HOW TO - Busters RCA Headunit Volume Fix Guide

[tommyb32]

ok just an update for everyone it works as expected you don't need to solder you can de-pin and re-pin. saves a fair amount of time and i had no need to bring the soldering iron out at all for this install 

[zippypooz]

Yeah found it mate thanks, interesting!...yeah they did fixed the problem, alls now good!!! Thanks!

[Z33]

On 28/02/2018 at 21:31, tommyb32 said:

ok just an update for everyone it works as expected you don't need to solder you can de-pin and re-pin. saves a fair amount of time and i had no need to bring the soldering iron out at all for this install 

Can confirm this method worked for me as well

[Bensson91]

Hello.

 

I have done this mod, but now my sub behinde the driver seat isnt working anymore.. any ideas?

[jktitties]

Sorry to revive an old threat - this was such a good guide and I used it last year, but now the pictures arent loading 😫 

 

I am actually trying to reverse my work as this worked perfectly but I've now replaced the Bose system to need to get back to standard lol 

 

*****

Update- if you want to see the photos on mobile you have to hold and click on the "broken image" icon and them click open link! Just incase anyone else gets caught with that 👍

Edited April 15, 2021 by jktitties

[ThreeFiddyZ]

I thought I'd update this thread just to share a problem I experienced with static/white noise through the stock Bose amp and stock Bose speakers after I followed this guide to modify the appropriate ISO harnesses/looms (to replace my Bose headunit with a Pioneer SPH-DA250DAB in my 350z) and the solution that I have found, in the hope it helps someone else out.

Unfortunately, after fitting my Pioneer SPH-DA250DAB headunit back in 2020, I had what I can only describe as a constant and non-fluctuating static/white noise from each speaker in the car, even with the volume muted/turned all the way down and the engine off. This occurred on all audio sources but was more noticeable when launching and using Android Auto, presumably because the software on my Pioneer headunit was configured to further increase the output volume when using Android Auto.

After investigating and researching this issue in an effort to try to get to the bottom of it once and for all, it dawned on me. When following the guide to use the speaker outputs instead of the RCA preouts on our aftermarket headunit, we are essentially connecting the high-level (amplified) speaker output of the aftermarket headunit to the low-level input of the stock Bose amp, which is typically fed a low-level (non-amplified) input. Whilst this configuration forces the aftermarket headunit and the stock Bose amp to amplify the output to the speakers (which results in a much needed volume increase, compared to volume across the RCA preouts) in my case this configuration seemed to result in static/white noise from each Bose speaker, which I suspected was due to excessive gain levels, which in my case could not be reduced via the Pioneer headunit or the stock Bose amp.

Armed with this new information and determined to find a solution, I found that many others have experienced similar issues when installing aftermarket headunits into different vehicles with stock Bose systems, and that the solution to this is to purchase and fit a line output converter (LOC).

So, that's what I did. I purchased a Scosche Oea4 4-Channel Adjustable Amplifier Interface from Amazon for £15, cut and soldered the speaker output cables on the brown harness (which was taken from the Autoleads PC2-76-4 adapter) to the input side speaker cables of the Scosche Oea4, then soldered the output side speaker cables of the Scosche Oea4 to the speaker cables that were created by following this guide.

Essentially, you'll end up with a Scosche Oea4 (or whichever LOC you prefer and purchase) situated in-between the brown speaker connector in the blue circle below (taken from the Autoleads PC2-76-4 adapter) and the sections of cable with heatshrink just above it (where you cut and joined the speaker cable to the dissected RCA cables previously, when following this guide). Excuse the hastily edited photo (courtesy of cs2000) below, but hopefully it makes it clear.
 

The Scosche Oea4 then allows you to manually fine decrease/fine tune the gain on each channel using a screwdriver to adjust and VOILA... no more static/white noise, all whilst maintaining decent volume output! 😁

Hopefully this helps anyone else with this issue and a big thanks @cs2000 for creating this guide and credit to @buster for the modification. It just needed a little fine tuning in my case!

 

Edited 36 minutes ago by ThreeFiddyZ