Alpine Amp Cuts Out

I'm running a Pioneer DEH-P6700MP to an Alpine MRV-F340 amp to 4 Infinity Perfect, component speakers.  When I put the volume to a moderate level, after a couple of minutes the amp cuts out.  I still have lows from the Bazoola BT8200, just no mids and highs.  I have tried adjusting the gain down, but then there is no volume.  I'm not trying to blow anyones eardrums,  I have a Diesel truck and with the windows down I need a little more volume.  I have 4 gauge wire directly from the battery to a block.  From there I have 8 gauge to the Alpine amp and to the Bazooa.  I have a good ground from the amp also with 8 gauge.  One more note:  If I fade to ALL front or All back, the amp NEVER cuts out.  Does this seem like a power problem?

Thanks for any help.

Corey

This problem started right after install.

Can anyone recommend an amp for these speakers.  Infinity 5 1/4" Perfects.

Infinity makes an amp that's 111w RMS X 4.

Corey

OK, a few points.  First, the new Infinity Kappa series are 2-ohm speakers.  Your Alpine amp should be able to handle a 2-ohm per channel load.  But be sure you have set it up properly.  It is rated at 45 watts per channel into 2-ohms.  It sounds to me like your gain is way too high, or you have a very bad ground connection.

Now there are a few misconceptions in some of the above posts.  "Clipping" is what happens when an amplifier is being over-driven and is distorting, usually due to too high an input level or too high a gain setting or too low an impedence load.  An amplifier that is cutting out is NOT clipping.  Your amp is cutting out.

Speakers do not "require" any certain power level.  They will work on whatever power you give them up to their thermal limits.  Some low-efficiency speakers sound better with certain minimum input, yes, but Infinity speakers tend to not be those.  They are fairly high efficiency speakers at 94db and should work just fine with less than 1 watt input.

Power wire size will not cause an amplifier to shut down or cut out all by itself.  A bad cable or a bad ground may cause an amplifier to cut out, but not because of any effect like "lack of power."  An amplifier will draw as much power as it needs through a cable and if it is too small, the cable will heat up and eventually fry.  A small alternator or a bad battery or a bad ground connection may cause "lack of power."  I believe your alternator is large enough for your setup, but you might want to get your electrical system checked for proper operation just to be safe.

Your Alpine amp will work just fine with those speakers as long as you set it up correctly.  Check your install and set the gain properly.

Thanks for the great info.

First, let me say that I've adjusted the gan from low to high and it doesn't effect when the amp cuts out.  If the gain is adjuted low, I have to give the system more volume to have it be heard.  It actually has to be turned up a lot just to get moderate volume.

Second, How do I set this amp up for 4 ohm or 2 ohm opperation.  Here's the manual: https://ecominet2.alpine-usa.com/html/asb/owner/mrv-f340_om.pdf .  I don't see how I would switch it from 4 to 2 ohm.  How do I check the ohm level with a dmm.  What is a dmm.  I have one of these: https://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=03482149000 .

I don't believe I have a wire problem because I don't get any cutting out if the speakers are faded in either direction (all front or all back).  Although I plan on making sure that they are all intact and working properly.

You guys are all a big help.  Thanks for all the info.

Corey

There is no "4-ohm" or "2-ohm" switch.  Your amplifier has a gain control for channels 1-2 (typically the "front" speakers) and for channels 3-4.  The other switches are for the built-in crossover.

Assuming you are sending a signal from your head unit to the amp using RCA cables, here's what I suggest:

Set both filter switches to "HP" and the crossover adjustment to 100Hz.  Turn both gain controls all the way to the left.  Play a test tone at about 1000Hz in your CD player and turn up the head unit volume until you hear the tone change.  This is the point of clipping in your head unit.  Turn it back down until the tone changes back to the original.  This is the maximum setting you can use on your head unit's volume control without clipping the signal.  Now slowly turn each gain control up until you hear the same sort of tone change, then back until it clears.

This will match the max output from your HU to the max output of your amp.

If the amplifier cuts out at any time during this process, one of several things is happening:  Either your ground is bad, or you have a shorted speaker or speaker wire, or you have bad/pinched RCA cables, or you have a defective amp.

Cheers and good luck.

I down loaded a 1000 hz test tone and will check it out tomorrow.  I hope I can figure something out.

Thanks for all the great help.

Yes it does.  It offers:

(1+3/2+4)  (3/4) and (1/2)  I have it set to 3/4.

Here's the manual https://ecominet2.alpine-usa.com/html/asb/owner/mrv-f340_om.pdf  .  On Page 12 there is a picture of all the switches on the MRV-F340. 

Corey

Well... I played the test tone today and set the amp up correctly.  With the tone playing and the gain turn all the way down I was able to turn the head unit all the way up.  No tone change what-so-ever.  Ouch! Very loud.  The I started to turn up the gain.   I went up a little less than half way and the tone changed.   I backed it off.  I made sure all the connections where tight, the ground may have been slightly loose.

The result.  The head unit has to be turned up more to get volume, no big deal.  The system did play louder and longer than it used to, but the amp did cut out after a while.

Back to the drawing board.

Corey

Pyromed1 wrote:

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Well... I played the test tone today and set the amp up correctly.  With the tone playing and the gain turn all the way down I was able to turn the head unit all the way up.  No tone change what-so-ever.  Ouch! Very loud.  The I started to turn up the gain.   I went up a little less than half way and the tone changed.   I backed it off.  I made sure all the connections where tight, the ground may have been slightly loose.

The result.  The head unit has to be turned up more to get volume, no big deal.  The system did play louder and longer than it used to, but the amp did cut out after a while.

Back to the drawing board.

Corey

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OK, now you can rule out the idea that the gain is too high and the amp is overloading.  Next, check if the amp is getting hot.  It may be a simple cooling issue.  Is the voltage at the amp dropping below 11 volts for some reason?  Many amps will shut down on low voltage.

I appreciate all the help here.  Thanks a lot.

Right after I installed the amp and it started cutting out, I installed a cooling fan.  The amp stays pretty cool, but that obviously wasn't the problem.

I will check the voltage asap.

Thanks again, Corey

Update:

My amp hasn't cut out again.  The only change I've made was to fade a couple of clicks to the front.   I've really cranked it up a few time with no problems.  I still plan to check the voltage.  I'l let you know when I do.

Corey