A question to those that know:

Problem: 2Ohm or 8Ohm sub

Amp delivers 220W bridged at 4Ohms

Running at 8Ohms It can only deliver 110W

If I were to run it at 2Ohms, but keeping the gain down, listening for clipping and keeping an eye on temperature should it be OK if I never "ask" the amp to deliver beyond 220W at 2Ohms?

Surely the current drawn at 2Ohm/220W is the same as current drawn at 4Ohm/220W.

If this is the case, the amp should be ok right???

That is, if I dont demand too much of it? (i.e 220W)

Now this is a very important question:

If I overdo it, will my amp a) cut out temporarily, blow its (replaceable and cheap) fuse or c) release its magic smoke and die?

The amp is an Infinity ra7502, so decent build quality Id hope.

Thanks

Jono

Disclaimer: the reason these bits are mismatched is because I mashed them together at low cost to see if I liked having a big sub or not.

I know the fact of the matter is that if I get the bug for bass I need a better amp. 300W at 2Ohm at the very least, Ideally more to avoid running the amp at full power, and allow for speaker upgrades.

In all honesty mate, I'd say stick with a single sub, and have everything set up as it wants to be.

Running a sub at too low an ohmage will not do it any good.

Hopefully it will keep tripping out... before blowing the fuse.

And if it doesn't trip out, hopefully the fuse will go before the amp does...

But, you will be testing the limits!!

I wouldn't recommend running at 2ohm if the amp isn't stable there.

Surely the current drawn at 2Ohm/220W is the same as current drawn at 4Ohm/220W.

The first thing to remember is that the power rating of your amp includes all the the losses due to the heat it produces so you never actually get 300w from a 300w amp.

Power = Current squared x Resistance (Impedance). Not just as simple as that for a source like an amp but looking at the effect on the power supply side at 220w an amp will be drawing 4 times the current running at 2 ohms than at 4 ohms. Do you see where this is going.

It's a bad idea.

I did it once and bridged 2x150w 4 ohm subs on a 300w amp. The thermal cut out came in everytime I pushed it even slightly hard. Eventually the amp packed up completely. Thermal cut outs have a life span and I exceeded mine.

you can buy the subs you have brand new for £89

get either the correct sub or the correct amp before it goes bye bye

£89 plus postage.

Makes me smile. I got it and the Alpine letterbox ported box designed for it (£49) for fifty quid, unused, ever. yay.

Shame its 2x4Ohm not 2x2Ohm, Oh well...

Ill run the amp at 8Ohm for safetys sake, and im keeping my eyes peeled for a 300W+ @ 2Ohm stable amp.

Then I can use the infi amp for a pair of speakers.

Problem is, im not sure I can be arsed taking the car apart for another RCA cable run, and there is no way I could be **** running speaker cable back again into the front doors. Might have to run the fronts alone on the alpine HU and run rears on the infi amp. Gonna keep the amps bolted to the sub for easy removal for camping etc. Should look quite comical.

When will manufacturers learn that a 4AWG power cable, decent speaker wire and a boot RCA should be standard kit!

Jono

shoulda said earlier mate, i only bought my second 2 2x4ohm 12" type S on friday

i could have bought a 2x2ohm and swapped

Ack!

Oh well nevermind, It does encourage me to buy a new anp though, which means Ill have a decent 2 channel amp spare, which means Ill have to buy some new rears to keep it company...

Jono