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Post by garbulky on Jun 7, 2015 11:43:37 GMT -5
Is the xpr 2 quad balanced? No. The only ones are XPA-1 L, XPA-1, XPR-1
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Post by stanlee on Jun 7, 2015 14:50:06 GMT -5
What's the difference between quad balanced and quad differential?
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Post by audiosyndrome on Jun 7, 2015 17:25:05 GMT -5
Balanced refers to the overall topology of the amplifier. Quad differential refers to the input stage topology of the amplifier and is MUCH less important than the former IMHO.
russ
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Post by stanlee on Jun 8, 2015 11:29:36 GMT -5
So quad balanced is much critical and better sounding than quad differential?
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KeithL
Administrator
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Post by KeithL on Jun 8, 2015 11:37:06 GMT -5
Unfortunately, while the individual DESIGN concepts are important, the way they are used is not at all consistent. A balanced SIGNAL uses two wires, one carrying the signal, and the other carrying an exact copy of it, but out of phase. At the receiving end, the two signals are subtracted from each other, which causes the legitimate signals to add together, but any noise picked up by both lines to cancel out. This is why balance connections are almost totally immune to picking up hum and certain other types of noise. (This is really important IF YOU HAVE A HUM PROBLEM or if you need to run really long interconnects.) A balanced DEVICE has two separate signal paths - one of which carries the normal signal, and the other of which carries an out of phase copy of it. The output is created by adding the two signals together. The idea there is that any DISTORTION created by the two halves of the device will be equal and out of phase, and so will cancel out when the two signals are added together (this process is functionally identical to the "subtraction" performed with balanced connections). Yo also may see a few dB less noise due to the cancellation. Notice that this is an entirely DIFFERENT benefit than what you get with a balanced connection. In a "fully balanced" or "fully differential" SYSTEM, you have both of these, and get the benefits of both. Also note that the two aren't necessarily related. You can have a balanced device with unbalanced connections, or an unbalanced device with balanced connections. A DIFFERENTIAL INPUT stage is a specific type of input circuitry. It is very important to note that differential input circuitry is used on the vast majority of equipment produced today - including equipment with unbalanced inputs. It is simply a type of input circuitry (it's a really good way to do it, but it's so good, and doesn't cost especially more than doing it any other way, so most things use it.) All modern op amps, including the nasty 25 cent ones, and the best ones made, have differential inputs. When we use the term "quad differential input", we're referring to the fact that the amp has balanced inputs, and is a balanced amp, and has "differential inputs all around" and they're "criss-crossed to minimize and cancel out distortion". The fact is that, industry wide, different manufacturers use the terms "dual differential" and "quad differential" to mean slightly different things, and there is no technical standard (or, rather, there are too many) so you can't know for sure exactly what someone means by it unless you see a schematic and can read it. HOWEVER, before you get too obsessed about who has which type of input, and whose product is or is not "fully differential", you should remember that all of this is just design in the service of good sound. Whenever you see claims that "balanced connections are better" or "fully differential amplifiers are better", there is always an unspoken assumption about "all else being equal". In reality, there's no way to know for sure that one PARTICULAR balanced design will be better than a DIFFERENT unbalanced design. The potential differences are small enough that other factors often end up making much more of a difference. (So a GOOD single-ended unbalanced product may well sound much better than a BAD fully differential one. Therefore, you should always consider the specs - and the actual sound quality - and consider the circuit topology to be merely "interesting". We use topologies like quad-differential inputs BECAUSE they help us to design amps that sound good - which is not the same as saying that any amp that uses them will sound good, or that any amp that lacks them will sound bad.. ) What's the difference between quad balanced and quad differential?
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KeithL
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Post by KeithL on Jun 8, 2015 13:45:01 GMT -5
McIntosh equipment is very nice - and all of it that I've heard sounds very good.... However, from what I've heard, their warranty service isn't what it used to be... (Google it for yourself). Perhaps he does have an infatuation with big watt amps and that's a good thing . Also, Emotiva is a viable alternative to spending the mega dinero on Mcintosh amps. I do think that the Mcintosh may be the right path though given his up and down experience with the XPR-5. The MC452 is the amp that the dealer used when I auditioned my F208 an it was phenomenal. If I was wealthier, I would have bought that amp. I like everything about it from the meters to the build quality to the binding posts. As I said previously, the F208 in my house never sounded close to what I heard at the dealer until I got the XMC-1. The XPR-2 further improved things but is it better than the mighty Mcintosh? Maybe yes maybe no...I have no idea except that the XPR-2 fit my budget well and sound fantastic. But there is that hiss! MC452 is fully balanced....if you can get a good deal... Thanks Isc. Knowing that the XPR 2 hisses as well helps narrow my decision. Also not having to worry about 20amp lines puts my OCD at ease. Yes the mac is a thing of beauty and knowing that it'll last a lifetime is probably why people are willing to pay that premium tag. Their warranty service is legendary as well from what I've heard. Speaking of being "fully balanced" what does it mean from an audio/sound perspective? I've heard of the term before but never quite understood what it does....are the XPR's fully balanced?
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Post by garbulky on Jun 8, 2015 14:07:03 GMT -5
Quad differential is Emotiva's way of saying it is fully balanced from end to end. So it means there's two sets of circuits for the signal one out of phase with each other. And it will cancel at the end of the amp. Dual differential is I think relating just to the inputs and not the whole "end to end" balanced that people understand as being fully balanced.
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Post by Boomzilla on Jun 8, 2015 14:25:03 GMT -5
Mac service depends heavily on the quality of the local authorized service center. At one time, McIntosh not only closely controlled their authorized service centers, but also put on the traveling McIntosh Clinic, where one could bring in any of their products for free assessment. Any more, there are no traveling clinics and there are far fewer (and now independent) service centers.
I've been very lucky - The nearest service center to me (about 70 miles away) is VERY competent, friendly, and (once the parts arrive from McIntosh) reasonably quick. I realize that not everyone has the luxury of a good service center, but I'd not hesitate to buy the brand for fear of service issues.
YMMV...
Boom
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Post by stanlee on Jun 8, 2015 23:47:47 GMT -5
Guys
Here's a technical question that I can't seem to get a definite answer to......if I have 2 amps (1 for HT 1 for stereo) and only use them one at a time not simultaneously, can I wire the amps separately to the same main speaker? Meaning each amp has it own speaker wire cable connected to the same main speaker, one amp hooked up via bananas and the other via spades.
I'm willing to unplug one amp completely from power while using the other.
Thanks in advance
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Post by jackpine on Jun 9, 2015 0:09:57 GMT -5
No.
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Post by bub on Jun 9, 2015 0:29:04 GMT -5
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Post by stanlee on Jun 9, 2015 1:29:15 GMT -5
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Post by stanlee on Jun 9, 2015 1:33:33 GMT -5
How would that device help Bub?
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Post by jackpine on Jun 9, 2015 7:25:12 GMT -5
The output impedance of an amplifier is much lower than your speakers eight ohms. The unused amp would be seen in parallel with the speaker and acting like a short.
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Post by Canuck_fr on Jun 9, 2015 7:37:14 GMT -5
Guys Here's a technical question that I can't seem to get a definite answer to......if I have 2 amps (1 for HT 1 for stereo) and only use them one at a time not simultaneously, can I wire the amps separately to the same main speaker? Meaning each amp has it own speaker wire cable connected to the same main speaker, one amp hooked up via bananas and the other via spades. I'm willing to unplug one amp completely from power while using the other. Thanks in advance One should NEVER do this. I myself did this once and literally fried an amplifier, Strangely the one that was fried was the one that was NOT on.
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Post by stanlee on Jun 9, 2015 10:32:55 GMT -5
Guys Here's a technical question that I can't seem to get a definite answer to......if I have 2 amps (1 for HT 1 for stereo) and only use them one at a time not simultaneously, can I wire the amps separately to the same main speaker? Meaning each amp has it own speaker wire cable connected to the same main speaker, one amp hooked up via bananas and the other via spades. I'm willing to unplug one amp completely from power while using the other. Thanks in advance One should NEVER do this. I myself did this once and literally fried an amplifier, Strangely the one that was fried was the one that was NOT on. Wow really? Shytes!!! So what would be the best way to use 2 different amps into one pair of speakers while keeping the 2 amps totally separate for 2 different applications in this case HT and stereo.
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KeithL
Administrator
Posts: 10,002
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Post by KeithL on Jun 9, 2015 11:36:09 GMT -5
Don't even think about connecting the outputs of two amps together - or to the same place. (Also don't even consider some sort of switch arrangement that relies on your remembering to open one switch before closing the other - even a momentary lapse of memory could fry an amp.) However, you can use a speaker switch to connect one or the other amp to the speakers.... just be careful to get one that ONLY EVER connects one amplifier at once - and remember to switch both the (-) and (+) lines since not all amps ground the "black terminal". It's probably a BAD idea to "simply use a speaker selector, like one of those pushbutton ones, and turn it around" since many of them allow for simultaneous connection of both speakers (which, if you're using it turned around, would connect the amps together). If you're wiring it yourself, simply use a pair of heavy duty DPDT switches (double-pole-double-throw) - a separate one for each channel - to switch both wires on the speaker from one amp to the other. Each amp goes to "one end" of the switch and the speaker goes to the "center" - that way you can only ever connect one amp at a time to the speaker and you can NEVER connect them together by accident.) Don't even THINK of doing it yourself unless that previous line "makes perfect sense to you" and you know what you're doing. It's pretty simple but, as someone already said, you can absolutely burn up one or both amplifiers if you wire it wrong. Note that, on our amps, you want the amps to be powered off when you flip the switch - it won't hurt anything, but, if you flip the switch with the amp on, it will probably go into protect. If you use regular heavy-duty bat switches (which are always "break-before-make") you can follow this diagram... Note that you will need a separate DPDT switch for EACH CHANNEL One should NEVER do this. I myself did this once and literally fried an amplifier, Strangely the one that was fried was the one that was NOT on. Wow really? Shytes!!! So what would be the best way to use 2 different amps into one pair of speakers while keeping the 2 amps totally separate for 2 different applications in this case HT and stereo.
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Post by bub on Jun 9, 2015 13:20:14 GMT -5
I will defer to saner minds. I used it to connect two set of mains on a 7 channel amp. Just switched the unbalanced to balanced on the amp for the two I wasn't using. Worked fine but absolutely different from what you asked about .
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Post by stanlee on Jun 9, 2015 15:21:22 GMT -5
Yeah I think it's better for me not to dive into the darkness and just stay in the light. Thanks for the input guys.
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Post by stanlee on Nov 10, 2015 11:42:17 GMT -5
Just an update:
Instead of upgrading to the mc452 for my 2 channel entertainment, I postponed it and went for the C2500 stereo pre-amp instead.
I wish I could invite every one of you into my humble abode to listen to some tunes. I simply can't describe how sweet the sound is now.....so sweet I could cry. And that's just with a XPR 5 amp.
Just imagine how dry my eyes would be when I get the 452!!!! Oh Lord thank you for my pair of ears and for Mcintosh.
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