RCA Audio Cables

[jstenger]

I have been looking at RCA audio cables, and my head is about to explode. 20 foot cables range from $8 to $80. I know you usually get what you pay for, but $80 for one 20 foot cable is crazy! I believe the 20 foot cables from Exile are T-Spec V8 series, although T-Spec also makes the V10 and V12 series. Not sure what Wet Sounds cables are, but they are pretty pricey. Just curious what others are running, and how much of a difference they make. I have looked at T-Spec, Raptor, Stinger, Scosche. and a few others. I will need four 20 footers to hook up my ZLD. All four cables will run up around the inside edge of the bow, and not be close to any power wires except for the turn on for the ZLD, which is very low in current. Thanks for any info.

[brain_rinse]

My suggestion: http://www.monoprice.com/Product?c_id=102&cp_id=10218&cs_id=1021814&p_id=2866&seq=1&format=2

[jmvotto]

Plus 1 on monoprice, great price and quality, no complaints here.

[bergermaister]

My suggestion: http://www.monoprice.com/Product?c_id=102&cp_id=10218&cs_id=1021814&p_id=2866&seq=1&format=2

Plus 2. I think those are the exact cables on my ZLD.

[jstenger]

Found this interesting video.

http://www.stevemeadedesigns.com/board/topic/162518-truth-about-rca-cables-coax-vs-twisted-pair/

[MLA]

The Wet Sounds RCA's that come in the port side EQ kit are top shelf for sure. A single 6 chnl + a long or short 2 chnl for the input, whether your head-unit is on the port or stbd side. This really reduces the bulk. I like to use 2 4 chnl cables when I can. If you can run your cables under the walkway, you could go with the 17ft Metra 4 chnl. They offer them in the V8, V10 and V12 series. The V8 series is a solid cable, I use them. One simple difference between price point and top of the line, is the insulation thickness. As the integrity of the conductor goes up, the thickness of the insulation, goes down.

You certainly do get what you pay for, but that doesnt always mean that inexpensive is cheap quality. You do not need the most expensive RCA cables to have a clean noise free system.

[Brianinpdx]

My take on RCA cables is a bit different than MLA's. Spending 15 years working @ Phoenix Gold taught me a lot about RCA product cable design. PG was actually a prime manufacturer back in the day and did all their own cable builds. The nuts and bolts of it really comes down to a couple of area's--- construction materials and construction costs. Breaking that down a bit further...Here's the lay of the land

- Look for a cable that offers twisted pair noise rejection. The key is the twisted pair of conductors. As the price of the cable goes up, so do the windings of the conductors. This costs the mfg more money. You'll see companies taught so many windings per mm.

- Look for a cable that is built well. All the fancy connectors are not going to help you in the marine world. In fact I'd prefer a middle of the line cable with injected ends over the metal barrel connectors due to rust. Fancy end connectors drive costs up.


As far as your ZLD you bought, why didn't you buy the kit version? It comes with all the cables and wire harness stuff needed for install for +50 bucks.

-Brian

[jstenger]

Brian,

Thanks for the info. I got the ZLD from a fellow Moomba owner. Otherwise I would have ordered it with the kit. Also, thanks for helping me with my SXT9 order.

[gregski]

- Look for a cable that offers twisted pair noise rejection. The key is the twisted pair of conductors. As the price of the cable goes up, so do the windings of the conductors. This costs the mfg more money. You'll see companies taught so many windings per mm.
That's true if the drivers/receivers are differential. If they are single ended (which the ZLD is) then a coax RCA is the right cable.

[mbusch5]

That's true if the drivers/receivers are differential. If they are single ended (which the ZLD is) then a coax RCA is the right cable.

Possibly a few stupid questions: If the ZLD is single ended what type of RCA's are included in their kits? Because they only sell the V8 series which is twisted pair.

Since I will be starting my stereo install soon, how do you determine if your amps are differential or single ended? I will be doing Wetsounds, but I do not see that info.

[gregski]

Possibly a few stupid questions: If the ZLD is single ended what type of RCA's are included in their kits? Because they only sell the V8 series which is twisted pair.

Since I will be starting my stereo install soon, how do you determine if your amps are differential or single ended? I will be doing Wetsounds, but I do not see that info.

Not stupid questions at all. The problem is the confusion that the industry intentionally creates to upsell expensive products.

All consumer level audio equipment like car stereos use single ended signals. The outputs from the stereo and the inputs to an amp are all single ended.. They use RCA connectors and a coax cable offers the best noise immunity. Differential audio signals usually use XLR connectors (link (http://en.wikipedia.org/wiki/XLR_connector)) You'll probably recognize these more as professional stage and studio equipment.

So pretty much if you see RCA connectors, the drivers/receivers are single ended.

For those cables you mention, the manufacturer is Metra and frankly, they appear to be using very liberal "marketing". Here is a link to their catalog: http://www.metraonline.com/files/catalogs/2014_TSPEC_CATALOG.pdf

The only cables that appear to be twisted pair are the V12 series but the weird part is that they actually look to have three conductor wires which doesn't even make sense. What does the third wire connect to? In the real world of signal transmission, there is shielded twisted pair, which is like a twisted pair but with a ground shield sort of like a coax but then you have 3 connections +/-/GND on each and all 3 conductors are certainly not braided like this.

It looks to me like they braided 3 wires because it looks fancy but it would only be for looks. Unless I'm missing something I would say that those V12s are pure gimmikry.

The V10s are "dual twist" but I have no idea what that really means. They appear to be a coax... which they should be. Some of their other selling features are "high tolerance compact machined metal end" and "Packaged in High-End Retail Box". Plenty of marketing here. They also list "Ultra-flexible PVC blended jacket" which is a good feature if you need it, such as tight installations. The V8s aren't in that catalog but they are also "dual twist" which again is unclear what it actually means.

The V6s look like fine RCAs to me, without the extra cost for the "high-end retail box".

[jstenger]

That's true if the drivers/receivers are differential. If they are single ended (which the ZLD is) then a coax RCA is the right cable.

I believe the ZLDMKII is a differential also. The inputs and outputs are insulated from the frame. I need to still do a continuity test to verify.

[jstenger]

All consumer level audio equipment like car stereos use single ended signals. The outputs from the stereo and the inputs to an amp are all single ended.. They use RCA connectors and a coax cable offers the best noise immunity. Differential audio signals usually use XLR connectors (link (http://en.wikipedia.org/wiki/XLR_connector)) You'll probably recognize these more as professional stage and studio equipment.

So pretty much if you see RCA connectors, the drivers/receivers are single ended.

I disagree as far as the Exile XM amps go. From what I have read, and testing I have done, the XM's are differential amps. Neither the center conductor nor the outer conductor are connected to the chassis or the power leads.

[David Analog]

No amplifier has the center conductor connected to chassis.
You will find almost NO amplifiers that have the input RCA shield DC connected to the chassis or the power supply ground. The shield ground is floating, in other words, perhaps 10kOhm above ground. But you are only measuring an AC circuit with DC. In any case, a floating input ground in no way indicates that the input section is balanced differential.

[gregski]

In any case, a floating input ground in no way indicates that the input section is balanced differential.
Exactly.

And it's worth pointing out that basically all amplifiers use differential op-amps so the manufacture may well state that they use differential amplifiers but in no way does this mean that the in/out signals are balanced differential signals. Restated: you use differential op-amps for single-ended signals.

Even if an amplifier used a differential input, the source output is single ended, so you'd still want to use a coax cable and drive it single-ended.

[jstenger]

Exactly.

And it's worth pointing out that basically all amplifiers use differential op-amps so the manufacture may well state that they use differential amplifiers but in no way does this mean that the in/out signals are balanced differential signals. Restated: you use differential op-amps for single-ended signals.

Even if an amplifier used a differential input, the source output is single ended, so you'd still want to use a coax cable and drive it single-ended.
What do you mean by differential op-amp?

[David Analog]

op-amp. operation amp. Integrated circuit. IC chip. Performs a designated function ending in a transistor (a low level processor and amplifier). Tiny as opposed to a bunch a space-consuming discrete components.
Some are linear amplifiers such as the chips that drive the HU or EQ preamp outputs. Some are for active crossover functions. Some are for EQ tone functions. Some are used at the amplifier inputs. The applications go on and on.

[mbusch5]

Not stupid questions at all. The problem is the confusion that the industry intentionally creates to upsell expensive products.

All consumer level audio equipment like car stereos use single ended signals. The outputs from the stereo and the inputs to an amp are all single ended.. They use RCA connectors and a coax cable offers the best noise immunity. Differential audio signals usually use XLR connectors (link (http://en.wikipedia.org/wiki/XLR_connector)) You'll probably recognize these more as professional stage and studio equipment.

So pretty much if you see RCA connectors, the drivers/receivers are single ended.

For those cables you mention, the manufacturer is Metra and frankly, they appear to be using very liberal "marketing". Here is a link to their catalog: http://www.metraonline.com/files/catalogs/2014_TSPEC_CATALOG.pdf

The only cables that appear to be twisted pair are the V12 series but the weird part is that they actually look to have three conductor wires which doesn't even make sense. What does the third wire connect to? In the real world of signal transmission, there is shielded twisted pair, which is like a twisted pair but with a ground shield sort of like a coax but then you have 3 connections +/-/GND on each and all 3 conductors are certainly not braided like this.

It looks to me like they braided 3 wires because it looks fancy but it would only be for looks. Unless I'm missing something I would say that those V12s are pure gimmikry.

The V10s are "dual twist" but I have no idea what that really means. They appear to be a coax... which they should be. Some of their other selling features are "high tolerance compact machined metal end" and "Packaged in High-End Retail Box". Plenty of marketing here. They also list "Ultra-flexible PVC blended jacket" which is a good feature if you need it, such as tight installations. The V8s aren't in that catalog but they are also "dual twist" which again is unclear what it actually means.

The V6s look like fine RCAs to me, without the extra cost for the "high-end retail box".

Thanks for the info, definitley shed some light. In an attempt to make it easy, basically using an "RCA" cable will work on everyday amps and stereo equipment weather its "dual twist" or "woven coax"? I noticed Wetsounds says "quad twist" so I'm sure its all gimmick.

[sandm]

both boats and some of my home audio from here:
http://www.knukonceptz.com/

never ordered their "high end" stuff, stuck mostly to mid-price and seems to perform good.

[gregski]

Thanks for the info, definitley shed some light. In an attempt to make it easy, basically using an "RCA" cable will work on everyday amps and stereo equipment weather its "dual twist" or "woven coax"? I noticed Wetsounds says "quad twist" so I'm sure its all gimmick.

Yes, a coax cable is the best choice for basically everything you'll find at home or in your car - anything with RCA connectors. And yes, I believe that "dual twist" is just a marketing word. Those cables certainly look like coax.

[MLA]

Theres a difference between a traditional coax with a woven conductor over a center conductor and twisted. Twisting prevents EMI. You see twisted conductors on such applications as ABS wheel speed sensor leads and crank and cam sensor leads that produce an AC voltage.

[gregski]

What do you mean by differential op-amp?

Generally we say "amp" to mean the box that you install in your boat or car. The actual components inside the amp are things like resistors, capacitors (passive components) and active components like op-amps. Op-amps are the fundamental electrical building block that are inside the "amp" in the signal path. Like David Analog said these are ICs (integrated circuits) - the chips and components on the circuit board.

[gregski]

Theres a difference between a traditional coax with a woven conductor over a center conductor and twisted. Twisting prevents EMI. You see twisted conductors on such applications as ABS wheel speed sensor leads and crank and cam sensor leads that produce an AC voltage.

Coax also prevents EMI. It's just a difference of how the signal is driven.

[MLA]

Coax also prevents EMI. It's just a difference of how the signal is driven.

And "twisted" is not a marketing gimmick, as some might say.

[gregski]

And "twisted" is not a marketing gimmick, as some might say.
They are playing off of the terminology of a twisted pair conductor, which is a good transmission line for a differential signal but are talking about the stranded wires of the coax shield? Twisting the shield conductors doesn't help with EMI, there's only one conductor. What you want is a solid continuous ground surface.

I would like to see a construction diagram of a "dual twist" coax. I stand by my statement that it is a marketing gimmick.

[David Analog]

Quote, "I would like to see a construction diagram of a "dual twist" coax. I stand by my statement that it is a marketing gimmick."

Not a marketing ploy. Just a basic description. Pretty simple. For most of the RCA cable length the left and right + positive and negative are intertwined. Then they split at each end and are single twisted pair for the short distance to the end terminals.

[gregski]

For most of the RCA cable length the left and right + positive and negative are intertwined. Then they split at each end and are single twisted pair for the short distance to the end terminals.
Ah, now that makes sense but the advantage would be cable size by sharing one shield, but it wouldn't improve noise immunity.

[jstenger]

This thread has been full of great info, but a couple questions have not been answered.

Brian - Are the XM amps and the ZLDMKII single ended or differential?

Anyone-How do you test to see if the equipment is single ended or differential?

From what I have read online, if the outer conductor is grounded, then it is single ended. If the outer conductor is not grounded, then it is a differential. Am I wrong?

[MLA]

This thread has been full of great info, but a couple questions have not been answered.

Brian - Are the XM amps and the ZLDMKII single ended or differential?

Anyone-How do you test to see if the equipment is single ended or differential?

From what I have read online, if the outer conductor is grounded, then it is single ended. If the outer conductor is not grounded, then it is a differential. Am I wrong?

Unfortunately, the waters have been muddied. None of that matters when pairing those together with a standard mobile audio stereo RCA's from Monster, Kicker, JL, Wet Sounds, Rockford, Metra T-Spec, Knu-Konceptz, Stinger, Mono-Price, on and on and on.