Question about American Pro VS1405 Car Audio Amplifier

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Problem I am having trouble keeping my amp on when I turn up my stereo. I am running it in stereo setting on the LPF and I have 2x10" subs at only 250watts each. I want to know how I can diagnose this problem of the amp cutting out when I turn up the music. Thanx.

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  • king nigget Dec 02, 2007

    my amp cuts out when i crank it up, but its not over heating!!! what's wrong???

  • PAtty123567 Jan 10, 2008

    Amp cuts out when i turn up the volume

  • madmachinst Feb 11, 2008

    replacing all the wire connectors and the light will not even come on to let me know i have power

  • helpwithamp Feb 11, 2008

    i have already replaced the fork wire ends on all. but no connection nor will the light come on to show i have power and my sterio will not play

    Can anyone HELP!


  • Anonymous Feb 18, 2008

    my amp cuts out when i turn up the volume
    The light on the amp is on when like it is suppose to be then when i turn it up to a certain volume it cuts out and the light is flashing

  • luckinchuk3 Apr 11, 2008

    power turns off on amp when volume is to high? how do i fix this problem?

    please someone help

  • Spanndiddy Apr 30, 2008

    im having the same problem everytime i turn up my stereo the bass cuts out. I have a good battery and i have a capacitor hooked up 2. I have a 2 sony xplod subs thy are 10, i tried just about everything but i dont know whats the problem

  • Anonymous Apr 30, 2008

    I've Got 2 12 Inch Volfenhag Subs Hooked Up To This Amp In Stereo @ 2 Ohms (Two 4Ohm Voice Coils).

    The Problem I'm Having Is That The Amp Goes Into Protect Mode Every Two Seconds No Matter What I Have Tried.

    I Have A 4 GA Power Wire Lights Dim A Little.Both Voice Coils Hooked Up Properly. Does This Amp Kick Out Because The Volfenhag Subs Have A DC Resistance Of 3.2 Ohms (1.6 Ohms X 2), Where It Should Be 2 Ohms? Or Does That Have Nothing To Do With It. I'm Running A Crunch GP2250 And It Works Fine, But Half The Watts. Need More Bass!!

  • freud_g May 19, 2008

    As Soon a turn On the radio my amp turn Protector ON, amp shut off. Does not matter of sound level, even at lower everything, the amp can't support the signal. Also disconnected the crossover input for test. Any work around be appreciate.

  • norm3 Jun 14, 2008

    I have a cambridge 640A azur amp, when i go to turn it up bout 2 thirds it clips out. I have put amp on top of cd player so there is more ventilation for amp, still have same prob i have checked all leads they seem fine, was wondering if speakers are ok they are eltax columns

  • Anonymous Jun 29, 2008

    i just bought a kaption 15" (spl 1500) and it sounds great but only for about 5 minutes then it shuts down the amp. i have everythig hooked up properly i know that and i know its not over heating cuz when i touch it its still cold.. the amp is the D700.1 please help thanks... josh



17 Answers

This has got to be the most useles sight i have ever come across

Posted on Aug 16, 2008


Get a capacitor then your problem will go away! if your clipping its because your amps power is not high enuf i.e. the ingine is eatin it too much. a capacitor will give it a constant 12v supply and ur problem shud disapear

Posted on Jun 21, 2008

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Put a relay on the remote wire because the remote from your radio does not have enough output for the high current amp

Posted on Jun 20, 2008

It seems both above answers are good but still lacking, sorry. Nether really explain how to fix the problem.

the First one is the most likely cause. especially if the amp cuts out immediately after it receives power. It doesn't have the chance to over heat.

The most frequent problem that ive seen in my 6 years of working on sound-systems. is that people don't know about the physics behind it. if an amp is made to match at 4ohms, and its "seeing" 2 or 8 or a different impedance. it could cause an internal failure, overheating, or it could short circuit the board due to the improper wiring of the speakers to the amp. If your not sure whats the best way to wire your speakers with your amp. try going to the Rockford Fosgate web site. and search their wiring help for your type of speakers. ie two dual voice-coil.

as for the overheating of an amp. its usually caused by one of two things. user stupidity, ie. 1 or more full hour of non stop high power level playing. or from improper wiring. witch could lead to overheating in just a few minutes. once again. check for the proper wiring of your type of speaker.

i personally tested a lot of different scenario's, and was shocked to find out an 80Wrms amp could over heat in less than 8 minutes(within 3 songs) because of improper wiring.

Posted on Jun 03, 2008

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First of all....if you have a frequency adjustment, keep it around 80 hertz on the low pass filter... this will keep frequencies that your sub can't play out, so that you aren't using unnecessary power. The next thing you have to do is turn the gain all the way down.... leave the gain down and then turn the volume of the stereo up nice and loud. With the volume nice and loud, turn up the gain of the amp until the sub is playing nicely and not cutting out. This is your proper gain adjustment. 
If you still have problems, your subs may be wired improperly... what kind of subs are they? Are they dual voice coil? Do you have each sub connected to a different channel or are they both connected to the same place? These are all factors in what kind of electrical load are being placed on your amplifier.

Posted on Mar 31, 2008

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Check and see how your sub is wired if you have a dual 2 ohm sub and your wired at one ohm your amp might not be able handle 1 ohm in stereo most ams are 2 ohm stereo and 4 ohm mono....check the wiring if it's pos. to pos. ....and neg. to neg try doin pos to negetive that will bring your ohms up to 4 then you'll be good

Posted on Mar 30, 2008

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I had the same problem, and it turned out to be something dumb. I had my ground wire from the amp connected to something i thought to be metal. A bad ground is the main problem for an amp cutting off when you turn up the volume. Use sandpaper or steel wool to brush off any paint and bolt the ground down securely. Use a voltmeter to find a good ground. Then turn it up!

Posted on Mar 13, 2008

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Make sure you have a good ground connection

Posted on Mar 06, 2008

  • dremail Mar 06, 2008

    also, make sure you are not going below 2 ohms stereo and not below 4 ohms mono (bridged)


Your amp may not be getting enough juice. What guage power & ground wire are you using? I recomend at least 4 ga. Try getting a capacitator if it only cuts out when you turn it up, or a high output alternator (sp?) You could also run a seperate batt. and use that for your system. Good luck man.

Posted on Jan 30, 2008

If you are running your subs bridged your amp will turn off to protect itself when the ohm load varies and drops below the safety level. peace

Posted on Jan 06, 2008

Check fuse in power wire it may be the fusable link also check output of the remote turn on wire

Posted on Jan 02, 2008

My brother had the same problem, it was a poor ground to the amp.

Posted on Dec 25, 2007

It might be your ground wire

Posted on Dec 13, 2007

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Ok, whoever wrote this last responce was talking half gibberish! he did have two points I did agree with tho-It may be overheating, or it may need more power fed to it. on the other hand, it may be that you have the subs hooked up in a way that is making the "ohm" load to low. for example: if you have two dual-voice-coil subs, each voice coil rated for 4 ohms, and you have them all hooked up in a parallel circuit -all positives going to the positive terminal in one line, and all negatives to negative terminal, then you are creating a load of only 1 ohm. this amp handles a minimum of 2 ohms. this means that the subs are not holding back the "engine" so to speak, so it's redlining when you "push the gas too much" and overheating. parallel halves the ohms everytime, and series doubles it, so if you put two 4 ohm coils in a parallel circuit, it would create a load of 2 ohms, respectively, if you hooked up that sub with the other sub (at 2 ohm load also) in a series circuit, you would add (not multiply) those ohms to get a 4 ohm load-in which case the amp stays happy:) keep the ohms between 2 and 16 ohms and it should stay that way-look up series and parallel circuits on google or something if you need a diagram, because I realize that this probably sounded like gibberish too-hehe.

later ya'll-enjoy this beast!

Posted on Oct 23, 2007

Try takng a look @ the wires are they too small?

Posted on Sep 08, 2007

It could also be that you might have your ohms wired too low for the amp.

Posted on Aug 19, 2007

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A possible explanation could be heating. the amp reaches its boiling point and cuts off. in this case, a fan may keep it from overheating. another option is a voultage problem, you may have to readjust the bias current. try measuring it if you know how). the amount of bias current depends on your output stage. something like: 20-50 mA for normal bipolar push pull probabely twice as much for darlington push pull and up to 250mA for MOS FET push pull.

Posted on Mar 14, 2006

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Hello again ronnieyannon,

It's probably best to allow the amp that is powering the subs to control the frequencies going to the sub(s). I would not use the lpf on both the head unit and the amp in any case. The control settings are not completely precise and you could end up with a lot of tweaking between the units to get the sound you want. I'd send full range to the amp and with it playing something with a lot of bass, set the 401s to "LP", the crossover slope to near maximum, and then adjust the frequency until it sounded best to me. Starting on page 11 of your manual are the Rockford-Fosgate recommended adjustment procedures, including setting the gains and the filter frequency.

Those numbers for the lpf on your head unit sounds like it allows you to decrease (-24dB), as well as increase (+6dB) the bass at the specific frequencies of 50, 63, 80 and 100Hz. You probably don't want to decrease the bass boost for subs. And the 401s will allow a boost up to 12dB and is variable from 50-250Hz.

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