Help!

ozzy · 19 February 2001, 00:39

I'm finally getting around to fitting my Alpine CTA-1505R headunit. Problem is the ISO connectors don't carry the power for the unit. I'm presuming it's due to the headunit's amp drawing more power than the ISO cables can support.

The Yellow cable is the battery connection, the black cable is the ground.

Has anyone experienced similar differences with outher units? How do you get power to the unit and where do you ground it. My Impreza has a ground cable (2nd image) for the std Philips unit.

Will this do to ground the Alpine unit? How difficult is it to run a cable directly from the car battery?

Stefan

chiark · 19 February 2001, 16:05

Stefan

The best place to take power may well be directly from the fuse board, which can be got at by removing the driver's side footwell surround, under the steering wheel. Two screws are all that hold it in, IIRC.

I cannot remember the colour of the accessory loop - a quick poke with a multimeter will confirm.

Splice and solder connections! No scotchloks please! Also ensure that you fuse the supply as close to the spur as possible using an in-line fuse holder with the appropriate rating fuse.

For ground, find a decent point of bare metal.

ozzy · 19 February 2001, 17:17

Thanks Chiark,

Since I'm off work training, I decided to pay a visit to my local ICE centre (MRD, Bathgate). They said that the CTA-1505R doesn't draw that big a load to not use the ISO connections. They receommended splicing the Power/Ground cables cable from the existing Subaru-ISO connector and connecting them to the headunits battery and ground cables.

Is this sound advice? I'm a bit concerened that the Subaru fuse rating isn't high enough (25A according to the Alpine install guide).

Stefan

chiark · 19 February 2001, 21:36

What does the unit actually require? If it recommends being protected by a 25A fuse, that's quite a bit of current and I doubt that the Subaru wiring is up to it.

If it actually takes 10A or so, I would say you're OK.

I suppose the worst that would happen if you did overload it is that you'd blow the fuse on the circuit. DO NOT replace the fuse with a bigger rated one, as the wiring will not take it!

If in any doubt, I'd go for splicing it into the main aux feed with separate 25A fuse. It may be worth trying it and seeing, though make sure you have a spare fuse

ozzy · 20 February 2001, 11:37

Thanks guys, I think I'll need to investgate the unit a bit more.

Funny thing though; I originally bought the unit when I still had my Golf GTi. I took it to an ICE installer in Glasgow and they simple cut the existing cables from the ISO and wired it directly into the HU.

Worked fine for over 18mths until I decided to fit it to the Impreza.

Stefan (still confused

)

rockin'Ru · 20 February 2001, 12:49

Glad I'm not alone.Nick's right.Todays HU's[head units]have rather large onboard amps and some even have the MOSFET amps in them,just like the component amps we all put in our cars.They make good power,but also require alot of power input,put out more heat in general,and even more heat when "under-wired".(not the bra's dude:eek

I'd tie that power wire right to the main fuse block input wire or right to the battery itself,especially if you're going to be relying on the HU to run your speakers.Most HU's now have a thermal shutdown sensor that kills it at around 140 degrees(F).
The ground is the equal half.Think of the positive and negative as one(but don't ever cross them).It has to be a good,clean,solid ground to produce maximum power.
You should be able to find one at the base of the console.
The fuse is only there to protect the car.It means the wire will handle a spike or short up to 25 amps before the circuit is broken,not the HU's power handling capabilitys(though I don't think it would want much more than that).
My motto;FEED IT!Just fuse it right also.
Just my 2 cents.
Steve