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I was looking at the Lexicon website and their new MC-8 processor comes with balanced outputs or not. Can anybody explain what they are talking about? Thanks.
What Do They Mean By Balanced?
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well, it has two "hot" wires that carry exactly the same signal, only in completely opposite polarity. For example, if the positive wire is +5v vs. the ground wire, the negative wire is exactly -5v vs. the ground wire (we are talking about voltage at a particular instant).
The benefit is that if there is any interference in the transmission of the signal, it is likely that the same interference will have exactly the same impact on both wires. Let's say that both wires are floated by a +100v static charge: that is the + wire is 105v and the negative wire is 95v.
Most of today's amps use differential input stage where such "common" interference can be easily rejected. Thus, the benefit of a balanced input.
I personally have doubt as to how useful it is for home applications.
The benefit is that if there is any interference in the transmission of the signal, it is likely that the same interference will have exactly the same impact on both wires. Let's say that both wires are floated by a +100v static charge: that is the + wire is 105v and the negative wire is 95v.
Most of today's amps use differential input stage where such "common" interference can be easily rejected. Thus, the benefit of a balanced input.
I personally have doubt as to how useful it is for home applications.
I just bought a Lexicon MC-12 and Lexicon amp using the balanced inputs. I can't speak to the technical side, but there is a big difference on the audio side.
After going from the RCA inputs to balanced, the sound was better (clearer) and the ground hum in the speakers disappeared.
I say, if you can go balanced, go for it.
Bjake
After going from the RCA inputs to balanced, the sound was better (clearer) and the ground hum in the speakers disappeared.
I say, if you can go balanced, go for it.
Bjake
just want to add a little bit, a lot of medical / biological instruments and those used for nuclear physics, places where the signal is extremely weak, use balanced input. Input impendance for those instruments tend to be in the Mohm range.
for line-level signals in a home application where interference usually isn't big and shielding is usually quite good, it is hard to imagine the benefits of balance input. Line-level output for example has output impedance of 47Kohm, so it is hard to pick up interference (unless you have a welding arc gun near by,
).
But you never know. I do agree that equipment with balance input tends to be of higher quality and price.
for line-level signals in a home application where interference usually isn't big and shielding is usually quite good, it is hard to imagine the benefits of balance input. Line-level output for example has output impedance of 47Kohm, so it is hard to pick up interference (unless you have a welding arc gun near by,
).But you never know. I do agree that equipment with balance input tends to be of higher quality and price.
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Thanks for the explanation guys.
"for line-level signals in a home application where interference usually isn't big and shielding is usually quite good, it is hard to imagine the benefits of balance input."
Balanced will also give much greater immunity to ground loop problems. Ground loops are fairly common in home setups with cable or sat. feeds.
Shawn
Balanced will also give much greater immunity to ground loop problems. Ground loops are fairly common in home setups with cable or sat. feeds.
Shawn
"After going from the RCA inputs to balanced, the sound was better (clearer) and the ground hum in the speakers disappeared. "
Be careful here as balanced signals run 6dB hotter then unbalanced. If you just swapped them out back to back without accounting for that level difference balanced will sound considerably better... but that can be an artifact of just playing louder.
If they helped get rid of a ground hoop eliminating that hum will clear up the sound though.
Shawn
Be careful here as balanced signals run 6dB hotter then unbalanced. If you just swapped them out back to back without accounting for that level difference balanced will sound considerably better... but that can be an artifact of just playing louder.
If they helped get rid of a ground hoop eliminating that hum will clear up the sound though.
Shawn
"it has two "hot" wires that carry exactly the same signal, only in completely opposite polarity. For example,"
Interestingly to reject noise you actually don't even need to have the two signals out of phase with each other on two lines. You can do it with the signal on just one of the two lines and the other carrying no signal at all.
The reason being is say you picked up 3dB of interference on the two lines. The interference is still common to both lines even though the signal is only on one line. When the balanced input stage of the amp receives the signal it will invert one line and combine the two. The inverted line with just noise on it will still cancel against the noise on the other line which is also carrying the signal.
Shawn
Interestingly to reject noise you actually don't even need to have the two signals out of phase with each other on two lines. You can do it with the signal on just one of the two lines and the other carrying no signal at all.
The reason being is say you picked up 3dB of interference on the two lines. The interference is still common to both lines even though the signal is only on one line. When the balanced input stage of the amp receives the signal it will invert one line and combine the two. The inverted line with just noise on it will still cancel against the noise on the other line which is also carrying the signal.
Shawn
Quote:
yes, as long as the other line isn't AC grounded. the key is that you pick up the difference between the two lines, thus rejecting the common interference.
| Originally posted by sfogg Interestingly to reject noise you actually don't even need to have the two signals out of phase with each other on two lines. You can do it with the signal on just one of the two lines and the other carrying no signal at all. |
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