Tony, let's talk cables

[79Bronco]

I know this probably belongs in the wiring forum, but I want to get Tony's opinion on this.

I recently purchased an amplifier with a balanced input port. Obviously in any quality build, the goal is to get the cleanest input signal to the amplifier. The problem is, my head unit does not have a balanced output, only unbalanced RCA's. Would it be worth it to get some RCA to XLR adapters and plug them in directly behind the RCA port. I've seen people do something similar with line drivers, but is there any real benefit in converting a 2 conductor signal up to a 3 conductor signal?

Here is my rationale and background:

I work in the underwater, offshore electronics industry so I have a pretty good idea about cables and connections. A lot of our customers want cables with twisted shielded pairs to eliminate electronic noise. I have even had customers request that we install a diode in between the conductor and the connector. Regardless, I recognize that the benefit of a balanced connection is to reduce electrical noise, but what else can be done here?

In short (too late I know) what can I do to improve this signal, will a line out driver that will convert the rca to balanced even be worth it? Why? or why not?

[xx1]

on those RCA to XLR adapters they only bridge one of the wires right? I can't remember which one, but I don't see a benefit in quality from that.

but again, I'm not tony.

[79Bronco]

So as I understand it, an RCA is a two-conductor system. One conductor carries the signal and one does not (the shield). The shield does not pick up much any electrical interference since it's kept at 0v; however, the positive conductor (the center pin on the RCA) does pick up electrical noise which is added to the signal already being carried from one electrical source to the other.

The signal is interpreted by measuring the difference in potential energy between the shield and the center pin. This includes both the signal and unwanted noise.

By introducing a third conductor, the electrical interference will still exist; however, it will exist on both the signal conductor and the (-) negative conductor. Since the negative conductor does not carry any signal, the system can "subtract out" the electrical noise that it detects on both the center (+) and negative (-) conductor.

[xx1]

sounds interesting, I've used rca to xlrs before, (not on car audio) I haven't noticed a difference. like when using true balanced xlr cables, but many factors could have contributed to that.

[qu1cks1lver56]

There's no way to get a balanced signal out of a headunit. RCA's are unbalanced. Unless there are headunits with balanced outputs, but I've never seen that.

[79Bronco]

bump?

[LZTYBRN]

A regular RCA to XLR adapter won't do anything. Both the shield and one of the conductors in the XLR are connected to the ground of the RCA, so it's besically the same as RCA just with a different connector.

If you actually want a balanced signal, you'd need something to actively convert it. I don't know much about this, but after some quick research I came across a couple things. Google "balun transformers" and "jensen transformers." Hopefully that helps.

Also, I'm curious what amp it is you got... car audio?

[79Bronco]

Here is one of the amps I'm using.

http://www.amazon.com/REF4-920-Soundstream-Reference-Series-Amplifier/dp/B002BS3PNS

All of soundstreams reference line has the option to use a balanced input like the one found on this amp.

After researching more about this input, it's basically a 6 conductor system that uses a plug that is very similar to the old-school computer mouse style plugs. It is the same input found on some sybilink amps, and it is the same cable as the zapco symbilink.

Soundstream sells a balanced line transmitter that converts the rca to a balanced output that can be seen here:

Edited January 19, 2013 by 79Bronco

[TonyD'Amore]

I know this probably belongs in the wiring forum, but I want to get Tony's opinion on this.

I recently purchased an amplifier with a balanced input port. Obviously in any quality build, the goal is to get the cleanest input signal to the amplifier. The problem is, my head unit does not have a balanced output, only unbalanced RCA's. Would it be worth it to get some RCA to XLR adapters and plug them in directly behind the RCA port. I've seen people do something similar with line drivers, but is there any real benefit in converting a 2 conductor signal up to a 3 conductor signal?

Here is my rationale and background:

I work in the underwater, offshore electronics industry so I have a pretty good idea about cables and connections. A lot of our customers want cables with twisted shielded pairs to eliminate electronic noise. I have even had customers request that we install a diode in between the conductor and the connector. Regardless, I recognize that the benefit of a balanced connection is to reduce electrical noise, but what else can be done here?

In short (too late I know) what can I do to improve this signal, will a line out driver that will convert the rca to balanced even be worth it? Why? or why not?

You would have to convert it to a balanced signal at the source and then transmit it as a balanced signal down a twisted pair cable to your amplifier. This may reject the noise better than transmitting an unbalanced signal down a coax cable. If using a good Coax cable, an unbalanced signal is typically pretty noise free in most installs. The problem is when someone uses "twisted pair" with an unbalanced signal. This doesn't work well. I've actually made a video on the topic, waiting for Steve to post it up.

Tony

[Kyblack76]

Damn Steve!! Get on the stick!!

Me want vid!!