Wire Gauge Question

[THUMP-LUMP]

Just a quick question...... Powering 2 amps, one is 2x75 and the other is 4x40 (310 watts total and both are low efficiency old school amps) with a 10ft. run, what gauge power wire would you use? I have been using 4ga but that is probably overkill. Do you think I can use 8ga without problems? The calcs say I can. Just looking for opinions. The only reason I'm considering 8ga is that it will lay under the carpet better.

[ttocs]

how big are the fuses on the amps?

[Eric D]

The power (watts) of the amplifier is not important, the current draw (amps) is. What ratings are each of the amplifiers?

If you add those values and a wire sizing chart says 8ga is good enough for that current draw, you should be fine with 8ga.

I have been using an 8ga wire on a 125W x 4 amplifier in my daily driver for years now. My vehicle is a truck though, so my power wire is quite a bit shorter than in a sedan for example.

[Chiapet]

1/0

[trickyricky]

I'd say if you have 4g already then why replace it? Unless each amp has a 4g run then it is an overkill but if both amps are sharing that one 4g run then your more than okay with that cable.

[THUMP-LUMP]

Well..... fuse size means next to nothing. RECOMMENDED fuse size means slightly more.
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Ultimately, you're right. Watts mean nothing and it comes down to amp draw and distance. The calc, from http://www.bcae1.com/ depends on wattage, amp efficiency and distance to arrive at a conclusion.
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I already have 4ga (what I have been using) and brand new 8ga. The two amps are an Orion GT420 on 2ohm (4x40) and an Phoenix Gold SA3.0x on 4 ohm (2x75). This is a new install of an old system so, I am free to change out things.
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I know 8ga will electrically work. This is why I was asking for an opinion. I guess I should have been more clear.

Sonically, will there be really any perceivable difference between the 8 and the 4 gauge? Given the approx. .3 voltage drop difference. My guess is that it maybe would make a subtle difference only when the system is pushed and probably not perceivable.

0/1 is not an option or an opinion.

[Eric D]

You are correct, the difference between 4ga and 8ga will not be perceivable.

Additionally if you like that 8ga lays flatter under the carpet, then you could use 2-8ga wires if you were concerned about the draw.

[ttocs]

sonically no you should hear no difference the concern is how hot the wire might get if you have too big of a fuse on it(needed to power the amps if they are big). Not sure what you mean by fuse size means nothing but recommended fuse size does. I mean I will agree that unrecomended fuse sizes in them would mean nothing but its just assumed when we talk fuse sizes we mean the recommended fuse size.

You can find 2000 watt old school amps with 20 amp fuses in them, or you can 2000 watt fuses with 100 amp fuses in them. One would be perfectly find to put up to 3 amps on an 8 awg the other would be taxing it. I always try to keep 8 gauge current under 60 amps at a worst case scenario.

[Chiapet]

While my answer was made in jest, in truth 1/0 would still be fine. The larger size helps keep wire cool for the power. While it is obviously overkill for the current system, it would help if you choose to upgrade down rhe road, stopping you from having ro pull out the old wire for something larger. I would stick with 4 gauge at minimum because at max power draw coupled with length of cable you could get a voltage drop as was already mentioned. Also the 8 gauge could get much warmer. Best to rin 4 then distribute via 8.

[THUMP-LUMP]

...... the concern is how hot the wire might get if you have too big of a fuse on it(needed to power the amps if they are big).

Then that would be a wire gauge issue and not a fuse issue, wouldn't it?

Not sure what you mean by fuse size means nothing but recommended fuse size does. I mean I will agree that unrecomended fuse sizes in them would mean nothing but its just assumed when we talk fuse sizes we mean the recommended fuse size.

That's IS what I meant, I was making the distinction. What is physically in the fuse holder means squat but what is recommended is slightly more important. Ultimately, it comes down to amperage draw that will dictate what the minimum gauge power wire is needed.

The Orion GT420 specs at 14amps max current draw. I can not find any specs for max current draw for the Phoenix Gold SA3.0X. FWIW......Looking through my old HiFonic Series VII manual puts a Odin (2x75 watts) @29 amps for current draw. I would imagine that they would be similar. Which would bring the total just shy of a nice round 45 amps current draw. Well shy of your 60 amp "worst case scenario" for 8ga cable.

I have had no reason to upgrade this system, other than replacing worn out heads, for over the last 20+ years. Though I am changing the old HiFonics Cyclops monoblock out for the PG SA3.0X to run the subs, I doubt I will want to change it in the future. 52 years old and one heart attack away from the big ash furnace.....this install will in all probability outlast me. The last install was in for 13 years.

As an aside......What xover do you think would be better from subs to mids. The one that is built into the PG3.0x or a Audio control 2XS?