So I Kracked open some Krystal RCA Kable

[Megalomaniac 0]

So I cracked open some Knukonceptz Krystal 4channel RCA cables that I just took out of my car(replaced with my own I made ). and as I suspected, quadruple shielding my ass!

None of the shields are grounded, I looked on both ends all look the same 2 wire conductor per rca. I cut that black heat wrap off on all of them.

1 side:

other side:

close up: they all look the same as this just different color conductor wires.

here is another shot of the Knu where the pants meets actual cable insulator

Looking for shielded RCAs? dont buy those...

[johnecon2001 82]

Eh they're still shielded.. just not a grounded shield. Which is kind of hard to do in a two conductor RCA.

[95Honda 486]

There may be a conductive braid on there, but it isn't shielded from anything but abrasion unless one, or both ends are connected to something (ground). Actually, that type of design can introduce more noise, as there is now more conductive surface area that is electrically isolated from anything, basically an antenna.... And that antenna runs right along side of the signal cables and induces all kinds of crap.

A few things to know-

1- Many car audio "Sheilded" cables are not actually using a shield...

2- There is no such thing as a "Balanced" cable if it has an RCA connector on the end

3- If you are buying a signal cable from most car audio companies, you are paying mostly for looks...

Edited June 27, 2008 by 95Honda

[Megalomaniac 0]

Eh they're still shielded.. just not a grounded shield. Which is kind of hard to do in a two conductor RCA.

yes it still has a shield, but it is not functional! for that cable it needs to be grounded atleast once for it to work. its merely looks.

I love how Knu's lawyers worded their site:

Krystal Kable 2 Channel 4M Twisted Pair RCA Cable

( Knukonceptz Item #KRY2.4M )

Description: The Krystal Kable is one of the best cables on the market. It is the Fort Knox of cables. This cable contains 4 different types of shield / noise rejection characteristics all in one cable!. Features Include:

* Twisted Pair, Copper Foil wrapped Audio Signal

* Sub-Layer PVC Jacket

* Mylar Foil shield

* Tinned Copper Braid Covering 98% of the surface area

* Gold Plated Metal Ends with Diagonal Kut Konnection

The 4 Meter (13') Cable is finished in a rugged translucent smoke color PVC.

no mention if its a functioning shield or not...cant sue sorry.

Edited June 27, 2008 by Megalomaniac

[Adrian_D 520]

Is this how a shielded RCA should look ?

[95Honda 486]

Yes, that would be a shielded cable.

If it had 2 conductors in the center of the cable plus the braid, only one end of the braid would have to be attached to ground, that would be what is called an electrostatic shield.

Your picture has plain coax, signal on the center wire with shield and signal ground on the outer braid. The benefit to using coax is that any noise picked up on the run of the cable will be returned to the equipment grounds instead of the audio sections. This usually will have lower noice than non-coax designs. But, simple twisted pair configs almost have just as good of noise reduction in a car, it is kind of a toss up.

For the best of both worlds, you ideally want twister pair surrounded by a shield, basically microphone cable. You use the twisted pair for signal and signal ground and then also attach one end of the braided shield to the circuit (connector) ground, sometimes you get lower noise from grounding at the source end (Head Unit) or the load end (amplifier) best thing is to try cable in both directions and see what sounds better...... This gives you the benefit of the twisted pair noise rejection AND the shield rejecetion of the braid. This is how I build all my cables. Seriously, there is nothing that will sound, measure or work better for car audio interconnects than microphone cable. I use the 20 awg Dayton brand from Parts Express, I think it is abou 10-20 cents a foot.... Plus, you can also use it for truly balanced connections.

[tosh 1]

i was going to order some of those krystal rca's. are you guys saying they are crap? or just not as good as they should be for the price. if so who has good rca cable,

[helotaxi 46]

There's nothing wrong with them and the level of radiated noise in the car environment is a joke. For the price (the Knu Klarity's are some of the cheapest on the market), I don't see how you could beat them.

I'm trying to figure out what the big deal is on this actually. They are twisted pair, right? If the shielding were grounded, it COULD in fact act like an antenna if the amp were to use differential inputs. Anything picked up by the shield could then be referenced with the audio signal and turned into noise. Of course the issue of radiated noise in the car, like I said, is a joke.

[Megalomaniac 0]

There's nothing wrong with them and the level of radiated noise in the car environment is a joke. For the price (the Knu Klarity's are some of the cheapest on the market), I don't see how you could beat them.

I'm trying to figure out what the big deal is on this actually. They are twisted pair, right? If the shielding were grounded, it COULD in fact act like an antenna if the amp were to use differential inputs. Anything picked up by the shield could then be referenced with the audio signal and turned into noise. Of course the issue of radiated noise in the car, like I said, is a joke.

mr.taxi, Knu is misleading the consumer in saying it is shielded 4 times. A shield is worthless unless its grounded somehow IMO. its not about if the cable will get rid of noise or not..for the most part at least, its more about the marketing. Just like you have strong feelings again Bose or even Monster for that matter.

yes there are downsides to grounding the shield. I could list them myself too, but i think in this situation it would be a good thing for them to grounded at least on one end.

[patented17 21]

Everyone stop buying from them, misleading us oh noes.

[95Honda 486]

These aren't shields if they are not grounded, period.

A shield will not introduce noise into a single ended, or especially balanced configuration if done properly, ever. Don't forget that with differential, balanced, that no part of the signal is referenced to or is traveling on the shielded ground. The signal is derived from the difference of voltage between the two signal carrying lines (180 degrees out of phase) and is never even introduced to ground or shield, that is why this topology has even more effective use of proper shielding.

A non-grounded shield is allowed to resonate easier (no dampening) and acts like an antenna. It runs parrelel to the signal cables and therefore inductively couples it's energy to the signal wires.

EMI can be an issue in a car, especially if you have modified the ignition system in any way. Often times magnitudes more than the home. Although, most good equipment is pretty immune to most of these problems. And most of our signal runs are short enough that they don't get a whole lot of EMI.

This isn't car audio were are talking here, it's basic electonics...

And yes, it is a marketing gimmic and is dishonest..

Edited June 29, 2008 by 95Honda

[audiolife 14]

i use unsheilded rcas and have always had better luck than with sheilded...but from what i have seen with knu cables is not bad infact he purchased another more expensive brand cable to show you that they dont ground the sheild either and at more than 2 times the cost. near the bottom with pictures

http://www.caraudio.com/forum/showthread.p...503#post4816503

Edited July 2, 2008 by audiolife

[helotaxi 46]

EMI can be an issue in a car, especially if you have modified the ignition system in any way. Often times magnitudes more than the home.

Really? Where exactly is this EMI coming from? Last time I checked the ignition modules were under the hood. Also last time I chacked the firewall, etc... are effectively a Faraday cage making the interior all but immume to EMI from outside (like the engine compartment is). All the electronics in the cabin of the car are enclosed in their own little Faraday cages and should present, likewise, zero EMI. Compared to the house, sorry the car is quiet. DC vs. AC power. Inside a metal box vs. not. The only noise issues I've ever seen in a car were from poor grounds or damaged components. This is compared to line hum and the like in the home.

This isn't car audio were are talking here, it's basic electonics...

Actually we're talking about applied electronics as it relates to car audio, but, whatever. And last I checked an antenna actually has to be wired to something in order to do anything. A piece of wire or shield or foil or what have you is not an antenna with both ends in free space...

[ramos 2]

Don't know about the shielding , but I do know the knu's have some huge barrel connectors on them. Be carefull when installing them on processors and such. Dave and I were pulling hair trying to figure out why his mids were summed mono and nothing else. Turned out the barrels on the knu's were so large, that when plugged into the deq processor the barrels were touching each other. I had to pull one side and wrap it in electrical tape to insulate it.

[dave_Edwards 1]

summing mono----oh no!!

[95Honda 486]

Anything allowed to resonate can act as antenna. I spent 6 years evaluating/writting test procedures for HEMP hardened 100db EMI/RFI shield rooms, they are now published as Air force technical orders. I have built and used a LISN and a marks bank E2 pulse generator.

I have had a car idle next to me and have heard his ignition noise through a (my) stock audio system, presumable from low ohm non-supression "race style" plug wires and probably some huge CD ignition system (MSD stickers all over the windows)...

But, what do I know...

[helotaxi 46]

I have had a car idle next to me and have heard his ignition noise through a (my) stock audio system, presumable from low ohm non-supression "race style" plug wires and probably some huge CD ignition system (MSD stickers all over the windows)...

I'm going to guess that you were listening to the radio at the time...