[hidehide]

Hi there. Talking with my local audio store, they said they draw power from the ignition part. So once the ignition is off, the amp powers off. However, in stock speaker settings , the music continues to play after ignition is off and only stops when I open the door..
Is there a better way for them to draw power so I can have the same experience as before upgrade?
Thanks in advance!

[Billfitz]

They should have drawn the power from the same source as the OEM system did.

[hidehide]

Originally Posted by Billfitz

They should have drawn the power from the same source as the OEM system did.

Thanks for the reply.
Forgot to mention, mine is base audio without amp to begin with..

[Billfitz]

Adding a separate amp would require tapping into the fuse box for additional current capacity. You could restore the original function by using a power relay connected to the power supply for the head unit to switch the power to the amp.

[hidehide]

Originally Posted by Billfitz

Adding a separate amp would require tapping into the fuse box for additional current capacity. You could restore the original function by using a power relay connected to the power supply for the head unit to switch the power to the amp.

Do you mean drawing from the current of the headunit for the amp? Will it risking a blown fuse or even a fire as I’m overloading the fuse that’s originally designed for powering just the headunit? I will be adding 2 amp and a dsp. So powering 3 units may even be more impractical? Will drawing power from the ignition current be a safer route?

Apologies if I said something that doesn’t make sense and please correct me as I have zero knowledge on these mechanical stuff.

[Billfitz]

Originally Posted by hidehide

Do you mean drawing from the current of the headunit for the amp?

No. The amp goes to its own fuse of ample capacity, but the power wire is routed through one of these, which turns the amp on and off, the trigger wire of the relay being wired to the head unit fuse:
https://www.amazon.com/OLS-Split-Cha...2v+power+relay

[Encanto]

Originally Posted by hidehide

Hi there. Talking with my local audio store, they said they draw power from the ignition part. So once the ignition is off, the amp powers off. However, in stock speaker settings , the music continues to play after ignition is off and only stops when I open the door..
Is there a better way for them to draw power so I can have the same experience as before upgrade?
Thanks in advance!

Use an aftermarket amp with signal sensing turn on or use a PAC TR-4.

Your "local audio store" should know this.

[enjoythemusic]

You may want to see this thread
http://f30.bimmerpost.com/forums/sho...t=turn+on+lead

Basically, use an empty fuse location and install proper fuse.

[hidehide]

Originally Posted by Billfitz

No. The amp goes to its own fuse of ample capacity, but the power wire is routed through one of these, which turns the amp on and off, the trigger wire of the relay being wired to the head unit fuse:
https://www.amazon.com/OLS-Split-Cha...2v+power+relay

Thanks everyone for chiming in!
So now I know the power relay is like a switch for turning on/off based on whether there are current passing through the triggering pole..
And my current setup is triggered based on ignition, so seems they connect relay triggering pole to the ignition fuse instead..
I found a f30 fuse box diagram on post #4 http://www.bimmerfest.com/forums/sho.../topics/796214
Can you guide me on which fuse # is for the headunit? I can then ask my shop to connect the relay triggering pole to this fuse instead.. Thanks.

[Billfitz]

I can't help there. The fuses are identified by pictures of what they power, it's not obvious to me which picture represents the radio tuner.

[hidehide]

Originally Posted by Billfitz

I can't help there. The fuses are identified by pictures of what they power, it's not obvious to me which picture represents the radio tuner.

Thanks. Seems there are no easy way. As my auto audio shop insist it’s too much hassle and risk other than doing their “usual” way, and since they are the only store to carry the brand I want. I guess I will stick with their way..

[Billfitz]

What they're really saying is that they don't know what they're doing.

[hidehide]

Originally Posted by Billfitz

What they're really saying is that they don't know what they're doing.

Yes unfortunately.. and I couldn’t find any guide for them to follow..
seems everyone is searching for the wire of the headunit..

[Encanto]

Originally Posted by hidehide

Yes unfortunately.. and I couldn’t find any guide for them to follow..
seems everyone is searching for the wire of the headunit..

I answered your question 5 posts above... and kind of insinuated that your "local shop" is incompetent.

Here we go again:

Originally Posted by Encanto

Use an aftermarket amp with signal sensing turn on or use a PAC TR-4.

- if you do not have an aftermarket amp yet then get one that turns on with the sensing of the high-level inputs. This will make the aftermarket amp to turn on/off exactly like the OEM HU.

- if you already have an aftermarket amp (not signal sensing) then get a PAC TR-4 and use any of the front OEM HU as its trigger and then connect its remote out wire to your aftermarket amp. This will make the aftermarket amp to turn on/off exactly like the OEM HU.

[Billfitz]

Going through my old notes when I was doing some wiring I found that the power to radio devices is represented by the circle with three crescent shaped 'waves', so that's positions 20, 28, 42 in the forward fuse box, 103 and 104 in the rear fuse box. One of those in the rear is probably there for the stock amp in a hi-fi or H-K configuration. Whether or not the 103 or 104 is active or not I can't say, they may only be if the car has hi-fi or H-K as stock. A good shop would be able to figure it out in ten minutes or less. One experienced with BMW wouldn't have to figure it out, they'd already know.

[hidehide]

Originally Posted by Encanto

I answered your question 5 posts above... and kind of insinuated that your "local shop" is incompetent.

Here we go again:



- if you do not have an aftermarket amp yet then get one that turns on with the sensing of the high-level inputs. This will make the aftermarket amp to turn on/off exactly like the OEM HU.

- if you already have an aftermarket amp (not signal sensing) then get a PAC TR-4 and use any of the front OEM HU as its trigger and then connect its remote out wire to your aftermarket amp. This will make the aftermarket amp to turn on/off exactly like the OEM HU.

Oops, I just reas the part of asking me to get an amp with signal sensing, and since I already have an amp installed, so I thought your post is irrelevant. Sorry about that.
I am adding a dsp now, and thought it’s an opportunity to ask the shop to rewrite the amp power wire for me as well. Well, it’s sad that there are no other shop I could go..
So back to your suggestion , PAC Tr-4, that looks like a power relay as suggested by Billfitz.

[Billfitz]

Originally Posted by hidehide

PAC Tr-4, that looks like a power relay as suggested by Billfitz.

Similar, not the same. It senses when a trigger device is turned on, in this case the head unit, then it allows power to be sent to the slave device, in this case the power amp. With a relay you'd connect its trigger to the head unit fuse, so when it's circuit is energized the relay would allow power to the amp. In both cases the PAC/relay would be connected to a fuse that's powered whenever the head unit fuse is powered, which is easily determined by metering, but if you're using a fuse that you already know is assigned to audio devices it narrows the search down considerably. If you connected it to a fuse that only works when the ignition is on you'd have the same problem that you do now.

[hidehide]

Both need to be connected to the fuse where the head unit is powered. So the main issue is to find out where the fuse for head unit is..

[Billfitz]

I told you how to identify the fuses associated with the audio components. Finding out which controls the head is easy, pull them one at a time. When the radio won't turn on you found it.

[hidehide]

Ok, I’m going to search for the fuse diagram in my ca and remove the one with radio sign one by one and see which will turn the headunit off. And then I will ask my audio shop to connect relay with that fuse..

[Billfitz]

Make sure they connect the relay power to a fuse that stays on when the ignition is off or all is for naught. I know the auxiliary outlet fuses stay on for a few minutes after the ignition is switched off. They're identified as a small dot inside of a larger semi-circle, and they're large enough to handle any amp current draw.

[hidehide]

Originally Posted by Billfitz

Make sure they connect the relay power to a fuse that stays on when the ignition is off or all is for naught. I know the auxiliary outlet fuses stay on for a few minutes after the ignition is switched off. They're identified as a small dot inside of a larger semi-circle, and they're large enough to handle any amp current draw.

Just wanted to double confirm that with a relay, I can actually connect to a power source that is on all time, as long as the trigger wire it connects to will turns off after the ignition is off for a while (same as the headunit)? Is there any minimum voltage requirement (e.g. 12V) for the triggering wire? Thanks!