I have removed the factory amp to replace it with something better and add subs. I am using an Audiocontrol EQS equalizer with high level inputs to convert to rca's for the amps. everything works, however I am getting engine noise from the front left channel. I have checked all wiring/connections and relocated the ground, and it is confusing that it is from only one channel. I have also purchased a brand new amp thinking that was the problem and still the same result. Has anyone come across problems such as this / any ideas?

 

Try reversing the RCA leads so that right is plugged into the left and vice versa. This will help you to trace the source of the problem. If the noise switches to the right channel then there is something wrong with the signal coming into the amp.

 

How is the amp hooked up (physical box)? How about the Eq?

PS: Otherwise, what is the sound like? I'm thinking about getting a similar eq setup (brand).

 

Its coming from the input from the HU, because it moves to whatever channel i connect it to.

 

The EQ has high level inputs (speaker wire connections) coming from the HU for the source input, and rca's out to the amp, power and ground into distribution blocks.

It sounds very nice when the car is not running. Other than the engine noise it would be great.

 

the outputs from the factory headunit are not high level...they are lowlevel. You should just attach RCA's right to them and run them into the EQS. One other thing is that back in my professional car audio days, even though the Audiocontrol peoces are good they tend to make noise in the system. You might want to get some very high end noise filters. Something from soundgate would be good

 

I originally had a soundgate loc installed, and i was having the same issue, and at the time i wasn't using the audiocontrol eqs. I bought that hoping it might be able to clear up the problem not using a loc

 

Make sure your RCA stay on one side, and the power wire goes to the other side. If you have both wires together, the RCA will catch the freqency from the power wire. And that result in getting the engine noise when u step on the gas pedal, it has a higher noise disturtion.

 

actually engine noise has more to do with a difference in the ground potential of the 2 components than it has to do with any of the RCA cables.
you can run rca's and power side by side and have no noise at all.
but you need to stay away from anything that has a coil in it, be it a relay, or even the ECU has transformers and coils in it.
engine noise is caused from what most people call a ground loop. it is simply the fact that the impeadance between components may be different and therefore they have different ground voltages in the preamplifier and input of the amp its connected to.
in your case you have engine noise because the factory amp probly has a floating ground while the amp you added has a common ground input. this forces the output of the stock amp to have an output ground equal to the input of the amp.
the best way to fix it is to use a transformer coupled ground loop isolator or GLI you can pick them up at radio shack and it will totally eliminate your noise issue.
a GLI electrically eleminates the input from the amp from the output of the stock amp.

 

where did you tap when you installed the loc or line driver? are your gain settings set properly?

if you are using a LOC dont splice any wires behind the HU... the best idea is to find the +/- speaker terminal and connect the LOC to that. also run long wire leads from the +/- terminal and mount your LOC close to the input of your power amp. try that and see if it works.

 

I'm confused. I'm removing the LOC from my setup... should I install the line driver to the wires coming from the HU up front? Or in the trunk before the amp?

I won't need the LOC any more right?

Some details like these I can't find any clear info on. Or maybe I'm just always tired because I read stuff at 11:53pm...

 

why are you not using the LOC? if you already have it dont get a line driver. I dont see the point in it.

 

I am not using an loc. I removed the factory amp and replaced it, i have the 4 channel inputs that originally went from the factory radio to the factory amp running into the audiocontrol eqs equalizer, then rca's from that to the amps.

 

Sometimes when I brake (or something else happens), a loud hic-up is heard coming from a tweeter. It's a bit annoying.

Also, the volume could be higher, and the gains are set a bit high on the amp (>90%).

I'm not going to replace it right away, though. I'm 4 weeks away from graduation. I'll wait until the money starts to roll in (after I get a job), and make some overall changes to the system (on my own, this time).

An eq really sounds interesting; however I might just install an aftermarket stereo with really good sound controls and pre-amp outputs -- all under the stock stereo.

Time will tell. First I need a job. Market is tough.

 

Shatter, do you still have your noise issue?

I agree with other statements here... the output from the head unit to the factory amplifier in the center console shouldn't need to go through the high-level inputs of the EQS.

And yes, the first thing I would do as an old-school Audio Control guy is bypass around the EQS entirely with a pair of RCA "bullet" connectors and see if it goes away. We NEVER sold the EQ's in Hondas back in the day... just the xovers like the 2XS. It's POSSIBLE that the noise will go away when the EQS is removed.

Here's a checklist of things to try:

1) It sounds as if you have a 4-channel amp. (You said that you replaced your factory amp, so I am assuming you did that with a four-channel amp.) Disconnect the RCA's temporarily from the rear channels of the amp, and re-check for engine noise. If it goes away, you have a ground loop between the front and rear channels of the amp and the head unit. Put a Ground-Loop Isolator on the rear channels and hoepfully your problem goes away.

2) Try grounding the shield of the RCA of the affected channel (the outer part) with a piece of wire and see what happens.

3) Did you have to extend the signal wires? If so, how did you extend them? According to the wiring diagram, there is a shield around those wires at some point. If you connected RCA cables to those wires with the connectors cut off of one end, it's *possible* that you are picking up noise on the way as you run parallel to some noise Honda harness (and there will be many harnesses radiating EM interference).

Let me know how it's going. Good luck.

 

High-level inputs are probably a bad choice of words here, it is speaker level inputs so I could avoid using an loc and killing the sound. I have tried connecting just to the amp bypassing the EQS with same results, i have also tried the ground loop isolators with the same results. I extended the signal wires with some triple shielded speaker wire, but i dont think the running of it all down the passenger side of the car is the issue because i ran a new line straight down the middle of the car not under or near anything to the amp to check that and I still get the same result. I do think that it has something to do with the shielding wires for the signal output that is causing the problem and trying to figure out how to bypas that.

 

Thanks for the info. Here are my thoughts:

1) If you do have a four-channel amp, try the test of disconnecting the rear channels. Just so we know.

2) Definitely take a piece of wire and ground the outer ring (holding it with your hand is fine if someone else can listen for the noise) to both of the front RCAs and see if it makes a difference.

3) I know you are swapping the RCA's at the EQS and at the amp. Have you gotten back into your center console and swapped your physical wire connections to the radio outputs? If test 2 works (and even if it doesn't), you may have something wrong with how you connected that channel - like maybe the shield ground didn't get grounded on that channel. According to the wiring diagram on the system, that harness from the head unit to the factory amp had (+) and (-) leads and a shield ground wrapped around it. I would definitely swap the L and R connections at the old amp location and check it again.

4) I don't know what triple-shielded speaker wire is, but speaker wires typically carry such high voltages that they simply can't pick up inducted noise - the signal-to-noise ratio is astronomical, so you never hear it. As a result, speaker wire doesn't usually need to be well shielded. I tend to do what Kimber and BMW have done for years - twist my pre-amp signal wires (or use RCA's from PG or Monster that are twisted pair).

Back in the 80's and 90's, Hondas were known for inducted engine noise, and shielded cable after shielded cable did not help. When we went to twisted pair, we eliminated all instances of inducted noise (that is, picked up by nearby harnesses). I do NOT think your noise is inducted on your speaker wires (else it would be on more than one channel, methinks) but I just thought I'd pass this on. I'd buy the cheapest twisted-pair RCA from Monster or PG and chop one end off and use that instead of speaker wire.

 

someone else just spliced unshielded rca connecters to the radio output at the connecter that leads to the amp without a line driver or eq. The TSX wiring diagram shows that the output of the radio is not shielded, its shielded at the amp end. The shorter the RCA splice cables, the better . Then use shielded twisted rca patch cords straight to your amp instead of the shielded speaker wire.

 

I'd still use twisted pair shielded RCA's, but absolutely, yeah, that's what should work.

 

It is a 4-channel A/D/S amp that I am using. I have tried disconnecting the rear channels with no success, I swapped the connections in the center console and it moves to the next speaker swapped with. I moved the ground of the radio to be grounded with the rest of the stereo equipment to make sure. I connected the signal connection for the channel just after the factory radio to keep it from going through the factory noise filter and that did not help either. I have not tried grounding the rca's yet, but so far i have not seen any reason for it to be a grounding issue. I also used mute plugs on the amp / EQS to see if it was coming from the equipment and it is completely silent so it is something from the factory radio. I have been troubleshooting this issue for almost 2 months now. How frustrating.

btw the cable I am using for signal is twisted Monster cable

 

shatter, you have a PM.

 

I have sort of a similar problem to what some people in this thread have. Basically I put in an aftermarket 4 channel amp and used the loc to run the rca. The thing is, I am getting noise from the speakers when the rcas are NOT plugged in.

I spliced the speaker harness and ran new wires to the back. Thing is I thought there might be some interference from my wire running so I ran a little test. I took one of my tweeters and hooked it up directly to the amp without the rcas plugged in and i STILL got some hissing noise from it. Any ideas anyone?

 

1) Where are your input gains set on the amp? High gains can allow you to hear the noise floor... Hissing noise is NOT engine noise. Engine noise sounds like a kazoo, varying with RPM.

2) Where did you connect the amp inputs? To speaker wires? Or to the preamp-signal wires between the factory amp and the factory radio? (Hint: These are behind the NOT AN ASHTRAY, so if you didn't go there, you probably have speaker wires.) If you did go behind NOT AN ASHTRAY, did you tap the OUTPUTS of the AMP or the INPUTS to the amp? (Big plug or smaller plug?)

3) If you did connect to the preamp wires, you may need to turn your amp gain DOWN and add a line driver up front (use the factory amp ACC line for power). Use a good one - the cheap ones sound crappy.

 

The input gains are set at pretty low volumes for the time being to isolate the problem.. oh.. and you are right, there are two different things going on.. when i drive the car i am getting ENGINE noise and not hissing noise when I rev up the rpms.. thanks for the clarification

I connected the amp inputs by splicing the audio unit harness from the factory amp. I took out the factory amp and spliced that harness to a davnavone loc (4 channel). I believe I tapped the smaller plug according to the tsx repair manual. I then ran two pairs of rca cables along the right side of the car to the amp.


Umm.. sorry to be a newbie but what's the difference of a line driver to a loc? Cuz my car is like this as mentioend before..

spliced audio unit harness --> 4 channel loc --> 2 pairs of rca (side of car ) --> amp in trunk.

 

The signal wires between the head unit and amp need NO LOC of any kind whatsoever. Measured on an oscilloscope, with a 1K sine wave, reaches about 850 mV at volume setting of 40 with no clipping. My Alpine 7904 hits 900mV with the same disc.

I recently installed an amp in a TSX with a GLI at the point that I tapped into the wires, and no noise (Kicker 300). If I turn the gains up on the amp, I get noise... but with the gains low, no noise. I tried a cheap line driver and the audible distortion was so bad we took it out. We still had plenty of volume.

The shields are still grounded because the original amp is still in place running the rear speaks.

So lose the LOC and connect the signal wires directly to some female RCA's (buy a cheap male to two-female Y-adapter and cut the male end off and strip the ends back, and connect the center to the + wire and te shield wires to the - wire.)

Then turn the input gain ALL THE WAY DOWN and see what engine noise and volume level you have.

Line-output converters take amplified signals and REDUCE them so they can go into a preamp input.

Line drivers take low-level preamp signals and increase them so that your amp inputs don't have to be turned up and that greater volumes can be attained.

 

So basically I have two options at this point..

a) install a line driver
b) run the audio unit wires straight to the rcas in the back, and splice it with a female RCA.

For option b, would you run like 20 gauge speaker wire all the way to the trunk then convert it to rca or convert it to the rca towards the front then run rcas to the back?

Also, which one is better.. a or b.. or is it preference?

 

I would only use a line driver if turning your gains ALL THE WAY DOWN gets rid of your noise.

Put the RCA's in the dash and run twisted-pair RCA's the length of the car to the trunk. Don't ever run pre-amp level signals on speaker wire.

 

i've more or less fixed most of my noise problems through tuning and reading through these posts again. Basically in my loc from davnavone, it was set to max (whatever max is). You can adjust the voltage (?) of the loc with 4 screws, one screw per channel. What I did is lower the settings on the loc, and the adjust the gains a little higher. After a little tuning, the engine noise went away.

Also, I made the ground cable shorter which helped a lot.

 

I still suspect that you would have better sound with the LOC removed, but oh, well.

 

hmm.. i did end up removing the loc and the sound quality is much better.. i dont have to deal with adjusting the loc settings anymore hehe..

However now, I don't have engine noise, just slight hissing noise.. my gains are set to their lowest setting currently. On classical sounds i can hear a slight hissing from the speakers.. As I said in som eother posts my ground cable is done via a ground distro block.. anymore suggestions guys?

 

Huh... where's your treble? Is there a treble on the amp?

I have heard some classical CD's that are terribly recorded... play the CD in a home stereo and see if you have the hiss.

 

Treble? umm there's no treble on my amp..?

Also, when I listen to some radio stations i get that hissing noise also..?!

 

Someamps have treble... don't know which ones you have.

What kinda amp do you have?

 

i have a mark anthony 800.1 something.. i'll look up the exact name a bit later

 

I just installed a JL 300/4 and I have no hiss... if your amp has hiss with the gains all the way down... any line drivers o other processors in line? What tweeters do you have? Where are the xovers set?

 

i have the kappa 60.3cs component set and the crossovers are in the glove compartment. No other line drivers present now. Right now, I ran everythign to my glove compartment.. the rca connectors the crossovers and such.

 

Do you hear the hiss when the system is off? Might the xover coils be picking up the fan motor directly behind the glove box?