it is ONLY rated for 8 ohm loads in monoblock configuration. Emotiva amps that are fully balanced are XPA-1 gen 1 and 2, XPA-1L gen 1 and 2, XPR-1, all models of the XPA gen 3 DR series (DR series only). Things that look fully balanced but are not are: The Emotiva UPA-1, The XPA gen 3 amp with one channel. The XPA HC-1. I don’t know the answer to this, but would the XPA-2 G2 be fully balanced when ran in mono block mode? Since you are bridging the amp and sending two channels (one + one -) to a single speaker. |
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KeithL
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Post by KeithL on Dec 5, 2019 12:08:34 GMT -5
Unless you read schematics, and can understand the fine distinctions involved, I would warn against reading too much into terms like that. (These distinctions are obvious on a schematic... it only gets complicated when you try to describe them in words.)
Although there is some overlap, the term "balanced" really describes a device configuration... while the term "differential" more describes a circuit configuration...
And, depending on the context, terms like "balanced" and "differential" can both mean somewhat different things.
For example, with modern solid state equipment, most balanced inputs are implemented using differential circuitry... However, the unbalanced inputs on all of our amps are also implemented using differential input circuitry... And it is possible to have a fully balanced amplifier that has no differential circuitry in it at all (although it would be unusual these days)... And each channel of an XPA-2 has a dual-differential stage inside it, even though the channel itself has an unbalanced input, and doesn't have a fully differential output...
(And, when we say "fully balanced - fully differential" we mean that an amp is "balanced and differential all the way through".)
Remember that the basic idea of all this is that, by treating the audio signal as "a pair or mirror-image signals", some errors common to both signals cancel out... So the result is lower distortion and better sound.
There is also no real industry standard accepted meaning for "quad differential" (at least not one that everybody actually agrees on) -
so you should read that as: "we use more differential stages in that amp than most of the other guys do in their amps and it helps us achieve better performance".
But, when all is said and done, what really matters is how it all performs, and how it sounds... This stuff is really just fine details about how we get there. 
garbulky You forgot the pa1, it's also "fully balanced". What's the difference between dual differential and quad differential ? |
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Post by emofrmcgy on Dec 5, 2019 12:10:41 GMT -5
Thanks Keith
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KeithL
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Post by KeithL on Dec 5, 2019 12:17:41 GMT -5
That pretty well sums it up.
With monoblocks - each amp has its own separate power supply - so you never have to worry about channel separation. And, since each one is separate, you can put each amp next to the speaker it's running if you like.
And, with the HC-1, you can also line up as many as you want on the same shelf. (Each HC-1 is half-width, and they can be placed side-by-side, with no space between them.)
The only real reason that most monoblocks are fully differential is that both of those things tend to appeal to the same group of people.
(And, no, it has nothing whatsoever with being able to deliver 8x the power into a 1 Ohm load  .)
So the Krell FPB250mc is a mono block and it runs 250w into 8, 500w into 4 and 1000w into 2 Does it mean that is "octo" differential? I think one of the points of the “fully balanced” discussion is that being a mono-block has no bearing on an amp’s balanced / differential design or status. It may be that due to the mono-blocks appeal to a more discriminate buyer (read ‘audiophile type’), that a larger percentage of mono-blocks are fully balanced, but that’s just conjecture. |
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Post by davidl81 on Dec 5, 2019 12:37:06 GMT -5
Interestingly enough - no. In its bridged configuration, the XPA-2 (G1 and G2) has a balanced input, and a differential output, but the entire signal path is not fully differential. (At one point along the way the audio signal exists as a single non-balanced signal.)
In stereo mode the balanced input signal for each channel is converted into an unbalanced signal to be fed to the input of each amp channel. The input circuitry for each amplifier channel itself uses a dual differential circuit - but that circuit is driven from an unbalanced signal. In bridged mode, the unbalanced signal which would normally be used to drive one channel is converted back into a balanced signal by a phase splitter. And this balanced/differential signal is then used to drive the two output channels - as a "differential pair".
(It's all very clear on a schematic, if you read schematics, but it can get complicated to explain in words.)
In contrast, in a fully differential amp, like the XPA-1, or an XPA-DR, the overall signal does NOT pass through an "unbalanced stage".
I don’t know the answer to this, but would the XPA-2 G2 be fully balanced when ran in mono block mode? Since you are bridging the amp and sending two channels (one + one -) to a single speaker. That makes sense Keith. I figured it may have been that way, but I was not sure. |
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Post by odedia on Dec 8, 2019 12:19:55 GMT -5
How would these compare to the XPA-1L?
Would I notice anything especially different with it being Class-H compared to Class A/AB?
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Post by gzubeck on Dec 10, 2019 23:21:33 GMT -5
I think there's three amps...
1) Make it good
2) Make it really good
3) Make it insanely good that it can only get better by improving the source signal.
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Post by leonski on Dec 11, 2019 14:21:47 GMT -5
How would these compare to the XPA-1L? Would I notice anything especially different with it being Class-H compared to Class A/AB? IF you could tell the difference you've better ears than 99% of everybody. 'H' is a power supply scheme and NOT output like A or A/B. As it turns out, an amp with an 'H' powersupply will probably also have an A or A/B output.... You'll drive yourself nuts worrying about stuff like that. What DON'T you like about your XP-1L? |
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Post by odedia on Dec 12, 2019 5:03:25 GMT -5
How would these compare to the XPA-1L? Would I notice anything especially different with it being Class-H compared to Class A/AB? You'll drive yourself nuts worrying about stuff like that. What DON'T you like about your XP-1L? Thanks. I LOVE my XPA-1L but one of them is acting up and it would be cheaper for me to buy a new amp than to ship it for repair. Regarding telling the difference - I can easily tell the difference between my XPA-3 (gen 1) and the XPA-1L (gen 2). Not sure if that’s a valid comparison though. |
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Post by leonski on Dec 12, 2019 13:50:10 GMT -5
I'll just suppose it's a valid comparison. Might be speaker dependent, to some extent.
Is one amp to be preferred or does each do something good or better than the other sos it ends up pretty much a 'wash'?
But you hit on ONE thing from EMO that really leaves me wanting.
Amp no longer made. (The XP-1L) and might not b supported. So? WHY can't you get the Schematic? You might know a Local who can fix it or has the ability.
It's NOT rocket science. Nothing proprietary. Parts are available with the exception of POSSIBLY the output devices if they are Darlingtons and circuit boards.
Other than that? NOTHING in that box can't be had. And no special knowledge.
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Post by rbk123 on Dec 12, 2019 15:21:32 GMT -5
Keith said they'd share the schematics with a local repairmen. I'd go that route first; he/she might not even need the schematics but if they did, they should be able to get them.
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Post by Hair Nick on Dec 13, 2019 11:06:30 GMT -5
For anyone looking to get a good deal on these, we will have an offer in early 2020 that you can take advantage of now.
Dan's "Eggnog Special" you can get 2 HC-1s PLUS the rack kit for $1,299. Email sales@emotiva.com and mention the "Eggnog Special".
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Post by donh50 on Dec 13, 2019 14:28:32 GMT -5
Are there any performance data into low-impedance loads like ESLs? That is, not a flat 2-ohm load, but something that dips below 2 ohms at HF? Power is not usually an issue but wondering about stability and such. Imagine no big deal, just curious.
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