Question about Phase Linear UPA424CS Car Audio Amplifier

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Phase Linear UPA424...No sound

I recently purchased a Phase Linear UPA424 amp about 2 days ago..I was working on my car, installing the spekers and what not and when i went to hook up the amp to the speakers i had nothing. It worked the day before just fine. I figured it might be the battery but still nothing. The unit is getting power and the green led has light, but no out put signal is comming from the amp.

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Re: Phase Linear UPA424...No sound

I hooked one of these up in my cherokee a few weeks ago and I wound up having it in for a coulpe days befor I got it working it would work briefly and stop I changed power wires twice before getting it going by using both sides of some 14 ga speaker wire for the + and ground

Posted on Mar 30, 2007

Re: Phase Linear UPA424...No sound

I returned it and got a new problems with the amp after that.

Posted on Jan 15, 2007

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Re: Phase Linear UPA424...No sound

I had the same problem with mine but i had the 224 version first worked nice just for a small system but i just got this one today and i hooked it up to a small sub box how i had the one before and it just dosent work the other one quit beforhand and i thought it just went bad so i figgerd id buy this one but after about and hr n 1/2 of work to show nothing kinda was a depressing moment, ive gone through my wireing about 4-5 times now and drawn it out 2 times on eveything ive done im just lost, ive even tryed diffrent rca and also tryed a diffrent radio and still nothjing tryed messing aorund with settings still nothing its kinda a bummer

Posted on Jan 15, 2007

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Free manual for mosfet phase linear upa424 240watt amplifier

You do have 12 volts connected to the remote connection, correct?

Dec 11, 2013 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

I have phase linear uv8, need to know how to get subs 2 work! Amp goes into protect mode when rca's r plugged in, there r 3 sets of preamp out puts 1 front left and front right, 2nd is rear left rear...

try testing the amp without speakers plugged in. Run the sub preamp out to the amp that you will drive the subs with, but don't wire up the subs yet. Test for protect mode kicking in.
Yes - unplug the rca ins from the amp. retest.
No - Problem lies within the sub wiring. What is the load on the amp (measure with an ohm meter)? If it is below 4ohms, chances are the amp can't dip that low. Give it more resistance by wiring it differently (series vs. parallel)


May 05, 2011 | Kicker Car Amplifiers

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Phase linear model UPA424 wire diagram


Jan 31, 2010 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

Runing jest back spekers

Yes, you will need to disconnect wires to the front speakers

Sep 05, 2009 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

Amps on woofers are fine just won't hit

your probably making your amp run to low ohms if its a 2 channel amp bridged to one channel you can probably only run it at four ohms

Also seeing as your subs are 2ohm dvc you can't wire them individually to 2ohm and use each channel separately. So i'd recommend buying a 2ohm stable monoblock or running it at four ohms. a 1400 watt amp'll still pound at 4ohms and it'll extend your amp's life span

Aug 29, 2009 | Pioneer GM-7200M Car Audio Amplifier

1 Answer

Whining noise from amp.

hear are couple things to try   try running your power and  (ground) both directly from your battery   to the amp and  to the receiver .. if this doesn't help try purchasing a noise suppressor  and wire your receiver threw this  it should solve your problem  

Feb 13, 2009 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

Amp is in protect mode, green light is on.

If the amp is going into protect, it likely has shorted output transistors. To eliminate other possible causes, read through the following page.

Amp in protect mode - troubleshooting

Let me know if you have any other questions.

Nov 29, 2008 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

My amp

Does it turn on (are the lights on... and if so is the "protect" light lit)?

Sep 23, 2007 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

Humming noise thru my speakers

You are getting engine noise through your amplifier. To solve this problem you will need to install a filter in-line with the DC path, or install a voltage regulator in-line with the DC path.

Sep 08, 2007 | Phase Linear UPA424CS Car Audio Amplifier

1 Answer

Amp is on, Subwoofer works, but no sound.

here is a short test you can try, remove the rca audio cable from the amp & connect a diskman or toher audio o/p device that you can hook up with the same rca wires, turn on the amp & see if you have sound. you can also remove the speaker wires from the sub & using multi meter read the ohm's of the sub, most subs are 4 ohm. Hope this help locate your problem

Oct 24, 2006 | Pioneer GM-7200M Car Audio Amplifier

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