hemoglobin23

Hey guys...just an update on my noise problem...Many thanx to all who helped...

Ok, I got the Knukoceptz balanced, twisted, etc. cables, and installed them. With the AC off there is NO noise...WOOHOO!!!!

BUT, with the AC on, there is slight noise, but you really have to listen for it...I guess the cables do help...

Can there be any other way to totally eliminate the noise or am I stuck...Also, I see that there is some hyperground product on the homepage of this sight...Would this help? Thanx...your guys' help has been much appreciated...

2007AcuraRL

There shouldn't be any noise even with AC on. Did you experiment with the outer ground shield (ie. grounding it at one side and then disconnecting the ground and grounding the other?) What brand and where is your amp grounded? Also, what brand of head unit and where is it grounded?

(one other poin to note: I have a Premier head unit with 6 volt preouts going to a Soundstream amp. the gains are way down on my amps because the signal off the head is so high. The higher you have to turn up the amp gains, the more prevalent any noise in the system will be. Also, is your amp screwed down to the metal of the car? I have seen some amps pic up engine whine when they are screwed down because a ground loop can be created between the amp chassis and the car).

hemoglobin23

Where is the outer ground shield? I am using the knukonceptz krystal konnektz and I didn't see any outer ground shield. I am usin U.S. Acoutics amp for my fronts and a Rockford Fosgate for my sub. I, too, have a premier HU, but I think it has 4V preouts.

I have the gain at half right now, but I am positive that if turned down lower it would eliminate the noise, but volume, as well...

Right now the amps aren't screwed down to anything (still in the works), just on the floor of the trunk. The HU is grounded to the chasis and the amps are grounded to the chasis (behind seats) at the same point.

Any other information you need i can provide...Thanx for the help 2002...

2007AcuraRL

SOUTHBOUND, help me out here. The interconnects hemoglobin23 bought are in pre-made lengths so he has no immediate access to the ground shield. Interestingly, my friend used the same brand of cables and i think most, but not all the noise went away. I never did have a chance to inspect his cables before he used them so i dont know how they are assembled.

On the other hand, in my car I soldered all my own cables (I had to solder about 16 ends- boy was that a pain!) using phoenix gold twisted pair so i had access to the ground shield, which i ended up not hooking up at all.

Do you think they soldered the ground shield to both ends of the RCAs hemoglobin is using?

HEMOGLOBIN23, can you unscew the ends of the RCA cables? if so, look carefully to see how many wires are soldered to the outer barrel of the plug. IF the shield was soldered on both ends, you will need a very fine tipped pair of dikes to carefully cut one end of the shield, since it should only be grounded on one side. You have to experiment also to see if you get better results with the shield attached only on the head unit side, ot only attached at the amp side. Also, you might email the knukonceptz guy and ask him how they handled the shield.

Lastly, US Amps, formerly US Accoustics was notorious for having amps that were suceptible to engine whine. I can remember doing installs in the shop where i ran all the wires correctly and no matter what, couldnt filter out all the noise, and then i'd swap in another brand of amp and wham! the noise was gone....

hemoglobin23

What do I do with the ground shield once cut? Do I leave it hanging or do I need to cover it up somehow?

Ah man, don't tell me the amp is the cause of the noise....(sigh). I do not want to get another one...BUT if I must for that damn noise to disappear...

Well, actually, I am hoping that the ground shield thingy will do the trick...

Oh yeah...you said try both ends...so do I simply tape off the cut end and leave the other connected? Also, what if I want to try the other side? Do I reconnected the snipped ground shield back, or leave it? Thanx

2007AcuraRL

there should be three wires inside each twisted pair. two are twisted around each other and carry the signal, and then around that is a braided shield. Its the braided shield you would need to cut, WITHOUT also cutting the twisted pair - signal wire. Assuming the braided shield is soldered along with the twisted pair - signal wire (connected to the outer barrel of the RCA plug, NOT the center tip), you would cut the shield. If memory serves me, you should try cutting the shield on the cable that is closest to the amp.

Southbound

hemoglobin,
2002 knows what of he speaks. He is telling you exactly what I would tell you to try.

If you can screw off the RCA connector, then you are in great shape. If not, I'd make up new connectors... but then soldering is second nature to me. Good cables should have a foil shield surrounded by a second (double shielded) braid. If there is a foil shield, usually there is a "drain" wire that runs the length of the conductor underneath the foil and is therefore the "ground" wire to use. In any case, you need to disconnect the Shield or drain wire from the body of the RCA WITHOUT disconnecting the other twisted signal wire.

This is exactly as 2002 has already instructed. Experimentation with ground loops takes time. But it's typically the only way to beat the pesky noise problem, and even then, it is sometimes less than 100% successful. But we should be able to get down into the negligible range.

TRY ALL SHIELD GROUNDING OPTIONS...

1. You may find that disconnecting the shield at one end will fix the problem. I would start at the amp end in the trunk, simply because it is most likely the easiest to get at.

2. If that doesn't help, disconnect the shield at the other HU end of the cable. Now the shield should be floating. This may or may not cause MORE noise... or as in 2002's case, it may fix your problem. Although I would doubt this configuration because you would still have continuity between the two RCA bodies via the twisted wire, and that arrangement produced the most noise in your last set of unbalanced cables.

3. If that still doesn't help... MY BEST guess for a total fix would be to connect ONE end of the shield DIRECTLY TO CHASSIS GROUND. You will have to solder an extension wire onto the existing drain wire or onto the end of the stripped braid. AND YES, Insulate this extension wire with some heat shrink tubing or some other sleeving stripped from a larger spare piece of wire. This will finally provide a complete STATIC GROUND SHIELD to the cable. Since the body of the RCAs are floating above ground in a BALANCED system... you still aren't getting a FULL grounded shield unless you connect the shield to CHASSIS ground. I suspect this will be your solution. (Just having the shield connected to the RCA body will not provide an actual GROUND shield, since the positive and negative inputs of a balanced circuit are floating above ground). The improvement that you have noticed thus far is probably due to the effects of the twisted pair cancelling out a lot of the common noise pickup that you experienced in the cheaper cables.

To fully shield the cable from picking up the noise in the first place, you will need to CHASSIS GROUND ONE END OF THE DRAIN OR BRAID. To do this you must FIRST disconnect and ISOLATE the shield from the RCA connector altogether. It may already be this way from the factory, just waiting for you to tie it to hard chassis ground??? IF not, it will take some desoldering work, but it's what you have to do. BE CAREFUL!!! DO NOT CONNECT THE SHIELD TO CHASSIS GROUND IF IT IS STILL CONNECTED TO THE BODY OF THE RCA, OR YOU COULD SMOKE THE AMP!!! Most likely the HU or amp would just become unbalanced again, but it could also be damaged, based upon the design. SO DISCONNECT THE SHIELDS FROM THE RCAs FIRST, before attempting any of the above mentioned configurations. You may need to connect BOTH ends of the shield to chassis ground, but I doubt it. You may also find that grounding one end works a bit better than the other.

If your RCAs are molded, and you can't open them up... then you are in a more difficult situation to try all of these various options. That's when I would cut and re-butt new RCAs... But, Let's cross that bridge, when and if we have to.

Just follow what 2002 has suggested above with some of my tips, and hopefully you will tame the beast. In any case, it sounds like you are a lot better off than before. If the AC causes the noise, does it change when you turn the fan level up more? It's starting to sound like you may also have noise on the power supply wire to the rear amp and/or new HU. In that case, a good quality inline noise suppression choke and cap on the power wire could also help you out with this annoying whine.

We'll beat this thing yet... patience and the correct technique will finally put a smile on your face along with a great sense of accomplishment!

GOOD LUCK!!!
SB

benzo555

Hemoglobin

Are you still using a filter on yours with the new twisted pairs? I had the same problem and it resolved with mine. But when the A/C is on, you can barely hear it.

The knuconcept wires does not have the shield exposed at all. You may have to splice them open to get to them. I was looking for this so called "shield" wire as well.

Also did you run the wires thru the center console? My old setup the speaker wires and RCAs were on the right side of the car and the pwr, remote was on the left side.

hemoglobin23

South thanx for the detailed instructions that I needed, and thanx to 2002 for coming to my early aid...

The Rca ends do screw off. I will try the recommended measures in due course. I hope it helps...I am still running the wires on the right side of the car, so I may first try running the wires done the center first...I'd have to take my car to a friend's place for a soldering iron.

Benzo, I am not using the filter anymore...SQ went down noticeably, and I am trying to get the "raw" sound that this system should...Boy do they sound sweet with the gains up...

Anyway, I will try the above mentioned steps, and will post an update...Thanx for all your help dudes...