Stereo Amp question
 

Well I need some help with my amps. Didn't get a chance to call Jon or Buzz today so maybe you guys can answer my questions.

I have the RF 750x needs a 60 amp fuse and the 250M needs a 20 amp. And my buddy gave me another amp (won't be used that often) that has it's own 40 amp fuse in the amp.

I have 4ga running from the battery to a 140 Amp fuse. Then 4ga running to DB blocks and 8ga out from them. Do I need to fuse the 750X and 250M with fuses on the 8ga.

Thanks

The fuse before the db is good enough

Just edited my post the fuse I have is a 140 amp breaker. Is that to big? Since the 750x and 250m only need 80 amp total.
The other amp will only be turned on when we are tied up and it needs a 40 amp fuse. So that takes me to 120 amp. The 140 amp looks fine then but what about when I don't have the other amp on?

Ask Jon[audiofn] he deals in that stuff all day, for my stuff instead of one big fuse are breaker i run separate fuses at each amp
Mark

Your best bet is to put a circuit breaker within 12 inches of the battery connection rated at 100 amps and then put a 50 amp fuse at the 750X and a 40 or 40 amp fuse at the 250.

The advantage to separate fuses is that if one ever blows you know which amp is in need of service.

I have a few more of the new Rockford Fosgate 750Xs and 250M and 500bd monos for sale if anyone wants a deal.

Andy Buzz

Yes it is too big. Also breakers do fail you are much better off with fuses. I don't sell the Rockfords but most of the larger amps require 4 guage just for themselves. I always run individual power and grounds for each amplifier. This is more expensive but the right way to do this. For your 3 amps 4 guage is not big enough. Every installer does things differrent. the way you have the system configurred it will not make the power you are expecting. I hope this helps. I know Audiofn will check in. Forrest

I second the individual power wires for each amp. Remember high quality wire with many strands. No solid core one piece wire.

If you are going to use a distribution block you are going to need 0 guage to the block and 4 guage off of that. Keep wires as short as possible and make sure your ground is as large as your power.

If you are capable of drawing 120 amps, protect it with a 100 amp circuit breaker. jmo

Now I can see why they say that there are 50 ways to skin a cat. In this case, there is a piece of information regarding Russ's system that noone is taking into account....

To determine the proper gauge of wire, you must determine not just load but also the distance of the run. The longer the distance, the higher the resisistance hence, higher amperage draw needs fatter or additional wire.

Russ's amps are mounted under the rear seat bench. The distance from amp to battery is probably 8 feet. 4 gauge is plenty. Also consider the load. Two of the amps are running coaxial speakers that dont demand juice like subwoofers do.

Based on the above, 4 gauge is more than enough.

I only gave a recommendation. I did not have all the info you had Andy. I also do not know about the Rockford line of amps. I try to avoid installing anything under the back seat or the engine compartment for obvious reasons and would not assume that this is where the amps are located. Forrest

Thanks all,

I guess I should have given more info. But you are all right.

The amp for the subs is under the back seat. And the amp for the boxed speakers is under there also. I have a 4ga wire running to them. 5 foot run.

The 750X is in the cabin it is a 15' run and I just ran 4ga to that today.

I fused everything: 750X with a 60amp inline the 250M with a 40amp inline and the other amp has it's own fuses. And I kept the 140amp fuse 18" from the bat.

I have never had a problem with the amp under the back seat. But I guess there is allways a first time.

Thanks

Russ