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Post by mattsf on Feb 14, 2014 13:31:22 GMT -5
I'm looking to get some decent amplifiers for my B&W PM-1 speakers. Could someone unpack the difference in the marketing language of some of the amplifier classes for me? - Most of the mono blocks (XPR-1, XPA-1, XPA-1L) are described as "Fully balanced, fully discrete, Quad Differential".
- The stereo amps (XPR-2, XPA-2) are described as "fully discrete, highly optimized dual differential"
What is the difference between quad and dual differential? And what does this mean for the sound? Are the stereo amps not fully balanced (the monoblocks are described this way, but the stereo amps are not)? What is the difference in their design that leads to this difference in marketing language? And more importantly, how does that affect the sound? |
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Post by garbulky on Feb 14, 2014 14:00:44 GMT -5
I may be not technically on the spot with this but the general idea is:
The quad differential fully balanced means that there's two separate circuits creating an inversion of the signal from the other. Then when they get combined any distortions picked up from the start to the end of that circuit are cancelled out due to the whole combining the inverted signal.
So if you have fully differential and balanced gear (Quad differential) like from the DAC to the amp, the distortions within each circuit get cancelled out.
So for instance
The DC-1 coupled to an XSP-1 to an XPA-1 L will be fully balanced from end to end.
Fully balanced differential components are expensive because basically you need two of everything. So for instance the XPA-100 monoblock is not fully balanced though it is a monoblock.
Dual differential differs because it does not have two of everything and doesn't do the whole inverted signals which cancel out distortions(basically). So dual differential is not unusual but fully balanced and differential is unusual, desirable, and usually very expensive. Emotiva, outlaw, and maybe ATI are the only companies I know that offer fully balanced designs at these price points (1k and less). Emotiva's codeword for this is quad differential or differential reference.
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arjna
Seeker Of Truth
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Post by arjna on Feb 14, 2014 15:34:41 GMT -5
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Post by repeetavx on Feb 14, 2014 16:14:11 GMT -5
arjna, thanks for the link. Very instructive. Now, let's see if my understanding makes sense to you guys. I'll partially quote Keith's key points so I won't confuse myself. A BALANCED CONNECTION is a connection BETWEEN two pieces of equipment that carries two equal and out of phase versions of the signal. A differential amplifier is a type of circuit design which has all sorts of benefits, and is widely used in many ways. A single differential amplifier works very well as the basis of the input circuitry on an unbalanced input. A pair of differential amplifiers is often used for a balanced input to a non-differential amplifier. (You could call this "dual differential".) If you now take a fully differential amplifier, and use a dual differential input for EACH of the two modules that comprise it, the result can be called "quad differential". |
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Post by milsap195 on Feb 14, 2014 21:35:47 GMT -5
I'm looking to get some decent amplifiers for my B&W PM-1 speakers. Could someone unpack the difference in the marketing language of some of the amplifier classes for me? - Most of the mono blocks (XPR-1, XPA-1, XPA-1L) are described as "Fully balanced, fully discrete, Quad Differential".
- The stereo amps (XPR-2, XPA-2) are described as "fully discrete, highly optimized dual differential"
What is the difference between quad and dual differential? And what does this mean for the sound? Are the stereo amps not fully balanced (the monoblocks are described this way, but the stereo amps are not)? What is the difference in their design that leads to this difference in marketing language? And more importantly, how does that affect the sound? I have wanted a pair of pm1. They are so pretty in person. |
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Post by creimes on Feb 14, 2014 23:04:01 GMT -5
I'd have to say the XPA-1L's would be nice for those PM-1's  I am biased though |
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Lsc
Emo VIPs 
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Post by Lsc on Feb 14, 2014 23:27:51 GMT -5
Emotiva and outlaw are the only companies I know that offer fully balanced designs. Emotiva's codeword for this is quad differential or differential reference. "I know" saved you here because this couldn't be more wrong if you left that out. Your suspension from answering questions has been reduced from 3 days to probation.  lol. Happy posting. |
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Post by garbulky on Feb 14, 2014 23:59:01 GMT -5
Emotiva and outlaw are the only companies I know that offer fully balanced designs. Emotiva's codeword for this is quad differential or differential reference. "I know" saved you here because this couldn't be more wrong if you left that out. Your suspension from answering questions has been reduced from 3 days to probation. lol. Happy posting. Yeah you're right. I meant to say Emotiva and Outlaw was the main companies that offer it at this price point. I think ATI may do some stuff too? Thanks for the catch. |
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Lsc
Emo VIPs
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Post by Lsc on Feb 15, 2014 0:16:20 GMT -5
"I know" saved you here because this couldn't be more wrong if you left that out. Your suspension from answering questions has been reduced from 3 days to probation. lol. Happy posting. Yeah you're right. I meant to say Emotiva and Outlaw was the main companies that offer it at this price point. I think ATI may do some stuff too? Thanks for the catch. Most big name high end companies have fully balanced gear and they had for a long time. And yes, if you are talking price points, Emo can't be touched for value as you know. ATI makes Outlaw (oem) last I checked. |
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Post by mattsf on Mar 21, 2014 12:41:27 GMT -5
Yes, they are beautiful. If you judge speaker on both how they look and sound (which I certainly do), they are a great choice. |
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I am biased though
lol. Happy posting.