Power For Amplifier

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EDC5
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Re: Power For Amplifier

Post by EDC5 » 09 Oct 2018, 19:01

I don't understand, the cable to the starter motor isn't 16mm^2 and that can pull hundred of amps no problem.

Any voltage drop (within reason) will be accounted for by the DC-DC converter in the amp surely?

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Re: Power For Amplifier

Post by white exec » 09 Oct 2018, 20:01

I suspect it has more to do with maxing up on the visible bits of the installation, rather than a realistic spec of the connections.
How much of the amp's internals are to that cross-section, I wonder? And the fuseholders and terrminations?

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Re: Power For Amplifier

Post by Xantippa » 11 Oct 2018, 07:01

EDC5 wrote:
09 Oct 2018, 19:01
I don't understand, the cable to the starter motor isn't 16mm^2 and that can pull hundred of amps no problem.

Any voltage drop (within reason) will be accounted for by the DC-DC converter in the amp surely?


And how long is that starter motor cable compared to amplifier cable? :roll:

Car amplifiers are not designed to work with dropping voltage.

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Re: Power For Amplifier

Post by white exec » 11 Oct 2018, 09:16

Which is why good sized capacitors are usually there.

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Re: Power For Amplifier

Post by Xantippa » 11 Oct 2018, 12:55

white exec wrote:
11 Oct 2018, 09:16
Which is why good sized capacitors are usually there.


You mean those external 1F or bigger capacitors that were used often a couple of years ago in car audio systems?

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Re: Power For Amplifier

Post by white exec » 11 Oct 2018, 13:56

No, something much more realistic and less show-off.

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Re: Power For Amplifier

Post by Xantippa » 11 Oct 2018, 17:52

white exec wrote:
11 Oct 2018, 13:56
No, something much more realistic and less show-off.


Can you give me an example? Car amplifiers are designed to be used with proper cabling and that´s why they don´t have big internal capacitors to compensate thick power cabling.

Here is one chart to determine how thick cable you need, are these all just for showing off and for selling more copper to car-audio-enthusiastics?
Marko.jpg
And I´ve seen it personally many times that lights on the dash go dim when you play loud bassy music with car audio -system that has got insufficient power cables or inproper grounding.
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Re: Power For Amplifier

Post by GiveMeABreak » 11 Oct 2018, 18:05

Image links won't work like that - I've downloaded that link and then uploaded the image to the forum directly - it would be easier in future if you can do the same so that images remain here if the external source changes later. Thanks :-D

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Re: Power For Amplifier

Post by white exec » 11 Oct 2018, 20:31

TBH, my main interest is in seeing a good car run superbly well as a means of transport.
That's why I run the Citroen I do, and not something more meagre, with large amounts of space taken up with over-loud audio.

At home, we have several audio systems of fairly high quality, including some of KEF's very best. I have also been building speakers and systems for some decades now, and have taken many sensible steps to preserve my hearing en route to age 70. One Farad capacitors in the confined space of a car don't really feature in all this, and I wish you luck with it. Each to their own, of course.

Now, where did I put that CD of Mahler's 8th, The Dream of Gerontius, and the Widor ? Oh, and the Celine Dion...

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Re: Power For Amplifier

Post by EDC5 » 11 Oct 2018, 20:45

I ran 6mm^2 power cable to the BSI area from my amplifier where it terminates in an add-a-fuse. Now I have always thought this to be sufficient as at the moment I am only running two focal speakers in the front.

I am planning to run a 10mm^2 cable from the battery fuse box to the back of the BSI and connect it to the 6mm^2 cable there for when I finally get around to fitting the rear speakers or a sub.

I might add a couple of high quality 0.1F screw terminal capacitors at the amplifier terminals if it becomes necessary. I'm thinking I could use my oscilloscope and probe the amplifier power terminals to determine the voltage drop.

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Re: Power For Amplifier

Post by Xantippa » 12 Oct 2018, 07:05

white exec wrote:
11 Oct 2018, 20:31
TBH, my main interest is in seeing a good car run superbly well as a means of transport.
That's why I run the Citroen I do, and not something more meagre, with large amounts of space taken up with over-loud audio.

At home, we have several audio systems of fairly high quality, including some of KEF's very best. I have also been building speakers and systems for some decades now, and have taken many sensible steps to preserve my hearing en route to age 70. One Farad capacitors in the confined space of a car don't really feature in all this, and I wish you luck with it. Each to their own, of course.

Now, where did I put that CD of Mahler's 8th, The Dream of Gerontius, and the Widor ? Oh, and the Celine Dion...


I´ve never used capacitors myself so don´t worry. I´ve just used big enough power cables. Main reason for good power supply for car amp is to prevent loss of dynamics - not loss of hearing. :rofl2:

Now my audio system consists of DLS 2-way system installed on damped front doors of X7 and very tiny Match M5DSP amplifier (with 10mm2 power cabling), so I don´t even have a sub on my system. And I´ve also had hifi-systems in my car and at home for 25 years, last years I´ve been listening with cardiode-dipole-speakers so no PA-systems at home either. :)

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Re: Power For Amplifier

Post by white exec » 12 Oct 2018, 08:42

All good fun!