Amp over heating and cutting off

Not to disappoint you too much, but the 1000 watts advertised is just marketing hype. If your amp is the PB781X, it should have only a single 15A fuse on it. Your battery provides 12.5 volts when the engine is off, so at most, your amp draws 187.5 watts of power. Draws, not outputs. No amp is 100% efficient due to heat. When your engine is running, assuming your alternator outputs 14.4 volts, your amp's maximum power draw is about 216 watts. Again, this is what your amp draws, not what it puts out. What you should focus on is the RMS (continuous) output, not Max or PMPO. Those numbers are useless, unfortunately.
Your amp is rated to output 50 watts per channel at 4 Ohms, and 75 watts per channel at 2 ohms. This is when wiring your channels separately, not bridged. I did not see true power specs for your amp while bridged, but it's possible you'll just get the full 150 watts to the single bridged output. Do not attempt to apply a 1 ohm load to your amplifier, as you will run the risk of damaging it. It's not designed to handle a 1 ohm load. If you're lucky, you'll blow a fuse before the amp is damaged, but either way, there is nothing to be gained by attempting it.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/reginald_bec291de192ca44f

not 550 watt,,250 x 2 ,,

• RMS Power Range : 250-500 Watts
• Number Of Channels: 2
• Maximum Power: 1000 Watts
• Low Frequency response: 10 Hz
• High Frequency Response: 40000 Hz
• Built In Crossovers: Yes
• Channel Separation: Yes

• 2-Channel Class-A/B Amplifier
• RMS Power (4 ohms): 250 watts x 2 chan.
• RMS Power (2 ohms): 375 watts x 2 chan.
• Bridged RMS Power: 500 watts x 1 chan.
• Min. Impedance Unbridged: 2 ohms
• Min. Impedance Bridged: 4 ohms
• Brushed Aluminum Chassis
• Top Mount Controls with Blue Illumination
• Cooling Fan
• Chrome DUB Fan Grille
• Glass Epoxy Circuit Board
• PWM MOSFET Power Supply
• THD: 0.02%
• S/N Ratio: 95 dB
• Input Sensitivity: 200mV - 4V
• Frequency Response: 10 Hz - 40 kHz
• Variable 18 dB/Oct. Hi-Pass / Low-Pass Crossover: 50 - 250 Hz
• Bass Boost: On/Off 12 dB
• 4-Way Protecion: Thermal, Short Circuit, Overload, and DC Offset
• Dimensions: 8-1/4" W x 2-1/8" H x 10-3/4" L

• Authorized Internet Dealer

Audiobahn DUB2502 2 Channel 250W 2 Class Amplifier at Onlinecarstereo com

http://www.audiobahn.com/index.php/help/tech-support/manuals/category/1-amplifiers

how much rms is the pyramid pb3818 5000w amp ?

• 4-Channel
• 350W X 2 Max @ 4ohm
• 700W X 1 Bridged @ 4ohm
• Dim: 2.4"H X 10.7"W X 6.9"L
• Mosfet Pwm Power Supply

You've got the gain to high and the amplifier is clipping the sound frequency causing it to distort. Possible problems are you have a bad speaker(s) and the reading is below 4 ohms. Each of the 4 channels can only take 4ohms. If your bridging 2 speakers to this amp you have to also make sure you are only bridging 4ohms anything lower will cause the amp to overheat. Dont put 2 speakers in parallel on one channel or you will definitely have more problems.

one channel in your amp is blown

mosfet have a built in shut off incase of a blown resistor, if the resistor blows,it will shut down the amp, the resistors job is to inhibit power to prevent overheating, you will have to check the OHMS of each resistor to find out which one has gone......hope this was helpfull

if i keeps blowing fuses then it means the amp is bad

Hello sunshanel,

You did not say what you have the amp connected to and what the impedance load is. It is only stable at 4 ohms and if a lower impedance is connected, say 2 subs in parallel, it would try to produce more power when you turn it up and would most likely blow the fuse. 20 amp sounds right for the amp. The power rating of 800 watts per channel is peak power, not RMS, and many low-end manufacturers tend to state bigger numbers in the ratings.

Hope this helps.

IT MAY MEAN THAT IT TAKES (2) 25 AMP FUSES
IF YOU HAVE THEM OUT SEE IF IT SAYS WHAT THEY ARE OR OPEN IT UP IT MAY SAY IT ON THE BOARD OR THE FUSE HOLDER OR LOOK @ THE SPECS ON THE AMP SEE WHAT THE TOTAL CURRENT IS YOU CAN ALWAYS START WITH A SMALLER AMPAGE LIKE 10 -20 AMP FUSE ALWAYS GO SMALLER