Team-BHP - View Single Post - So.... why do we need those thick wires??

low_bass_makker · 23rd November 2007, 10:48

Kenwood KAC-9103D Mono subwoofer amplifier 900 watts RMS x 1 at 2 ohms at Crutchfield.com

and

JBL Grand Touring Series GTO75.4 II 4-channel car amplifier 104 watts RMS X 4 at Crutchfield.com

both the amps has 30 x 2 amps fuse. Also the 4 channel will work on speaker duty that is with HPF, so the current consumption will be quite less of that amp. But anyways a simple logic you can go for a single 4 gauge cable as it is capable of handling 150 amps. (30+30 + 30+30 = 120 amps fuse total) as the 8 gauge will be less for your application.

Recommended Power and Ground Cable Sizes -> check the Power & Ground Cable Specs chart

Or

One can calculate the Ampere

For the Kenwood as it is D class I am assuming it to be 80 % efficient so the max current watts it will draw will be 900 watts + 20 % = 1080 watts

so 1080 / 12 = 90 amps

The above case will happen when you play a sine wave and never possible with music.

For the JBL amp Max it can give is 104 x 4 or 284 x 2 but since you are using it for 4 channel I will take 104 x 4 = 416 watts . Bening it AB class I will assume it 50 % efficent so the total watts drawn will be 416 + 50% = 832 watts

so 832 / 12 = 69.3 amps

Now one more important thing to consider here is that since you are using the amp in Speaker duty the peak current demand will be never 69.3 amps. so you can consider it less also. Anyways total demand is now 90 + 69.3 = 159.3 amps which can be considerd to be 150 easily. Which a 4 gauge (25mmsq) cable can easily handle without any problem.

So calculate it anyway you just need a 4 gauge (25mmsq) cable for the job even if you upgrade your speaker amp also.

23rd November 2007, 10:48	#87 (permalink)
low_bass_makker Senior - BHPian Join Date: Mar 2006 Location: Faridabad Posts: 5,798	Kenwood KAC-9103D Mono subwoofer amplifier 900 watts RMS x 1 at 2 ohms at Crutchfield.com and JBL Grand Touring Series GTO75.4 II 4-channel car amplifier 104 watts RMS X 4 at Crutchfield.com both the amps has 30 x 2 amps fuse. Also the 4 channel will work on speaker duty that is with HPF, so the current consumption will be quite less of that amp. But anyways a simple logic you can go for a single 4 gauge cable as it is capable of handling 150 amps. (30+30 + 30+30 = 120 amps fuse total) as the 8 gauge will be less for your application. Recommended Power and Ground Cable Sizes -> check the Power & Ground Cable Specs chart Or One can calculate the Ampere For the Kenwood as it is D class I am assuming it to be 80 % efficient so the max current watts it will draw will be 900 watts + 20 % = 1080 watts so 1080 / 12 = 90 amps The above case will happen when you play a sine wave and never possible with music. For the JBL amp Max it can give is 104 x 4 or 284 x 2 but since you are using it for 4 channel I will take 104 x 4 = 416 watts . Bening it AB class I will assume it 50 % efficent so the total watts drawn will be 416 + 50% = 832 watts so 832 / 12 = 69.3 amps Now one more important thing to consider here is that since you are using the amp in Speaker duty the peak current demand will be never 69.3 amps. so you can consider it less also. Anyways total demand is now 90 + 69.3 = 159.3 amps which can be considerd to be 150 easily. Which a 4 gauge (25mmsq) cable can easily handle without any problem. So calculate it anyway you just need a 4 gauge (25mmsq) cable for the job even if you upgrade your speaker amp also. __________________ 156.6 db, naa....time is coming to cross it......