There seems to be 2 groups of thought on keeping the stock head unit....

Group one says you need a line out converter like Audiolinks PD4 just after the head unit because the leads are speaker level and then you canrun RCAs to your new amp. The PD4 has a ground loop isolator built in and it has adjustable features that make the system sound great with no noise, hum or hiss.

Group two says the leads coming out of the head unit are pre outs but just not RCA connecors so if you solder on some RCA plugs to these wires you can then plug these into a ground loop isolator to remove and interference and then run RCAs to your new amp. They say by not using a LOC the sound is cleaner and there is no noise, hum or hiss.

So which is the answer? The second method is a lot less expensive but the first method gives a lot more control over the signal. WHAT DO I DO?!?!?! This is so confusing!

 

yup...i'd like to know the answer too. i plan to install an eq this weekend...probably an audio control 4.1 (thanks NOLACLS for the idea....but only if i can find it locally). so, i would like to know if soldering rcas would make a diff. if not, i'll use the LOC. the hiss is there but not noticeable to me when driving and when the music is up. but a cleaner sound is always welcome.

someone...please answer this question. i'll attempt to call bose tomorrow....i'm not even sure if they're the manufacturers of our stock unit.....

 

The answer is....

NO LOC!

Solder RCA plugs onto the wires coming out of the head unit before it gets to the factory amp.

I have had mine set up this way for 8+ months and no problems whatsoever... and really good sound.

I don't understand what the deal is with using the LOC... I don't know why anyone would want to use it when the 'rca way' works so well. I will say it is probably easier to do... but it just can't be as clean.

 

any particular way to solder these things? where do the positives and negatives of the head unit go on the rcas. thanks!

 

While I'd agree that you can get away with not using a LOC, the idea behind it is to eliminate pops, tics and hiss that come along with not using a LOC.

Since the whole idea of upgrading the factory system is improving sound quality, I submit that the few extra bux spent on a LOC is money well spent because a) it simplifies installation b) it improves sound quality c) it properly matches up impedenances, voltages and grounds on all of the equipment in the car.

Don't take my word for it, though... search for "pop" "tick" and "hiss" after an upgrade in this forum.

Happy listening.

 

RCA cables: the inner is positive, outter is negative.

HU: check the sound template in my sig. for wiring color coded.

 

FIRST WE HAVE...

NO LOC!

Solder RCA plugs onto the wires coming out of the head unit before it gets to the factory amp.

I have had mine set up this way for 8+ months and no problems whatsoever... and really good sound.


AND THEN WE HAVE...


While I'd agree that you can get away with not using a LOC, the idea behind it is to eliminate pops, tics and hiss that come along with not using a LOC.

Since the whole idea of upgrading the factory system is improving sound quality, I submit that the few extra bux spent on a LOC is money well spent because a) it simplifies installation b) it improves sound quality c) it properly matches up impedenances, voltages and grounds on all of the equipment in the car.

So which is it!?!?! I am going nuts here. Has anyone actually attempted both methods and found one to be better. Does the "RCA way" have any hiss hum or pops when the amps come on? Does the PD4 make you turn up the gain on the amps more? Does it introduce any noise of its own? Please refute what has been said here and clear this up because these are two seemingly OPPOSITE positions on the subject of what sounds better when keeping the stock head unit.

 

I went with the LOC connected after the stock amp. No problem. IcyCL had noise problem but with a ground loop isolator, it's gone.
Havent tried out the other way and would never try out the other way cuz the stock amp is out of the system.

Why dont you try it both way so you can decide on your own? the LOC is not that expensive. Try both ways and let us know so there wouldnt be another confused member about this issue

 

I'm with SilverKnight on this one... not saying you can't do this without a LOC, just that it's easier to get a good result with one.

One comment about output voltage, however: it's my understanding that the head unit puts out about .5 volts, which is why some people have problems they don't use a LOC. (See the "Amp + Sub install questions" thread for an example of this.)

- Brian

 

If the head unit is putting out only .5 Volts for line level signal wouldn't it be better to just use a line driver and send the amp 5-8 volts of signal. Audio Control makes a lot of line drivers and line driver/EQs for about the same amount of money as the Audiolink PD4 (which only puts out 2.5 Volts) The only advantage I see for the PD4 is that you retain fader capability since its 4 channel, but how many of us actually use the fader control in the first place? I know I dont. It seems something like the Audio Control EQL (EQ+Line Driver) would be the better choice to improve the signal going to our aftermarket amps plus it allows us to balance the signal so our system has a flat response like the Bose system did (although now its balanced for good amps and speakers)

 

And why would you have pops and clicks from not using a LOC?

Perhaps a bad install, but no technical reason for it if you hook everything up with good connections. Where you get the signal input is going to have absolutely no effect on whether or not you get thumping when everything powers up, that has to do with how everything was installed.

I doubt anyone here will argue that eliminating the stock amp from the loop makes for better sound quality. Taking that extra source of noise and distortion out of the equation seems to be the right choice if you are looking for the best sound quality possible. Otherwise, you are compounding noise from the stock amp and the extra noise and distortion added by the LOC.

As far as the voltage is concerned, I don't know the exact voltage number, but I have the leads from the head unit connected directly to my AudioControl 3xs and from there into my Precision Power amp. I have the gains on both the crossover and amp in the nominal position, indicating that the voltage is sufficient to create a usable signal.

Given, I am just using this setup to power my sub, but I can't see any reason it would be any different for powering highs.

I did have to use the ground loop isolator, but once installed, all system noise is completely gone. No pops, clicks, alternator noise, or turn on thump whatsoever.

 

This is my EXACT point the Audio Control 3xs cross over also acts as a line driver boosting the signal up to 5 Volts. This allows you to use the gain on the amp at the "normal postion" The lowest Voltage it puts out is 2 Volts so if the factory head unit puts out .5 Volts you now have increased the signal strength 4 to 10 times what it was depending on the output Voltage you select. That is why you can set your gain on your amp to a "normal setting" and get a loud clear signal.

So my point is you need a Line Out Convertor for tapping into the signal after the amp or a Line Driver in some form to boost the signal before the amp.

So now what we need is to solder RCAs onto the factory head wires going to the amp. Plug those leads into a ground loop isolator. Run RCAs from there to a line driver and from there to your amp. Is that right? Have I finally figured this out?

 

Yes, if you're going to use the AudioControl with a ground loop isolator, you've got the voltage boost you need and you don't need an LOC. If you don't have something to boost the voltage, the LOC is still necessary. Good job staying focused till you got the answer you needed!

- Brian

 

you go it. now what i want to know is how do i remove the stock radio. i'm gonna install one of those line drivers and an eq and i want to mount the eq on top of the stereo...right on that pad holder space.