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-   -   Brand New Clarion HU defective? Noise in subwoofer (https://www.team-bhp.com/forum/car-entertainment/34978-brand-new-clarion-hu-defective-noise-subwoofer.html)

Hi folks,

A friend of my returning from the US got me the Clarion DXZ675USB HU and I was finally to get it installed yesterday (changed from Pioneer 5850).

Everything sounds great, but there is this cric-cric sound I can hear coming from the subwoofer.:Frustrati This is especially noticeable in-between tracks, or when there are few instruments playing in any particular song. Also, in aux-in mode (with nothing connected to aux-in).

Speakers: Front 4" Illusion Electra 4.1 component speakers and a pair of Infinity coaxials are directly driven by the HU.

My subwoofer (Ground Zero GZTW 12MK2) is driven by a Blau 2-ch amp (GTA Special MKII)

Wiring in Monster (original) and stereo RCA cable for amp/sub is original Ichibahn .

The installer has cross-checked wiring, checking for loose end, grounding, etc... but found everything okay.

He changed the subwoofer (to a Blau one) and amp (to a 200-watt pio) one for testing, but the problem persisted. He also connected the sub to the rear out preouts (this HU has 3 sets of preouts), but there was no noise using the rear speakers preout.

So it this is HU problem - or is it a thing that can be sorted out by maybe using a 4-channel amp or a noise filter? Or connecting all speakers via amps (another 4-channel one)? Is it anything to do with the 5.6 volt pream voltage? Or is the HU defective?

Any ideas folks. please: help.

Try the sub in another system, or try another sub in yours. Obvious, but worth suggesting if overlooked...

Phaji he has tried changing the sub.

I think SUB is not at fault here.

My doubt goes in the HU ground. Try grounding the RCA ground with the HU ground. This type of noises is due to grounding issue.

Will try that sirji, but what exactly is RCA ground?

The RCA has two connectors the inner plug and the outer one. Try grounding the outer one.

Okay will try that morning.

Also, noticed that in the Aux mode with nothing in aux (this is when I can best reproduce the scratchy sound as there is no music playing), each time I increase or decrease main volume using the slide-up/down controls, the kritch-kritch comes with every slide of the volume slider...so this points more to a ground problem, right? Or am I wrong here?

this is sounding more and more electrical based.. not Hu based.. i could be totally wrong though.
Have your grounding checked out bro.

this is a grounding issue. the sound is called "noise" and you will need a noise filter relay. it would come for some 200-250 bucks.

It may happen due to grounding, some wire touching each other (should not be the case here) or just bad quality wire (e.g. non-coaxial).

get a relay and you should be good.

I am suffering with this for almost 10 months and now i have got used to it :-)

Thanks rajismine,

I will be looking into the grounding issue today. I don't think it is bad wires. My wiring (Monster 4ga, Monster subwoofer amp/wires, Ichibahn RCA) is really an overkill for my setup, but yes maybe some wires are touching each other.

Will know after doing the RCA and HU grounding as suggested by LBM.

Also, there is a digital car clock occupying the lower slot of the DIN slot; could it be the culprit? Strangely, I never got this trouble with the older Pio 5850 HU.

The noise filter - which is a really good model which actually works?

johy: I dont think the "noise filter" will be of any help.

It seems like a head unit problem. I doubt the head unit was shipped to you with a problem, maybe one of the pre-outs touched some metal part of the amp/ car chassis during installation very briefly.

Please try out what LBM has suggested.

If possible, take it to some good service center and explain the problem to them. They should know what to look for in the HU.

Got the RCAs grounded, but problem still persists. My RCA cables run on side of the car and the Power cables run on the other side.

Also, after coming back from the installer noticed that with a USB pen drive connected, the scratchy sound is around 50% less - wondering if the USB cable is the culprit here. The USB cable is quite long and the installer has brought it out from just below the steering wheel shaft rod. Just wondering.

Thanks B&T. Preouts touching the car chassis seem unlikely, as they all had plastic caps on them plus the installer put additional tape over the plastic caps to secure them. Also, am going to find out if there is a good service center/person who can deal with this problem.

Then if there is 50 % reduction then it is bound to the grounding issue. Like Ajay Bhai suggested try checking the ground of the amp and HU again. If this not helps try placing the ground at any other location.

Okies sir - am going to double-check the grounding/grounding site this time.

1. is the cric cric sound the same as the kritch kritch sound?
2. is the sound only coming from the sub and only via the sub pre outs?
3. is the sound coming when you are driving or does it come when the car is idling (engine runing but car not moving)?
4. I think the HU comes with up down volume button or is it a slider. slider controls were discontinued ages ago so I wonder.
5. did you recieve the HU packed in it's thermocol housing or did you friend throw away the packaging and get just the HU.

I suspect that the sub RCA outs (bumped in transit) were damaged and there is a damaged solder joint on the PCB. If this so the problem is easy to fix.