Installing an amp info...

[HMG1K]

I'm refreshing my myself on installing an amp in my Elegance - it's been 17 years since I last did it (!) - and I came across this excelent reference site in America...

There are step by step guides here:

http://www.crutchfield.com/S-2dcbIQf...ps.html?page=2

And a basic video guide here:

http://www.crutchfield.com/learningc...tml?format=mov

Good reference, if like me, you want a refresher - or panicing over a simple job!

[Nick Mann]

Big cable from the battery, fused near the battery. Cable from the stereo remote signal to the signal in on the amp. Earth cable.

Speaker cable.

Phono cables.

Job done!

[n13l pm]

What amp/setup you looking to install geeza?

[Turbo_Steve]

*cough* that'd be two big cables from the battery....using the body as earth is notorious for voltage drop and noise. If you're going to the hassle of running one, you might as well run two! And chances are, you'll be running phonos as well.....

[Nick Mann]

Surely if you've got a decent earth to your body, then that will be a pretty decent path back? Hmmm....... Next time I'm playing with cable I'll run an earth in too.

I certainly don't get noise that I notice, although the only amped speaker is the sub in the boot, so I may just not notice....

[Turbo_Steve]

It's true it probably is overkill...law of diminishing returns etc etc.

Noise is usually higher frequency stuff, although you can pick up all sorts of clicks and buzzes, especially on older fords and on french cars.

I always do it because it's easier to run both cables at once anyway, because you DO get voltage drop through the body of the car: it's not always a particularly good earth, and because the manufacturer usually runs independant earths for most of the sensors on the car that connect back to the ECU. Admittedly this is mainly when the leads are sheilded, but..nonetheless, they must know something

[CANDEE]

I only have about 0.1v drop on my leggie and i ground to the chassis... kinda helps that i have 2g from the battery and a yellow top...

[HMG1K]

What amp/setup you looking to install geeza?

Re-installing my old kit I had in my 6G Galant...

Kenwood KAC 745 - 4 channel amp...

To go with...

Kenwood KGC 759 - MASK cassette had unit...
Kenwood KGC 9044 - single DIN 11-band graphic equalizer...
Kenwood KSC-WA 82 - sub...
Kenwood KFC-HQT15ie - tweeters...
Pioneer TS-E 1796 - 3-way speakers (x4)...

Rewiring the speakers with thicker, high quality cable and running all 4 speakers off the amp as before.

[Nick Mann]

Hmmm..... I'll measure the voltage drop next time I'm messing around. I have a reasonable earthing kit too, so I would imagine it will be small, but I'm interested to find out now!

[Turbo_Steve]

Worst I've seen is a massive 3 Volts! It was a Renault 19, though.

[CANDEE]

Hmmm..... I'll measure the voltage drop next time I'm messing around. I have a reasonable earthing kit too, so I would imagine it will be small, but I'm interested to find out now!

I usually have a 2g ground from the battery to chassis and will make myself a 8g grounding kit as well as upgrading my battery and chassis grounds to 0g.

[Turbo_Steve]

I'd run the 0AWG to the back as well. But then I'm mental...I always have to use line drivers or a balanced feed.

[CANDEE]

I dont need 0g as i only need 4g for my amps but i have 2g from the battery and 4g to the amps

Oh and its better to have grounds that are bigger than your power wire

[Turbo_Steve]

I dont need 0g as i only need 4g for my amps but i have 2g from the battery and 4g to the amps

Oh and its better to have grounds that are bigger than your power wire

I always used 4awg until I started measuring the voltage drop down the cables. My amps (2 of them) specified 8awg and a current draw of 30A and 40A.
And here's the thing...peak current draw...even with the amps fused at 30A and 40A.....was 100A!
By upgrading the cables to 0awg, I found the peak current dropped to 90A. Where did the 10A go? I can only assume RMS peak voltage drop.
Certainly on the 4awg I'd would revert to protection mode quite a bit.





Why should the earth be bigger than the positive? Where's the extra voltage/current coming from? Noise?

[Turbo_Steve]

oops. double post. muppet.

[Azzaw1980]

Why not have a dual charging system with a battery in the boot and be done with it?? hehe. well thats my plan for the future anyway

[Turbo_Steve]

Actually, there is a lot to be said for that.
I've used a split charger on my old Mazda, but with a diode pack fitted:
This meant the system primarily used the main engine battery, but was continutally "topped up" by a small 100Ah lead YUASA cell in the boot, effectively like a large cap.

Since then, I've experimented with fitting larger power caps to the amps power supplies. It makes a huge difference, and I really don't know why manufacturers don't do it as standard: it's only a few quids.

The cheapest way so far seems to be an upgrade to the onboard caps and plenty thick power cable. Of course, it really depends what the amp is doing:
Mid and Treble don't seem to suffer much.
Driving 4 15" cones at 2ohms whilst listening to a live recording (uncompressed) of something bassy with lots of transients (funky bass player, double bass, live drums) will really max out your power requirements.

[CANDEE]

I always used 4awg until I started measuring the voltage drop down the cables. My amps (2 of them) specified 8awg and a current draw of 30A and 40A.
And here's the thing...peak current draw...even with the amps fused at 30A and 40A.....was 100A!
By upgrading the cables to 0awg, I found the peak current dropped to 90A. Where did the 10A go? I can only assume RMS peak voltage drop.
Certainly on the 4awg I'd would revert to protection mode quite a bit.





Why should the earth be bigger than the positive? Where's the extra voltage/current coming from? Noise?

I have never had my amps in protection with 4g to the distro and 8g to the amps. I had a check of the temp with 2g to the distro and 4g to the amps yesterday and they were pretty warm after only 1 hour of being used......

I think its to help stop noise in the system....

[Roberto]

I have to say for power, once the amps warrent it, it has to be 0g.

Never had a problem with using the chassis ground, as long as its nice and clean and makes a really good contact.
Plus I added an engine grounding kit.

Add in a 1F Cap and I'm laughing.

Might get back to mental systems again some day, but 1 x 4 channel amp and a Sub amp is enough for now.
thinks that's more than mental anyway......for now

[CANDEE]

I currently have 1 x 4 channel and 1 x 2 channel(for the sub) with a yellow top optima and a cap isnt needed..

I used to have a 525cca battery with the same setup with no issues at all as well