Well it all depends on how much power your amp is running. Too small a wire and your amp will not produce the power it is rated for and potentially heat the wiring up and cause a fire. Below is a chart for wire gauge purposes. Using the formula Power = Current x Voltage, you can figure out what gauge wire you need for your system.



For example, if the gauge of wire in the OEM wiring harness is 16 and you want to use that wire for another amp, the maximum power rated amp you would want to hook up to the system using the chart above is 3.7amps x 12volts = 44.4 watts maximum output. These are max output numbers so you would probably want a 20 watt RMS amp which is very small in today's terms. i.e. the OEM wiring is only good for the OEM amp or something around the same power output.

Now if you had a 300 watt amp, you would need to upgrade the wiring to a minimum of 300 watt/12 volt = 25 amps gives approx 8 gauge wiring but you will want to get the next larger gauge to be safe for that particular system.

Think of it in terms of water and a hose. The amp requires a certain amount of flow in order to operate at normal capacity. If you supply the amp with too small a hose, there won't be enough flow so it won't perform as it should. The bigger the hose, the more flow is available for the amp to to draw from. Amps will only draw as much current as requested so the term the bigger the better will allow the amp to perform as it was intended. Hope that makes sense.

Doug

 

hi all.
ive some PMs on this.

to spend more quality on my query...

Ive a big 500W sub amp amp. It draws 1A doing nothing, and then as its class D draws about 20% more than the speaker sunk power. The power is a modulated draw that follows the signal as the cheap *** amp has little supply capacitance. Any big amp aslo has a step up power supply that will work fine to about 8V droop. I have a huge electrnics lab and lots of capacitors. My instinct is thta my sub amp, even cranking, will not draw anything near 10A average, long term. To make the peak to peak current draw an average ill use a big cap bank...say stupid big...half a farad.

my question was has anyone popped a fuse, as a fuse is an averaging device to protect from wiring harness fire. ...if no-one has a had a fuse blow I wont bother with the running of a rube-goldberg lead from the battery.

The other reason..and why im writing here..is that i do want to document this with a thread of pictures. my intent is to have this big sub a removable item for times when say i vacation and need the space...of when i pack the family skiis. the idea is ill have a 4-6pin in-line connectors set that i can just unplug to remove the amp.

I think ill try all this "anyway" and post results..look here again next week.

but thanks to all for posting.

-dan

 

Dan, did you try your theory? I have a 2001 A6 that has non-Bose system with the sub in the trunk. I replaced the head unit and front speakers, and have the RCA signal running to the sub / rear speaker amp. My next step is the replacement of this amp and an addition of my own sub, and I was wondering about the same thing. I'm looking at a 250W RMS amp with a 12" ported sub, I dread running wires through the firewall...

 

Hey Guys Great thread I need a little help though. I am just adding a sub and amp in addition to the stock one, what wires exactly (color/colors) from the stock bose amp are the ones to splice the RCA'S from and also is one a remote or can be used as one? Thanks and Please Help!

 

I Am As Well going to Not Just bypass a good Stock Amp I Need To Know Exaclty How to wire it up and the colors. Please Anyone ... Also Is it a good increase ? I was thinking about just powering the backs again or somehow back and Doors idk.
What are the Stock Bose Amplifier Specs so i know. How many ways from factory does that amp push and all ..... THANk You

 

I would think your biggest plus to this is now having an option to install 4 ohm speakers and get hopefully better sound?