Noise Depressor = Ground Loop Isolator?

[edministrator]

Dear sifus,

I had my ICE installed last few days by an installer and faced the "aeroplane" problem. I went back to the installer and they charged me for a ground loop isolator (crown brand). Is it the same as noise depressor? It is connected in between the RCA input to the power amp. Will it reduce the quality of the overall sound system?

The bloody installer just simply accuse my amp have problem lah, crossover problem la, etc etc before even troubleshooting the root cause in the first place! I was so mad because they are almost reluctant to help me troubleshoot. I spent RM350 for the stupid imperfect installation (cables provided by installer). Most probably because I did not buy any product from them in the first place, so they want to rip me off as much as possible.

After installation of the ground loop isolator, the aeroplane sound is gone but I noticed a sound moderate "thud" sound from my speakers everytime i turn on and off my HU volume (from level 1 to 0, and from level 0 to 1, no problem from 1 to 2 and above) or changing source from CD to FM, and switching FM channels. I think its due to the power output differences during the switchings? Is there anything I can do to eliminate the "thud" sound everytime changing source/turning on and off volume? Maybe some sort of power line filter or something? I am a newbie in ICE but I am slowly learning by reading from various forums on the net.

My setup:
Pioneer DEH-P7750MP
Audiobahn A6004T
MB Quart DSD216
Rockford Fosgate 6.5" Tube

Please help, sifu! Thanx...

 

[kyheng]

http://www.zerotohundred.com/newforums/showthread.php?t=28003&page=4

See the above thread, the statement that came Dev. I think you better check you earthing first. If can try to get refund back from them on this noise depressor. I can say the shop is cheating you....
Your HU got 3 pre-outs, 2 for speakers and 1 for sub. Yor amp is a 4 channel amp I assume. if yes then you can connect it from your Hu to amp direct without any problem.
7750 got built in crossover why you still need a pre-amp and crossover? If you can install less component the possiblity for airplane is less.
From your setup, is more like a basic setup, for own listening only, not for outside people to listen.
I using 5750 also with 3 pre-outs. Only now have some airplane sound. Have to work hard now, so no time to trouble shoot yet. Going to try the way what Dev have said, grind the paint off then earth the amps. But only I will try not to sholder it first, will bolt it like normal first.

 

[edministrator]

Thanx kyheng, it would be a MIRACLE if they would refund me anything at all! i am just so sick and tired of the attitude of these people that tries to rip people off. He even made some of the stupidest comment:

- your amp got problem lah, why u buy this amp? you see la, how to fix now???
- i "think" your crossover problem la, your MB Quart made in china one, not orginal. (I asked him how to know its an imitation? no reply...)
- where you get your HU? maybe faulty leh...

by the way, I paid extra RM50 for the "ground loop isolator' and some belt to tie my tube to the car seat (despite my first instalation of RM350)! They are not acting professionally and would simply give any reasons to keep you off their tails.

kyheng bro, I think you misundertand my statement above, so let me clarify:

1. My crossover came with my MB Quart component speakers, so it is only reasonable to install together as it compliments the speakers.

2. I have no pre-amp in between, only my HU and my 4-channel poweramp, but they add in a device so called 'ground loop isolator' (it says so in on the device sticker) in between the RCA connection to get rid of the aeroplane sound, and i was wondering if it is the same device as a noise depressor?

i have faced a very hard time with the installer, and i think in the future i would just DIY and troubleshoot myself with the help of the friendly ZTH forumers and perhaps some friends that have some knowledge in ICE.

Just now I found out that they pull the RCA cable parallel together with the power cable, I think it might be the cause for the aeroplane sound too... I tried bolting earth to the chassis (the area with no paint), but still have aeroplane sound without the isolator.

 

[GTR]

did u check the aeroplane sound come from ur sub or ur component speakers?

 

[edministrator]

every channel. :-)

 

[Zenn]

if possible maybe u can borrow a friends amp that u know has no problems and put it in your system. then u know if it is amps fault or the amp grounding. also maybe the HU has inadequate ground or power, or even the remote power to the amp, due to bad wiring or splicing or metal contact.

i also believe in prevention is better than cure

 

[kyheng]

Sorry for misunderstand you. So your's is a passive crossover, not active. I come out this statement is because of the installer said crossover got problem. But I think that fellow really is a useless guy, a passive crossover also can give you problem.
If you want to DIY yourself, for a start is you can try to check the earthing first, then if you want, you can change all the cable, from amp till your speakers. It will be very costly if you buy it from accessories shop. So the best is you buy at electronic shop.
Then when you relay your cable, try to seperate the power cable from speakers and RCA cable. (1 of the cause of airplane)
The cable budget : power cable/earthing cable, 4awg 1 meter : rm4.50, speaker cable like AV use one, 1 meter : rm1. This price is from my hometown, Seremban.
The most important part : Your earthing..

 

[edministrator]

it was great to hear from you guys! really appreciate it!

Zenn, I am VERY SURE it is not the amp's fault since the isolator installed to remove the noise is fitted BEFORE the input of the amp. And this amp I got it 2nd hand from my friend, I tested the amp in his car setup. He bought some other more powerful amp to power his 15" sub.

kyheng, I think I would just recycle the cables and perhaps purchase a longer power cable to pull from the driver seat side to the amp and pull the current RCA cables from the passenger seat to prevent parallel cable setup. Perhaps do some re-grounding. I'm on a very tight budget.

This is going to take a lot of effort and time to do. I am still currently studying part time and working full time, some more exam coming soon. Guess will need to postpond my DIY til next month, holiday season... keep the info coming! Even though I might not be able to do anything now, I sure will read and learn more on ICE setup so can educate myself and perhaps other people so they will get bulshitted by some irresponsible installers!

Cheers!

 

[kyheng]

Well, since your amp is 2nd hand, it may have no problem when it follow your friend. It may have problem when follow you... But this factor I will always try to put a side first as last resort. Is abit childish if say like this, only the incompetant installers will say like this..

 

[appleyard]

edministrator

you can start seperating the rca and the power cables. If the aeroplane sound still there then check your grounding. if that doesnt solve that it might be your amp.

you dont need preamp for your setup and you can use your HU xover for LPF and HPF settings or you can do it from your amp.

 

[howiechoo]

some cheapo rca cable will breate the sound....