I've just had a couple of Audison amplifiers (an LRx4.300 and a SRx1) installed into my 2005 G35x and the shop hooked into the Bose signal prior to the Bose Amp. Now the Audison amps don't have balanced inputs like that of the JL 'slash' series amp but I'm wondering if any one else has had any luck with amplifiers with 'unbalanced' inputs ? Is my only choice to re-install the Bose amp and use a convertor like Audiocontrols LC6 ?

With those of you using LOC type products do you here any noise or hiss etc. from the speakers at all ?

Thanks

 

The alternator whine could be a couple problems. Firstly, do you have LOCs installed? Secondly, the amp power wires may be too close to your RCAs (if you have LOCs). Also might be a bad ground of your amps (too long of a ground wire, wrong gauge of wire, not enough grounded contact to *bare* metal). Not familiar with Audison amps...sometimes cheapo amps will contribute to hiss and whine.

Most probably it is the ground of the amps, I would check that first. Then, I would try moving the wires around near the amp, farther from each other and see what happens.

Hope this helps...
doc

 

Audison amps are great. Cost a bit more than I care to spend on amps though. I would have the audio shop who did the install find the issue and resolve it. You paid for the labor aready.

 

The Audison amps are far from being cheap, and are some of the best amps made. I've looked at the grounding and it's solid with the use of 4 guage wire. The RCA cables used are also of the highest quality. Due to the space requirement the power cables are close to the RCA cables but they don't run together for any real distance. The alternator whine is less than the hiss though. And the hiss more than triples with the car running compared to when it's off. I have a feeling it all stems from the Bose HU signal lines being unshielded and that I can only use half of the balanced pair.

I don't have any LOC's installed right now. But I'm hoping that this will all be resolved with the use of an Audiocontrol LC6 (a six channel LOC) which will be installed after the Bose Amp. The shop really didn't want to keep the Bose AMP in the whole loop, but it seems there is no way around it.

 

Are you still using the Bose amp to drive any speakers? If not, why not just yank it out of there....

Hopefully, adding the LOC will make the hiss go away. I ran shielded RCAs from my aftermarket HU to my aftermarket amps so I don't have any whine. But, when I did use the stock wire harness in the trunk with LOCs to an aftermarket amp (before my HU DD swap), I don't remember having any whine or hiss. So it might just be the need for an LOC.

I agree that you should take it back to your installer, they should try and make the whine go away, not you.

doc

 

The Bose AMP is currently sitting at my desk at work and we are all laughing at it's small size. I had the shop also install three unused RCA cables that run to where the HU is in the event I do a DD swap, but I'd like find if I can get a Rosewood DD instead of the aluminum to match my existing interior. But that for the future.

The shop is going to do what is neccessary to get me 'perfect sound' but if I can findout what others have already gone through it will save a lot of trial and error, and the shop won't need my car for so long. It was bad enough that I had to leave them my baby for 10 days so far.

 

I have a Ven4 LOC attached to the wires before the Bose amp (Bose amp has been removed). I don't know if it'll help with your noise but its not an issue in my car.

 

Thanks for the input Spud, I didn't know that was possible.

Anyone else using an LOC without the Bose AMP ??

 

I have tried to get rid of the buzz for a month.......this is what I found........the factory wire loom includes the stereo signal and stereo speaker wires but also all the other wires in the trunk, including power, turn signal, brake lights, fuel pump. etc. etc...........If you turn on the ignition without starting the car and hear the buzz......your hearing the fuel pump, if you activate the turn signal and hear the click click click.....you are picking up the power signals transferred to the HU signal wires. I tried LOCS and filters to no avail....I finally ran a set of RCAs down the center of the car, cut the existing factory HU signal wires......no more buzz!

I also measured the output from the stock bose HU with an oscilliscope and it measured 2.2 V peak to peak, no need for a LOC......the output is low enough.....I am not using one and have the HU RCAs attached directly to my xover.

 

Well I just got my car back again. The installer hooked up an LC6 without the bose amp and found the signal level too low to be usable. He then hooked up the Bose Amp with the LC6 after it and well everything came to life !!! Everything sounded so much better and all of that nasty stuff like hiss, noise and alternator whine is all gone, and I mean completely gone !!!

I had him do a pink noise test with a 1/3 octave RTA and we adjusted my EQ for a near flat response shaped like a happy smile. And what we found was quite interesting. Here are my settings after equalization:

32 0
48 0
64 0
90 0
125 0
180 0
250 +1db
500 -3db
1000 -2db
2000 +12db
4000 +3db
8000 +6db
16000 -3db

With these setting the response is completely flat from about 250Hz to 8000Hz.
As you can see the stock system has a BIG dip at 2500 Hz (on his RTA) as my EQ only has 1/2 and single octave adjustment the closest setting was at 2000 Hz. regardless it was off by 12 db !!

For those of you interested I installed Focal 165K2P's in the front with 165CV's in the rear. The sub I chose was a Boston Acoustic's G510 (dual 4 ohm voice coil). Amps were a 4 channel Audison (LRx4.300) 4x65 watts and a single channel Audision (SRx1) 1x350 watts. I have a sub volume control installed in the cigarette ashtray location. And finally an AudioControl LC6 was used as the LOC and the EQ was a old (10years) LA Sound LEQ1026.