Which one?

[4DRB16A]

Well I finally got me some subs installed today after putting a 4-Channel amp on my Polk Audio DB 6.5"s.

I got 2 Memphis PR 12"s powered by a Memphis PR 150.2 amp. (pounds hard)

I pulled out of the shop jamming loud and pouding pretty good and after about 10 mins of driving the sub amp shut off , so I turned the volume down and the subs cut back on . So I took it back to the shop and the guy told me that I need to rebuild my alternator to a bigger ampere. (Right now I think I am at 60 with the stock B16a one.) I went to the local Battery Man and he said that he couldnt get a rebuild kit due to the casing was small or something like that. But he could make another Honda alternator fit that is 90 amp.

My question is should I get a 2.0 Farad cap or get the 90 amp alt?

Thanks,
4DRB16A

 

[VTECPOWER]

I would say capacitor, it will hold the charge. And your alt will re-charge it.

 

[neonmike]

first things first, did you get the dual voice coil pr 12's or the single voice coil ones. if you have the duals there is your reason that the amp is shuttin off, they probably wired it up to be 1 ohm and the amp is not 1 ohm stable. you can have the subs wired in series parrallel to stop the amp from overheating and shuting off. this does not sound like an electrical problem to me it sounds like a case of tryin to overwork the amp. i would check that first befor i was goin to spend money on stuff that is more than likely not needed.

 

[E_SolSi]

 

[phyregod]

I'd first try to cross refrence a higher amperage honda alternator.. Being a b-series I immagine several would fit. Or maybe just replace yours.. Could be worn out and only kickin 30 amps.

You need to create make more power. A capacitor won't do that.

 

[E_SolSi]

the amp shutting off then turning back on sounds like thermal protection to me
like mike said he is probly wired wrong... trying to push the amp to an ohm load that it cant handle
amp heats up and shuts off... when it cools off it will turn back on

amps generally dont shut off because they are not getting enough amps
unless you are starving the whole damn car for power in which case your lights should be dim as fuck and the car should be about to stall

take the car to autozone or where ever... they do free battery and alternator tests... have them check it out for you

 

[phunky.buddha]

Something's overheating. There isn't a "storage" area for charge in your car that will just empty and shut down the amp after it runs out of juice except for the battery- and at that point, your entire car would shut down too. In any case, your battery running down or your alternator being too small isn't going to cycle your amp on and off 10 minutes at at time.

Make sure the amp is getting proper cooling, and make sure that all the wiring is set up correctly.

 

[4DRB16A]

Yeah I rode around tonight and checked the amp and it was hot as hell. My lights do not dim at all. So I think it just a prob with the amp, the subs are SVC 4-ohm subs wired parrell and bridged pushing around 250x2 @ 2 ohms.

Here is the spec on the amp:

http://www.memphiscaraudio.com/products/de...?cat=&id=63&p=2

I am going back to the shop tomorrow and have them find out why amp is overheating and make them fix it.

 

[phunky.buddha]

That's the problem- when you wire two 4 ohm speakers in parallel, you present a 2 ohm load to the amp. When you bridge two channels, each channel sees half the load presented to the amp- that's why you get the increase in power. Normally, your bridged setup going into a single 4 ohm speaker would be fine because each channel on the amp would be seeing 2 ohms, but since you're already running a 2 ohm load into the amp, each channel is only seeing 1 ohm of load. I doubt your amp likes that too much.

 

[neonmike]

some one hit the nail on the head

 

[4DRB16A]

I turned down my gain a hair and it doesnt cut out as much only if I crank it up too high.

This is the way I have it wired up:

http://akamaipix.crutchfield.com/graphics/...ohmSVC_2ohm.gif

And my amp is 2 ohm stable so it should be hooked up correct, right?

 

[phunky.buddha]

Yes, your amp is 2 ohm stable- but you're not understanding what's really going on. Each one of your channels is 2 ohm stable ON ITS OWN. If you run both channels at 2 ohms, you're fine- but you're not. If both your subs were rated at 2 ohms, and you wired each one to one channel of the amp without putting them in parallel, you would be ok. Since you're putting a 2 ohm load on BOTH channels at once, each channel is only seeing 1 ohm. Get it? It's not stable. It doesn't matter if you turn down the gain- it's not going to help.

 

[4DRB16A]

Quoted post[/post]]
Yes, your amp is 2 ohm stable- but you're not understanding what's really going on. Each one of your channels is 2 ohm stable ON ITS OWN. If you run both channels at 2 ohms, you're fine- but you're not. If both your subs were rated at 2 ohms, and you wired each one to one channel of the amp without putting them in parallel, you would be ok. Since you're putting a 2 ohm load on BOTH channels at once, each channel is only seeing 1 ohm. Get it? It's not stable. It doesn't matter if you turn down the gain- it's not going to help.

So if I were to trade the 4 ohm subs for 8 ohm then it would be on a 2 ohm load bridged right?

P.S. Thanks for the help!

 

[phunky.buddha]

Yes, it would work fine the exact way you have it wired if you trade the 4 ohm subs for 8 ohm subs.

You're welcome.

 

[4DRB16A]

OMG this shop is stupid as hell!!! Come to find out the subs are DVC and they
were wired up this way!!! I am going down there today and demanding to get
SVC subs and I am going to get another amp since this one has seen abuse.

 

[neonmike]

you ca nkeep those subs just wire them in series parrallel and you'll be fine

 

[Cashizslick]

Quoted post[/post]]
you ca nkeep those subs just wire them in series parrallel and you'll be fine

And whatever they charged you to install the system you should demand back since they did it wrong.

 

[neonmike]

i wouldn't ask for money back on the install cuse technically they did there job, however i would ask for a new amp because of the strain that was put on yours and leave it at that. and then find a new place to shop at for your stereo equipment.

 

[4DRB16A]

Well I have them wired in series right now and they sound OK, but I told them that I did not like that amp and I wanted to upgrade to this amp:

http://www.memphiscaraudio.com/products/de...?cat=&id=98&p=2

This should make it slam a little harder compared to the 100X2 rms Im pushing now.

Got his talked down to $300 for this amp only $100 more than the 150.2.

 

[4DRB16A]

Well the new amp that I am going to get uses 20 more amps than the current one. My amp I have on my mids/highs is the only way that cuts out when I have it cranked up too high. Right now I have a 60 amp alternator...my question is when I get this new amp should I go ahead and upgrade my alt to a 90 amp and will that play it suffiently?