Hello all.
I was asking this question over on a car audio forum as I see this more in car audio, but wasn't getting very many responses that were actually useful and not really backed by great data.
Here is the question: Why do amps that have ONLY rca inputs have balanced/differential inputs? What are their benefits?
Example: https://jlaudio.zendesk.com/hc/en-us/articles/209357588-Differential-Balanced-Inputs
Balanced can be done technically with 2 conductors as long as both carry a signal and same impedance to ground, so I suppose you can have a balanced signal on RCA's (I couldn't find any "in the wild" examples though).
I have read both of these by Bill Whitlock. AMAZING reads, well worth it. They both have basically the same info.
https://centralindianaaes.files.word...notes-v1-0.pdf
https://www.jensen-transformers.com/...ic-seminar.pdf
Pg 16 from the Jensen Article: From this, it seems that unbalanced, single ended sources, doesn't benefit from differential amplifiers
Pg 22 from the Jensen Article: This again says single ended sources, since they have different impedances to ground, won't benefit from an amp input that is "balanced and differential". Nothing really comes from the differential part it appears.
Pg 29 from the Jensen linked article:
This is where I get confused, in the second "correct" example, wouldn't the shield being connected to ground and to the sleeve of the RCA, which is connected to pin 3, cause the lo and hi conductor to have unequal impedances to ground? So how do we get noise rejection here? The signal can no longer be balanced with unequal impedances to ground!
I was asking this question over on a car audio forum as I see this more in car audio, but wasn't getting very many responses that were actually useful and not really backed by great data.
Here is the question: Why do amps that have ONLY rca inputs have balanced/differential inputs? What are their benefits?
Example: https://jlaudio.zendesk.com/hc/en-us/articles/209357588-Differential-Balanced-Inputs
Balanced can be done technically with 2 conductors as long as both carry a signal and same impedance to ground, so I suppose you can have a balanced signal on RCA's (I couldn't find any "in the wild" examples though).
I have read both of these by Bill Whitlock. AMAZING reads, well worth it. They both have basically the same info.
https://centralindianaaes.files.word...notes-v1-0.pdf
https://www.jensen-transformers.com/...ic-seminar.pdf
Pg 16 from the Jensen Article: From this, it seems that unbalanced, single ended sources, doesn't benefit from differential amplifiers
Pg 22 from the Jensen Article: This again says single ended sources, since they have different impedances to ground, won't benefit from an amp input that is "balanced and differential". Nothing really comes from the differential part it appears.
Pg 29 from the Jensen linked article:
This is where I get confused, in the second "correct" example, wouldn't the shield being connected to ground and to the sleeve of the RCA, which is connected to pin 3, cause the lo and hi conductor to have unequal impedances to ground? So how do we get noise rejection here? The signal can no longer be balanced with unequal impedances to ground!