Installing a 4 channel amp with one sub

[scotchnsoda 10+ year member]

So I just bought a sub and amp off of craigslist, and this is what came with it.

Alpine V-power MRP-F240 amp

and a JL audio 10W3 sub in an enclosed box.

What I want to know is can I use all 4 channels to power the sub? Or will some of the power of the amp be wasted?

I've attached some pictures of the sub and amp and stuff so you can see the inputs and stuff better.

On that last picture, there are two reds and two blacks. I don't know if thats usual or not.

Click to read more...

 

[jrwalte 10+ year member]

you should have come here before buying. That's one ghetto setup //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif It looks like the guy even wired it in series by running two independent wire runs instead of just daisy changing from one VC to the other.

At least you got an OK sub. You're going to have to take that sub out to figure out which ohm it is. The back of the sub should say D2, D4 or D6. But no matter what, that amp is no good for this sub. I'm thinking it is D2 since that's the only one that could work with that amp wired in series.

Until you can get a better amp, the only option is bridging it on channel 3 & 4 for 100 watt at 4 ohm. The sub can handle 300.

 

[kovemaster559 5,000+ posts]

wire to the coils brige amp to two channels

 

[jrwalte 10+ year member]

wire to the coils brige amp to two channels

Only if the sub happens to be a D4 can he do that. The amp only supports down to 4 ohm bridged.

 

[scotchnsoda 10+ year member]

you should have come here before buying. That's one ghetto setup //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif It looks like the guy even wired it in series by running two independent wire runs instead of just daisy changing from one VC to the other.
At least you got an OK sub. You're going to have to take that sub out to figure out which ohm it is. The back of the sub should say D2, D4 or D6. But no matter what, that amp is no good for this sub. I'm thinking it is D2 since that's the only one that could work with that amp wired in series.

Until you can get a better amp, the only option is bridging it on channel 3 & 4 for 100 watt at 4 ohm. The sub can handle 300.

Well I'll look for a mono amp then, I suppose. I don't even have a wiring kit yet, so I guess I'll take this whole thing one step at a time. Ether that or a two channel amp, right? Any recommendations?

 

[jrwalte 10+ year member]

Well I'll look for a mono amp then, I suppose. I don't even have a wiring kit yet, so I guess I'll take this whole thing one step at a time. Ether that or a two channel amp, right? Any recommendations?

When you get a new one you might as well get a mono d class. You need to determine what ohm you can wire that sub to before deciding on an amp.

 

[scotchnsoda 10+ year member]

When you get a new one you might as well get a mono d class. You need to determine what ohm you can wire that sub to before deciding on an amp.

So the ohm of the sub is listed on the back of it? I've researched ohms, and I still don't know what they mean. Can I change the number of ohms that the sub runs at?

 

[jrwalte 10+ year member]

You can only work with ohms to get what you want by using different wiring schemes. You can't change them. Do a google search on sub wiring diagram to see.

The back of the sub won't tell you the ohm it is, but it should mention the model, D2, D4, D6, which also happens to be the ohm load of each voice coil.

 

[scotchnsoda 10+ year member]

K so I just took the sub out of the box. It's a D4 so 4 ohms. How am I going to want to wire it? Like this:?

Also, would the Cerwin vega xl300 in this thread be a good choice for an amp?

http://www.caraudio.com/forum/showthread.php?t=319264

Oh, one more thing. How do I know what gauge of wiring to get? If I'm only powering one 10" sub, shouldn't 8 gauge be enough? What other wires do I need?

 

[TurdFergueson2 5,000+ posts]

you should have come here before buying. That's one ghetto setup //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif It looks like the guy even wired it in series by running two independent wire runs instead of just daisy changing from one VC to the other.
At least you got an OK sub. You're going to have to take that sub out to figure out which ohm it is. The back of the sub should say D2, D4 or D6. But no matter what, that amp is no good for this sub. I'm thinking it is D2 since that's the only one that could work with that amp wired in series.

Until you can get a better amp, the only option is bridging it on channel 3 & 4 for 100 watt at 4 ohm. The sub can handle 300.

It may just be 2 runs of + and - coming off each terminal. I did it like that when I didn't know any better.

 

[GearGuy2001 10+ year member]

It may just be 2 runs of + and - coming off each terminal. I did it like that when I didn't know any better.

Maybe the guy wanted to make sure the sub's weak point wasn't in the wiring (ie too cheap to purchase quality wire so he doubled the wire he had)

 

[scotchnsoda 10+ year member]

Is this a good amp for my sub?

Cerwin vega xl300 in this thread:

http://www.caraudio.com/forum/showthread.php?t=319264

Also, what gauge of wiring do I need? My friend has an 8 gauge wiring kit. Is that good enough?

 

[jrwalte 10+ year member]

As I said earlier, you shoudn't shop for an amp until you determine the ohm of your sub. It can make a big difference in the amp you need.

If your sub is a D2, it'll work, but you're better off getting a 400 or 500RMS amp - it's rated 300. It's good to go a little over the rated RMS of your subs because amps don't always give the actual output they say they can.

FYI,

You can find that amp online new for $80.

 

[scotchnsoda 10+ year member]

As I said earlier, you shoudn't shop for an amp until you determine the ohm of your sub. It can make a big difference in the amp you need.
If your sub is a D2, it'll work, but you're better off getting a 400 or 500RMS amp - it's rated 300. It's good to go a little over the rated RMS of your subs because amps don't always give the actual output they say they can.

FYI,

You can find that amp online new for $80.

I posted earlier that it's 4 ohm. D4. Sorry about that

 

[romans535 10+ year member]

I also agree that this amp does not suit your sub, you might want to use that for mids or highs, but if thats all you have for now you might be able to bridge it to 2 channel one channel per voicecoil(thats if its the right ohms) good luck