Do they represent the total power consumption of the amp?

 

What three fuses?
There is most likely a fuse off the power line.
There might be a fuse on the output of the amplifier.

 

What sort of amplifiers??
Really. There are more different kids of amplifiers than kinds of cars!
One amplifier I worked on had tyhree fuses, because the incoming power was 240 volts, plus neutral. And then there was a fuse for the high voltage supply. That was an "Ameritron Linear" amplifier that I fixed for a Radio Ham friend.
There was a PA amplifier that had options for different input voltages and a selector switchit could run on 12 voltsDC or 110 volts AC or 220 volts AC. It had a fuse for each voltage. It was army surplus when I saw it back in 1962.

 

What sort of amplifiers??
Really. There are more different kids of amplifiers than kinds of cars!
One amplifier I worked on had tyhree fuses, because the incoming power was 240 volts, plus neutral. And then there was a fuse for the high voltage supply. That was an "Ameritron Linear" amplifier that I fixed for a Radio Ham friend.
There was a PA amplifier that had options for different input voltages and a selector switchit could run on 12 voltsDC or 110 volts AC or 220 volts AC. It had a fuse for each voltage. It was army surplus when I saw it back in 1962.

I forgot there different kimds of amplifiers, sorry.
I meant a car audio power amplifier, mine hase three 25v fuses and the voltage input was 12-18v, it piqued my interest et how they worked

 

Here's a pic for reference

 

Probably one for each speaker output and one for positive supply , easy to check.

 

I would think, as @Dodgydave suggests, the power supply and each output channel. But, 25A seems a bit on the salty side for speaker outputs.

To answer the question: no, it will not reflect the total current limit for the amplifier. Whatever they are doing, they are not in a series, the are protecting three circuits.

 

Given that it is a stereo amplifier, that means that there are actually two independent amplifiers in the assembly. A fuse rated to handle that total load would be excessively big to protect against ONE amplifier overloading. In addition, most higher power automotive system amplifiers use an inverter to boost the voltage for the amplifiers. And that inverter also would have a protective fuse. So that is why there would be three fuses.
BASED ON THE CONNECTION TERMINALS, my guess is that this is a fairly high power amplifier, and thus my evaluation would apply.
The other possibility, which I have also seen, is that the fuses are all in parallel, in order to have an adequate current capacity in that fuse style. I saw that in a UPS device on one occasion. It is a poor choice, but it had been done. Not recommended.

 

Hi, firstly your amplifier type matters. However, the three fuses in an amplifier do not represent the total power consumption. Each fuse protects circuit from damage of overcurrent.

Its a mono amplifier 800w rms on 1 ohm load, also checked the output, seems like they're all connected when i checked it with my multitester(i think they did 2 outputs for better wire distribution but still maintaining the parallel connection)

 

ATC style fuses are only available up to 30A. If your amplifier requires 75A of fuse, then they use (3) 25A fuses in parallel. This is common and has been done forever. If total current through them exceeds the combined current rating, they will all pop quickly. I've got 3 or 4 old 2-channel class A/B amplifiers from the 1990's sitting on my shelf that are made the same way, some of 2 fuses some have 3.

 

ATC style fuses are only available up to 30A. If your amplifier requires 75A of fuse, then they use (3) 25A fuses in parallel. This is common and has been done forever. If total current through them exceeds the combined current rating, they will all pop quickly. I've got 3 or 4 old 2-channel class A/B amplifiers from the 1990's sitting on my shelf that are made the same way, some of 2 fuses some have 3.

Holy shit i think this is the answer, computing wattage with the given input voltage of 12v and 3x25amps fuses you get 900w and considering this is a class d amp with an efficiency 90%+ then you get... Give or take 800w which what it was rated for

 

If it is an 800W amplifier it probably draws about 70A at 12V for it’s peak output so 75A of fusing wouldn’t be out of line.

That is to say, it probably does represent close to the peak load you can expect if you run the amp at full power. (Answer to your question above, revised.)

 

I suppose the size of the screw terminals for the power input suggests something like that.

By the way, use ferrules on those wires. Stranded cable, especially with a lot of small gauge conductors, will not do well mechanically in such a terminal, and stray conductors easily cause shorts.

 

I suppose the size of the screw terminals for the power input suggests something like that.

By the way, use ferrules on those wires. Stranded cable, especially with a lot of small gauge conductors, will not do well mechanically in such a terminal, and stray conductors easily cause shorts.

Noted, will do this and thanks a lot every for commenting

 

Its a mono amplifier 800w rms on 1 ohm load, also checked the output, seems like they're all connected when i checked it with my multitester(i think they did 2 outputs for better wire distribution but still maintaining the parallel connection)

I am trying to imagine the sound level in a vehicle with an 800 watt sound system. It might be louder than standing between two fuel dragsters half a second after they get the green light. What sort of "music" needs to be that loud??

 

I am trying to imagine the sound level in a vehicle with an 800 watt sound system. It might be louder than standing between two fuel dragsters half a second after they get the green light. What sort of "music" needs to be that loud??

In car audio, there is an unreasonable desire for bass frequencies. The ”music” is sometimes secondary to the bass…

 

I am trying to imagine the sound level in a vehicle with an 800 watt sound system. It might be louder than standing between two fuel dragsters half a second after they get the green light. What sort of "music" needs to be that loud??

Oh i wasnt planning on using all that 800w since it's only able to output 300w on 4 ohm load, i also wanted some clean output for my subs so i dont clip on the lows and preseve the coils for more life span. Thanks again for input

 

Its a mono amplifier 800w rms on 1 ohm load

No it's not. Not unless the output is bridgeable. You might be using it as a mono, but it's actually a stereo amp.

 

No it's not. Not unless the output is bridgeable. You might be using it as a mono, but it's actually a stereo amp.
View attachment 293247

The purpose of two channel output is for wire distribution but it still operates on 1 channel/mono represented by the .1 on KD800.1
They're internally parrallel
(confirmed this theory when my multitester showed that the positive on left and right were a complete shortcuicuit same with negative)

 

No it's not. Not unless the output is bridgeable. You might be using it as a mono, but it's actually a stereo amp.
View attachment 293247

This could be their way of allowing more conductors on the same output, for lower resistance at higher currents. This is also common on the power input side of some really big amps, they'll use multiple 1awg connectors. Some of the higher wattage speakers have multiple voice coils, typically 2, so this would also be a convenient way to give each voice coil it's own set of wires.

One thing to keep in mind, especially with the older amplifiers, is car audio competitions is a thing and manufacturers use it to sell amplifiers (and other equipment). Cars are grouped by power classes. The power at a specific ohm load. i.e. one class for up to 100w at 4-ohm, one for 200w at 4-ohm, etc.. so then it became very popular for car audio amps to put out some smaller power number at 4-ohm, but enormous amounts into very low impedances, some stable down to 1/4 ohm. This way they could compete in say the 100w class, but actually have 1000w+ available. Anyway, audio amplifiers are neat and this guy tests a bunch for anyone who is interested: