TheKleinschmidt

I decided to add a 4 channel amp to my setup this weekend to power my Alpine Type r front speakers. What a TREMENDOUS difference. I can't believe I ran these speakers for so long off the head unit. Currently though, my mono sub amp powers on but doesn't kick and I think because its not getting enough power. Here is my current setup and do I need a capacitor for the sub to begin working?

Alpine IDA-X305 headunit
Alpine M450 Mono Amp
Alpine Type R 10' sub 4ohm load
Rockford Fosgate R300 4 channel amp - bridged in 2 channel mode
Alpine 6.5' Type R speakers

4 gauge wiring kit with 8 gauge splitting to each amp

Alpine Mono sub turns on but doesn't kick...not enough power?

Thanks

darkknight1999

The short answer is... no. You don't need a cap. Install a 4gauge or at least an 8 gauge ground wire for each amp, but 4 gauge would be better.

However assuming you have either Alpine SWR-1023D or the Alpine SWR-10D2, both of which are grossly under powered with that mono amp running in 4ohm. Either of those subs should be feed a least 500watts... you're only feeding the sub about 225watts with that Alpine amp.

So you can do a couple different things... get a different Alpine sub and wire it for 2ohm, so you can use that mono amp to its fullest and use the 400 watts it can produce in 2ohm; or ditch both those amps and get an Alpine PDX-V9 and solve all your problems at once and it will leave you 2 extra channels that you can use for rear speakers later on.

TheKleinschmidt

I do have the SWR-1042D amp. Funny thing is, I just added the Rockford amp but before that I was running the same Alpine amp with an 8 gauge kit (power and ground) both at 4ohm and 2ohm and it worked perfectly. Once I added the additional amp and upped the gauge to 4 it stopped working. The Alpine amp light turns out but no kick and I reduced the ohm load from 2 to 4 to see if it would help. I could switch the 4 gauge ground wire from the Rockford to the Alpine (even though 8) worked in the past) and see if that helps.

Out of curiosity, when is a capacitor needed? I've done some reading online about them but just can't find that magic explanation on when you actually need it.

I appreciate the help though

TPhong

Unless you're running some ridiculous sounding stereo, you really don't need a capacitor. If it got to that point, I'd look into getting a stronger alternator and bigger battery (preferably some kind of deep cycle).

TheKleinschmidt

Nothing crazy. Just 1 type R 10' sub and just front Alpine Type r speakers

Toms1989

Power caps = Biggest con going...

It's just another point to charge.

Best thing to do, upgrage the big 3, it's cheap as chips to do, a larger capacity battery, or a dry cell battery like an Optima Yellowtop

All it consists of is a larger AWG wire going from Battery to chasis, Positive battery to alternator, and engine to chasis.

Reduces light dimming, and in a nutshell a better flow of current.

2big4aS2000

with today's digital amps, no caps do much, older amps yes, they cant hurt, as it has beend said, do the big 3, a good big battery, and use a good wire OFC only,

jguthrie

I understand the questionability of capacitors. They trickle charge and spend that storage to push the amp, but once out, it will behave the same as not having a capacitor. So, they do help when they have juice, but are more of a Band-Aid. I do not use them. However, that being said, isn't our alternator rated at 105Amps? I want to run 2 amps which I believe sum up to 180Amps. What should I do?


Should I:
Get a different battery
Upgrade gauge where alternator is concerned
Run 0 or 2 gauge wire to the distribution block (for amp power)
Upgrade my alternator somehow

The previous owner had a 10" sub and the 6.5 door components running on a US Amps XT1600.4. This amp is fused with 3x25Amp = 75Amps. My current work in progress is as follows: I'm going to take this 4 channel amp and continue to run the two 6.5 door components and add 2 additional 5 1/4 components behind the seat like darkknight1999. Adding to that, I will then power the sub with an AQ1200D which is fused as 3x40Amps = 120Amps. I still have a single 4 gauge power wire from battery to distribution block, with 4 gauge to each amp after that. Each amp has 4 gauge ground direct to chasis.


By the way, I also have a jeep and jeep owners were big supporters of optima batteries. However, their consensus now is that they are mid-grade at best.

Ragnarok043

first of all your amp is not producing that much power, those are peak numbers rated under optimal conditions. kind of like how cars have a top speed rating but the chances of you reaching that number is next to none. second you're basing your calculations on the fuse, if you amp was truly pulling that much power you'd blow the fuse every single time you turn on the amp. you should be looking at the RMS rating, even then those numbers can be artificially manipulated by bumping the voltage. base on the RMS rating both amps combined is 510 + 800 = 1310 watts divide that by 12 volts equals 109 amps again those numbers are probably manipulated if say they used a 16 volt power source to test then you're looking at 1310 divided by 16 volts equals 81 amps. i didnt even include loss of efficiencies into this, basic rule of thumb that i learned is that you should be paying $1 per watt, anything less than that i would be wary of the actual power rating.

back on topic, you can check out the post i made about caps in this thread https://www.s2ki.com/s2000/topic/987...t__p__22144857

jguthrie

OIC. Even though the amp is fused a certain way, that amount is for the unlikely max condition. One amp is heavily overrated so it would never likely draw high amperage for any duration. The thing is, when reading the audio forums (diyma), members say a good way to tell the true power of an amp is by checking what it's fused for. Higher fuse amounts suggest more power. That's where I got the idea. My amps RMS wise are 100w RMS X4 channels and 800w RMS X1 channel. So, (1200w / 12.7v)= 94.5Amps. I am taking the 12.7 from an assumption to fill in the value.

Can I measure the RMS watt output of an amp with a DMM?