Fosgate T1500 Hissing/squealing noise from amp itself

[1aespinoza Premium Member]

Not yet. What exactly is "battery load"?

It is a tester with a simple resistance that draws alot of power from a battery. After that "pull" the voltmeter shows the battery charge right after. I got one like this at Harbor Freight for $20.

 

[Mitchell Fosgate III]

It is a tester with a simple resistance that draws alot of power from a battery. After that "pull" the voltmeter shows the battery charge right after. I got one like this at Harbor Freight for $20.View attachment 62229

Just $20 dollars for this tester? I got a multimeter I just bought from Wal-mart. The analog multimeter. I wanted the digital but it cost $43.00 dollars. The analog multimeter cost me $21.43 dollars. Though the probes are shorter, less than some other probes. I might uninstall it and see if I can change the probes to make it longer. Useful. The radios I measured like Delco Radios from Mexico comes in at just about 4 ohms. Touch the black probe to the metal chassis and the red probe to any one of the male pins of the delco 16 pin or 24 pin slots.​

 

[Deiimos]

I’m thinking your voltage is just dropping a bit too much for the amp causing it to shut off. Digital meters can be a bit slow and you may not be seeing the true peak of the drop when it shuts off.

I would think your stock alternator / battery would be just enough for that RF amp, but that may not always be the case, or a problem with the battery as mentioned having it load tested. Not sure how old the battery is, but if its a 2020, it might be nearing it's end of life.

Would also think that RF amp is new enough technology that it is unlikely to squeal / hiss, but was sort of common with some older class D amps. I had a couple MTX amps that you could hear them hiss with your ear close to them, but wasn’t a problem (an old 1501D from 2001 or so, and a 6500D if I recall). I think I had an Orion that did it as well (or maybe it emitted a light oscillator whine out of the sub slightly), forget, but some amps would make audible noise from their output inductors if your ear was within a few feet from it. Not sure if this is a thing for the RF amps like this.

Is it hissing out of the subs? Or just with your ear next to the amp itself? Could ask in the car audio section over at https://www.diyaudio.com/community/forums/car-audio.38/ where it is 99% car amplifier repair, someone there may know if it is normal for that model amp.