Okay, I just started installing my audio system in my tsx today. I'm using Mercmans harness to connect to my amp. I'm running a JL 300/4 which has the balance differential inputs. So I ran the speaker wires to my speakers just to test out the speakers and I'm getting a lot of hissing/whining noises. I've checked to make sure no other wire is touching the harness, grounding and everything I can think of but I'm still getting the hissing sound. I notice when ever I touch the merman rca wires, the whining sound changes a little. Anyone have any idea what's going on?

 

Are your RCAs running alongside your power and/or ground wires? That caused a whine in one of my installs.

 

no, power cable is running along the passenger side door and the ground cable isn't near it.

 

well this morning I was tuning the amp a little, setting the gain. the hissing noise is a lot lower now but it's still noticeable. can it be that my ground wire is smaller than my power wire? i'm running a 4ga power wire and a 8ga ground wire. the ground wire is bolted down to bare metal also.

 

not sure if it's the cause of your noise or not, but those wires should ALWAYS be the same size. you need to upgrade the ground wire to 4ga.

 

I'll try that tonight. During the day I notice that it isn't as bad because of all the noise outside, but at night when it's really quiet, you can hear it pretty well.

 

Well, I connected my ipod straight to my amp this morning and notice a big difference. There was no hissing or whining at all. The sound was much cleaner and clearer than before. Plugged the mercman harness back in and the hissing/whining came back again...

Maybe I'll just wait till mercman releases the balun.

 

Not sure his balun will help. Have you tried to unplug the rca's then plug in one at a time to determine if you are getting noise through all 4? Maybe only a problem with one. I would upgrade that ground cable first of all. Even if it doesn't fix the problem, needs to be done. You could also replace the stock ground cable from the battery to the chassis. (grind the paint off on the ground point on the chassis under the hood) If you still have noise, try each RCA one at a time to see if only one or 2 are problems. If that is the case, move them around (front to rear inputs, read to front inputs to verify that it's comeing throught the RCA's and isn't a problem with the amp. Search the web for good troubleshooting procedures.

 

I have a good idea what is wrong. I have another member testing a fix. I’ll post more details when I get back from vacation and have a chance to go over his test results.

Sit tight I’ll post the solution in a few days.

The gain switch on the JL should be set for low and the gain adjusted with a 0dB test tone. Setting it to the high position will cause a lot of hiss.

jeff

 

alright, changed the ground wire to a 4ga wire and it's still the same.

i've already set the gain to low and tested it with a 0db test tone yesterday and that did help out.

 

ahhh the joys of the TSX headunit acura sure didn't make life easy for audiophiles did they?

 

I sent you a PM.
Apparently JL made some changes to the input stage on the slash 2 amps. There is a large amount of RFI in the TSX and the amp input stage should block it. The new JLs are demodulating it and this is what is causing your hiss. Don’t worry it’s not your install or your power wires.

I’m going to incorporate RFI protection in the harness. As soon as I have the fix ready I’ll let you know. I won’t be long, I just need a few days to run some final tests and order some parts.

jeff

 

hmm.. i'm actually running the first version of the slash amp I believe. it's the 300/4 not the 300/4v2

 

I have the same setup and also hear a slight hiss/whining. I have the gains set correctly and it hasn't bothered me enough to post about it, but after reading this thread I'd like to hear about the fix. Please keep us updated!

 

any updates yet?

 

Yes,
I tested a few mods yesterday and selected the best one. I’m going to install the mods in one cable and test that for a few days. I have to order a large quantity of parts to build more harnesses and should have them by next week. I’ll PM you when I have a new modified harness ready for you.

The problem is (was) (still is) that the HU amplifies any RF (radio Frequency) signal on the audio output leads. The TSX is a hot bed of RF activity and extending the HU audio lines makes for a good antenna. The mods kill the RF before it can enter the HU and be amplified and demodulated to cause hiss. Some HU and amp combos are more sensitive to this the others. My system is quiet but I see the noise on my test instrument. The mods only work in the RF range and are transparent to the audio.

jeff

 

This is the same problem I have been experiencing with my JL setup. Hope this does the trick as the hiss and noise is driving me crazy. Will this fix be an add on to the Mercman Harness or a new Harness?

 

I'm hoping it's an add on.

 

i feel for ya guys, good luck with troubleshooting your problems. If anyone can figure it out it's Mercman!

 

I have installed the mods on a harness and will be testing (driving around and listing to my music) tomorrow. The mods eliminate all the RFI at the input of the JL and the output of the HU.

Since I don’t have the hiss on my install I used test equipment to look at the signals at the input and out put of the JL. I’ll post some photos in a few days to so the before and after S/N.
The Mods need to be installed at each end of the cable. You could just do the RCA end but you would have to buy additional connectors to make dongles. This would get expensive and doesn’t completely block the RFI (although it reduces it significantly).

The parts for the mod cost about $10 so I’m going to raise the price of the harness to cover the costs. I have a quantity of parts on order and I will start building modified harness next week.

jeff

 

I’ve added some RFI protection to the harness. The mods prevent the large RF signal from entering the HU or amp where it can cause hiss.
This is a very low signal level into the amp (about 50mv or .05 volts) I used this to emphasize the noise.

jeff

 

I'm having this engine whine too, just tried grounding at a new area and its still there. When the radio is off, there is no whine, but the whine goes up with the RPM, fortunately my stereos always blasting so i can't really hear it. it kinda sounds like a weak supercharger

 

The RFI will cause a constant hiss regardless of HU volume setting. An Alternator whine is usually a ground issue, the fact that it goes away when you shut of the HU tells me that it might be a bad HU ground or XM/Nav unit ground. The balanced lines are immune to noise pick up so the whine is originating at the HU or amp. You are using an amp with balanced inputs correct?

jeff

 

Yup, same setup as the rest of these guys, a 500/1 and a 300/4. I never had the whine before putting the aftermarket 4ch amp in. Can you take a picture of where you grounded your amps in the trunk?

 

amp ground point

 

Just sent the payment for the new harness. Good thing I didn't put the center console back together.

 

I kept the clips out of my console because I knew that I would be back in there a few times while designing the harness. Now when I have to test something I just pull the storage try out and reach in to unplug the harness. I’m going to finally install one of my finished harnesses this weekend. I still have the prototype installed with the breadboard.

The harness will ship Tuesday. The post office is closed today for that guy who thought he found India.

Let me know how you like it.

jeff

 

Jeff,

Will This be an add-on to the original mercman harness or will I need to order an all new harness? I am assuming the latter since it would need to be fixed on both ends.

 

Seems like it's the whole harness. He's sending me a brand new harness with the new design, but I sent him the money for it. Once I get the harness and everything works out fine, he said I can send back my old harness for a full refund.

 

I want to make it clear that this is not a “fix” for the harness rather an added circuit to do what the HU and amp should be doing. I will be installing the circuit in all the new harnesses I build but will be raising the price to cover the costs of the components. I did the first two for free because of the “Beta” testing required. I haven’t given mods or retro fits any thought because its takes about two hours for me to do (it’s faster to make a new harness). I’m not saying that I won’t offer a mod but I can’t do it for free.

Give me a few days to think it over and get the feedback from my Beta testers.

Both my original BALUN and the new circuit I’m testing reject RFI, this protection should be in the input and output stages not the cable. It works great in the cable though.

jeff

 

just checked the tracking number, looks like it came in today. I'll check it out when I get home tonight and update you guys on this.

 

Ok, tested out the harness tonight and I have to say that there was a big improvement. I can't even hear any hissing/whining anymore. The music is much clearer and just sounds a whole lot better than before. I'm really happy with this change.

 

Thats great news. It sounds like I may finally get rid of the hiss/noise. Mercman I sent you a PM.

 

thats awesome man, nothing like the feeling of finally having closure on something like that! now you can finally enjoy your system!

 

I too noticed an improvement in the mid and highs. Horns and female voices seemed more detailed. I though it was just me. Anyway I’m glad it worked for you, I’m installing mine this weekend.

I know I’m going to get a lot of requests for moded harnesses. I haven’t decided on a final price to cover the additional components. I’ll post the info as soon as I know.

jeff

 

had a chance to listen to my system again this morning. I did notice that you can still hear the hissing but it's barely noticeable. I can only hear it when I have my ear next to the speaker. Besides that, it's not noticeable when you're just sitting in your seat. everything seems great so far.

 

Are you using the stock head unite?
If it is not a mono amp then unplug one set of rca cables and see if the hmmm is still there....then do the same for the otherside this way you can determine whether it is both channels or only one. If it is only one you could then switch the cables that produce no hmmm to the other channel and see if there is a hmm or not, if there is no hmmm then most likely the other cables are the cause. You have to identify the source of the problem by testing the individual components. This task is a lot easier to accomplish if you ae the one who installed the sytem, and for those who did not install their system this may be difficult.

 

it's not that big of a deal. It's not even noticeable until I put my ear up to the speaker. It's the same for all four speakers I have hooked up to the amp.

 

If your cables are longer then you need and you have the excess length of the cables around the amp it could cause noise, try moving the extra cable around some.
Also try upgrading your rca cables

 

The interconnect cables are balanced and so is the input of the JL amp, this makes the interconnect cables immune to noise pick up. Any noise picked up by the cable is canceled by the amp’s inputs. You could rap the interconnect cables around the alternator if you want and it would not introduce noise with a balanced amp.

The hiss was caused by Radio Frequency interference (lots of sources in the TSX) getting back into the factory HU and interfering with the audio circuits. This produced an unbalance noise output that the JL could not reject. I added RF suppression to the cable so that the signal can’t enter the HU.

jeff