Question about Alpine MRV-F345 Car Audio Amplifier

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Have 2 amps, 1 for subs, other for speakers. The one for speakers just started shutting off

If I turn the volume up past half it shuts down and when I turn key off it resets and works till volume is raised again

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Re: have 2 amps, 1 for subs, other for speakers. The one...

This can be caused by too low of an ohm load, such as wiring subs in parallel at lower ohms than amp recommends. Or short speaker to body of car can cause it, or amp could have an internal problem. Like stated above try each speaker or disconnect one at a time to see if it is a speaker/wiring doing it. If amp gets too hot can also do it, but often it is overcurrent in the amp if it does it with high volume. Another less common issue could be lack of power so amp is drawing voltage too low for it to run, like if your fuse/wiring has a bad spot cutting down current or is not large enough/corroded/bad ground/etc.

Posted on Apr 22, 2008

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Re: have 2 amps, 1 for subs, other for speakers. The one...

Are the amplifiers identical?


Do both amps shut off?

Posted on Oct 11, 2007

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What should my setting be on car stereo...Keeps shutting off subs at half available volume.

If your amp is shutting off when you turn up the volume it means that it's clipping. This is very bad for both your subs and amp. The reason this happens is because your amp doesn't supply enough wattage for your subs and the capacitors are being drained of power causing your subs to cut out. As far as ohms this is not a setting. It is resistance and is very very important to have your ohm load correct or it can cause damage to your amp n subs. For a better understanding of ohm loads visit and put the number of subs and the ohm value and it will give you the wiring diagrams for the different ohm loads. then u need to look at your amp manual to see what ohm loads it is stable at.

May 14, 2014 | Virtual Reality VR3 Car Amp

1 Answer

Amp shuts down under load - If I turn the volume from the head unit up past about 16 it shuts off. I've had it for a while and haven't had this issue until recently. Thanks!

If you added or changed speakers and the impedance (ohms) is not the same, it could overload the amp depending on which way the speakers are wired (parallel or in series).

Apr 10, 2014 | Alpine - Mrx-v70 X Power - 5 Channel 360w...

1 Answer

Speakers cutting in and out at high volume

The amp is going into protect on the two channels powering the speakers. Turn down the gain on those two channels. You also may want to consider crossing over the speakers a little higher than they are now.

The rating on those speakers are way too high. 6.5's and 6x9's will take 50-100 clean watts tops before they start to break up.

The best solution to get it perfect is....unplug the subs. Turn the gain on the speaker channels all the way down. Then turn up the deck 80% as high as it will go. Play a song. Then increase the gain on the amp until the speakers are as load as they go without distortion. Shut off the car, replugg in the subs and do the same thing. Gain on sub channels all the way down, deck then to 80%, find a bass heavy song, then turn gain up until subs become distorted. If you do this procedure your speakers and subs will be "gain matched" to the proper levels.

Good Luck

Dec 07, 2013 | Kicker IX500.4 4-Channel 500 Watt Car...

1 Answer

I have a kenwood kac-9152d amplifer and it works just fine for about 10 minutes then just shuts off and subs dont work, about 30 seconds later my amp turns back on with the subs.

make sure it's well ventilated. If there's no air flow, then there is no way of cooling down and to protect itself it will shut off. Make sure the speakers are wired correctly as per amp specs. too many subs or subs connected improperly can draw too much current and shut the amp off, but you will notice this when you turn up the volume to a certain point and the amp shuts down.

Aug 30, 2011 | Kenwood KAC-9152D Car Audio Amplifier

1 Answer

Hi there, ive got a 4500 watt amp connected to the two 1500 watts subs i bridge the two subs and it sounds greater than any other sub that ive had before....BUT lately it starts to play up,the maximum of...

could have shorted coil, check resistance on each speaker and compare, should be rated @ 4 or 8 ohms, or disconnect both then run individualy to test output

Dec 30, 2009 | JBL GTO14001 Car Amp

4 Answers

I have a jl 1000/1 amp hooke up to 2 12 w6 subs and when i turn the volume up half way the speakers cut out and amp stops working but i turn the volume back down and it works fine. what could this be?...

what is happening is the amp is going into protect mode because it most likely is at the wrong oms and is getting over loaded and shutting itself down to protect it self!

do you know what ohm load you are presenting to the amp? or what ohm are the subs ?

if you correct the ohm load it will fix your issue and make the system sound way better! let me know if you have any more question and let me know about the ohms! good luck

Oct 02, 2009 | Jl Audio 1000/1 Car Audio Amplifier

2 Answers

Jh202 amp works for a few minutes stops for a few minutes any ideas

Sounds like the amp is going into Protection Mode. Does yours have green LED light then RED LED on it? The green is power and the red is Protection. You will need to either change the OHMS wiring or Put A Fan on it to Keep it Cool Inside.

May 11, 2009 | MTX JackHammer JH202 Car Audio Amplifier

2 Answers

JL 300/2 v2 Power Light Blinks, No sound out of Sub. Works in friends Car HELP

Are you sure you don't have any shorted wiring or defective speakers?

Sep 30, 2008 | Jl Audio 300/2 Car Audio Amplifier

1 Answer

Amp Turns of when i put the volume up to 20

if it only happens when you turn it up, you could be sending it too hot of a signal and its clipping so the amp is protecting it self and shutting off. Try lowering the input gain on the amp and see if that helps. It's also possible that your speakers are pulling to much power when you have it turned up that high and the amp is shutting down to keep from overheating. I don't know what or how many speakers you have hooked up, but if you have a sub, try it without that and see if you have the same problem. If you don't have a sub, disconnect the largest woofers you have. Different speakers have different ratings for how efficient they are. It's usually measured by how much SPL 1W will produce. You want to disconnect the speakers that are pulling the most power and try it again. If your speaker is pulling more power than your amp can supply, your amp could shut off because of that. As well as cook the voice coils in the speaker and damage the amp. It's always better to have too much power in your amp than not enough. There's an old joke I learned in audio engineering school "I can pass a square wave.....once."

Jun 13, 2008 | Ultra Linear UL-2200D Car Audio Amplifier

2 Answers

Feedback/maxing out speakers.....

starting from amp,what is the rca connected directly to. headunit or adoption?

May 05, 2007 | MTX RT202 Car Audio Amplifier

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