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ER4S Balanced Cable

post #1 of 5
8/18/10 at 3:18pm
Thread Starter 

Hey guys I have a question in regards to how adding a resistor works in a balanced audio cable.

 

In order for the ER4 to be considered an "S-type", there needs to be x2 75ohm resistors in series with both the left and right channels. However, in a balanced application, where ground and lead are opposite (yet equal), does that mean I would need 2 additional resistors for the the left and right channel grounds (so total 4 resistors, one per wire)?

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post #2 of 5
8/18/10 at 4:40pm

you can do it either way. One resistor is cheaper, 2 resistors works well if you happen to have a bunch of 47 ohm resistors kicking around.

 

Incidentally, the S-resistor is actually ~95ohms NOT 75. 75 ohms is the adapter, plus the 23 (or whatever) thats in the pod on the P...

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post #3 of 5
8/18/10 at 7:13pm
Thread Starter 

Hey nikongod, just the guy to talk to haha. I was wondering if you could explain how it'll work either way? What are the benefits (if any) of 4 resistors vs 2?

 

Ohh i see what you mean with the value being 95. I thought the value of drive was naturally 27 ohms, but according to the dated Dr. Xin ER4 article, the drive has 5 ohm resistance and the cable itself has 2 ohms (20ohm resistors being in the pod).

 

So If I was completely redesigning the cable from the ground up, I guess my best bet would be 100ohm resistors

 

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post #4 of 5
8/18/10 at 8:36pm

I looked for a second to find a good link to support it... grumbles. My google fu is weak tonight.

 

Anyways, to understand why the single resistor works with a balanced amp the easiest thing to do is look at a passive speaker crossover, and a single ended or balanced amplifier (SE=the amplifier drives the speaker from one end, balanced=both ends). If you take this speaker, with a generic common crossover which typically has all the inductors/caps/whatnot on the in phase terminal (and seldom on both... read on) and try it on both of these amps the sound will be identical. The fact that the passive components are in only on one side of the speaker has no bearing on the performance on how the system works. 

 

We could take it a step further and show that with the passive components on the "ground" side of the speaker when driven from the above SE amp there is no audible difference (perhaps put a phase switch in the preamp to satisfy the absolute phase folks) compared to when they are on the "driven" terminal.


Edited by nikongod - 8/18/10 at 8:39pm
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post #5 of 5
8/24/10 at 12:33pm
Thread Starter 

Cool good to know,

 

I'm considering the Vishay Z-Foil resistors, which are ridiculously pricey but I figure go big or go home. Good to know I'll only need two

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