**** alternator whine!!!!

[knightsdaze 10+ year member]

I posted a thread recently, describing in detail all my equipment, and my alt whine problem.., I wound some 14 gauge wire around my head units RCA's, and then "double grounded" my BRAND NEW Pioneer 9400BH head unit from the H.U. chassis to a solid point of ground in the rear of my Jeep, where my 2nd battery, and ALL my amps are grounded as well.. STILL HAVE THAT SAME HORRIBLE WHINE!! I want some opinions on noise suppressors.. any and ALL opinions would be much appreciated., that ingress noise is making me nuts, and I'm not real stable to begin with., sayin? Time for bed. PEACE YALL.. BTW, If anyone mentions the PICO fuse PLEASE KNOW that I've NEVER worked on my system with the Battery's connected.. and Ive NEVER pulled an RCA cable off with the system active either.. It's fine when im cranking it, but when I play ANYTHING at low volume it sounds like ***. Thanks again and have a good night.

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[Worlddre 5,000+ posts]

There are some things you should look for when trying to diagnose a ground loop. First you need to locate the source of the problem. Start by checking the input voltages at each component in the system. Check the battery and then the Hu and amplifiers. A ground loop by definition is a difference in electrical potential between electrical components so if any of the components has a voltage different than that at the battery it could be causing your problem. If all voltages are equal start isolating components in the signal path. Connect the radio to an amplifier outside the vehicle if the problem goes away then the prob is not the radio. Next do the same with the amplifier if the problem goes away then it's not the amplifier and could be an issue wih your wiring. Run a set of RCAs outside of the car to your amplifier to try and rule out the RCAs. Now the only thing you have left is the speaker wire. If one of the speaker wires is touching ground somewhere it can cause engine noise as well. Pull and reroute your wires inspecting every inch to make sure they are to frayed any where.

 

[chargdbassbuick 10+ year member]

just install a ground loop isolator , problem fixed , hope i could help //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Vern Dee]

Which Ground Loop Isolator specifically are you talking about...What brand or model number?

I bought a Power Acoustik PD-931NB on Amazon, along with the 4 year warranty. I installed it in my BMW 740i and it works great. The touch screen is just like an iPad, and the DVD/MP3/CD player plays better than the BMW original unit.

Out of the box the speaker level outs, are 17W RMS X 4, so for just the head unit power, it sounds good.

There was no alternator noise with the speaker level outputs... but...

Here's my only problem, that I am asking for your help on, from anyone out there that has had this problem: I hooked up an Alpine amp via the RCA Preamp outs... and I have high pitched alternator noise. When I mute the head unit, or disconnect the RCAs, it stops. So its coming from the head unit, not the Amp. I have tried grounding the head unit to the same point as the Amp, and an Exterminator inline noise suppressor. PLEASE...can anybody help me get rid of the Alternator Whine ???

Which Ground Loop Isolator specifically are you talking about...What brand or model number? Thanks, Vern

 

[maylar 10+ year member]

David Navone's N-62 is good:

N-62 is a two-channel high quality floating ground adapter - $17.90 : Zen Cart!, The Art of E-commerce

Or, you could use speaker level inputs instead of RCA preouts if your amp has that capability. No ground reference means no ground loops.

 

[Vern Dee]

Maylar, Thanks for the help and advice. I have a JL Audio Amp ordered, that will have speaker level inputs. Someone told me that using the speaker level inputs degrades the sound/signal quality...is that correct, or is it basically the same sound quality as the pre-outs?

Thanks, Vern

 

[dragnix 5,000+ posts]

Pretty sure using speaker outs will limit your control as you cannot use the gain

 

[maylar 10+ year member]

Speaker outputs are actually better than preouts in terms of noise susceptability. The audio community says there's more distortion though I've never seen THD numbers to back that up. I'm driving the front stage in my system with speaker level (wiring convenience) and it sounds good to me. And as I mentioned, no ground loops means vey little chance of alt whine.

BTW I used a Radio Shack ground loop isolator on a previous install and the alt whine went away. It was on a sub amp so I didn't care about freq response etc.

 

[knightsdaze 10+ year member]

I started this thread end of July, and just saw it kinda went a different direction.. anyway, I ended up buying a dd-1 and found my h.u. limit, and set my amp gains RIGHT. No unwanted noise at all since. What a HUGE overall difference, and no more worrying about clipping either..

 

[butterMilk 10+ year member]

Hey knight, sorry to get off topic but what db track did you use for the dd1.(1khz and 40hz)

I just received my dd1, i think i tried -5 and wasn't loud enough for the subs, then I used -10. Just a lil worried that the -10 might allow to much distortion.

 

[knightsdaze 10+ year member]

I used track 5, but I have a hot signal cuz of the combo of my Audiocontrol four.1+6xs (both have linedrivers) so my sub amp gain is set all the way down. The biggest surprise that I got was finding the limit on my head unit. I use to always play it safe and never go over 40 (it goes to 62) but when I put the dd-1 on it it didn't see distortion till I hit 60!! now i leave my h.u. set to 57-58 and use the Four.1 as the master volume control.. What a freakin difference, but because our setups are most likely very different, I probably didnt help you much...

 

[knightsdaze 10+ year member]

try it on track 7.

 

[butterMilk 10+ year member]

Yeah my HU doesn't distort until 39/40 but I have it set so I never turn my volume past 26-27. Would it sound better if i set it up so I could turn the HU up to a higher volume?

 

[knightsdaze 10+ year member]

Yeah my HU doesn't distort until 39/40 but I have it set so I never turn my volume past 26-27. Would it sound better if i set it up so I could turn the HU up to a higher volume?

You want to find and "set' (or remember) your volume at the highest possible before distortion for max voltage output. for example my head unit has 4v pre-outs, BUT your'e only approaching that 4v at the highest volume.. ya mean? If yours doesn't distort untill 39/40 then I'd run it at 37/38.. I like a lil room for error, but that's just me. This will allow ur amp to see the srongest (cleanest) signal possible, and then set ur gains on the amps accordingly.